Mixed Topics

THE DIAGNOSIS: Rheumatoid Vasculitis

A diagnosis of rheumatoid vasculitis (RV) was made based on the clinical features, histopathology, and laboratory results in the setting of rheumatoid arthritis (RA). The distal gangrene was surgically managed with bilateral transmetatarsal amputation followed by ankle collagen graft placement. The patient was started on a prednisone taper for 1 month (40 mg/d for 3 days, then 30 mg/d for 3 days, then 20 mg/d for 24 days) before transitioning to rituximab (375 mg/m² once weekly for 4 weeks), which improved the size and depth of the ulcers.

Rheumatoid vasculitis is an inflammatory disease that affects small- to medium-sized blood vessels in patients with RA. The pathogenesis involves immune complex deposition and complement system activation, leading to vessel wall destruction.¹ Rheumatoid vasculitis is an extra-articular complication of RA that primarily is observed in seropositive patients with long-standing severe disease.^1,2 The mean duration between RA diagnosis and RV onset is 10 to 14 years.² Rheumatoid vasculitis manifests heterogeneously and can affect many organs; however, it most frequently affects the skin. Cutaneous manifestations vary in severity. Palpable purpura, pyoderma gangrenosum, and distal ulcers can be seen in addition to extensive digital ischemia with necrosis, as was present in our patient.¹

When RA patients present with skin changes that are concerning for vasculitis, RV should be suspected. Currently, there are no validated diagnostic criteria for RV. Diagnosis is made based on clinical presentation and tissue biopsy. Histopathology shows small- and medium-sized vessel wall destruction with neutrophilic, granulomatous, or lymphocytic infiltration, which may be observed only in the lower dermis sparing superficial vessels.³ Direct immunofluorescence shows IgM, IgA, and C3 deposition within and around vessels.^3,4 Laboratory findings including elevated inflammatory markers, positive rheumatoid factor, positive anti–cyclic citrullinated peptide, and hypocomplementemia support a diagnosis of RV.^1,2

Mortality rates for RV remain high, necessitating aggressive treatment. High-dose corticosteroids typically are combined with immunosuppressant or biologic agents, frequently cyclophosphamide or rituximab.¹ Consistent with other reported cases, our patient’s ulcers improved with rituximab and oral steroids.

The differential diagnosis for our patient included type I cryoglobulinemia, cutaneous polyarteritis nodosa (CPAN), peripheral vascular disease (PVD), and nonuremic calciphylaxis. Type I cryoglobulinemia manifests due to direct occlusion of vessels by precipitation of monoclonal immunoglobulin.⁵ It commonly is associated with lymphoproliferative diseases such as Waldenström macroglobulinemia and multiple myeloma. While our patient’s history of RA was a risk factor for mixed cryoglobulinemia as opposed to type I cryoglobulinemia, the clinical presentation aligned more closely with type I cryoglobulinemia. The clinical manifestations of type I cryoglobulinemia are related to intravascular obstruction, including Raynaud phenomenon, retiform purpura, ischemic ulcers, distal gangrene, and cold-induced urticaria.^6-8 Type I cryoglobulinemia also frequently has neurologic and renal manifestations. Histopathology, along with the detection of serum cryoglobulins, is the gold standard for diagnosing cryoglobulinemia.⁶ On histopathology, type I cryoglobulinemia typically shows a thrombotic vasculopathy with amorphous eosinophilic periodic acid–Schiff–positive thrombi.⁷ False-negative results are particularly common with serum cryoglobulins, so repeat testing often is needed. While many clinical features overlap, RV is the most likely diagnosis in a patient with long-standing RA who is negative for cryoglobulins and has no history of lymphoproliferative disorders.

Cutaneous polyarteritis nodosa is a necrotizing vasculitis that similarly affects small- and medium-sized vessels. The exact etiology is unknown, but the high prevalence of anti–phosphatidylserine/prothrombin complex antibodies among patients with CPAN suggests that prothrombin bound to apoptotic endothelial cells may initiate the immune response.⁹ Underlying infection and inflammatory and autoimmune diseases (including group A beta-hemolytic streptococcus, hepatitis B, inflammatory bowel disease, myasthenia gravis, and RA) also may trigger CPAN.^9,10,11 The most common clinical manifestations of CPAN are tender subcutaneous nodules, livedo reticularis, leg ulcers, and cutaneous necrosis. Extracutaneous symptoms such as myalgias and arthralgias also can be associated with CPAN. There is no specific serologic test to diagnose CPAN; the diagnosis is made based on clinicopathologic correlation, with characteristic histopathology showing leukocytoclastic vasculitis in the small- and medium-sized arteries of the deep dermis or hypodermis.⁹

Peripheral vascular disease is a manifestation of atherosclerosis that affects the legs. Risk factors for atherosclerosis, especially smoking and diabetes mellitus, similarly increase the risk for PVD.¹² The most common clinical manifestation of PVD is intermittent claudication, but rarely PVD can progress to critical limb ischemia, which is characterized by pain at rest, nonhealing ulcers, or gangrene of the legs.¹² Common findings on physical examination include diminished or absent pedal pulses, abnormal skin color, and skin that is cool to the touch.¹² The standard diagnostic test for PVD affecting the legs is evaluation via the ankle-brachial index, with a score of 0.90 or lower being diagnostic of PVD, a score of 0.91 to 1.00 being borderline, and a score of 1.01 to 1.40 being normal.¹³

Calciphylaxis most frequently is seen in patients with end-stage kidney disease; however, it also has been less commonly reported in patients with normal kidney function, known as nonuremic calciphylaxis. It is characterized by calcification of arteries, arterioles, and soft tissues, which can lead to thrombosis and eventually ischemia and necrosis of the skin.¹⁴ Calciphylaxis initially causes tender, indurated, erythematous to purpuric plaques that quickly progress to retiform and stellate ulcers with overlying necrotic eschars.¹⁵ Disease typically occurs on the legs and areas that are rich in adipose tissue, such as the abdomen and thighs.¹⁶ Skin biopsy is needed for diagnosis of calciphylaxis. Characteristic histopathologic findings include calcification, microvascular thrombosis, and fibrointimal hyperplasia of small dermal and subcutaneous arteries and arterioles.¹⁶

We present a rare case of RV in a patient with well-controlled RA. While the incidence of RV is decreasing in the United States and United Kingdom due to the initiation of earlier and more aggressive RA therapies, mortality remains high.¹ Thus, it is important to include RV in the differential diagnosis when there are skin changes concerning vasculitis in patients with seropositive, longstanding RA, even if the RA is well controlled.

THE DIAGNOSIS: Rheumatoid Vasculitis

A diagnosis of rheumatoid vasculitis (RV) was made based on the clinical features, histopathology, and laboratory results in the setting of rheumatoid arthritis (RA). The distal gangrene was surgically managed with bilateral transmetatarsal amputation followed by ankle collagen graft placement. The patient was started on a prednisone taper for 1 month (40 mg/d for 3 days, then 30 mg/d for 3 days, then 20 mg/d for 24 days) before transitioning to rituximab (375 mg/m² once weekly for 4 weeks), which improved the size and depth of the ulcers.

Rheumatoid vasculitis is an inflammatory disease that affects small- to medium-sized blood vessels in patients with RA. The pathogenesis involves immune complex deposition and complement system activation, leading to vessel wall destruction.¹ Rheumatoid vasculitis is an extra-articular complication of RA that primarily is observed in seropositive patients with long-standing severe disease.^1,2 The mean duration between RA diagnosis and RV onset is 10 to 14 years.² Rheumatoid vasculitis manifests heterogeneously and can affect many organs; however, it most frequently affects the skin. Cutaneous manifestations vary in severity. Palpable purpura, pyoderma gangrenosum, and distal ulcers can be seen in addition to extensive digital ischemia with necrosis, as was present in our patient.¹

When RA patients present with skin changes that are concerning for vasculitis, RV should be suspected. Currently, there are no validated diagnostic criteria for RV. Diagnosis is made based on clinical presentation and tissue biopsy. Histopathology shows small- and medium-sized vessel wall destruction with neutrophilic, granulomatous, or lymphocytic infiltration, which may be observed only in the lower dermis sparing superficial vessels.³ Direct immunofluorescence shows IgM, IgA, and C3 deposition within and around vessels.^3,4 Laboratory findings including elevated inflammatory markers, positive rheumatoid factor, positive anti–cyclic citrullinated peptide, and hypocomplementemia support a diagnosis of RV.^1,2

Mortality rates for RV remain high, necessitating aggressive treatment. High-dose corticosteroids typically are combined with immunosuppressant or biologic agents, frequently cyclophosphamide or rituximab.¹ Consistent with other reported cases, our patient’s ulcers improved with rituximab and oral steroids.

The differential diagnosis for our patient included type I cryoglobulinemia, cutaneous polyarteritis nodosa (CPAN), peripheral vascular disease (PVD), and nonuremic calciphylaxis. Type I cryoglobulinemia manifests due to direct occlusion of vessels by precipitation of monoclonal immunoglobulin.⁵ It commonly is associated with lymphoproliferative diseases such as Waldenström macroglobulinemia and multiple myeloma. While our patient’s history of RA was a risk factor for mixed cryoglobulinemia as opposed to type I cryoglobulinemia, the clinical presentation aligned more closely with type I cryoglobulinemia. The clinical manifestations of type I cryoglobulinemia are related to intravascular obstruction, including Raynaud phenomenon, retiform purpura, ischemic ulcers, distal gangrene, and cold-induced urticaria.^6-8 Type I cryoglobulinemia also frequently has neurologic and renal manifestations. Histopathology, along with the detection of serum cryoglobulins, is the gold standard for diagnosing cryoglobulinemia.⁶ On histopathology, type I cryoglobulinemia typically shows a thrombotic vasculopathy with amorphous eosinophilic periodic acid–Schiff–positive thrombi.⁷ False-negative results are particularly common with serum cryoglobulins, so repeat testing often is needed. While many clinical features overlap, RV is the most likely diagnosis in a patient with long-standing RA who is negative for cryoglobulins and has no history of lymphoproliferative disorders.

Cutaneous polyarteritis nodosa is a necrotizing vasculitis that similarly affects small- and medium-sized vessels. The exact etiology is unknown, but the high prevalence of anti–phosphatidylserine/prothrombin complex antibodies among patients with CPAN suggests that prothrombin bound to apoptotic endothelial cells may initiate the immune response.⁹ Underlying infection and inflammatory and autoimmune diseases (including group A beta-hemolytic streptococcus, hepatitis B, inflammatory bowel disease, myasthenia gravis, and RA) also may trigger CPAN.^9,10,11 The most common clinical manifestations of CPAN are tender subcutaneous nodules, livedo reticularis, leg ulcers, and cutaneous necrosis. Extracutaneous symptoms such as myalgias and arthralgias also can be associated with CPAN. There is no specific serologic test to diagnose CPAN; the diagnosis is made based on clinicopathologic correlation, with characteristic histopathology showing leukocytoclastic vasculitis in the small- and medium-sized arteries of the deep dermis or hypodermis.⁹

Peripheral vascular disease is a manifestation of atherosclerosis that affects the legs. Risk factors for atherosclerosis, especially smoking and diabetes mellitus, similarly increase the risk for PVD.¹² The most common clinical manifestation of PVD is intermittent claudication, but rarely PVD can progress to critical limb ischemia, which is characterized by pain at rest, nonhealing ulcers, or gangrene of the legs.¹² Common findings on physical examination include diminished or absent pedal pulses, abnormal skin color, and skin that is cool to the touch.¹² The standard diagnostic test for PVD affecting the legs is evaluation via the ankle-brachial index, with a score of 0.90 or lower being diagnostic of PVD, a score of 0.91 to 1.00 being borderline, and a score of 1.01 to 1.40 being normal.¹³

Calciphylaxis most frequently is seen in patients with end-stage kidney disease; however, it also has been less commonly reported in patients with normal kidney function, known as nonuremic calciphylaxis. It is characterized by calcification of arteries, arterioles, and soft tissues, which can lead to thrombosis and eventually ischemia and necrosis of the skin.¹⁴ Calciphylaxis initially causes tender, indurated, erythematous to purpuric plaques that quickly progress to retiform and stellate ulcers with overlying necrotic eschars.¹⁵ Disease typically occurs on the legs and areas that are rich in adipose tissue, such as the abdomen and thighs.¹⁶ Skin biopsy is needed for diagnosis of calciphylaxis. Characteristic histopathologic findings include calcification, microvascular thrombosis, and fibrointimal hyperplasia of small dermal and subcutaneous arteries and arterioles.¹⁶

We present a rare case of RV in a patient with well-controlled RA. While the incidence of RV is decreasing in the United States and United Kingdom due to the initiation of earlier and more aggressive RA therapies, mortality remains high.¹ Thus, it is important to include RV in the differential diagnosis when there are skin changes concerning vasculitis in patients with seropositive, longstanding RA, even if the RA is well controlled.

THE DIAGNOSIS: Rheumatoid Vasculitis

A diagnosis of rheumatoid vasculitis (RV) was made based on the clinical features, histopathology, and laboratory results in the setting of rheumatoid arthritis (RA). The distal gangrene was surgically managed with bilateral transmetatarsal amputation followed by ankle collagen graft placement. The patient was started on a prednisone taper for 1 month (40 mg/d for 3 days, then 30 mg/d for 3 days, then 20 mg/d for 24 days) before transitioning to rituximab (375 mg/m² once weekly for 4 weeks), which improved the size and depth of the ulcers.

Rheumatoid vasculitis is an inflammatory disease that affects small- to medium-sized blood vessels in patients with RA. The pathogenesis involves immune complex deposition and complement system activation, leading to vessel wall destruction.¹ Rheumatoid vasculitis is an extra-articular complication of RA that primarily is observed in seropositive patients with long-standing severe disease.^1,2 The mean duration between RA diagnosis and RV onset is 10 to 14 years.² Rheumatoid vasculitis manifests heterogeneously and can affect many organs; however, it most frequently affects the skin. Cutaneous manifestations vary in severity. Palpable purpura, pyoderma gangrenosum, and distal ulcers can be seen in addition to extensive digital ischemia with necrosis, as was present in our patient.¹

When RA patients present with skin changes that are concerning for vasculitis, RV should be suspected. Currently, there are no validated diagnostic criteria for RV. Diagnosis is made based on clinical presentation and tissue biopsy. Histopathology shows small- and medium-sized vessel wall destruction with neutrophilic, granulomatous, or lymphocytic infiltration, which may be observed only in the lower dermis sparing superficial vessels.³ Direct immunofluorescence shows IgM, IgA, and C3 deposition within and around vessels.^3,4 Laboratory findings including elevated inflammatory markers, positive rheumatoid factor, positive anti–cyclic citrullinated peptide, and hypocomplementemia support a diagnosis of RV.^1,2

Mortality rates for RV remain high, necessitating aggressive treatment. High-dose corticosteroids typically are combined with immunosuppressant or biologic agents, frequently cyclophosphamide or rituximab.¹ Consistent with other reported cases, our patient’s ulcers improved with rituximab and oral steroids.

The differential diagnosis for our patient included type I cryoglobulinemia, cutaneous polyarteritis nodosa (CPAN), peripheral vascular disease (PVD), and nonuremic calciphylaxis. Type I cryoglobulinemia manifests due to direct occlusion of vessels by precipitation of monoclonal immunoglobulin.⁵ It commonly is associated with lymphoproliferative diseases such as Waldenström macroglobulinemia and multiple myeloma. While our patient’s history of RA was a risk factor for mixed cryoglobulinemia as opposed to type I cryoglobulinemia, the clinical presentation aligned more closely with type I cryoglobulinemia. The clinical manifestations of type I cryoglobulinemia are related to intravascular obstruction, including Raynaud phenomenon, retiform purpura, ischemic ulcers, distal gangrene, and cold-induced urticaria.^6-8 Type I cryoglobulinemia also frequently has neurologic and renal manifestations. Histopathology, along with the detection of serum cryoglobulins, is the gold standard for diagnosing cryoglobulinemia.⁶ On histopathology, type I cryoglobulinemia typically shows a thrombotic vasculopathy with amorphous eosinophilic periodic acid–Schiff–positive thrombi.⁷ False-negative results are particularly common with serum cryoglobulins, so repeat testing often is needed. While many clinical features overlap, RV is the most likely diagnosis in a patient with long-standing RA who is negative for cryoglobulins and has no history of lymphoproliferative disorders.

Cutaneous polyarteritis nodosa is a necrotizing vasculitis that similarly affects small- and medium-sized vessels. The exact etiology is unknown, but the high prevalence of anti–phosphatidylserine/prothrombin complex antibodies among patients with CPAN suggests that prothrombin bound to apoptotic endothelial cells may initiate the immune response.⁹ Underlying infection and inflammatory and autoimmune diseases (including group A beta-hemolytic streptococcus, hepatitis B, inflammatory bowel disease, myasthenia gravis, and RA) also may trigger CPAN.^9,10,11 The most common clinical manifestations of CPAN are tender subcutaneous nodules, livedo reticularis, leg ulcers, and cutaneous necrosis. Extracutaneous symptoms such as myalgias and arthralgias also can be associated with CPAN. There is no specific serologic test to diagnose CPAN; the diagnosis is made based on clinicopathologic correlation, with characteristic histopathology showing leukocytoclastic vasculitis in the small- and medium-sized arteries of the deep dermis or hypodermis.⁹

Peripheral vascular disease is a manifestation of atherosclerosis that affects the legs. Risk factors for atherosclerosis, especially smoking and diabetes mellitus, similarly increase the risk for PVD.¹² The most common clinical manifestation of PVD is intermittent claudication, but rarely PVD can progress to critical limb ischemia, which is characterized by pain at rest, nonhealing ulcers, or gangrene of the legs.¹² Common findings on physical examination include diminished or absent pedal pulses, abnormal skin color, and skin that is cool to the touch.¹² The standard diagnostic test for PVD affecting the legs is evaluation via the ankle-brachial index, with a score of 0.90 or lower being diagnostic of PVD, a score of 0.91 to 1.00 being borderline, and a score of 1.01 to 1.40 being normal.¹³

Calciphylaxis most frequently is seen in patients with end-stage kidney disease; however, it also has been less commonly reported in patients with normal kidney function, known as nonuremic calciphylaxis. It is characterized by calcification of arteries, arterioles, and soft tissues, which can lead to thrombosis and eventually ischemia and necrosis of the skin.¹⁴ Calciphylaxis initially causes tender, indurated, erythematous to purpuric plaques that quickly progress to retiform and stellate ulcers with overlying necrotic eschars.¹⁵ Disease typically occurs on the legs and areas that are rich in adipose tissue, such as the abdomen and thighs.¹⁶ Skin biopsy is needed for diagnosis of calciphylaxis. Characteristic histopathologic findings include calcification, microvascular thrombosis, and fibrointimal hyperplasia of small dermal and subcutaneous arteries and arterioles.¹⁶

We present a rare case of RV in a patient with well-controlled RA. While the incidence of RV is decreasing in the United States and United Kingdom due to the initiation of earlier and more aggressive RA therapies, mortality remains high.¹ Thus, it is important to include RV in the differential diagnosis when there are skin changes concerning vasculitis in patients with seropositive, longstanding RA, even if the RA is well controlled.

Artificial intelligence (AI) applications are expanding rapidly in healthcare. AI powered tools are increasingly used in everyday medical practice, assisting clinicians with tasks such as diagnosis, treatment planning, data analysis, and patient monitoring, effectively integrating AI into routine clinical decision making. Despite its potential to fundamentally transform the practice of medicine and healthcare delivery, AI in healthcare remains largely unregulated, with a lack of common standards to guide responsible design, development, and adoption of AI-based tools to guide clinical care.

