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In this edition of “How I will treat my next patient,” I highlight three studies presented at the World Conference on Lung Cancer (WCLC 2019) regarding the use of tissue biomarkers to predict benefit when immune checkpoint inhibitors (ICIs) are combined with chemotherapy in the treatment of stage IV non–small cell lung cancer (NSCLC) patients.
TMB in nonsquamous NSCLC
Marina C. Garassino, MD, and colleagues examined tumor mutation burden (TMB) to predict benefit from pembrolizumab in the KEYNOTE-189 study. KEYNOTE-189 was a double-blind comparison of first-line chemotherapy plus either pembrolizumab or placebo in 616 patients with stage IV nonsquamous NSCLC who were randomized 2:1 to the treatment arms.
Overall, adding pembrolizumab to pemetrexed and platinum significantly improved overall survival (hazard ratio, 0.49), progression-free survival (HR, 0.52), and overall response rate (47.6% vs. 18.9%). Benefit was observed in all analyzed subgroups, including patients with programmed death-ligand 1 (PD-L1) of less than 1%, 1%-49%, and 50% or greater.
In 293 patients – less than 50% of the total participants in the trial – with evaluable TMB data, TMB as a continuous variable showed no significant association with overall survival, progression-free survival, or overall response rate. There was no cut point at which TMB predicted outcome from treatment.
Similarly, Corey Langer, MD, and colleagues presented an exploratory analysis of the randomized, phase 2 KEYNOTE-021 trial (open label, pembrolizumab plus chemotherapy in 70 stage IV nonsquamous NSCLC patients). There was no association between tissue TMB and overall survival, progression-free survival, or overall response rate. In patients with tissue TMB greater than 175 mutations/exome and less than 175 mutations/exome, the overall response rate was 71% and 61%, respectively.
Both presenters recommended that tissue TMB not yet be used in therapeutic decision making.
How these results influence clinical practice
TMB has been associated with response to ICIs, but there is little information regarding whether TMB predicts for response to chemotherapy, either given alone or with ICIs. Logistical issues have limited the clinical utility of TMB. There are a variety of methodologies to measure TMB and no consensus on the ideal cut point for defining benefit from ICI therapy.
While TMB remains a marker of interest, the two presentations at WCLC 2019 demonstrate that additional research is needed to define whether TMB needs to be combined with other markers in an algorithm or matrix to guide decision making or whether we should focus entirely on identifying better biomarkers of immunogenicity.
PD-L1 expression and overall survival
Federico Cappuzzo, MD, and colleagues reported a subset analysis of IMpower131, a randomized, phase 3 trial of chemotherapy plus or minus atezolizumab as first-line therapy in 1,021 patients with stage IV squamous NSCLC. Patients were randomized to arm A (atezolizumab plus carboplatin plus paclitaxel), arm B (atezolizumab plus carboplatin plus nab-paclitaxel) or arm C (carboplatin plus nab-paclitaxel). Investigator-assessed progression-free survival, reported at the 2018 annual meeting of the American Society of Clinical Oncology, showed a small (about 21 days), but statistically significant, improvement in median progression-free survival in arm B versus arm C. The progression-free survival benefit was seen in all PD-L1-positive subgroups. At WCLC 2019, he reported the final overall survival results of arms B versus C.
Median overall survival in the intent-to-treat population was 14.2 months with atezolizumab versus 13.5 months without it (HR, 0.88). Patients with high PD-L1 expression (14% and 13% of patients in the groups, respectively), experienced dramatic, clinically important improvement in overall survival with atezolizumab plus chemotherapy, compared with chemotherapy alone (median of 23.4 vs. 10.2 months; HR, 0.48).
In IMpower 131, PD-L1-high expression was defined as TC3 or IC3 – expression on greater than 50% of tumor cells or greater than 10% of immune cells. Patients were also categorized as PD-L1 positive (TC 1/2/3 or IC 1/2/3 – expression of PD-L1 on 1% or greater of tumor cells or immune cells) or PD-LI negative (TC 0 or IC 0 – expression on less than 1% of cells). The PD-L1-positive and negative subsets did not demonstrate improved overall survival with atezolizumab.
How these results influence clinical practice
As noted above, in NSCLC patients (regardless of histology), we need biomarkers that predict benefit from ICIs alone and additive benefit when ICIs are combined with other, potentially toxic therapies. In the subset analysis of IMpower 131, despite clinically relevant differences in overall survival for the “PD-L1-high” patients, the PD-L1-positive patients did not benefit, so PD-L1 tumor proportion score remains an imperfect biomarker.
To put this report in its proper context, it will be important to analyze the details of the final manuscript of IMpower 131, particularly the comparison of arms A plus B versus C and the proportion of arm C patients who ultimately received an ICI in the second- or later-line setting. In the meantime, clinicians will select their ICI and chemotherapy regimen of choice, utilizing PD-L1 expression as an “eyebrow raiser,” but not an exclusionary criteria – as they did prior to WCLC 2019.
Dr. Lyss has been a community-based medical oncologist and clinical researcher for more than 35 years, practicing in St. Louis. His clinical and research interests are in the prevention, diagnosis, and treatment of breast and lung cancers and in expanding access to clinical trials to medically underserved populations.
In this edition of “How I will treat my next patient,” I highlight three studies presented at the World Conference on Lung Cancer (WCLC 2019) regarding the use of tissue biomarkers to predict benefit when immune checkpoint inhibitors (ICIs) are combined with chemotherapy in the treatment of stage IV non–small cell lung cancer (NSCLC) patients.
TMB in nonsquamous NSCLC
Marina C. Garassino, MD, and colleagues examined tumor mutation burden (TMB) to predict benefit from pembrolizumab in the KEYNOTE-189 study. KEYNOTE-189 was a double-blind comparison of first-line chemotherapy plus either pembrolizumab or placebo in 616 patients with stage IV nonsquamous NSCLC who were randomized 2:1 to the treatment arms.
Overall, adding pembrolizumab to pemetrexed and platinum significantly improved overall survival (hazard ratio, 0.49), progression-free survival (HR, 0.52), and overall response rate (47.6% vs. 18.9%). Benefit was observed in all analyzed subgroups, including patients with programmed death-ligand 1 (PD-L1) of less than 1%, 1%-49%, and 50% or greater.
In 293 patients – less than 50% of the total participants in the trial – with evaluable TMB data, TMB as a continuous variable showed no significant association with overall survival, progression-free survival, or overall response rate. There was no cut point at which TMB predicted outcome from treatment.
Similarly, Corey Langer, MD, and colleagues presented an exploratory analysis of the randomized, phase 2 KEYNOTE-021 trial (open label, pembrolizumab plus chemotherapy in 70 stage IV nonsquamous NSCLC patients). There was no association between tissue TMB and overall survival, progression-free survival, or overall response rate. In patients with tissue TMB greater than 175 mutations/exome and less than 175 mutations/exome, the overall response rate was 71% and 61%, respectively.
Both presenters recommended that tissue TMB not yet be used in therapeutic decision making.
How these results influence clinical practice
TMB has been associated with response to ICIs, but there is little information regarding whether TMB predicts for response to chemotherapy, either given alone or with ICIs. Logistical issues have limited the clinical utility of TMB. There are a variety of methodologies to measure TMB and no consensus on the ideal cut point for defining benefit from ICI therapy.
While TMB remains a marker of interest, the two presentations at WCLC 2019