But this is changing. In mid-January, the US Department of Health & Human Services released its Strategic Plan for the Use of AI in Health, Human Services, and Public Health (available at www.healthit.gov), presenting an approach to catalyze innovation, promote trustworthy AI development, democratize technologies and resources, and cultivate AI-empowered workforces and organizational cultures. While there is no immediate regulatory impact, the plan does provide important insights into how the federal government thinks about AI, which will be a part of driving regulations in the future. As crucial stakeholders in the health AI universe and advocates for its responsible use in clinical practice, it is critical that we as clinicians keep abreast of developments in this rapidly evolving space. 

 

In this month’s issue of GI & Hepatology News, we summarize a recent systematic review and meta-analysis highlighting worsening health disparities for Hispanic adults with MASLD. We also report the results of an industry-sponsored study comparing the real-world clinical effectiveness of GI Genius (an AI-driven tool) with that of standard colonoscopy.

In February’s Member Spotlight, we introduce you to international AGA member Dr. Tossapol Kerdsirichairat (clinical associate professor of gastroenterology at Bumrungrad International Hospital in Bangkok, Thailand), who shares his insights regarding the challenges and rewards of practicing gastroenterology at one of the largest private hospitals in Southeast Asia. ‘Tos’ is one of roughly 25% of AGA members who live and work outside the United States.

Finally, this month’s In Focus column from The New Gastroenterologist focuses on management of chronic constipation, a highly prevalent condition that significantly impacts the quality of life of many of our patients. We hope you enjoy this and all the exciting content in our February issue.

Megan A. Adams, MD, JD, MSc

Editor in Chief

Artificial intelligence (AI) applications are expanding rapidly in healthcare. AI powered tools are increasingly used in everyday medical practice, assisting clinicians with tasks such as diagnosis, treatment planning, data analysis, and patient monitoring, effectively integrating AI into routine clinical decision making. Despite its potential to fundamentally transform the practice of medicine and healthcare delivery, AI in healthcare remains largely unregulated, with a lack of common standards to guide responsible design, development, and adoption of AI-based tools to guide clinical care.

But this is changing. In mid-January, the US Department of Health & Human Services released its Strategic Plan for the Use of AI in Health, Human Services, and Public Health (available at www.healthit.gov), presenting an approach to catalyze innovation, promote trustworthy AI development, democratize technologies and resources, and cultivate AI-empowered workforces and organizational cultures. While there is no immediate regulatory impact, the plan does provide important insights into how the federal government thinks about AI, which will be a part of driving regulations in the future. As crucial stakeholders in the health AI universe and advocates for its responsible use in clinical practice, it is critical that we as clinicians keep abreast of developments in this rapidly evolving space. 

 

In this month’s issue of GI & Hepatology News, we summarize a recent systematic review and meta-analysis highlighting worsening health disparities for Hispanic adults with MASLD. We also report the results of an industry-sponsored study comparing the real-world clinical effectiveness of GI Genius (an AI-driven tool) with that of standard colonoscopy.

In February’s Member Spotlight, we introduce you to international AGA member Dr. Tossapol Kerdsirichairat (clinical associate professor of gastroenterology at Bumrungrad International Hospital in Bangkok, Thailand), who shares his insights regarding the challenges and rewards of practicing gastroenterology at one of the largest private hospitals in Southeast Asia. ‘Tos’ is one of roughly 25% of AGA members who live and work outside the United States.

Finally, this month’s In Focus column from The New Gastroenterologist focuses on management of chronic constipation, a highly prevalent condition that significantly impacts the quality of life of many of our patients. We hope you enjoy this and all the exciting content in our February issue.

Megan A. Adams, MD, JD, MSc

Editor in Chief

Artificial intelligence (AI) applications are expanding rapidly in healthcare. AI powered tools are increasingly used in everyday medical practice, assisting clinicians with tasks such as diagnosis, treatment planning, data analysis, and patient monitoring, effectively integrating AI into routine clinical decision making. Despite its potential to fundamentally transform the practice of medicine and healthcare delivery, AI in healthcare remains largely unregulated, with a lack of common standards to guide responsible design, development, and adoption of AI-based tools to guide clinical care.

But this is changing. In mid-January, the US Department of Health & Human Services released its Strategic Plan for the Use of AI in Health, Human Services, and Public Health (available at www.healthit.gov), presenting an approach to catalyze innovation, promote trustworthy AI development, democratize technologies and resources, and cultivate AI-empowered workforces and organizational cultures. While there is no immediate regulatory impact, the plan does provide important insights into how the federal government thinks about AI, which will be a part of driving regulations in the future. As crucial stakeholders in the health AI universe and advocates for its responsible use in clinical practice, it is critical that we as clinicians keep abreast of developments in this rapidly evolving space. 

 

In this month’s issue of GI & Hepatology News, we summarize a recent systematic review and meta-analysis highlighting worsening health disparities for Hispanic adults with MASLD. We also report the results of an industry-sponsored study comparing the real-world clinical effectiveness of GI Genius (an AI-driven tool) with that of standard colonoscopy.

In February’s Member Spotlight, we introduce you to international AGA member Dr. Tossapol Kerdsirichairat (clinical associate professor of gastroenterology at Bumrungrad International Hospital in Bangkok, Thailand), who shares his insights regarding the challenges and rewards of practicing gastroenterology at one of the largest private hospitals in Southeast Asia. ‘Tos’ is one of roughly 25% of AGA members who live and work outside the United States.

Finally, this month’s In Focus column from The New Gastroenterologist focuses on management of chronic constipation, a highly prevalent condition that significantly impacts the quality of life of many of our patients. We hope you enjoy this and all the exciting content in our February issue.

Megan A. Adams, MD, JD, MSc

Editor in Chief

TOPLINE:

The use of valaciclovir as prophylaxis prevents herpes zoster (HZ) in patients with systemic lupus erythematosus (SLE) receiving anifrolumab treatment, with no cases of zoster reported during the follow-up period in patients receiving valaciclovir.

METHODOLOGY:

• Anifrolumab, a human monoclonal antibody binding to type I interferon receptor subunit 1, increases the risk for HZ in patients with SLE; however, specific recommendations to prevent HZ are currently nonexistent for patients with SLE receiving anifrolumab.
• Researchers conducted a multicenter observational study in France from November 2021 to July 2024 to evaluate the prophylactic benefits of valaciclovir in 132 patients with SLE (mean age, 42 years; 92% women) treated with anifrolumab for ≥ 3 months.
• Among these patients, 87 received either 500 mg/d valaciclovir (n = 69) or 1000 mg/d valaciclovir (n = 18) as prophylaxis, whereas 45 did not receive valaciclovir.
• The patients were followed up for a median duration of 234 days under anifrolumab treatment, with monitoring for the development of herpes zoster.

TAKEAWAY:

• The risk for HZ was significantly lower in patients who received valaciclovir than in those who did not (hazard ratio, 0.08; P = .01).
• None of the patients treated with valaciclovir developed HZ during the survey period.
• The frequency of HZ in patients who did not receive valaciclovir increased progressively from 2.2% at 3 months to 6.2% at 6 months, reaching 23% at 12 months.
• None of the reported cases of HZ required hospitalization or led to anifrolumab discontinuation, although one patient developed neuralgia.

IN PRACTICE:

“Prophylactic treatment with valaciclovir is effective for preventing HZ [herpes zoster] infection in SLE patients treated with anifrolumab,” the authors wrote. “This finding is particularly relevant for SLE patients who cannot receive the recombinant HZ vaccine or for whom it is unavailable,” they added.

SOURCE:

The study was led by Ludovic Trefond, MD, PhD, Centre Hospitalier Universitaire de Clermont-Ferrand in France. It was published online on January 4, 2025, in RMD Open.

LIMITATIONS:

The observational design of the study and the low number of herpes zoster events during the follow-up period may have affected the robustness of the findings.

DISCLOSURES:

The authors did not receive any specific grants. Some authors reported having financial relationships with various pharmaceutical companies.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

The use of valaciclovir as prophylaxis prevents herpes zoster (HZ) in patients with systemic lupus erythematosus (SLE) receiving anifrolumab treatment, with no cases of zoster reported during the follow-up period in patients receiving valaciclovir.

METHODOLOGY:

• Anifrolumab, a human monoclonal antibody binding to type I interferon receptor subunit 1, increases the risk for HZ in patients with SLE; however, specific recommendations to prevent HZ are currently nonexistent for patients with SLE receiving anifrolumab.
• Researchers conducted a multicenter observational study in France from November 2021 to July 2024 to evaluate the prophylactic benefits of valaciclovir in 132 patients with SLE (mean age, 42 years; 92% women) treated with anifrolumab for ≥ 3 months.
• Among these patients, 87 received either 500 mg/d valaciclovir (n = 69) or 1000 mg/d valaciclovir (n = 18) as prophylaxis, whereas 45 did not receive valaciclovir.
• The patients were followed up for a median duration of 234 days under anifrolumab treatment, with monitoring for the development of herpes zoster.

TAKEAWAY:

• The risk for HZ was significantly lower in patients who received valaciclovir than in those who did not (hazard ratio, 0.08; P = .01).
• None of the patients treated with valaciclovir developed HZ during the survey period.
• The frequency of HZ in patients who did not receive valaciclovir increased progressively from 2.2% at 3 months to 6.2% at 6 months, reaching 23% at 12 months.
• None of the reported cases of HZ required hospitalization or led to anifrolumab discontinuation, although one patient developed neuralgia.

IN PRACTICE:

“Prophylactic treatment with valaciclovir is effective for preventing HZ [herpes zoster] infection in SLE patients treated with anifrolumab,” the authors wrote. “This finding is particularly relevant for SLE patients who cannot receive the recombinant HZ vaccine or for whom it is unavailable,” they added.

SOURCE:

The study was led by Ludovic Trefond, MD, PhD, Centre Hospitalier Universitaire de Clermont-Ferrand in France. It was published online on January 4, 2025, in RMD Open.

LIMITATIONS:

The observational design of the study and the low number of herpes zoster events during the follow-up period may have affected the robustness of the findings.

DISCLOSURES:

The authors did not receive any specific grants. Some authors reported having financial relationships with various pharmaceutical companies.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

The use of valaciclovir as prophylaxis prevents herpes zoster (HZ) in patients with systemic lupus erythematosus (SLE) receiving anifrolumab treatment, with no cases of zoster reported during the follow-up period in patients receiving valaciclovir.

METHODOLOGY:

• Anifrolumab, a human monoclonal antibody binding to type I interferon receptor subunit 1, increases the risk for HZ in patients with SLE; however, specific recommendations to prevent HZ are currently nonexistent for patients with SLE receiving anifrolumab.
• Researchers conducted a multicenter observational study in France from November 2021 to July 2024 to evaluate the prophylactic benefits of valaciclovir in 132 patients with SLE (mean age, 42 years; 92% women) treated with anifrolumab for ≥ 3 months.
• Among these patients, 87 received either 500 mg/d valaciclovir (n = 69) or 1000 mg/d valaciclovir (n = 18) as prophylaxis, whereas 45 did not receive valaciclovir.
• The patients were followed up for a median duration of 234 days under anifrolumab treatment, with monitoring for the development of herpes zoster.

TAKEAWAY:

• The risk for HZ was significantly lower in patients who received valaciclovir than in those who did not (hazard ratio, 0.08; P = .01).
• None of the patients treated with valaciclovir developed HZ during the survey period.
• The frequency of HZ in patients who did not receive valaciclovir increased progressively from 2.2% at 3 months to 6.2% at 6 months, reaching 23% at 12 months.
• None of the reported cases of HZ required hospitalization or led to anifrolumab discontinuation, although one patient developed neuralgia.

IN PRACTICE:

“Prophylactic treatment with valaciclovir is effective for preventing HZ [herpes zoster] infection in SLE patients treated with anifrolumab,” the authors wrote. “This finding is particularly relevant for SLE patients who cannot receive the recombinant HZ vaccine or for whom it is unavailable,” they added.

SOURCE:

The study was led by Ludovic Trefond, MD, PhD, Centre Hospitalier Universitaire de Clermont-Ferrand in France. It was published online on January 4, 2025, in RMD Open.

LIMITATIONS:

The observational design of the study and the low number of herpes zoster events during the follow-up period may have affected the robustness of the findings.

DISCLOSURES:

The authors did not receive any specific grants. Some authors reported having financial relationships with various pharmaceutical companies.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

According to a secondary analysis of the 24-month Myopia Outcome Study of Atropine in Children (MOSAIC) trial, 0.05% atropine eye drops were more effective in controlling myopia progression and axial elongation than placebo eye drops in children despite causing blurred vision and photophobia in some participants.

METHODOLOGY:

• Researchers conducted a secondary analysis of the 3-year results of the MOSAIC trial to investigate the efficacy and safety of different atropine regimens in treatment-naive children aged 6-16 years with a spherical equivalent ≤ −0.50 diopters (D).
• They analyzed data of 199 children in Europe with myopia (mean age, 13.9 years; 60.8% girls) who were randomly assigned to either group 1 (nightly placebo for 2 years followed by 0.05% atropine eye drops for 1 year; n = 66) or group 2 (nightly 0.01% atropine eye drops for 2 years followed by another random assignment to nightly placebo, tapering placebo, or tapering of 0.01% atropine eye drops for 1 year; n = 133).
• The nightly and tapered placebo groups were combined as a single treatment group for the sake of analysis.
• The primary outcome measures included observed changes in the progression of myopia, assessed using cycloplegic spherical equivalent refraction and axial length from month 24 to month 36.

TAKEAWAY:

• Children in the 0.01% atropine then placebo groups showed greater spherical equivalent progression (adjusted difference, –0.13 D; P = .01) and axial elongation (adjusted difference, 0.06 mm; P = .008) than those in the placebo then 0.05% atropine group.
• Children in the placebo then 0.05% atropine group also experienced less axial elongation (P = .04) than those in the 0.01% atropine then tapering 0.01% atropine group.
• Among participants using 0.05% atropine, 15% reported blurred near vision and 8% reported photophobia, whereas 3% reported blurred near vision and 0% reported photophobia in the 0.01% atropine then tapering 0.01% atropine group.
• Despite experiencing adverse events, no participants in the placebo then 0.05% atropine group discontinued treatment, with 92% completing the 36-month visit and 81% adhering to the treatment regimen.

IN PRACTICE:

“Recognizing a 2-year delay in treatment initiation in the group of children originally assigned to placebo, 0.05% atropine eyedrops slowed both myopia progression and axial eye growth over the course of a 1-year period,” the authors of the study wrote.

SOURCE:

This study was led by James Loughman, PhD, of the Centre for Eye Research Ireland, Dublin. It was published online in JAMA Ophthalmology.

LIMITATIONS:

Limitations included smaller sample sizes across treatment groups in year 3 and potential carry-over effects for participants transitioning from 0.01% atropine to placebo or tapered dosing. Because the study lacked an untreated control group, rebound myopia progression could be measured based only on the expected third-year results from the 0.01% atropine then placebo groups. The age of participants during the third year may have affected the ability to detect rebound progression.

DISCLOSURES:

This study was supported partly by a grant from the Health Research Board; Fighting Blindness, Ireland; and Vyluma. Some authors reported receiving grants, nonfinancial support, or consultant fees or having several other ties with Vyluma and other sources.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

TOPLINE:

According to a secondary analysis of the 24-month Myopia Outcome Study of Atropine in Children (MOSAIC) trial, 0.05% atropine eye drops were more effective in controlling myopia progression and axial elongation than placebo eye drops in children despite causing blurred vision and photophobia in some participants.

METHODOLOGY:

• Researchers conducted a secondary analysis of the 3-year results of the MOSAIC trial to investigate the efficacy and safety of different atropine regimens in treatment-naive children aged 6-16 years with a spherical equivalent ≤ −0.50 diopters (D).
• They analyzed data of 199 children in Europe with myopia (mean age, 13.9 years; 60.8% girls) who were randomly assigned to either group 1 (nightly placebo for 2 years followed by 0.05% atropine eye drops for 1 year; n = 66) or group 2 (nightly 0.01% atropine eye drops for 2 years followed by another random assignment to nightly placebo, tapering placebo, or tapering of 0.01% atropine eye drops for 1 year; n = 133).
• The nightly and tapered placebo groups were combined as a single treatment group for the sake of analysis.
• The primary outcome measures included observed changes in the progression of myopia, assessed using cycloplegic spherical equivalent refraction and axial length from month 24 to month 36.

TAKEAWAY:

• Children in the 0.01% atropine then placebo groups showed greater spherical equivalent progression (adjusted difference, –0.13 D; P = .01) and axial elongation (adjusted difference, 0.06 mm; P = .008) than those in the placebo then 0.05% atropine group.
• Children in the placebo then 0.05% atropine group also experienced less axial elongation (P = .04) than those in the 0.01% atropine then tapering 0.01% atropine group.
• Among participants using 0.05% atropine, 15% reported blurred near vision and 8% reported photophobia, whereas 3% reported blurred near vision and 0% reported photophobia in the 0.01% atropine then tapering 0.01% atropine group.
• Despite experiencing adverse events, no participants in the placebo then 0.05% atropine group discontinued treatment, with 92% completing the 36-month visit and 81% adhering to the treatment regimen.

IN PRACTICE:

“Recognizing a 2-year delay in treatment initiation in the group of children originally assigned to placebo, 0.05% atropine eyedrops slowed both myopia progression and axial eye growth over the course of a 1-year period,” the authors of the study wrote.

SOURCE:

This study was led by James Loughman, PhD, of the Centre for Eye Research Ireland, Dublin. It was published online in JAMA Ophthalmology.

LIMITATIONS:

Limitations included smaller sample sizes across treatment groups in year 3 and potential carry-over effects for participants transitioning from 0.01% atropine to placebo or tapered dosing. Because the study lacked an untreated control group, rebound myopia progression could be measured based only on the expected third-year results from the 0.01% atropine then placebo groups. The age of participants during the third year may have affected the ability to detect rebound progression.

DISCLOSURES:

This study was supported partly by a grant from the Health Research Board; Fighting Blindness, Ireland; and Vyluma. Some authors reported receiving grants, nonfinancial support, or consultant fees or having several other ties with Vyluma and other sources.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

TOPLINE:

According to a secondary analysis of the 24-month Myopia Outcome Study of Atropine in Children (MOSAIC) trial, 0.05% atropine eye drops were more effective in controlling myopia progression and axial elongation than placebo eye drops in children despite causing blurred vision and photophobia in some participants.

METHODOLOGY:

• Researchers conducted a secondary analysis of the 3-year results of the MOSAIC trial to investigate the efficacy and safety of different atropine regimens in treatment-naive children aged 6-16 years with a spherical equivalent ≤ −0.50 diopters (D).
• They analyzed data of 199 children in Europe with myopia (mean age, 13.9 years; 60.8% girls) who were randomly assigned to either group 1 (nightly placebo for 2 years followed by 0.05% atropine eye drops for 1 year; n = 66) or group 2 (nightly 0.01% atropine eye drops for 2 years followed by another random assignment to nightly placebo, tapering placebo, or tapering of 0.01% atropine eye drops for 1 year; n = 133).
• The nightly and tapered placebo groups were combined as a single treatment group for the sake of analysis.
• The primary outcome measures included observed changes in the progression of myopia, assessed using cycloplegic spherical equivalent refraction and axial length from month 24 to month 36.

TAKEAWAY:

• Children in the 0.01% atropine then placebo groups showed greater spherical equivalent progression (adjusted difference, –0.13 D; P = .01) and axial elongation (adjusted difference, 0.06 mm; P = .008) than those in the placebo then 0.05% atropine group.
• Children in the placebo then 0.05% atropine group also experienced less axial elongation (P = .04) than those in the 0.01% atropine then tapering 0.01% atropine group.
• Among participants using 0.05% atropine, 15% reported blurred near vision and 8% reported photophobia, whereas 3% reported blurred near vision and 0% reported photophobia in the 0.01% atropine then tapering 0.01% atropine group.
• Despite experiencing adverse events, no participants in the placebo then 0.05% atropine group discontinued treatment, with 92% completing the 36-month visit and 81% adhering to the treatment regimen.

IN PRACTICE:

“Recognizing a 2-year delay in treatment initiation in the group of children originally assigned to placebo, 0.05% atropine eyedrops slowed both myopia progression and axial eye growth over the course of a 1-year period,” the authors of the study wrote.

SOURCE:

This study was led by James Loughman, PhD, of the Centre for Eye Research Ireland, Dublin. It was published online in JAMA Ophthalmology.

LIMITATIONS:

Limitations included smaller sample sizes across treatment groups in year 3 and potential carry-over effects for participants transitioning from 0.01% atropine to placebo or tapered dosing. Because the study lacked an untreated control group, rebound myopia progression could be measured based only on the expected third-year results from the 0.01% atropine then placebo groups. The age of participants during the third year may have affected the ability to detect rebound progression.

DISCLOSURES:

This study was supported partly by a grant from the Health Research Board; Fighting Blindness, Ireland; and Vyluma. Some authors reported receiving grants, nonfinancial support, or consultant fees or having several other ties with Vyluma and other sources.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

MRI-invisible prostate lesions. It sounds like the stuff of science fiction and fantasy, a creation from the minds of H.G. Wells, who wrote The Invisible Man, or J.K. Rowling, who authored the Harry Potter series.

But MRI-invisible prostate lesions are real. And what these lesions may, or may not, indicate is the subject of intense debate.

MRI plays an increasingly important role in detecting and diagnosing prostate cancer, staging prostate cancer as well as monitoring disease progression. However, on occasion, a puzzling phenomenon arises. Certain prostate lesions that appear when pathologists examine biopsied tissue samples under a microscope are not visible on MRI. The prostate tissue will, instead, appear normal to a radiologist’s eye.

Why are certain lesions invisible with MRI? And is it dangerous for patients if these lesions are not detected? 

Some experts believe these MRI-invisible lesions are nothing to worry about.

If the clinician can’t see the cancer on MRI, then it simply isn’t a threat, according to Mark Emberton, MD, a pioneer in prostate MRIs and director of interventional oncology at University College London, England.

Laurence Klotz, MD, of the University of Toronto, Ontario, Canada, agreed, noting that “invisible cancers are clinically insignificant and don’t require systematic biopsies.”

Emberton and Klotz compared MRI-invisible lesions to grade group 1 prostate cancer (Gleason score ≤ 6) — the least aggressive category that indicates the cancer that is not likely to spread or kill. For patients on active surveillance, those with MRI-invisible cancers do drastically better than those with visible cancers, Klotz explained.

But other experts in the field are skeptical that MRI-invisible lesions are truly innocuous.

Although statistically an MRI-visible prostate lesion indicates a more aggressive tumor, that is not always the case for every individual, said Brian Helfand, MD, PhD, chief of urology at NorthShore University Health System, Evanston, Illinois.

MRIs can lead to false negatives in about 10%-20% of patients who have clinically significant prostate cancer, though estimates vary.

In one analysis, 16% of men with no suspicious lesions on MRI had clinically significant prostate cancer identified after undergoing a systematic biopsy. Another analysis found that about 35% of MRI-invisible prostate cancers identified via biopsy were clinically significant.

Other studies, however, have indicated that negative MRI results accurately indicate patients at low risk of developing clinically significant cancers. A recent JAMA Oncology analysis, for instance, found that only seven of 233 men (3%) with negative MRI results at baseline who completed 3 years of monitoring were diagnosed with clinically significant prostate cancer.

When a patient has an MRI-invisible prostate tumor, there are a couple of reasons the MRI may not be picking it up, said urologic oncologist Alexander Putnam Cole, MD, assistant professor of surgery, Harvard Medical School, Boston, Massachusetts. “One is that the cancer is aggressive but just very small,” said Cole.

“Another possibility is that the cancer looks very similar to background prostate tissue, which is something that you might expect if you think about more of a low-grade cancer,” he explained.

The experience level of the radiologist interpreting the MRI can also play into the accuracy of the reading.

But Cole agreed that “in general, MRI visibility is associated with molecular and histologic features of progression and aggressiveness and non-visible cancers are less likely to have aggressive features.”

The genomic profiles of MRI-visible and -invisible cancers bear this out.

According to Todd Morgan, MD, chief of urologic oncology at Michigan Medicine, University of Michigan, Ann Arbor, the gene expression in visible disease tends to be linked to more aggressive prostate tumors whereas gene expression in invisible disease does not.

In one analysis, for instance, researchers found that four genes — PHYHD1, CENPF, ALDH2, and GDF15 — associated with worse progression-free survival and metastasis-free survival in prostate cancer also predicted MRI visibility.

“Genes that are associated with visibility are essentially the same genes that are associated with aggressive cancers,” Klotz said.

 

Next Steps After Negative MRI Result

What do MRI-invisible lesions mean for patient care? If, for instance, a patient has elevated PSA levels but a normal MRI, is a targeted or systematic biopsy warranted?

The overarching message, according to Klotz, is that “you don’t need to find them.” Klotz noted, however, that patients with a negative MRI result should still be followed with periodic repeat imaging.

Several trials support this approach of using MRI to decide who needs a biopsy and delaying a biopsy in men with normal MRIs.

The recent JAMA Oncology analysis found that, among men with negative MRI results, 86% avoided a biopsy over 3 years, with clinically significant prostate cancer detected in only 4% of men across the study period — four in the initial diagnostic phase and seven in the 3-year monitoring phase. However, during the initial diagnostic phase, more than half the men with positive MRI findings had clinically significant prostate cancer detected.

Another recent study found that patients with negative MRI results were much less likely to upgrade to higher Gleason scores over time. Among 522 patients who underwent a systematic and targeted biopsy within 18 months of their grade group 1 designation, 9.2% with negative MRI findings had tumors reclassified as grade group 2 or higher vs 27% with positive MRI findings, and 2.3% with negative MRI findings had tumors reclassified as grade group 3 or higher vs 7.8% with positive MRI findings.

These data suggest that men with grade group 1 cancer and negative MRI result “may be able to avoid confirmatory biopsies until a routine surveillance biopsy in 2-3 years,” according to study author Christian Pavlovich, MD, professor of urologic oncology at the Johns Hopkins University School of Medicine, Baltimore.

Cole used MRI findings to triage who gets a biopsy. When a biopsy is warranted, “I usually recommend adding in some systematic sampling of the other side to assess for nonvisible cancers,” he noted.

Sampling prostate tissue outside the target area “adds maybe 1-2 minutes to the procedure and doesn’t drastically increase the morbidity or risks,” Cole said. It also can help “confirm there is cancer in the MRI target and also confirm there is no cancer in the nonvisible areas.” 

According to Klotz, if imaging demonstrates progression, patients should receive a biopsy — in most cases, a targeted biopsy only. And, Klotz noted, skipping routine prostate biopsies in men with negative MRI results can save thousands of men from these procedures, which carry risks for infections and sepsis.

Looking beyond Gleason scores for risk prediction, MRI “visibility is a very powerful risk stratifier,” he said.

A version of this article appeared on Medscape.com.

MRI-invisible prostate lesions. It sounds like the stuff of science fiction and fantasy, a creation from the minds of H.G. Wells, who wrote The Invisible Man, or J.K. Rowling, who authored the Harry Potter series.

But MRI-invisible prostate lesions are real. And what these lesions may, or may not, indicate is the subject of intense debate.

MRI plays an increasingly important role in detecting and diagnosing prostate cancer, staging prostate cancer as well as monitoring disease progression. However, on occasion, a puzzling phenomenon arises. Certain prostate lesions that appear when pathologists examine biopsied tissue samples under a microscope are not visible on MRI. The prostate tissue will, instead, appear normal to a radiologist’s eye.

Why are certain lesions invisible with MRI? And is it dangerous for patients if these lesions are not detected? 

Some experts believe these MRI-invisible lesions are nothing to worry about.

If the clinician can’t see the cancer on MRI, then it simply isn’t a threat, according to Mark Emberton, MD, a pioneer in prostate MRIs and director of interventional oncology at University College London, England.

Laurence Klotz, MD, of the University of Toronto, Ontario, Canada, agreed, noting that “invisible cancers are clinically insignificant and don’t require systematic biopsies.”

Emberton and Klotz compared MRI-invisible lesions to grade group 1 prostate cancer (Gleason score ≤ 6) — the least aggressive category that indicates the cancer that is not likely to spread or kill. For patients on active surveillance, those with MRI-invisible cancers do drastically better than those with visible cancers, Klotz explained.

But other experts in the field are skeptical that MRI-invisible lesions are truly innocuous.

Although statistically an MRI-visible prostate lesion indicates a more aggressive tumor, that is not always the case for every individual, said Brian Helfand, MD, PhD, chief of urology at NorthShore University Health System, Evanston, Illinois.

MRIs can lead to false negatives in about 10%-20% of patients who have clinically significant prostate cancer, though estimates vary.

In one analysis, 16% of men with no suspicious lesions on MRI had clinically significant prostate cancer identified after undergoing a systematic biopsy. Another analysis found that about 35% of MRI-invisible prostate cancers identified via biopsy were clinically significant.

Other studies, however, have indicated that negative MRI results accurately indicate patients at low risk of developing clinically significant cancers. A recent JAMA Oncology analysis, for instance, found that only seven of 233 men (3%) with negative MRI results at baseline who completed 3 years of monitoring were diagnosed with clinically significant prostate cancer.

When a patient has an MRI-invisible prostate tumor, there are a couple of reasons the MRI may not be picking it up, said urologic oncologist Alexander Putnam Cole, MD, assistant professor of surgery, Harvard Medical School, Boston, Massachusetts. “One is that the cancer is aggressive but just very small,” said Cole.

“Another possibility is that the cancer looks very similar to background prostate tissue, which is something that you might expect if you think about more of a low-grade cancer,” he explained.

The experience level of the radiologist interpreting the MRI can also play into the accuracy of the reading.

But Cole agreed that “in general, MRI visibility is associated with molecular and histologic features of progression and aggressiveness and non-visible cancers are less likely to have aggressive features.”

The genomic profiles of MRI-visible and -invisible cancers bear this out.

According to Todd Morgan, MD, chief of urologic oncology at Michigan Medicine, University of Michigan, Ann Arbor, the gene expression in visible disease tends to be linked to more aggressive prostate tumors whereas gene expression in invisible disease does not.

In one analysis, for instance, researchers found that four genes — PHYHD1, CENPF, ALDH2, and GDF15 — associated with worse progression-free survival and metastasis-free survival in prostate cancer also predicted MRI visibility.

“Genes that are associated with visibility are essentially the same genes that are associated with aggressive cancers,” Klotz said.

 

Next Steps After Negative MRI Result

What do MRI-invisible lesions mean for patient care? If, for instance, a patient has elevated PSA levels but a normal MRI, is a targeted or systematic biopsy warranted?

The overarching message, according to Klotz, is that “you don’t need to find them.” Klotz noted, however, that patients with a negative MRI result should still be followed with periodic repeat imaging.

Several trials support this approach of using MRI to decide who needs a biopsy and delaying a biopsy in men with normal MRIs.

The recent JAMA Oncology analysis found that, among men with negative MRI results, 86% avoided a biopsy over 3 years, with clinically significant prostate cancer detected in only 4% of men across the study period — four in the initial diagnostic phase and seven in the 3-year monitoring phase. However, during the initial diagnostic phase, more than half the men with positive MRI findings had clinically significant prostate cancer detected.

Another recent study found that patients with negative MRI results were much less likely to upgrade to higher Gleason scores over time. Among 522 patients who underwent a systematic and targeted biopsy within 18 months of their grade group 1 designation, 9.2% with negative MRI findings had tumors reclassified as grade group 2 or higher vs 27% with positive MRI findings, and 2.3% with negative MRI findings had tumors reclassified as grade group 3 or higher vs 7.8% with positive MRI findings.

These data suggest that men with grade group 1 cancer and negative MRI result “may be able to avoid confirmatory biopsies until a routine surveillance biopsy in 2-3 years,” according to study author Christian Pavlovich, MD, professor of urologic oncology at the Johns Hopkins University School of Medicine, Baltimore.

Cole used MRI findings to triage who gets a biopsy. When a biopsy is warranted, “I usually recommend adding in some systematic sampling of the other side to assess for nonvisible cancers,” he noted.

Sampling prostate tissue outside the target area “adds maybe 1-2 minutes to the procedure and doesn’t drastically increase the morbidity or risks,” Cole said. It also can help “confirm there is cancer in the MRI target and also confirm there is no cancer in the nonvisible areas.” 

According to Klotz, if imaging demonstrates progression, patients should receive a biopsy — in most cases, a targeted biopsy only. And, Klotz noted, skipping routine prostate biopsies in men with negative MRI results can save thousands of men from these procedures, which carry risks for infections and sepsis.

Looking beyond Gleason scores for risk prediction, MRI “visibility is a very powerful risk stratifier,” he said.

A version of this article appeared on Medscape.com.

MRI-invisible prostate lesions. It sounds like the stuff of science fiction and fantasy, a creation from the minds of H.G. Wells, who wrote The Invisible Man, or J.K. Rowling, who authored the Harry Potter series.

But MRI-invisible prostate lesions are real. And what these lesions may, or may not, indicate is the subject of intense debate.

MRI plays an increasingly important role in detecting and diagnosing prostate cancer, staging prostate cancer as well as monitoring disease progression. However, on occasion, a puzzling phenomenon arises. Certain prostate lesions that appear when pathologists examine biopsied tissue samples under a microscope are not visible on MRI. The prostate tissue will, instead, appear normal to a radiologist’s eye.

Why are certain lesions invisible with MRI? And is it dangerous for patients if these lesions are not detected? 

Some experts believe these MRI-invisible lesions are nothing to worry about.

If the clinician can’t see the cancer on MRI, then it simply isn’t a threat, according to Mark Emberton, MD, a pioneer in prostate MRIs and director of interventional oncology at University College London, England.

Laurence Klotz, MD, of the University of Toronto, Ontario, Canada, agreed, noting that “invisible cancers are clinically insignificant and don’t require systematic biopsies.”

Emberton and Klotz compared MRI-invisible lesions to grade group 1 prostate cancer (Gleason score ≤ 6) — the least aggressive category that indicates the cancer that is not likely to spread or kill. For patients on active surveillance, those with MRI-invisible cancers do drastically better than those with visible cancers, Klotz explained.

But other experts in the field are skeptical that MRI-invisible lesions are truly innocuous.

Although statistically an MRI-visible prostate lesion indicates a more aggressive tumor, that is not always the case for every individual, said Brian Helfand, MD, PhD, chief of urology at NorthShore University Health System, Evanston, Illinois.

MRIs can lead to false negatives in about 10%-20% of patients who have clinically significant prostate cancer, though estimates vary.

In one analysis, 16% of men with no suspicious lesions on MRI had clinically significant prostate cancer identified after undergoing a systematic biopsy. Another analysis found that about 35% of MRI-invisible prostate cancers identified via biopsy were clinically significant.

Other studies, however, have indicated that negative MRI results accurately indicate patients at low risk of developing clinically significant cancers. A recent JAMA Oncology analysis, for instance, found that only seven of 233 men (3%) with negative MRI results at baseline who completed 3 years of monitoring were diagnosed with clinically significant prostate cancer.

When a patient has an MRI-invisible prostate tumor, there are a couple of reasons the MRI may not be picking it up, said urologic oncologist Alexander Putnam Cole, MD, assistant professor of surgery, Harvard Medical School, Boston, Massachusetts. “One is that the cancer is aggressive but just very small,” said Cole.

“Another possibility is that the cancer looks very similar to background prostate tissue, which is something that you might expect if you think about more of a low-grade cancer,” he explained.

The experience level of the radiologist interpreting the MRI can also play into the accuracy of the reading.

But Cole agreed that “in general, MRI visibility is associated with molecular and histologic features of progression and aggressiveness and non-visible cancers are less likely to have aggressive features.”

The genomic profiles of MRI-visible and -invisible cancers bear this out.

According to Todd Morgan, MD, chief of urologic oncology at Michigan Medicine, University of Michigan, Ann Arbor, the gene expression in visible disease tends to be linked to more aggressive prostate tumors whereas gene expression in invisible disease does not.

In one analysis, for instance, researchers found that four genes — PHYHD1, CENPF, ALDH2, and GDF15 — associated with worse progression-free survival and metastasis-free survival in prostate cancer also predicted MRI visibility.

“Genes that are associated with visibility are essentially the same genes that are associated with aggressive cancers,” Klotz said.

 

Next Steps After Negative MRI Result

What do MRI-invisible lesions mean for patient care? If, for instance, a patient has elevated PSA levels but a normal MRI, is a targeted or systematic biopsy warranted?

The overarching message, according to Klotz, is that “you don’t need to find them.” Klotz noted, however, that patients with a negative MRI result should still be followed with periodic repeat imaging.

Several trials support this approach of using MRI to decide who needs a biopsy and delaying a biopsy in men with normal MRIs.

The recent JAMA Oncology analysis found that, among men with negative MRI results, 86% avoided a biopsy over 3 years, with clinically significant prostate cancer detected in only 4% of men across the study period — four in the initial diagnostic phase and seven in the 3-year monitoring phase. However, during the initial diagnostic phase, more than half the men with positive MRI findings had clinically significant prostate cancer detected.

Another recent study found that patients with negative MRI results were much less likely to upgrade to higher Gleason scores over time. Among 522 patients who underwent a systematic and targeted biopsy within 18 months of their grade group 1 designation, 9.2% with negative MRI findings had tumors reclassified as grade group 2 or higher vs 27% with positive MRI findings, and 2.3% with negative MRI findings had tumors reclassified as grade group 3 or higher vs 7.8% with positive MRI findings.

These data suggest that men with grade group 1 cancer and negative MRI result “may be able to avoid confirmatory biopsies until a routine surveillance biopsy in 2-3 years,” according to study author Christian Pavlovich, MD, professor of urologic oncology at the Johns Hopkins University School of Medicine, Baltimore.

Cole used MRI findings to triage who gets a biopsy. When a biopsy is warranted, “I usually recommend adding in some systematic sampling of the other side to assess for nonvisible cancers,” he noted.

Sampling prostate tissue outside the target area “adds maybe 1-2 minutes to the procedure and doesn’t drastically increase the morbidity or risks,” Cole said. It also can help “confirm there is cancer in the MRI target and also confirm there is no cancer in the nonvisible areas.” 

According to Klotz, if imaging demonstrates progression, patients should receive a biopsy — in most cases, a targeted biopsy only. And, Klotz noted, skipping routine prostate biopsies in men with negative MRI results can save thousands of men from these procedures, which carry risks for infections and sepsis.

Looking beyond Gleason scores for risk prediction, MRI “visibility is a very powerful risk stratifier,” he said.

A version of this article appeared on Medscape.com.

TOPLINE:

Glucarpidase treatment in patients with methotrexate-associated acute kidney injury is linked to 2.7 times higher odds of kidney recovery and faster recovery time. The enzyme also reduces the risk for grade ≥ 2 neutropenia and transaminitis by half vs no glucarpidase treatment.

METHODOLOGY:

• Researchers conducted a multicenter cohort study involving 708 adults with methotrexate-associated acute kidney injury from 28 cancer centers across the United States.
• Analysis utilized a sequential target trial emulation framework to compare outcomes between 209 patients who received glucarpidase within 4 days of methotrexate initiation and 499 patients who did not.
• The primary endpoint was kidney recovery at hospital discharge, defined as survival with serum creatinine < 1.5-fold baseline without dialysis dependence.
• Secondary endpoints included time-to-kidney recovery, neutropenia and transaminitis on day 7, and time-to-death.

TAKEAWAY:

• Glucarpidase administration was associated with adjusted odds ratio [aOR] of 2.70 (95% CI, 1.69-4.31) and adjusted hazard ratio [aHR] of 1.88 (95% CI, 1.18-3.33) for time-to-kidney recovery.
• Treatment with glucarpidase reduced the risk for grade ≥ 2 neutropenia (aOR, 0.50; 95% CI, 0.28-0.91) and grade ≥ 2 transaminitis (aOR, 0.31; 95% CI, 0.13-0.77) on day 7.
• Female patients showed greater benefit from glucarpidase treatment than male patients (P = .02 for interaction).
• No significant difference was observed in time-to-death between glucarpidase-treated and glucarpidase-untreated patients (aHR, 0.76; 95% CI, 0.49-1.18).

IN PRACTICE:

“These data suggest glucarpidase may improve both renal and extrarenal outcomes in patients with MTX-AKI [methotrexate-acute kidney injury],” the authors of the study wrote.

SOURCE:

This study was led by Shruti Gupta, MD, MPH, and David E. Leaf, MD, MMSc, Brigham and Women’s Hospital in Boston, Massachusetts. It was published online in Blood.

LIMITATIONS:

According to the authors, residual confounding cannot be excluded despite adjustment for multiple variables. While glucarpidase-treated patients had similar distributions of most baseline characteristics, they showed greater severity of illness, including more comorbidities, concomitant nephrotoxic medications, higher 24-hour methotrexate levels, and more severe acute kidney injury. This study was limited to patients treated at large, US-based academic centers, potentially affecting generalizability to smaller hospitals or countries where glucarpidase is unavailable.

DISCLOSURES:

This study was funded by BTG International. Gupta disclosed ties with BTG International, Dana-Farber Cancer Institute’s Wong Foundation, Janssen, AstraZeneca, and the National Institute of Diabetes and Digestive and Kidney Diseases (K23DK125672). Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

Glucarpidase treatment in patients with methotrexate-associated acute kidney injury is linked to 2.7 times higher odds of kidney recovery and faster recovery time. The enzyme also reduces the risk for grade ≥ 2 neutropenia and transaminitis by half vs no glucarpidase treatment.

METHODOLOGY:

• Researchers conducted a multicenter cohort study involving 708 adults with methotrexate-associated acute kidney injury from 28 cancer centers across the United States.
• Analysis utilized a sequential target trial emulation framework to compare outcomes between 209 patients who received glucarpidase within 4 days of methotrexate initiation and 499 patients who did not.
• The primary endpoint was kidney recovery at hospital discharge, defined as survival with serum creatinine < 1.5-fold baseline without dialysis dependence.
• Secondary endpoints included time-to-kidney recovery, neutropenia and transaminitis on day 7, and time-to-death.

TAKEAWAY:

• Glucarpidase administration was associated with adjusted odds ratio [aOR] of 2.70 (95% CI, 1.69-4.31) and adjusted hazard ratio [aHR] of 1.88 (95% CI, 1.18-3.33) for time-to-kidney recovery.
• Treatment with glucarpidase reduced the risk for grade ≥ 2 neutropenia (aOR, 0.50; 95% CI, 0.28-0.91) and grade ≥ 2 transaminitis (aOR, 0.31; 95% CI, 0.13-0.77) on day 7.
• Female patients showed greater benefit from glucarpidase treatment than male patients (P = .02 for interaction).
• No significant difference was observed in time-to-death between glucarpidase-treated and glucarpidase-untreated patients (aHR, 0.76; 95% CI, 0.49-1.18).

IN PRACTICE:

“These data suggest glucarpidase may improve both renal and extrarenal outcomes in patients with MTX-AKI [methotrexate-acute kidney injury],” the authors of the study wrote.

SOURCE:

This study was led by Shruti Gupta, MD, MPH, and David E. Leaf, MD, MMSc, Brigham and Women’s Hospital in Boston, Massachusetts. It was published online in Blood.

LIMITATIONS:

According to the authors, residual confounding cannot be excluded despite adjustment for multiple variables. While glucarpidase-treated patients had similar distributions of most baseline characteristics, they showed greater severity of illness, including more comorbidities, concomitant nephrotoxic medications, higher 24-hour methotrexate levels, and more severe acute kidney injury. This study was limited to patients treated at large, US-based academic centers, potentially affecting generalizability to smaller hospitals or countries where glucarpidase is unavailable.

DISCLOSURES:

This study was funded by BTG International. Gupta disclosed ties with BTG International, Dana-Farber Cancer Institute’s Wong Foundation, Janssen, AstraZeneca, and the National Institute of Diabetes and Digestive and Kidney Diseases (K23DK125672). Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

Glucarpidase treatment in patients with methotrexate-associated acute kidney injury is linked to 2.7 times higher odds of kidney recovery and faster recovery time. The enzyme also reduces the risk for grade ≥ 2 neutropenia and transaminitis by half vs no glucarpidase treatment.

METHODOLOGY:

• Researchers conducted a multicenter cohort study involving 708 adults with methotrexate-associated acute kidney injury from 28 cancer centers across the United States.
• Analysis utilized a sequential target trial emulation framework to compare outcomes between 209 patients who received glucarpidase within 4 days of methotrexate initiation and 499 patients who did not.
• The primary endpoint was kidney recovery at hospital discharge, defined as survival with serum creatinine < 1.5-fold baseline without dialysis dependence.
• Secondary endpoints included time-to-kidney recovery, neutropenia and transaminitis on day 7, and time-to-death.

TAKEAWAY:

• Glucarpidase administration was associated with adjusted odds ratio [aOR] of 2.70 (95% CI, 1.69-4.31) and adjusted hazard ratio [aHR] of 1.88 (95% CI, 1.18-3.33) for time-to-kidney recovery.
• Treatment with glucarpidase reduced the risk for grade ≥ 2 neutropenia (aOR, 0.50; 95% CI, 0.28-0.91) and grade ≥ 2 transaminitis (aOR, 0.31; 95% CI, 0.13-0.77) on day 7.
• Female patients showed greater benefit from glucarpidase treatment than male patients (P = .02 for interaction).
• No significant difference was observed in time-to-death between glucarpidase-treated and glucarpidase-untreated patients (aHR, 0.76; 95% CI, 0.49-1.18).

IN PRACTICE:

“These data suggest glucarpidase may improve both renal and extrarenal outcomes in patients with MTX-AKI [methotrexate-acute kidney injury],” the authors of the study wrote.

SOURCE:

This study was led by Shruti Gupta, MD, MPH, and David E. Leaf, MD, MMSc, Brigham and Women’s Hospital in Boston, Massachusetts. It was published online in Blood.

LIMITATIONS:

According to the authors, residual confounding cannot be excluded despite adjustment for multiple variables. While glucarpidase-treated patients had similar distributions of most baseline characteristics, they showed greater severity of illness, including more comorbidities, concomitant nephrotoxic medications, higher 24-hour methotrexate levels, and more severe acute kidney injury. This study was limited to patients treated at large, US-based academic centers, potentially affecting generalizability to smaller hospitals or countries where glucarpidase is unavailable.

DISCLOSURES:

This study was funded by BTG International. Gupta disclosed ties with BTG International, Dana-Farber Cancer Institute’s Wong Foundation, Janssen, AstraZeneca, and the National Institute of Diabetes and Digestive and Kidney Diseases (K23DK125672). Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

To the Editor:

Indeterminate cell histiocytosis (ICH) is a rare neoplastic dendritic cell disorder with a poorly understood histogenesis and pathogenesis.¹ The clinical manifestation of ICH is broad and can include isolated or multiple papules or nodules on the face, neck, trunk, arms, or legs. Our case demonstrates a rare occurrence of ICH that initially was misdiagnosed and highlights the use of cobimetinib, a MEK inhibitor, as a potential new therapeutic option for ICH.

A 74-year-old man with a history of type 2 diabetes mellitus presented for evaluation of a progressive pruritic rash of approximately 5 years’ duration. The eruption previously had been diagnosed as Langerhans cell histiocytosis. It started on the chest and spread to the face, neck, trunk, and arms. The patient denied systemic symptoms and had no known history of malignancy.

Physical examination revealed pink to orange smooth papules, nodules, and small plaques on the ears, cheeks, trunk, neck, and arms (Figure 1). Baseline laboratory results showed a normal complete blood count and comprehensive metabolic panel, elevated lactate dehydrogenase and erythrocyte sedimentation rate, and hyperlipidemia. Serology for hepatitis B and C was negative. Bone marrow biopsy was normal, and positron emission tomography/ computed tomography demonstrated no evidence of extracutaneous disease. A punch biopsy of a lesion on the left forearm revealed epithelioid histiocytic proliferation in the dermis extending into the subcutis with a background infiltrate of small lymphocytes. Immunohistochemistry was positive for CD1a and CD56 and was variably positive for CD4 but negative for CD163, CD68, S100, Langerin, cyclin D1, myeloperoxidase, CD21, and CD23. No mutation was detected in BRAF codon 600. Given the negative Langerin stain, these findings were compatible with a diagnosis of ICH. After considering the lack of standard treatment options as well as the recent approval of cobimetinib for histiocytic disorders, we initiated treatment with cobimetinib at the standard dose of 60 mg daily for 21 days followed by a 7-day break.

One month into treatment, the patient’s lesions were less erythematous, and he reported improvement in pruritus. Two months into treatment, there was continued improvement in cutaneous symptoms with flattening of the lesions on the chest and back. At this time, the patient developed edema of the face and ears (Figure 2) and reported weakness, blurred vision, and decreased appetite. He was advised to take an additional 7-day treatment break before resuming cobimetinib at a decreased dose of 40 mg daily. The patient returned to the clinic 1 month later with improved systemic symptoms and continued flattening of the lesions. Five months into treatment, the lesions had continued to improve with complete resolution of the facial plaques (Figure 3).

Indeterminate cell histiocytosis is a rarely diagnosed condition characterized by the proliferation of indeterminate histiocytes that morphologically and immunophenotypically resemble Langerhans cells but lack their characteristic Birbeck granules.² There is no standard treatment for ICH, but previous reports have described improvement with a variety of treatment options including methotrexate,^3,4 UVB phototherapy,⁵ and topical delgocitinib 0.5%.⁶

Because histiocytic disorders are characterized by mutations in the mitogen-activated protein kinase pathway, it is possible that they would be responsive to MEK inhibition. Cobimetinib, a MEK inhibitor initially approved to treat metastatic melanoma, was approved by the US Food and Drug Administration to treat histiocytic disorders in October 2022.⁷ The approval followed the release of data from a phase 2 trial of cobimetinib in 18 adults with various histiocytic disorders, which demonstrated an 89% (16/18) overall response rate with 94% (17/18) of patients remaining progression free at 1 year.⁸ While cobimetinib has not specifically been studied in ICH, given the high response rate in histiocytic disorders and the lack of standard treatment options for ICH, the decision was made to initiate treatment with cobimetinib in our patient. Based on the observed improvement in our patient, we propose cobimetinib as a treatment option for patients with cutaneous ICH and recommend additional studies to confirm its safety and efficacy in patients with this disorder.

To the Editor:

Indeterminate cell histiocytosis (ICH) is a rare neoplastic dendritic cell disorder with a poorly understood histogenesis and pathogenesis.¹ The clinical manifestation of ICH is broad and can include isolated or multiple papules or nodules on the face, neck, trunk, arms, or legs. Our case demonstrates a rare occurrence of ICH that initially was misdiagnosed and highlights the use of cobimetinib, a MEK inhibitor, as a potential new therapeutic option for ICH.

A 74-year-old man with a history of type 2 diabetes mellitus presented for evaluation of a progressive pruritic rash of approximately 5 years’ duration. The eruption previously had been diagnosed as Langerhans cell histiocytosis. It started on the chest and spread to the face, neck, trunk, and arms. The patient denied systemic symptoms and had no known history of malignancy.

Physical examination revealed pink to orange smooth papules, nodules, and small plaques on the ears, cheeks, trunk, neck, and arms (Figure 1). Baseline laboratory results showed a normal complete blood count and comprehensive metabolic panel, elevated lactate dehydrogenase and erythrocyte sedimentation rate, and hyperlipidemia. Serology for hepatitis B and C was negative. Bone marrow biopsy was normal, and positron emission tomography/ computed tomography demonstrated no evidence of extracutaneous disease. A punch biopsy of a lesion on the left forearm revealed epithelioid histiocytic proliferation in the dermis extending into the subcutis with a background infiltrate of small lymphocytes. Immunohistochemistry was positive for CD1a and CD56 and was variably positive for CD4 but negative for CD163, CD68, S100, Langerin, cyclin D1, myeloperoxidase, CD21, and CD23. No mutation was detected in BRAF codon 600. Given the negative Langerin stain, these findings were compatible with a diagnosis of ICH. After considering the lack of standard treatment options as well as the recent approval of cobimetinib for histiocytic disorders, we initiated treatment with cobimetinib at the standard dose of 60 mg daily for 21 days followed by a 7-day break.

One month into treatment, the patient’s lesions were less erythematous, and he reported improvement in pruritus. Two months into treatment, there was continued improvement in cutaneous symptoms with flattening of the lesions on the chest and back. At this time, the patient developed edema of the face and ears (Figure 2) and reported weakness, blurred vision, and decreased appetite. He was advised to take an additional 7-day treatment break before resuming cobimetinib at a decreased dose of 40 mg daily. The patient returned to the clinic 1 month later with improved systemic symptoms and continued flattening of the lesions. Five months into treatment, the lesions had continued to improve with complete resolution of the facial plaques (Figure 3).

Indeterminate cell histiocytosis is a rarely diagnosed condition characterized by the proliferation of indeterminate histiocytes that morphologically and immunophenotypically resemble Langerhans cells but lack their characteristic Birbeck granules.² There is no standard treatment for ICH, but previous reports have described improvement with a variety of treatment options including methotrexate,^3,4 UVB phototherapy,⁵ and topical delgocitinib 0.5%.⁶

Because histiocytic disorders are characterized by mutations in the mitogen-activated protein kinase pathway, it is possible that they would be responsive to MEK inhibition. Cobimetinib, a MEK inhibitor initially approved to treat metastatic melanoma, was approved by the US Food and Drug Administration to treat histiocytic disorders in October 2022.⁷ The approval followed the release of data from a phase 2 trial of cobimetinib in 18 adults with various histiocytic disorders, which demonstrated an 89% (16/18) overall response rate with 94% (17/18) of patients remaining progression free at 1 year.⁸ While cobimetinib has not specifically been studied in ICH, given the high response rate in histiocytic disorders and the lack of standard treatment options for ICH, the decision was made to initiate treatment with cobimetinib in our patient. Based on the observed improvement in our patient, we propose cobimetinib as a treatment option for patients with cutaneous ICH and recommend additional studies to confirm its safety and efficacy in patients with this disorder.

To the Editor:

Indeterminate cell histiocytosis (ICH) is a rare neoplastic dendritic cell disorder with a poorly understood histogenesis and pathogenesis.¹ The clinical manifestation of ICH is broad and can include isolated or multiple papules or nodules on the face, neck, trunk, arms, or legs. Our case demonstrates a rare occurrence of ICH that initially was misdiagnosed and highlights the use of cobimetinib, a MEK inhibitor, as a potential new therapeutic option for ICH.

A 74-year-old man with a history of type 2 diabetes mellitus presented for evaluation of a progressive pruritic rash of approximately 5 years’ duration. The eruption previously had been diagnosed as Langerhans cell histiocytosis. It started on the chest and spread to the face, neck, trunk, and arms. The patient denied systemic symptoms and had no known history of malignancy.

Physical examination revealed pink to orange smooth papules, nodules, and small plaques on the ears, cheeks, trunk, neck, and arms (Figure 1). Baseline laboratory results showed a normal complete blood count and comprehensive metabolic panel, elevated lactate dehydrogenase and erythrocyte sedimentation rate, and hyperlipidemia. Serology for hepatitis B and C was negative. Bone marrow biopsy was normal, and positron emission tomography/ computed tomography demonstrated no evidence of extracutaneous disease. A punch biopsy of a lesion on the left forearm revealed epithelioid histiocytic proliferation in the dermis extending into the subcutis with a background infiltrate of small lymphocytes. Immunohistochemistry was positive for CD1a and CD56 and was variably positive for CD4 but negative for CD163, CD68, S100, Langerin, cyclin D1, myeloperoxidase, CD21, and CD23. No mutation was detected in BRAF codon 600. Given the negative Langerin stain, these findings were compatible with a diagnosis of ICH. After considering the lack of standard treatment options as well as the recent approval of cobimetinib for histiocytic disorders, we initiated treatment with cobimetinib at the standard dose of 60 mg daily for 21 days followed by a 7-day break.

One month into treatment, the patient’s lesions were less erythematous, and he reported improvement in pruritus. Two months into treatment, there was continued improvement in cutaneous symptoms with flattening of the lesions on the chest and back. At this time, the patient developed edema of the face and ears (Figure 2) and reported weakness, blurred vision, and decreased appetite. He was advised to take an additional 7-day treatment break before resuming cobimetinib at a decreased dose of 40 mg daily. The patient returned to the clinic 1 month later with improved systemic symptoms and continued flattening of the lesions. Five months into treatment, the lesions had continued to improve with complete resolution of the facial plaques (Figure 3).

Indeterminate cell histiocytosis is a rarely diagnosed condition characterized by the proliferation of indeterminate histiocytes that morphologically and immunophenotypically resemble Langerhans cells but lack their characteristic Birbeck granules.² There is no standard treatment for ICH, but previous reports have described improvement with a variety of treatment options including methotrexate,^3,4 UVB phototherapy,⁵ and topical delgocitinib 0.5%.⁶

Because histiocytic disorders are characterized by mutations in the mitogen-activated protein kinase pathway, it is possible that they would be responsive to MEK inhibition. Cobimetinib, a MEK inhibitor initially approved to treat metastatic melanoma, was approved by the US Food and Drug Administration to treat histiocytic disorders in October 2022.⁷ The approval followed the release of data from a phase 2 trial of cobimetinib in 18 adults with various histiocytic disorders, which demonstrated an 89% (16/18) overall response rate with 94% (17/18) of patients remaining progression free at 1 year.⁸ While cobimetinib has not specifically been studied in ICH, given the high response rate in histiocytic disorders and the lack of standard treatment options for ICH, the decision was made to initiate treatment with cobimetinib in our patient. Based on the observed improvement in our patient, we propose cobimetinib as a treatment option for patients with cutaneous ICH and recommend additional studies to confirm its safety and efficacy in patients with this disorder.

Hidradenitis suppurativa (HS) is a debilitating dermatologic condition characterized by recurrent episodes of neutrophilic inflammation affecting the apocrine and pilosebaceous units that most commonly affects individuals aged 20 to 40 years. Originating from the hair follicles, inflammation initiates the formation of painful nodules and abscesses that can progress to sinus tracts or fistulas accompanied by the development of extensive scarring, exquisite pain, and malodorous drainage.¹ The lesions most commonly occur in intertriginous zones as well as areas rich in apocrine glands. The distinctive and sometimes irreversible clinical features of HS profoundly influence patients’ well-being and have lasting social, personal, and emotional impacts on their lives.²

Bimekizumab is a monoclonal antibody that specifically targets IL-17A and IL-17F, aiming to inhibit the downstream effects responsible for the chronic inflammation and tissue damage characteristic of HS.³ In HS lesions, IL-17 cytokines produced by T helper 17 (Th17) cells stimulate the production of chemokines (such as CC motif chemokine ligand 20) and neutrophil-attracting chemokines (including C-X-C motif chemokine ligands 1 and 8), cytokines (such as granulocyte colony-stimulating factor and IL-19), and epidermal antimicrobial proteins.^1,2 This cascade results in the chemotaxis of monocytes and neutrophils in the skin, recruiting additional Th17 and myeloid cells and further amplifying IL-17 production.¹

Bimekizumab’s mechanism of action strategically disrupts this feed-forward inflammatory loop, decreasing the transcription of neutrophil-attracting chemokines, IL-19, and epidermal antimicrobial proteins (Figure).^1,2 This leads to diminished recruitment of Th17 cells and inhibits the chemotaxis of monocytes and neutrophils in the skin, effectively addressing the chronic inflammation and tissue damage characteristic of HS.

We present a comprehensive review of the current standards of care, the underlying molecular pathophysiology of HS, and evaluation of the efficacy and safety of bimekizumab.

Evaluating HS Severity

The Hurley staging system provides a valuable framework for evaluating the severity of HS based on lesion characteristics. Stage I is characterized by abscess formation without tracts or scars. Stage II is characterized by recurrent abscesses with sinus tracts and scarring. Stage III is characterized by diffuse involvement, multiple interconnected sinus tracts, and abscesses across an entire area, leaving little to no uninvolved skin.⁴

Treatment strategies for HS vary based on Hurley staging (eTable).^5-11 For mild cases (stage I), topical and intralesional therapies are common, while moderate to severe cases (stages II and III) may require extensive surgical approaches or systemic drugs such as antibiotics, hormonal therapies, retinoids, or immunosuppressive/biologic agents.²

Adalimumab, an anti–tumor necrosis factor (TNF) α monoclonal antibody, was the first US Food and Drug Administration (FDA)–approved biologic for HS. Secukinumab, a monoclonal antibody against IL-17A, subsequently was approved by the FDA for moderate to severe HS.¹² Off-label use of biologics including infliximab and ustekinumab expands the available treatment options for HS. In one Phase II randomized clinical trial (RCT), infliximab showed efficacy in reducing Hidradenitis Suppurativa Severity Index scores, with 26.7% (4/15) of patients achieving a 50% or greater reduction compared to placebo, although this was not statistically significant. Similarly, ustekinumab demonstrated promising results, with 47.1% (8/17) of patients achieving Hidradenitis Suppurativa Clinical Response (HiSCR) at week 40.² This multifaceted approach aims to address the varying degrees of severity and optimize outcomes for individuals with HS.

Molecular Pathophysiology of HS

The pathogenesis of HS is multifactorial, involving a complex interplay of genetic, environmental, and behavioral factors.² Approximately 33% to 40% of patients with HS worldwide report a first-degree relative with the condition, indicating a hereditary element with an autosomal-dominant transmission pattern and highlighting the global relevance of genetic factors in HS.⁴ Hidradenitis suppurativa is highly prevalent in individuals with obesity, likely due to increased intertriginous surface area, skin friction, sweat production, and hormonal changes in these patients. Smoking also commonly is associated with HS, with nicotine potentially contributing to increased follicular plugging.¹ Hormonal influences also play a role, as evidenced by a greater prevalence of HS in females, disease onset typically occurring between puberty and menopause, and symptomatic fluctuations correlating with menstrual cycles and exogenous hormones.⁴

Altered infundibular keratinization with subsequent hyperkeratosis/occlusion and innate immune pathway activation are key events leading to development of HS.¹ These events are mediated by release of pathogen- and danger-associated molecular patterns, leading to inflammasome-mediated IL-1α release, followed by downstream cytokine release.² Elevated levels of TNF-α, IL-1Β, IL-10, IL-17, and particularly IL-17A have been detected in HS lesional skin. The IL-17 family comprises multiple members, namely IL-17A, IL-17C, IL-17E, and IL17F. IL-17A and IL-17F often are co-expressed and secreted predominantly by a subset of CD4+ T helper cells, namely Th17 cells.² IL-17 cytokines exert pro-inflammatory effects, influencing immune cell activity and contributing to skin inflammation, particularly in HS.

Given the pivotal role of IL-17 in the pathogenesis of HS, the exploration of IL-17–targeted agents has become a focal point in clinical research. Bimekizumab, a novel IL-17 inhibitor, has emerged as a promising candidate, offering a potential breakthrough in the treatment landscape for individuals affected by HS.

Bimekizumab for HS Management

A phase II, double-blind, placebo-controlled RCT included 90 patients with moderate to severe HS (age range, 18-70 years) who were randomly assigned in a 2:1:1 ratio to receive either bimekizumab 320 mg every 2 weeks (with a 640-mg loading dose at baseline)(n=46), placebo (n=21), or adalimumab 40 mg once weekly from week 4 onward (following an initial 160-mg loading dose at baseline and 80-mg dose at week 2)(n=21). The study included a 12-week treatment period followed by a 20-week safety follow-up period. The primary endpoint was the achievement of HiSCR₅₀—defined as a reduction of at least 50% nodules, coupled with no increase in the number of abscesses or draining fistulas relative to baseline—at week 12. Additionally, the study assessed the number of patients who achieved a modified HiSCR with 75% reduction (HiSCR₇₅) of combined abscess and inflammatory nodule count or a modified HiSCR with 90% reduction (HiSCR₉₀). At week 12, the modeled response rates were estimated using a Bayesian logistic regression model. For HiSCR₅₀, the modeled rate for bimekizumab was 57.3%, with an observed rate of 62.5% (25/40), compared to a modeled rate of 26.1% for placebo (observed rate, 27.8% [5/18]). The posterior probability of superiority for bimekizumab over placebo was 0.998. By week 12, bimekizumab-treated patients achieved modeled HiSCR₇₅ and HiSCR₉₀ rates of 46.0% and 32.0%, respectively, with observed rates of 50.0% (20/40) for HiSCR₇₅ and 35.0% (14/40) for HiSCR₉₀. In comparison, placebo-treated patients achieved modeled HiSCR75 and HiSCR₉₀ rates of 10.0% and 0%, respectively, with observed rates of 11.1% (2/18) for HiSCR₇₅ and 0% (0/18) for HiSCR₉₀. Adalimumab-treated participants demonstrated intermediate results, achieving modeled HiSCR₇₅ and HiSCR₉₀ rates of 35.0% and 15.0%, respectively, with observed rates of 38.88% (7/18) for HiSCR₇₅ and 16.66% (3/18) for HiSCR₉₀.⁷

Bimekizumab was effective in the treatment of moderate to severe HS with comparable results to adalimumab.⁷ The incidence of treatment-emergent adverse events was similar across treatment arms (bimekizumab, 69.6% [32/46]; placebo, 61.9% [13/21]; adalimumab, 71.4% [15/21]). The most common treatment-emergent adverse events in the biologic treatment arms were infections (43.5% [20/46] in the bimekizumab group and 42.9% [9/21] in the adalimumab group), skin and subcutaneous tissue disorders (28.3% [13/46] in the bimekizumab group and 42.9% [9/21] in the adalimumab group), and general disorders/administration site conditions (21.7% [10/46] in the bimekizumab group and 23.8% [5/21] in the adalimumab group). Serious adverse events occurred in 4.3% (2/46) of patients in the bimekizumab group, 9.5% (2/21) of patients in the placebo group, and 4.8% (1/21) of patients in the adalimumab group. Serious adverse events that required hospitalization were due to anemia and empyema in the bimekizumab group; worsening HS in the adalimumab group; and myocardial infarction, hypoesthesia, headache, and dizziness in the placebo group. No deaths occurred in this study. Overall, bimekizumab was well tolerated, and discontinuation rates were low across all arms. The primary reason for discontinuation was withdrawal of consent (not due to an adverse event) or loss to follow-up.⁷

Two completed 48-week phase III RCTs, BE HEARD I and BE HEARD II, evaluated the efficacy and safety of bimekizumab in patients with moderate to severe HS.¹³ In both trials, 2 bimekizumab dosing regimens (320 mg every 2 weeks and 320 mg every 4 weeks) were compared with placebo during the 16-week initial and 32-week maintenance treatment periods. The primary endpoint of week 16 was achieved by 47.8% (138/289) and 51.9% (151/291) of patients receiving bimekizumab every 2 weeks in BE HEARD I (n=505) and BE HEARD II (n=509), respectively, compared with 29.2% (21/72) and 32.4% (24/74) of the placebo group. The bimekizumab 320 mg every 4 weeks dosing regimen met the primary endpoint only in BE HEARD II, with 53.5% (77/144) of patients achieving HiSCR₅₀ compared to 32.4% (24/74) with placebo (P=0.0038).¹³ Both trials met the key secondary endpoint of HiSCR₇₅ at week 16 for bimekizumab 320 mg every 2 weeks vs placebo. In BE HEARD I, 33.6% (97/289) of patients receiving bimekizumab achieved HiSCR₇₅ versus 18.1% (13/72) taking placebo. In BE HEARD II, 35.7% (104/291) of patients receiving bimekizumab achieved HiSCR₇₅ vs 16.2% (12/74) taking placebo. Responses were maintained or increased through week 48 in both trials. The most common treatment-emergent adverse events through week 48 were worsening HS, COVID-19 infection, diarrhea, oral candidiasis, and headache.¹³

A smaller scale case series investigated the use of bimekizumab in 4 female patients aged 20 to 62 years with moderate to severe HS and concomitant plaque or inverse psoriasis.⁸ A monthly loading dose of 320 mg was given during weeks 0 to 12 followed by a maintenance dose of 320 mg administered every 8 weeks. The International Hidradenitis Suppurativa Score System, visual analogue scale, and Dermatology Life Quality Index were used to assess the effectiveness of therapy by comparing scores before and after 4 and 16 weeks of treatment. A reduction of pain and improvement of HS lesions was observed in 3 (75.0%) patients after the first dosage of bimekizumab, with completed remission of HS by week 16. The fourth patient (25.0%) experienced substantial improvement in all measures, although not complete remission. All 4 patients remained on bimekizumab, and no adverse effects were reported.⁸

A meta-analysis evaluated 16 RCTs of 9 biologics and 3 small-molecule inhibitors in 2076 patients with HS.¹⁰ Secukinumab was not included in this meta-analysis. Only adalimumab (risk ratio, 1.77; 95% CI, 1.44-2.17) and bimekizumab (risk ratio, 2.25; 95% CI, 1.03-4.92) were superior to placebo in achieving HiSCR response at weeks 12 to 16 in 5 RCTs and 1 RCT, respectively; however, no statistically significant differences were noted between adalimumab and bimekizumab (P=.56). This analysis concluded that adalimumab and bimekizumab are the only 2 biologics efficacious in reaching HiSCR and consistently improved both disease severity and quality of life in patients with HS with an acceptable safety profile.¹⁰ Furthermore, these biologics had no increase in serious adverse events when compared to placebo.¹⁰

A network meta-analysis of 10 clinical trials involving more than 900 total participants evaluated nonsurgical therapies for HS. The analysis used Surface Under the Cumulative Ranking curve (SUCRA) values to estimate the efficacy of treatments in achieving clinical response according to HiSCR criteria. These values range from 0% to 100%, with 100% representing the best possible ranking for efficacy. Bimekizumab showed the highest estimated efficacy with a SUCRA value of 67%, followed by adalimumab (64%), anakinra (49%), and placebo (19%). These SUCRA values indicate the relative ranking of treatments, with higher values suggesting greater likelihood of achieving clinical response, rather than representing the actual percentage of patients achieving HiSCR. Bimekizumab was found to be more efficacious than placebo (P<.05).¹⁴

Building on the initial evidence of bimekizumab’s efficacy, BE HEARD I and BE HEARD II addressed some limitations of prior studies, including small sample sizes and insufficient stratification.¹³ Notably, stratification by baseline Hurley stage severity (ie, the most severe stage of disease assigned at baseline) and baseline systemic antibiotic use helped mitigate bias and ensured a more robust assessment of treatment efficacy; however, certain limitations persist. While the trials demonstrated rapid and clinically meaningful responses maintained up to 48 weeks, longer-term data beyond this period are limited, leaving gaps in understanding the durability of treatment effects over years. Additionally, despite appropriate stratification, the generalizability of the findings to broader patient populations remains unclear, as trial participants may not fully represent the diversity of patients seen in clinical practice.¹³

Future research is needed to address these limitations. The use of validated HS biomarkers as endpoints could enhance the ability to evaluate biologic efficacy and identify predictors of response. Comparative studies with other biologics also are warranted to establish the relative efficacy of bimekizumab within the growing therapeutic landscape for HS. Finally, real-world evidence from larger and more diverse populations will be critical to confirm the trial findings and assess long-term safety and effectiveness in routine clinical practice.¹³

Conclusion

The existing literature and recent phase III RCTs, BE HEARD I and BE HEARD II, demonstrate that bimekizumab is an effective treatment for moderate to severe HS, with robust efficacy according to HiSCR scores and sustained responses through 48 weeks. These trials addressed some prior limitations, including small sample sizes and insufficient stratification, providing a more comprehensive evaluation of bimekizumab’s clinical impact. The safety profile of bimekizumab remains favorable, with low discontinuation rates and manageable adverse events, such as infection, gastrointestinal upset, headache, and injection-site reactions. Long-term efficacy and safety data beyond 48 weeks still are needed to fully establish its durability and impact in diverse populations. The recent FDA approval of bimekizumab for moderate to severe HS provides patients with a new treatment option, offering a more positive clinical outlook.

Hidradenitis suppurativa (HS) is a debilitating dermatologic condition characterized by recurrent episodes of neutrophilic inflammation affecting the apocrine and pilosebaceous units that most commonly affects individuals aged 20 to 40 years. Originating from the hair follicles, inflammation initiates the formation of painful nodules and abscesses that can progress to sinus tracts or fistulas accompanied by the development of extensive scarring, exquisite pain, and malodorous drainage.¹ The lesions most commonly occur in intertriginous zones as well as areas rich in apocrine glands. The distinctive and sometimes irreversible clinical features of HS profoundly influence patients’ well-being and have lasting social, personal, and emotional impacts on their lives.²

Bimekizumab is a monoclonal antibody that specifically targets IL-17A and IL-17F, aiming to inhibit the downstream effects responsible for the chronic inflammation and tissue damage characteristic of HS.³ In HS lesions, IL-17 cytokines produced by T helper 17 (Th17) cells stimulate the production of chemokines (such as CC motif chemokine ligand 20) and neutrophil-attracting chemokines (including C-X-C motif chemokine ligands 1 and 8), cytokines (such as granulocyte colony-stimulating factor and IL-19), and epidermal antimicrobial proteins.^1,2 This cascade results in the chemotaxis of monocytes and neutrophils in the skin, recruiting additional Th17 and myeloid cells and further amplifying IL-17 production.¹

Bimekizumab’s mechanism of action strategically disrupts this feed-forward inflammatory loop, decreasing the transcription of neutrophil-attracting chemokines, IL-19, and epidermal antimicrobial proteins (Figure).^1,2 This leads to diminished recruitment of Th17 cells and inhibits the chemotaxis of monocytes and neutrophils in the skin, effectively addressing the chronic inflammation and tissue damage characteristic of HS.

We present a comprehensive review of the current standards of care, the underlying molecular pathophysiology of HS, and evaluation of the efficacy and safety of bimekizumab.

Evaluating HS Severity

The Hurley staging system provides a valuable framework for evaluating the severity of HS based on lesion characteristics. Stage I is characterized by abscess formation without tracts or scars. Stage II is characterized by recurrent abscesses with sinus tracts and scarring. Stage III is characterized by diffuse involvement, multiple interconnected sinus tracts, and abscesses across an entire area, leaving little to no uninvolved skin.⁴

Treatment strategies for HS vary based on Hurley staging (eTable).^5-11 For mild cases (stage I), topical and intralesional therapies are common, while moderate to severe cases (stages II and III) may require extensive surgical approaches or systemic drugs such as antibiotics, hormonal therapies, retinoids, or immunosuppressive/biologic agents.²

Adalimumab, an anti–tumor necrosis factor (TNF) α monoclonal antibody, was the first US Food and Drug Administration (FDA)–approved biologic for HS. Secukinumab, a monoclonal antibody against IL-17A, subsequently was approved by the FDA for moderate to severe HS.¹² Off-label use of biologics including infliximab and ustekinumab expands the available treatment options for HS. In one Phase II randomized clinical trial (RCT), infliximab showed efficacy in reducing Hidradenitis Suppurativa Severity Index scores, with 26.7% (4/15) of patients achieving a 50% or greater reduction compared to placebo, although this was not statistically significant. Similarly, ustekinumab demonstrated promising results, with 47.1% (8/17) of patients achieving Hidradenitis Suppurativa Clinical Response (HiSCR) at week 40.² This multifaceted approach aims to address the varying degrees of severity and optimize outcomes for individuals with HS.

Molecular Pathophysiology of HS

The pathogenesis of HS is multifactorial, involving a complex interplay of genetic, environmental, and behavioral factors.² Approximately 33% to 40% of patients with HS worldwide report a first-degree relative with the condition, indicating a hereditary element with an autosomal-dominant transmission pattern and highlighting the global relevance of genetic factors in HS.⁴ Hidradenitis suppurativa is highly prevalent in individuals with obesity, likely due to increased intertriginous surface area, skin friction, sweat production, and hormonal changes in these patients. Smoking also commonly is associated with HS, with nicotine potentially contributing to increased follicular plugging.¹ Hormonal influences also play a role, as evidenced by a greater prevalence of HS in females, disease onset typically occurring between puberty and menopause, and symptomatic fluctuations correlating with menstrual cycles and exogenous hormones.⁴

Altered infundibular keratinization with subsequent hyperkeratosis/occlusion and innate immune pathway activation are key events leading to development of HS.¹ These events are mediated by release of pathogen- and danger-associated molecular patterns, leading to inflammasome-mediated IL-1α release, followed by downstream cytokine release.² Elevated levels of TNF-α, IL-1Β, IL-10, IL-17, and particularly IL-17A have been detected in HS lesional skin. The IL-17 family comprises multiple members, namely IL-17A, IL-17C, IL-17E, and IL17F. IL-17A and IL-17F often are co-expressed and secreted predominantly by a subset of CD4+ T helper cells, namely Th17 cells.² IL-17 cytokines exert pro-inflammatory effects, influencing immune cell activity and contributing to skin inflammation, particularly in HS.

Given the pivotal role of IL-17 in the pathogenesis of HS, the exploration of IL-17–targeted agents has become a focal point in clinical research. Bimekizumab, a novel IL-17 inhibitor, has emerged as a promising candidate, offering a potential breakthrough in the treatment landscape for individuals affected by HS.

Bimekizumab for HS Management

A phase II, double-blind, placebo-controlled RCT included 90 patients with moderate to severe HS (age range, 18-70 years) who were randomly assigned in a 2:1:1 ratio to receive either bimekizumab 320 mg every 2 weeks (with a 640-mg loading dose at baseline)(n=46), placebo (n=21), or adalimumab 40 mg once weekly from week 4 onward (following an initial 160-mg loading dose at baseline and 80-mg dose at week 2)(n=21). The study included a 12-week treatment period followed by a 20-week safety follow-up period. The primary endpoint was the achievement of HiSCR₅₀—defined as a reduction of at least 50% nodules, coupled with no increase in the number of abscesses or draining fistulas relative to baseline—at week 12. Additionally, the study assessed the number of patients who achieved a modified HiSCR with 75% reduction (HiSCR₇₅) of combined abscess and inflammatory nodule count or a modified HiSCR with 90% reduction (HiSCR₉₀). At week 12, the modeled response rates were estimated using a Bayesian logistic regression model. For HiSCR₅₀, the modeled rate for bimekizumab was 57.3%, with an observed rate of 62.5% (25/40), compared to a modeled rate of 26.1% for placebo (observed rate, 27.8% [5/18]). The posterior probability of superiority for bimekizumab over placebo was 0.998. By week 12, bimekizumab-treated patients achieved modeled HiSCR₇₅ and HiSCR₉₀ rates of 46.0% and 32.0%, respectively, with observed rates of 50.0% (20/40) for HiSCR₇₅ and 35.0% (14/40) for HiSCR₉₀. In comparison, placebo-treated patients achieved modeled HiSCR75 and HiSCR₉₀ rates of 10.0% and 0%, respectively, with observed rates of 11.1% (2/18) for HiSCR₇₅ and 0% (0/18) for HiSCR₉₀. Adalimumab-treated participants demonstrated intermediate results, achieving modeled HiSCR₇₅ and HiSCR₉₀ rates of 35.0% and 15.0%, respectively, with observed rates of 38.88% (7/18) for HiSCR₇₅ and 16.66% (3/18) for HiSCR₉₀.⁷

Bimekizumab was effective in the treatment of moderate to severe HS with comparable results to adalimumab.⁷ The incidence of treatment-emergent adverse events was similar across treatment arms (bimekizumab, 69.6% [32/46]; placebo, 61.9% [13/21]; adalimumab, 71.4% [15/21]). The most common treatment-emergent adverse events in the biologic treatment arms were infections (43.5% [20/46] in the bimekizumab group and 42.9% [9/21] in the adalimumab group), skin and subcutaneous tissue disorders (28.3% [13/46] in the bimekizumab group and 42.9% [9/21] in the adalimumab group), and general disorders/administration site conditions (21.7% [10/46] in the bimekizumab group and 23.8% [5/21] in the adalimumab group). Serious adverse events occurred in 4.3% (2/46) of patients in the bimekizumab group, 9.5% (2/21) of patients in the placebo group, and 4.8% (1/21) of patients in the adalimumab group. Serious adverse events that required hospitalization were due to anemia and empyema in the bimekizumab group; worsening HS in the adalimumab group; and myocardial infarction, hypoesthesia, headache, and dizziness in the placebo group. No deaths occurred in this study. Overall, bimekizumab was well tolerated, and discontinuation rates were low across all arms. The primary reason for discontinuation was withdrawal of consent (not due to an adverse event) or loss to follow-up.⁷

Two completed 48-week phase III RCTs, BE HEARD I and BE HEARD II, evaluated the efficacy and safety of bimekizumab in patients with moderate to severe HS.¹³ In both trials, 2 bimekizumab dosing regimens (320 mg every 2 weeks and 320 mg every 4 weeks) were compared with placebo during the 16-week initial and 32-week maintenance treatment periods. The primary endpoint of week 16 was achieved by 47.8% (138/289) and 51.9% (151/291) of patients receiving bimekizumab every 2 weeks in BE HEARD I (n=505) and BE HEARD II (n=509), respectively, compared with 29.2% (21/72) and 32.4% (24/74) of the placebo group. The bimekizumab 320 mg every 4 weeks dosing regimen met the primary endpoint only in BE HEARD II, with 53.5% (77/144) of patients achieving HiSCR₅₀ compared to 32.4% (24/74) with placebo (P=0.0038).¹³ Both trials met the key secondary endpoint of HiSCR₇₅ at week 16 for bimekizumab 320 mg every 2 weeks vs placebo. In BE HEARD I, 33.6% (97/289) of patients receiving bimekizumab achieved HiSCR₇₅ versus 18.1% (13/72) taking placebo. In BE HEARD II, 35.7% (104/291) of patients receiving bimekizumab achieved HiSCR₇₅ vs 16.2% (12/74) taking placebo. Responses were maintained or increased through week 48 in both trials. The most common treatment-emergent adverse events through week 48 were worsening HS, COVID-19 infection, diarrhea, oral candidiasis, and headache.¹³

A smaller scale case series investigated the use of bimekizumab in 4 female patients aged 20 to 62 years with moderate to severe HS and concomitant plaque or inverse psoriasis.⁸ A monthly loading dose of 320 mg was given during weeks 0 to 12 followed by a maintenance dose of 320 mg administered every 8 weeks. The International Hidradenitis Suppurativa Score System, visual analogue scale, and Dermatology Life Quality Index were used to assess the effectiveness of therapy by comparing scores before and after 4 and 16 weeks of treatment. A reduction of pain and improvement of HS lesions was observed in 3 (75.0%) patients after the first dosage of bimekizumab, with completed remission of HS by week 16. The fourth patient (25.0%) experienced substantial improvement in all measures, although not complete remission. All 4 patients remained on bimekizumab, and no adverse effects were reported.⁸

A meta-analysis evaluated 16 RCTs of 9 biologics and 3 small-molecule inhibitors in 2076 patients with HS.¹⁰ Secukinumab was not included in this meta-analysis. Only adalimumab (risk ratio, 1.77; 95% CI, 1.44-2.17) and bimekizumab (risk ratio, 2.25; 95% CI, 1.03-4.92) were superior to placebo in achieving HiSCR response at weeks 12 to 16 in 5 RCTs and 1 RCT, respectively; however, no statistically significant differences were noted between adalimumab and bimekizumab (P=.56). This analysis concluded that adalimumab and bimekizumab are the only 2 biologics efficacious in reaching HiSCR and consistently improved both disease severity and quality of life in patients with HS with an acceptable safety profile.¹⁰ Furthermore, these biologics had no increase in serious adverse events when compared to placebo.¹⁰

A network meta-analysis of 10 clinical trials involving more than 900 total participants evaluated nonsurgical therapies for HS. The analysis used Surface Under the Cumulative Ranking curve (SUCRA) values to estimate the efficacy of treatments in achieving clinical response according to HiSCR criteria. These values range from 0% to 100%, with 100% representing the best possible ranking for efficacy. Bimekizumab showed the highest estimated efficacy with a SUCRA value of 67%, followed by adalimumab (64%), anakinra (49%), and placebo (19%). These SUCRA values indicate the relative ranking of treatments, with higher values suggesting greater likelihood of achieving clinical response, rather than representing the actual percentage of patients achieving HiSCR. Bimekizumab was found to be more efficacious than placebo (P<.05).¹⁴

Building on the initial evidence of bimekizumab’s efficacy, BE HEARD I and BE HEARD II addressed some limitations of prior studies, including small sample sizes and insufficient stratification.¹³ Notably, stratification by baseline Hurley stage severity (ie, the most severe stage of disease assigned at baseline) and baseline systemic antibiotic use helped mitigate bias and ensured a more robust assessment of treatment efficacy; however, certain limitations persist. While the trials demonstrated rapid and clinically meaningful responses maintained up to 48 weeks, longer-term data beyond this period are limited, leaving gaps in understanding the durability of treatment effects over years. Additionally, despite appropriate stratification, the generalizability of the findings to broader patient populations remains unclear, as trial participants may not fully represent the diversity of patients seen in clinical practice.¹³

Future research is needed to address these limitations. The use of validated HS biomarkers as endpoints could enhance the ability to evaluate biologic efficacy and identify predictors of response. Comparative studies with other biologics also are warranted to establish the relative efficacy of bimekizumab within the growing therapeutic landscape for HS. Finally, real-world evidence from larger and more diverse populations will be critical to confirm the trial findings and assess long-term safety and effectiveness in routine clinical practice.¹³

Conclusion

The existing literature and recent phase III RCTs, BE HEARD I and BE HEARD II, demonstrate that bimekizumab is an effective treatment for moderate to severe HS, with robust efficacy according to HiSCR scores and sustained responses through 48 weeks. These trials addressed some prior limitations, including small sample sizes and insufficient stratification, providing a more comprehensive evaluation of bimekizumab’s clinical impact. The safety profile of bimekizumab remains favorable, with low discontinuation rates and manageable adverse events, such as infection, gastrointestinal upset, headache, and injection-site reactions. Long-term efficacy and safety data beyond 48 weeks still are needed to fully establish its durability and impact in diverse populations. The recent FDA approval of bimekizumab for moderate to severe HS provides patients with a new treatment option, offering a more positive clinical outlook.

Hidradenitis suppurativa (HS) is a debilitating dermatologic condition characterized by recurrent episodes of neutrophilic inflammation affecting the apocrine and pilosebaceous units that most commonly affects individuals aged 20 to 40 years. Originating from the hair follicles, inflammation initiates the formation of painful nodules and abscesses that can progress to sinus tracts or fistulas accompanied by the development of extensive scarring, exquisite pain, and malodorous drainage.¹ The lesions most commonly occur in intertriginous zones as well as areas rich in apocrine glands. The distinctive and sometimes irreversible clinical features of HS profoundly influence patients’ well-being and have lasting social, personal, and emotional impacts on their lives.²

Bimekizumab is a monoclonal antibody that specifically targets IL-17A and IL-17F, aiming to inhibit the downstream effects responsible for the chronic inflammation and tissue damage characteristic of HS.³ In HS lesions, IL-17 cytokines produced by T helper 17 (Th17) cells stimulate the production of chemokines (such as CC motif chemokine ligand 20) and neutrophil-attracting chemokines (including C-X-C motif chemokine ligands 1 and 8), cytokines (such as granulocyte colony-stimulating factor and IL-19), and epidermal antimicrobial proteins.^1,2 This cascade results in the chemotaxis of monocytes and neutrophils in the skin, recruiting additional Th17 and myeloid cells and further amplifying IL-17 production.¹

Bimekizumab’s mechanism of action strategically disrupts this feed-forward inflammatory loop, decreasing the transcription of neutrophil-attracting chemokines, IL-19, and epidermal antimicrobial proteins (Figure).^1,2 This leads to diminished recruitment of Th17 cells and inhibits the chemotaxis of monocytes and neutrophils in the skin, effectively addressing the chronic inflammation and tissue damage characteristic of HS.

We present a comprehensive review of the current standards of care, the underlying molecular pathophysiology of HS, and evaluation of the efficacy and safety of bimekizumab.

Evaluating HS Severity

The Hurley staging system provides a valuable framework for evaluating the severity of HS based on lesion characteristics. Stage I is characterized by abscess formation without tracts or scars. Stage II is characterized by recurrent abscesses with sinus tracts and scarring. Stage III is characterized by diffuse involvement, multiple interconnected sinus tracts, and abscesses across an entire area, leaving little to no uninvolved skin.⁴

Treatment strategies for HS vary based on Hurley staging (eTable).^5-11 For mild cases (stage I), topical and intralesional therapies are common, while moderate to severe cases (stages II and III) may require extensive surgical approaches or systemic drugs such as antibiotics, hormonal therapies, retinoids, or immunosuppressive/biologic agents.²

Adalimumab, an anti–tumor necrosis factor (TNF) α monoclonal antibody, was the first US Food and Drug Administration (FDA)–approved biologic for HS. Secukinumab, a monoclonal antibody against IL-17A, subsequently was approved by the FDA for moderate to severe HS.¹² Off-label use of biologics including infliximab and ustekinumab expands the available treatment options for HS. In one Phase II randomized clinical trial (RCT), infliximab showed efficacy in reducing Hidradenitis Suppurativa Severity Index scores, with 26.7% (4/15) of patients achieving a 50% or greater reduction compared to placebo, although this was not statistically significant. Similarly, ustekinumab demonstrated promising results, with 47.1% (8/17) of patients achieving Hidradenitis Suppurativa Clinical Response (HiSCR) at week 40.² This multifaceted approach aims to address the varying degrees of severity and optimize outcomes for individuals with HS.

Molecular Pathophysiology of HS

The pathogenesis of HS is multifactorial, involving a complex interplay of genetic, environmental, and behavioral factors.² Approximately 33% to 40% of patients with HS worldwide report a first-degree relative with the condition, indicating a hereditary element with an autosomal-dominant transmission pattern and highlighting the global relevance of genetic factors in HS.⁴ Hidradenitis suppurativa is highly prevalent in individuals with obesity, likely due to increased intertriginous surface area, skin friction, sweat production, and hormonal changes in these patients. Smoking also commonly is associated with HS, with nicotine potentially contributing to increased follicular plugging.¹ Hormonal influences also play a role, as evidenced by a greater prevalence of HS in females, disease onset typically occurring between puberty and menopause, and symptomatic fluctuations correlating with menstrual cycles and exogenous hormones.⁴

Altered infundibular keratinization with subsequent hyperkeratosis/occlusion and innate immune pathway activation are key events leading to development of HS.¹ These events are mediated by release of pathogen- and danger-associated molecular patterns, leading to inflammasome-mediated IL-1α release, followed by downstream cytokine release.² Elevated levels of TNF-α, IL-1Β, IL-10, IL-17, and particularly IL-17A have been detected in HS lesional skin. The IL-17 family comprises multiple members, namely IL-17A, IL-17C, IL-17E, and IL17F. IL-17A and IL-17F often are co-expressed and secreted predominantly by a subset of CD4+ T helper cells, namely Th17 cells.² IL-17 cytokines exert pro-inflammatory effects, influencing immune cell activity and contributing to skin inflammation, particularly in HS.

Given the pivotal role of IL-17 in the pathogenesis of HS, the exploration of IL-17–targeted agents has become a focal point in clinical research. Bimekizumab, a novel IL-17 inhibitor, has emerged as a promising candidate, offering a potential breakthrough in the treatment landscape for individuals affected by HS.

Bimekizumab for HS Management

A phase II, double-blind, placebo-controlled RCT included 90 patients with moderate to severe HS (age range, 18-70 years) who were randomly assigned in a 2:1:1 ratio to receive either bimekizumab 320 mg every 2 weeks (with a 640-mg loading dose at baseline)(n=46), placebo (n=21), or adalimumab 40 mg once weekly from week 4 onward (following an initial 160-mg loading dose at baseline and 80-mg dose at week 2)(n=21). The study included a 12-week treatment period followed by a 20-week safety follow-up period. The primary endpoint was the achievement of HiSCR₅₀—defined as a reduction of at least 50% nodules, coupled with no increase in the number of abscesses or draining fistulas relative to baseline—at week 12. Additionally, the study assessed the number of patients who achieved a modified HiSCR with 75% reduction (HiSCR₇₅) of combined abscess and inflammatory nodule count or a modified HiSCR with 90% reduction (HiSCR₉₀). At week 12, the modeled response rates were estimated using a Bayesian logistic regression model. For HiSCR₅₀, the modeled rate for bimekizumab was 57.3%, with an observed rate of 62.5% (25/40), compared to a modeled rate of 26.1% for placebo (observed rate, 27.8% [5/18]). The posterior probability of superiority for bimekizumab over placebo was 0.998. By week 12, bimekizumab-treated patients achieved modeled HiSCR₇₅ and HiSCR₉₀ rates of 46.0% and 32.0%, respectively, with observed rates of 50.0% (20/40) for HiSCR₇₅ and 35.0% (14/40) for HiSCR₉₀. In comparison, placebo-treated patients achieved modeled HiSCR75 and HiSCR₉₀ rates of 10.0% and 0%, respectively, with observed rates of 11.1% (2/18) for HiSCR₇₅ and 0% (0/18) for HiSCR₉₀. Adalimumab-treated participants demonstrated intermediate results, achieving modeled HiSCR₇₅ and HiSCR₉₀ rates of 35.0% and 15.0%, respectively, with observed rates of 38.88% (7/18) for HiSCR₇₅ and 16.66% (3/18) for HiSCR₉₀.⁷

Bimekizumab was effective in the treatment of moderate to severe HS with comparable results to adalimumab.⁷ The incidence of treatment-emergent adverse events was similar across treatment arms (bimekizumab, 69.6% [32/46]; placebo, 61.9% [13/21]; adalimumab, 71.4% [15/21]). The most common treatment-emergent adverse events in the biologic treatment arms were infections (43.5% [20/46] in the bimekizumab group and 42.9% [9/21] in the adalimumab group), skin and subcutaneous tissue disorders (28.3% [13/46] in the bimekizumab group and 42.9% [9/21] in the adalimumab group), and general disorders/administration site conditions (21.7% [10/46] in the bimekizumab group and 23.8% [5/21] in the adalimumab group). Serious adverse events occurred in 4.3% (2/46) of patients in the bimekizumab group, 9.5% (2/21) of patients in the placebo group, and 4.8% (1/21) of patients in the adalimumab group. Serious adverse events that required hospitalization were due to anemia and empyema in the bimekizumab group; worsening HS in the adalimumab group; and myocardial infarction, hypoesthesia, headache, and dizziness in the placebo group. No deaths occurred in this study. Overall, bimekizumab was well tolerated, and discontinuation rates were low across all arms. The primary reason for discontinuation was withdrawal of consent (not due to an adverse event) or loss to follow-up.⁷

Two completed 48-week phase III RCTs, BE HEARD I and BE HEARD II, evaluated the efficacy and safety of bimekizumab in patients with moderate to severe HS.¹³ In both trials, 2 bimekizumab dosing regimens (320 mg every 2 weeks and 320 mg every 4 weeks) were compared with placebo during the 16-week initial and 32-week maintenance treatment periods. The primary endpoint of week 16 was achieved by 47.8% (138/289) and 51.9% (151/291) of patients receiving bimekizumab every 2 weeks in BE HEARD I (n=505) and BE HEARD II (n=509), respectively, compared with 29.2% (21/72) and 32.4% (24/74) of the placebo group. The bimekizumab 320 mg every 4 weeks dosing regimen met the primary endpoint only in BE HEARD II, with 53.5% (77/144) of patients achieving HiSCR₅₀ compared to 32.4% (24/74) with placebo (P=0.0038).¹³ Both trials met the key secondary endpoint of HiSCR₇₅ at week 16 for bimekizumab 320 mg every 2 weeks vs placebo. In BE HEARD I, 33.6% (97/289) of patients receiving bimekizumab achieved HiSCR₇₅ versus 18.1% (13/72) taking placebo. In BE HEARD II, 35.7% (104/291) of patients receiving bimekizumab achieved HiSCR₇₅ vs 16.2% (12/74) taking placebo. Responses were maintained or increased through week 48 in both trials. The most common treatment-emergent adverse events through week 48 were worsening HS, COVID-19 infection, diarrhea, oral candidiasis, and headache.¹³

A smaller scale case series investigated the use of bimekizumab in 4 female patients aged 20 to 62 years with moderate to severe HS and concomitant plaque or inverse psoriasis.⁸ A monthly loading dose of 320 mg was given during weeks 0 to 12 followed by a maintenance dose of 320 mg administered every 8 weeks. The International Hidradenitis Suppurativa Score System, visual analogue scale, and Dermatology Life Quality Index were used to assess the effectiveness of therapy by comparing scores before and after 4 and 16 weeks of treatment. A reduction of pain and improvement of HS lesions was observed in 3 (75.0%) patients after the first dosage of bimekizumab, with completed remission of HS by week 16. The fourth patient (25.0%) experienced substantial improvement in all measures, although not complete remission. All 4 patients remained on bimekizumab, and no adverse effects were reported.⁸

A meta-analysis evaluated 16 RCTs of 9 biologics and 3 small-molecule inhibitors in 2076 patients with HS.¹⁰ Secukinumab was not included in this meta-analysis. Only adalimumab (risk ratio, 1.77; 95% CI, 1.44-2.17) and bimekizumab (risk ratio, 2.25; 95% CI, 1.03-4.92) were superior to placebo in achieving HiSCR response at weeks 12 to 16 in 5 RCTs and 1 RCT, respectively; however, no statistically significant differences were noted between adalimumab and bimekizumab (P=.56). This analysis concluded that adalimumab and bimekizumab are the only 2 biologics efficacious in reaching HiSCR and consistently improved both disease severity and quality of life in patients with HS with an acceptable safety profile.¹⁰ Furthermore, these biologics had no increase in serious adverse events when compared to placebo.¹⁰

A network meta-analysis of 10 clinical trials involving more than 900 total participants evaluated nonsurgical therapies for HS. The analysis used Surface Under the Cumulative Ranking curve (SUCRA) values to estimate the efficacy of treatments in achieving clinical response according to HiSCR criteria. These values range from 0% to 100%, with 100% representing the best possible ranking for efficacy. Bimekizumab showed the highest estimated efficacy with a SUCRA value of 67%, followed by adalimumab (64%), anakinra (49%), and placebo (19%). These SUCRA values indicate the relative ranking of treatments, with higher values suggesting greater likelihood of achieving clinical response, rather than representing the actual percentage of patients achieving HiSCR. Bimekizumab was found to be more efficacious than placebo (P<.05).¹⁴

Building on the initial evidence of bimekizumab’s efficacy, BE HEARD I and BE HEARD II addressed some limitations of prior studies, including small sample sizes and insufficient stratification.¹³ Notably, stratification by baseline Hurley stage severity (ie, the most severe stage of disease assigned at baseline) and baseline systemic antibiotic use helped mitigate bias and ensured a more robust assessment of treatment efficacy; however, certain limitations persist. While the trials demonstrated rapid and clinically meaningful responses maintained up to 48 weeks, longer-term data beyond this period are limited, leaving gaps in understanding the durability of treatment effects over years. Additionally, despite appropriate stratification, the generalizability of the findings to broader patient populations remains unclear, as trial participants may not fully represent the diversity of patients seen in clinical practice.¹³

Future research is needed to address these limitations. The use of validated HS biomarkers as endpoints could enhance the ability to evaluate biologic efficacy and identify predictors of response. Comparative studies with other biologics also are warranted to establish the relative efficacy of bimekizumab within the growing therapeutic landscape for HS. Finally, real-world evidence from larger and more diverse populations will be critical to confirm the trial findings and assess long-term safety and effectiveness in routine clinical practice.¹³

Conclusion

The existing literature and recent phase III RCTs, BE HEARD I and BE HEARD II, demonstrate that bimekizumab is an effective treatment for moderate to severe HS, with robust efficacy according to HiSCR scores and sustained responses through 48 weeks. These trials addressed some prior limitations, including small sample sizes and insufficient stratification, providing a more comprehensive evaluation of bimekizumab’s clinical impact. The safety profile of bimekizumab remains favorable, with low discontinuation rates and manageable adverse events, such as infection, gastrointestinal upset, headache, and injection-site reactions. Long-term efficacy and safety data beyond 48 weeks still are needed to fully establish its durability and impact in diverse populations. The recent FDA approval of bimekizumab for moderate to severe HS provides patients with a new treatment option, offering a more positive clinical outlook.

The cutting edge of treating solid tumors with cell therapies got notably sharper in 2024.

First came the US Food and Drug Administration (FDA) approval in February 2024 of the tumor-infiltrating lymphocyte (TIL) therapy lifileucel in unresectable or metastatic melanoma that had progressed on prior immunotherapy, the first cellular therapy for any solid tumor. Then came the August FDA approval of afamitresgene autoleucel in unresectable or metastatic synovial sarcoma with failed chemotherapy, the first engineered T-cell therapy for cancers in soft tissue. 

“This was a pipe dream just a decade ago,” Alison Betof Warner, MD, PhD, lead author of a lifileucel study (NCT05640193), said in an interview with Medscape Medical News. “At the start of 2024, we had no approvals of these kinds of products in solid cancers. Now we have two.”

As the director of Solid Tumor Cell Therapy and leader of Stanford Medicine’s Melanoma and Cutaneous Oncology Clinical Research Group, Betof Warner has been at the forefront of developing commercial cell therapy using tumor-infiltrating lymphocytes (TILs). 

“The approval of lifileucel increases confidence that we can get these therapies across the regulatory finish line and to patients,” Betof Warner said during the interview. She was not involved in the development of afamitresgene autoleucel.

 

‘Reverse Engineering’

In addition to her contributions to the work that led to lifileucel’s approval, Betof Warner was the lead author on the first consensus guidelines on management and best practices for tumor-infiltrating lymphocyte cell therapy. 

Betof Warner began studying TILs after doing research with her mentors in immuno-oncology, Jedd D. Wolchok and Michael A. Postow. Their investigations — including one that Betof Warner coauthored — into how monoclonal antibodies and checkpoint inhibitors, such as ipilimumab or nivolumab, might extend the lives of people with advanced unresectable or metastatic melanoma inspired her to push further to find ways to minimize treatment while maximizing outcomes for patients. Betof Warner’s interest overall, she said in the interview, is in capitalizing on what can be learned about how the immune system controls cancer.

“What we know is that the immune system has the ability to kill cancer,” Betof Warner said. “Therefore we need to be thinking about how we can increase immune surveillance. How can we enhance that before a patient develops advanced cancer? 

Betof Warner said that although TILs are now standard treatment in melanoma, there is about a 30% response rate compared with about a 50% response rate in immunotherapy, and the latter is easier for the patient to withstand. 

“Antibodies on the frontline are better than going through a surgery and then waiting weeks to get your therapy,” Betof Warner said in the interview. “You can come into my clinic and get an antibody therapy in 30 minutes and go straight to work. TILs require patients to be in the hospital for weeks at a time and out of work for months at a time.”

In an effort to combine therapies to maximize best outcomes, a phase 3 trial (NCT05727904) is currently recruiting. The TILVANCE-301 trial will compare immunotherapy plus adoptive cell therapy vs immunotherapy alone in untreated unresectable or metastatic melanoma. Betof Warner is not a part of this study.

 

Cell Therapies Include CAR T Cells and TCRT

In general, adoptive T-cell therapies such as TILs involve the isolation of autologous immune cells that are removed from the body and either expanded or modified to optimize their efficacy in fighting antigens, before their transfer to the patient as a living drug by infusion.

In addition to TILs, adoptive cell therapies for antitumor therapeutics include chimeric antigen receptor (CAR) T cells and engineered T-cell receptor therapy (TCRT).

In CAR T-cell therapy and TCRT, naive T cells are harvested from the patient’s blood then engineered to target a tumor. In TIL therapy, tumor-specific T cells are taken from the patient’s tumor. Once extracted, the respective cells are expanded billions of times and then delivered back to the patient’s body, said Betof Warner. 

“The main promise of this approach is to generate responses in what we know as ‘cold’ tumors, or tumors that do not have a lot of endogenous T-cell infiltration or where the T cells are not working well, to bring in tumor targeting T cells and then trigger an immune response,” Betof Warner told an audience at the American Society of Clinical Oncology (ASCO) 2024 annual meeting.

TIL patients also receive interleukin (IL)-2 infusions to further stimulate the cells. In patients being treated with TCRT, they either receive low or no IL-2, Betof Warner said in her ASCO presentation, “Adopting Cutting-Edge Cell Therapies in Melanoma,” part of the session Beyond the Tip of the Iceberg: Next-Generation Cell-Based Therapies. 

Betof Warner takes Medscape Medical News through the history and ongoing investigations of cellular therapies for solid tumors, including her own research on these treatments. 

 

Decades in the Making

The National Cancer Institute began investigating TILs in the late 1980s, with the current National Cancer Institute (NCI) surgery chief, Steven Rosenberg, MD, PhD, leading the first-ever trials that showed TILs could shrink tumors in people with advanced melanoma.

Since then, NCI staff and others have also investigated TILs beyond melanoma and additional cell therapies based on CAR T cells and TCRT for antitumor therapeutics. 

“TCRs are different from CAR Ts because they go after intracellular antigens instead of extracellular antigens,” said Betof Warner. “That has appeal because many of the tumor antigens we’re looking for will be intracellular.” 

Because CAR T cells only target extracellular antigens, their utility is somewhat limited. Although several CAR T-cell therapies exist for blood cancers, there currently are no approved CAR T-cell therapies for solid tumors. However, several trials of CAR T cells in gastrointestinal cancers and melanoma are ongoing, said Betof Warner, who is not a part of these studies.

“We are starting to see early-phase efficacy in pediatric gliomas,” Betof Warner said, mentioning a study conducted by colleagues at Stanford who demonstrated potential for anti-GD2 CAR T-cell therapy in deadly pediatric diffuse midline gliomas, tumors on the spine and brain.

In their study, nine out of 11 participants (median age, 15 years) showed benefit from the cell therapy, with one participant’s tumors resolving completely. The results paved the way for the FDA to grant a Regenerative Medicine Advanced Therapy designation for use of anti-GD2 CAR T cells in H3K27M-positive diffuse midline gliomas. 

The investigators are now recruiting for a phase 1 trial (NCT04196413). Results of the initial study were published in Nature last month.

Another lesser-known cell therapy expected to advance at some point in the future for solid tumors is use of the body’s natural killer (NK) cells. “They’ve been known about for a long time, but they are more difficult to regulate, which is one reason why it has taken longer to make NK cell therapies,” said Betof Warner, who is not involved in the study of NK cells. “One of their advantages is that, potentially, there could be an ‘off the shelf’ NK product. They don’t necessarily have to be made with autologous cells.”

 

Risk-Benefit Profiles Depend on Mechanism of Action

If the corresponding TCR sequence of a tumor antigen is known, said Betof Warner, it is possible to use leukapheresis to generate naive circulating lymphocytes. Once infused, the manufactured TCRTs will activate in the body the same as native cells because the signaling is the same.
An advantage to TCRT compared with CAR T-cell therapy is that it targets intracellular proteins, which are significantly present in the tumor, Betof Warner said in her presentation at ASCO 2024. She clarified that tumors will usually be screened for the presence of this antigen before a patient is selected for treatment with that particular therapy, because not all antigens are highly expressed in every tumor. 

“Furthermore, the tumor antigen has to be presented by a major histocompatibility complex, meaning there are human leukocyte antigen restrictions, which impacts patient selection,” she said.

A risk with both TCRT and CAR T-cell therapy, according to Betof Warner, is that because there are often shared antigens between tumor and normal tissues, on-target/off-tumor toxicity is a risk.

“TILs are different because they are nonengineered, at least not for antigen recognition. They are polyclonal and go after multiple targets,” Betof Warner said. “TCRs and CARs are engineered to go after one target. So, TILs have much lower rates of on-tumor/off-target effects, vs when you engineer a very high affinity receptor like a TCR or CAR.”

A good example of how this amplification of TCR affinity can lead to poor outcomes is in metastatic melanoma, said Betof Warner. 

In investigations (NCI-07-C-0174 and NCI-07-C-0175) of TCRT in metastatic melanoma, for example, the researchers were targeting MART-1 or gp100, which are expressed in melanocytes. 

“The problem was that these antigens are also expressed in the eyes and ears, so it caused eye inflammation and hearing loss in a number of patients because it wasn’t specific enough for the tumor,” said Betof Warner. “So, if that target is highly expressed on normal tissue, then you have a high risk.”

 

Promise of PRAME

Betof Warner said the most promising TCRT at present is the investigational autologous cell therapy IMA203 (NCT03688124), which targets the preferentially expressed antigen (PRAME). Although PRAME is found in many tumors, this testis antigen does not tend to express in normal, healthy adult tissues. Betof Warner is not affiliated with this study. 

“It’s maybe the most exciting TCRT cell in melanoma,” Betof Warner told her audience at the ASCO 2024 meeting. Because the expression rate of PRAME in cutaneous and uveal melanoma is at or above 95% and 90%, respectively, she said “it is a really good target in melanoma.”

Phase 1a results reported in late 2023 from a first-in-human trial of IMA203 involving 13 persons with highly advanced melanoma and a median of 5.5 previous treatments showed a 50% objective response rate in the 12 evaluable results. The duration of response ranged between 2.2 and 14.7 months (median follow-up, 14 months).

The safety profile of the treatment was favorable, with no grade 3 adverse events occurring in more than 10% of the cohort, and no grade 5 adverse events at all.

Phase 1b results published in October by maker Immatics showed that in 28 heavily pretreated metastatic melanoma patients, IMA203 had a confirmed objective response rate of 54% with a median duration of response of 12.1 months, while maintaining a favorable tolerability profile. 

 

Accelerated Approvals, Boxed Warnings

The FDA granted accelerated approvals for both lifileucel, the TIL therapy, and afamitresgene autoleucel, the TCRT. 

Both were approved with boxed warnings. Lifileucel’s warning is for treatment-related mortality, prolonged severe cytopenia, severe infection, and cardiopulmonary and renal impairment. Afamitresgene autoleucel’s boxed warning is for serious or fatal cytokine release syndrome, which may be severe or life-threatening.

With these approvals, the bar is now raised on TILs and TCRTs, said Betof Warner.

The lifileucel trial studied 73 patients whose melanoma had continued to metastasize despite treatment with a programmed cell death protein (PD-1)/ programmed death-ligand (PD-L1)–targeted immune checkpoint inhibitor and a BRAF inhibitor (if appropriate based on tumor mutation status), and whose lifileucel dose was at least 7.5 billion cells (the approved dose). The cohort also received a median of six IL-2 (aldesleukin) doses. 

The objective response rate was 31.5% (95% CI, 21.1-43.4), and median duration of response was not reached (lower bound of 95% CI, 4.1).

In the afamitresgene autoleucel study, 44 of 52 patients with synovial sarcoma received leukapheresis and a single infusion of afamitresgene autoleucel. 

The overall response rate was 43.2% (95% CI, 28.4-59.0). The median time to response was 4.9 weeks (95% CI, 4.4-8), and the median duration of response was 6 months (lower bound of 95% CI, 4.6). Among patients who were responsive to the treatment, 45.6% and 39.0% had a duration of response of 6 months or longer and 12 months or longer, respectively.

 

New Hope for Patients

Betof Warner and her colleagues are now recruiting for an open-label, phase 1/2 investigation of the safety and efficacy of the TIL therapy OBX-115 in adult advanced solid tumors in melanoma or non–small cell lung cancer. The first-in-human results of a previous trial were presented at the ASCO 2024 meeting, and OBX-115 received FDA fast track designation in July.

“I think the results are really promising,” said Betof Warner. “This is an engineered TIL that does not require administering IL-2 to the patient. There were four out of the nine patients who responded to the treatment and there were no dose-limiting toxicities, no cytokine and no intracranial — all of which is excellent.”

For Betof Warner, the possibility that by using their own immune system, patients with advanced and refractory cancers could soon have a one-time treatment with a cell therapy rather than innumerable bouts of chemotherapy pushes her onward.

“The idea that we can treat cancer one time and have it not recur for years — that’s pushing the start of saying there’s a cure of cancer. That a person could move on from cancer like they move on from an infection. That is the potential of this work. We’re not there yet, but that’s where we need to think and dream big,” she said.

Betof Warner disclosed consulting/advisory roles with BluePath Solutions, Bristol-Myers Squibb/Medarex, Immatics, Instil Bio, Iovance Biotherapeutics, Lyell Immunopharma, Merck, Novartis, and Pfizer and research funding and travel expenses from Iovance Biotherapeutics.

 

A version of this article appeared on Medscape.com.

The cutting edge of treating solid tumors with cell therapies got notably sharper in 2024.

First came the US Food and Drug Administration (FDA) approval in February 2024 of the tumor-infiltrating lymphocyte (TIL) therapy lifileucel in unresectable or metastatic melanoma that had progressed on prior immunotherapy, the first cellular therapy for any solid tumor. Then came the August FDA approval of afamitresgene autoleucel in unresectable or metastatic synovial sarcoma with failed chemotherapy, the first engineered T-cell therapy for cancers in soft tissue. 

“This was a pipe dream just a decade ago,” Alison Betof Warner, MD, PhD, lead author of a lifileucel study (NCT05640193), said in an interview with Medscape Medical News. “At the start of 2024, we had no approvals of these kinds of products in solid cancers. Now we have two.”

As the director of Solid Tumor Cell Therapy and leader of Stanford Medicine’s Melanoma and Cutaneous Oncology Clinical Research Group, Betof Warner has been at the forefront of developing commercial cell therapy using tumor-infiltrating lymphocytes (TILs). 

“The approval of lifileucel increases confidence that we can get these therapies across the regulatory finish line and to patients,” Betof Warner said during the interview. She was not involved in the development of afamitresgene autoleucel.

 

‘Reverse Engineering’

In addition to her contributions to the work that led to lifileucel’s approval, Betof Warner was the lead author on the first consensus guidelines on management and best practices for tumor-infiltrating lymphocyte cell therapy. 

Betof Warner began studying TILs after doing research with her mentors in immuno-oncology, Jedd D. Wolchok and Michael A. Postow. Their investigations — including one that Betof Warner coauthored — into how monoclonal antibodies and checkpoint inhibitors, such as ipilimumab or nivolumab, might extend the lives of people with advanced unresectable or metastatic melanoma inspired her to push further to find ways to minimize treatment while maximizing outcomes for patients. Betof Warner’s interest overall, she said in the interview, is in capitalizing on what can be learned about how the immune system controls cancer.

“What we know is that the immune system has the ability to kill cancer,” Betof Warner said. “Therefore we need to be thinking about how we can increase immune surveillance. How can we enhance that before a patient develops advanced cancer? 

Betof Warner said that although TILs are now standard treatment in melanoma, there is about a 30% response rate compared with about a 50% response rate in immunotherapy, and the latter is easier for the patient to withstand. 

“Antibodies on the frontline are better than going through a surgery and then waiting weeks to get your therapy,” Betof Warner said in the interview. “You can come into my clinic and get an antibody therapy in 30 minutes and go straight to work. TILs require patients to be in the hospital for weeks at a time and out of work for months at a time.”

In an effort to combine therapies to maximize best outcomes, a phase 3 trial (NCT05727904) is currently recruiting. The TILVANCE-301 trial will compare immunotherapy plus adoptive cell therapy vs immunotherapy alone in untreated unresectable or metastatic melanoma. Betof Warner is not a part of this study.

 

Cell Therapies Include CAR T Cells and TCRT

In general, adoptive T-cell therapies such as TILs involve the isolation of autologous immune cells that are removed from the body and either expanded or modified to optimize their efficacy in fighting antigens, before their transfer to the patient as a living drug by infusion.

In addition to TILs, adoptive cell therapies for antitumor therapeutics include chimeric antigen receptor (CAR) T cells and engineered T-cell receptor therapy (TCRT).

In CAR T-cell therapy and TCRT, naive T cells are harvested from the patient’s blood then engineered to target a tumor. In TIL therapy, tumor-specific T cells are taken from the patient’s tumor. Once extracted, the respective cells are expanded billions of times and then delivered back to the patient’s body, said Betof Warner. 

“The main promise of this approach is to generate responses in what we know as ‘cold’ tumors, or tumors that do not have a lot of endogenous T-cell infiltration or where the T cells are not working well, to bring in tumor targeting T cells and then trigger an immune response,” Betof Warner told an audience at the American Society of Clinical Oncology (ASCO) 2024 annual meeting.

TIL patients also receive interleukin (IL)-2 infusions to further stimulate the cells. In patients being treated with TCRT, they either receive low or no IL-2, Betof Warner said in her ASCO presentation, “Adopting Cutting-Edge Cell Therapies in Melanoma,” part of the session Beyond the Tip of the Iceberg: Next-Generation Cell-Based Therapies. 

Betof Warner takes Medscape Medical News through the history and ongoing investigations of cellular therapies for solid tumors, including her own research on these treatments. 

 

Decades in the Making

The National Cancer Institute began investigating TILs in the late 1980s, with the current National Cancer Institute (NCI) surgery chief, Steven Rosenberg, MD, PhD, leading the first-ever trials that showed TILs could shrink tumors in people with advanced melanoma.

Since then, NCI staff and others have also investigated TILs beyond melanoma and additional cell therapies based on CAR T cells and TCRT for antitumor therapeutics. 

“TCRs are different from CAR Ts because they go after intracellular antigens instead of extracellular antigens,” said Betof Warner. “That has appeal because many of the tumor antigens we’re looking for will be intracellular.” 

Because CAR T cells only target extracellular antigens, their utility is somewhat limited. Although several CAR T-cell therapies exist for blood cancers, there currently are no approved CAR T-cell therapies for solid tumors. However, several trials of CAR T cells in gastrointestinal cancers and melanoma are ongoing, said Betof Warner, who is not a part of these studies.

“We are starting to see early-phase efficacy in pediatric gliomas,” Betof Warner said, mentioning a study conducted by colleagues at Stanford who demonstrated potential for anti-GD2 CAR T-cell therapy in deadly pediatric diffuse midline gliomas, tumors on the spine and brain.

In their study, nine out of 11 participants (median age, 15 years) showed benefit from the cell therapy, with one participant’s tumors resolving completely. The results paved the way for the FDA to grant a Regenerative Medicine Advanced Therapy designation for use of anti-GD2 CAR T cells in H3K27M-positive diffuse midline gliomas. 

The investigators are now recruiting for a phase 1 trial (NCT04196413). Results of the initial study were published in Nature last month.

Another lesser-known cell therapy expected to advance at some point in the future for solid tumors is use of the body’s natural killer (NK) cells. “They’ve been known about for a long time, but they are more difficult to regulate, which is one reason why it has taken longer to make NK cell therapies,” said Betof Warner, who is not involved in the study of NK cells. “One of their advantages is that, potentially, there could be an ‘off the shelf’ NK product. They don’t necessarily have to be made with autologous cells.”

 

Risk-Benefit Profiles Depend on Mechanism of Action

If the corresponding TCR sequence of a tumor antigen is known, said Betof Warner, it is possible to use leukapheresis to generate naive circulating lymphocytes. Once infused, the manufactured TCRTs will activate in the body the same as native cells because the signaling is the same.
An advantage to TCRT compared with CAR T-cell therapy is that it targets intracellular proteins, which are significantly present in the tumor, Betof Warner said in her presentation at ASCO 2024. She clarified that tumors will usually be screened for the presence of this antigen before a patient is selected for treatment with that particular therapy, because not all antigens are highly expressed in every tumor. 

“Furthermore, the tumor antigen has to be presented by a major histocompatibility complex, meaning there are human leukocyte antigen restrictions, which impacts patient selection,” she said.

A risk with both TCRT and CAR T-cell therapy, according to Betof Warner, is that because there are often shared antigens between tumor and normal tissues, on-target/off-tumor toxicity is a risk.

“TILs are different because they are nonengineered, at least not for antigen recognition. They are polyclonal and go after multiple targets,” Betof Warner said. “TCRs and CARs are engineered to go after one target. So, TILs have much lower rates of on-tumor/off-target effects, vs when you engineer a very high affinity receptor like a TCR or CAR.”

A good example of how this amplification of TCR affinity can lead to poor outcomes is in metastatic melanoma, said Betof Warner. 

In investigations (NCI-07-C-0174 and NCI-07-C-0175) of TCRT in metastatic melanoma, for example, the researchers were targeting MART-1 or gp100, which are expressed in melanocytes. 

“The problem was that these antigens are also expressed in the eyes and ears, so it caused eye inflammation and hearing loss in a number of patients because it wasn’t specific enough for the tumor,” said Betof Warner. “So, if that target is highly expressed on normal tissue, then you have a high risk.”

 

Promise of PRAME

Betof Warner said the most promising TCRT at present is the investigational autologous cell therapy IMA203 (NCT03688124), which targets the preferentially expressed antigen (PRAME). Although PRAME is found in many tumors, this testis antigen does not tend to express in normal, healthy adult tissues. Betof Warner is not affiliated with this study. 

“It’s maybe the most exciting TCRT cell in melanoma,” Betof Warner told her audience at the ASCO 2024 meeting. Because the expression rate of PRAME in cutaneous and uveal melanoma is at or above 95% and 90%, respectively, she said “it is a really good target in melanoma.”

Phase 1a results reported in late 2023 from a first-in-human trial of IMA203 involving 13 persons with highly advanced melanoma and a median of 5.5 previous treatments showed a 50% objective response rate in the 12 evaluable results. The duration of response ranged between 2.2 and 14.7 months (median follow-up, 14 months).

The safety profile of the treatment was favorable, with no grade 3 adverse events occurring in more than 10% of the cohort, and no grade 5 adverse events at all.

Phase 1b results published in October by maker Immatics showed that in 28 heavily pretreated metastatic melanoma patients, IMA203 had a confirmed objective response rate of 54% with a median duration of response of 12.1 months, while maintaining a favorable tolerability profile. 

 

Accelerated Approvals, Boxed Warnings

The FDA granted accelerated approvals for both lifileucel, the TIL therapy, and afamitresgene autoleucel, the TCRT. 

Both were approved with boxed warnings. Lifileucel’s warning is for treatment-related mortality, prolonged severe cytopenia, severe infection, and cardiopulmonary and renal impairment. Afamitresgene autoleucel’s boxed warning is for serious or fatal cytokine release syndrome, which may be severe or life-threatening.

With these approvals, the bar is now raised on TILs and TCRTs, said Betof Warner.

The lifileucel trial studied 73 patients whose melanoma had continued to metastasize despite treatment with a programmed cell death protein (PD-1)/ programmed death-ligand (PD-L1)–targeted immune checkpoint inhibitor and a BRAF inhibitor (if appropriate based on tumor mutation status), and whose lifileucel dose was at least 7.5 billion cells (the approved dose). The cohort also received a median of six IL-2 (aldesleukin) doses. 

The objective response rate was 31.5% (95% CI, 21.1-43.4), and median duration of response was not reached (lower bound of 95% CI, 4.1).

In the afamitresgene autoleucel study, 44 of 52 patients with synovial sarcoma received leukapheresis and a single infusion of afamitresgene autoleucel. 

The overall response rate was 43.2% (95% CI, 28.4-59.0). The median time to response was 4.9 weeks (95% CI, 4.4-8), and the median duration of response was 6 months (lower bound of 95% CI, 4.6). Among patients who were responsive to the treatment, 45.6% and 39.0% had a duration of response of 6 months or longer and 12 months or longer, respectively.

 

New Hope for Patients

Betof Warner and her colleagues are now recruiting for an open-label, phase 1/2 investigation of the safety and efficacy of the TIL therapy OBX-115 in adult advanced solid tumors in melanoma or non–small cell lung cancer. The first-in-human results of a previous trial were presented at the ASCO 2024 meeting, and OBX-115 received FDA fast track designation in July.

“I think the results are really promising,” said Betof Warner. “This is an engineered TIL that does not require administering IL-2 to the patient. There were four out of the nine patients who responded to the treatment and there were no dose-limiting toxicities, no cytokine and no intracranial — all of which is excellent.”

For Betof Warner, the possibility that by using their own immune system, patients with advanced and refractory cancers could soon have a one-time treatment with a cell therapy rather than innumerable bouts of chemotherapy pushes her onward.

“The idea that we can treat cancer one time and have it not recur for years — that’s pushing the start of saying there’s a cure of cancer. That a person could move on from cancer like they move on from an infection. That is the potential of this work. We’re not there yet, but that’s where we need to think and dream big,” she said.

Betof Warner disclosed consulting/advisory roles with BluePath Solutions, Bristol-Myers Squibb/Medarex, Immatics, Instil Bio, Iovance Biotherapeutics, Lyell Immunopharma, Merck, Novartis, and Pfizer and research funding and travel expenses from Iovance Biotherapeutics.

 

A version of this article appeared on Medscape.com.

The cutting edge of treating solid tumors with cell therapies got notably sharper in 2024.

First came the US Food and Drug Administration (FDA) approval in February 2024 of the tumor-infiltrating lymphocyte (TIL) therapy lifileucel in unresectable or metastatic melanoma that had progressed on prior immunotherapy, the first cellular therapy for any solid tumor. Then came the August FDA approval of afamitresgene autoleucel in unresectable or metastatic synovial sarcoma with failed chemotherapy, the first engineered T-cell therapy for cancers in soft tissue. 

“This was a pipe dream just a decade ago,” Alison Betof Warner, MD, PhD, lead author of a lifileucel study (NCT05640193), said in an interview with Medscape Medical News. “At the start of 2024, we had no approvals of these kinds of products in solid cancers. Now we have two.”

As the director of Solid Tumor Cell Therapy and leader of Stanford Medicine’s Melanoma and Cutaneous Oncology Clinical Research Group, Betof Warner has been at the forefront of developing commercial cell therapy using tumor-infiltrating lymphocytes (TILs). 

“The approval of lifileucel increases confidence that we can get these therapies across the regulatory finish line and to patients,” Betof Warner said during the interview. She was not involved in the development of afamitresgene autoleucel.

 

‘Reverse Engineering’

In addition to her contributions to the work that led to lifileucel’s approval, Betof Warner was the lead author on the first consensus guidelines on management and best practices for tumor-infiltrating lymphocyte cell therapy. 

Betof Warner began studying TILs after doing research with her mentors in immuno-oncology, Jedd D. Wolchok and Michael A. Postow. Their investigations — including one that Betof Warner coauthored — into how monoclonal antibodies and checkpoint inhibitors, such as ipilimumab or nivolumab, might extend the lives of people with advanced unresectable or metastatic melanoma inspired her to push further to find ways to minimize treatment while maximizing outcomes for patients. Betof Warner’s interest overall, she said in the interview, is in capitalizing on what can be learned about how the immune system controls cancer.

“What we know is that the immune system has the ability to kill cancer,” Betof Warner said. “Therefore we need to be thinking about how we can increase immune surveillance. How can we enhance that before a patient develops advanced cancer? 

Betof Warner said that although TILs are now standard treatment in melanoma, there is about a 30% response rate compared with about a 50% response rate in immunotherapy, and the latter is easier for the patient to withstand. 

“Antibodies on the frontline are better than going through a surgery and then waiting weeks to get your therapy,” Betof Warner said in the interview. “You can come into my clinic and get an antibody therapy in 30 minutes and go straight to work. TILs require patients to be in the hospital for weeks at a time and out of work for months at a time.”

In an effort to combine therapies to maximize best outcomes, a phase 3 trial (NCT05727904) is currently recruiting. The TILVANCE-301 trial will compare immunotherapy plus adoptive cell therapy vs immunotherapy alone in untreated unresectable or metastatic melanoma. Betof Warner is not a part of this study.

 

Cell Therapies Include CAR T Cells and TCRT

In general, adoptive T-cell therapies such as TILs involve the isolation of autologous immune cells that are removed from the body and either expanded or modified to optimize their efficacy in fighting antigens, before their transfer to the patient as a living drug by infusion.

In addition to TILs, adoptive cell therapies for antitumor therapeutics include chimeric antigen receptor (CAR) T cells and engineered T-cell receptor therapy (TCRT).

In CAR T-cell therapy and TCRT, naive T cells are harvested from the patient’s blood then engineered to target a tumor. In TIL therapy, tumor-specific T cells are taken from the patient’s tumor. Once extracted, the respective cells are expanded billions of times and then delivered back to the patient’s body, said Betof Warner. 

“The main promise of this approach is to generate responses in what we know as ‘cold’ tumors, or tumors that do not have a lot of endogenous T-cell infiltration or where the T cells are not working well, to bring in tumor targeting T cells and then trigger an immune response,” Betof Warner told an audience at the American Society of Clinical Oncology (ASCO) 2024 annual meeting.

TIL patients also receive interleukin (IL)-2 infusions to further stimulate the cells. In patients being treated with TCRT, they either receive low or no IL-2, Betof Warner said in her ASCO presentation, “Adopting Cutting-Edge Cell Therapies in Melanoma,” part of the session Beyond the Tip of the Iceberg: Next-Generation Cell-Based Therapies. 

Betof Warner takes Medscape Medical News through the history and ongoing investigations of cellular therapies for solid tumors, including her own research on these treatments. 

 

Decades in the Making

The National Cancer Institute began investigating TILs in the late 1980s, with the current National Cancer Institute (NCI) surgery chief, Steven Rosenberg, MD, PhD, leading the first-ever trials that showed TILs could shrink tumors in people with advanced melanoma.

Since then, NCI staff and others have also investigated TILs beyond melanoma and additional cell therapies based on CAR T cells and TCRT for antitumor therapeutics. 

“TCRs are different from CAR Ts because they go after intracellular antigens instead of extracellular antigens,” said Betof Warner. “That has appeal because many of the tumor antigens we’re looking for will be intracellular.” 

Because CAR T cells only target extracellular antigens, their utility is somewhat limited. Although several CAR T-cell therapies exist for blood cancers, there currently are no approved CAR T-cell therapies for solid tumors. However, several trials of CAR T cells in gastrointestinal cancers and melanoma are ongoing, said Betof Warner, who is not a part of these studies.

“We are starting to see early-phase efficacy in pediatric gliomas,” Betof Warner said, mentioning a study conducted by colleagues at Stanford who demonstrated potential for anti-GD2 CAR T-cell therapy in deadly pediatric diffuse midline gliomas, tumors on the spine and brain.

In their study, nine out of 11 participants (median age, 15 years) showed benefit from the cell therapy, with one participant’s tumors resolving completely. The results paved the way for the FDA to grant a Regenerative Medicine Advanced Therapy designation for use of anti-GD2 CAR T cells in H3K27M-positive diffuse midline gliomas. 

The investigators are now recruiting for a phase 1 trial (NCT04196413). Results of the initial study were published in Nature last month.

Another lesser-known cell therapy expected to advance at some point in the future for solid tumors is use of the body’s natural killer (NK) cells. “They’ve been known about for a long time, but they are more difficult to regulate, which is one reason why it has taken longer to make NK cell therapies,” said Betof Warner, who is not involved in the study of NK cells. “One of their advantages is that, potentially, there could be an ‘off the shelf’ NK product. They don’t necessarily have to be made with autologous cells.”

 

Risk-Benefit Profiles Depend on Mechanism of Action

If the corresponding TCR sequence of a tumor antigen is known, said Betof Warner, it is possible to use leukapheresis to generate naive circulating lymphocytes. Once infused, the manufactured TCRTs will activate in the body the same as native cells because the signaling is the same.
An advantage to TCRT compared with CAR T-cell therapy is that it targets intracellular proteins, which are significantly present in the tumor, Betof Warner said in her presentation at ASCO 2024. She clarified that tumors will usually be screened for the presence of this antigen before a patient is selected for treatment with that particular therapy, because not all antigens are highly expressed in every tumor. 

“Furthermore, the tumor antigen has to be presented by a major histocompatibility complex, meaning there are human leukocyte antigen restrictions, which impacts patient selection,” she said.

A risk with both TCRT and CAR T-cell therapy, according to Betof Warner, is that because there are often shared antigens between tumor and normal tissues, on-target/off-tumor toxicity is a risk.

“TILs are different because they are nonengineered, at least not for antigen recognition. They are polyclonal and go after multiple targets,” Betof Warner said. “TCRs and CARs are engineered to go after one target. So, TILs have much lower rates of on-tumor/off-target effects, vs when you engineer a very high affinity receptor like a TCR or CAR.”

A good example of how this amplification of TCR affinity can lead to poor outcomes is in metastatic melanoma, said Betof Warner. 

In investigations (NCI-07-C-0174 and NCI-07-C-0175) of TCRT in metastatic melanoma, for example, the researchers were targeting MART-1 or gp100, which are expressed in melanocytes. 

“The problem was that these antigens are also expressed in the eyes and ears, so it caused eye inflammation and hearing loss in a number of patients because it wasn’t specific enough for the tumor,” said Betof Warner. “So, if that target is highly expressed on normal tissue, then you have a high risk.”

 

Promise of PRAME

Betof Warner said the most promising TCRT at present is the investigational autologous cell therapy IMA203 (NCT03688124), which targets the preferentially expressed antigen (PRAME). Although PRAME is found in many tumors, this testis antigen does not tend to express in normal, healthy adult tissues. Betof Warner is not affiliated with this study. 

“It’s maybe the most exciting TCRT cell in melanoma,” Betof Warner told her audience at the ASCO 2024 meeting. Because the expression rate of PRAME in cutaneous and uveal melanoma is at or above 95% and 90%, respectively, she said “it is a really good target in melanoma.”

Phase 1a results reported in late 2023 from a first-in-human trial of IMA203 involving 13 persons with highly advanced melanoma and a median of 5.5 previous treatments showed a 50% objective response rate in the 12 evaluable results. The duration of response ranged between 2.2 and 14.7 months (median follow-up, 14 months).

The safety profile of the treatment was favorable, with no grade 3 adverse events occurring in more than 10% of the cohort, and no grade 5 adverse events at all.

Phase 1b results published in October by maker Immatics showed that in 28 heavily pretreated metastatic melanoma patients, IMA203 had a confirmed objective response rate of 54% with a median duration of response of 12.1 months, while maintaining a favorable tolerability profile. 

 

Accelerated Approvals, Boxed Warnings

The FDA granted accelerated approvals for both lifileucel, the TIL therapy, and afamitresgene autoleucel, the TCRT. 

Both were approved with boxed warnings. Lifileucel’s warning is for treatment-related mortality, prolonged severe cytopenia, severe infection, and cardiopulmonary and renal impairment. Afamitresgene autoleucel’s boxed warning is for serious or fatal cytokine release syndrome, which may be severe or life-threatening.

With these approvals, the bar is now raised on TILs and TCRTs, said Betof Warner.

The lifileucel trial studied 73 patients whose melanoma had continued to metastasize despite treatment with a programmed cell death protein (PD-1)/ programmed death-ligand (PD-L1)–targeted immune checkpoint inhibitor and a BRAF inhibitor (if appropriate based on tumor mutation status), and whose lifileucel dose was at least 7.5 billion cells (the approved dose). The cohort also received a median of six IL-2 (aldesleukin) doses. 

The objective response rate was 31.5% (95% CI, 21.1-43.4), and median duration of response was not reached (lower bound of 95% CI, 4.1).

In the afamitresgene autoleucel study, 44 of 52 patients with synovial sarcoma received leukapheresis and a single infusion of afamitresgene autoleucel. 

The overall response rate was 43.2% (95% CI, 28.4-59.0). The median time to response was 4.9 weeks (95% CI, 4.4-8), and the median duration of response was 6 months (lower bound of 95% CI, 4.6). Among patients who were responsive to the treatment, 45.6% and 39.0% had a duration of response of 6 months or longer and 12 months or longer, respectively.

 

New Hope for Patients

Betof Warner and her colleagues are now recruiting for an open-label, phase 1/2 investigation of the safety and efficacy of the TIL therapy OBX-115 in adult advanced solid tumors in melanoma or non–small cell lung cancer. The first-in-human results of a previous trial were presented at the ASCO 2024 meeting, and OBX-115 received FDA fast track designation in July.

“I think the results are really promising,” said Betof Warner. “This is an engineered TIL that does not require administering IL-2 to the patient. There were four out of the nine patients who responded to the treatment and there were no dose-limiting toxicities, no cytokine and no intracranial — all of which is excellent.”

For Betof Warner, the possibility that by using their own immune system, patients with advanced and refractory cancers could soon have a one-time treatment with a cell therapy rather than innumerable bouts of chemotherapy pushes her onward.

“The idea that we can treat cancer one time and have it not recur for years — that’s pushing the start of saying there’s a cure of cancer. That a person could move on from cancer like they move on from an infection. That is the potential of this work. We’re not there yet, but that’s where we need to think and dream big,” she said.

Betof Warner disclosed consulting/advisory roles with BluePath Solutions, Bristol-Myers Squibb/Medarex, Immatics, Instil Bio, Iovance Biotherapeutics, Lyell Immunopharma, Merck, Novartis, and Pfizer and research funding and travel expenses from Iovance Biotherapeutics.

 

A version of this article appeared on Medscape.com.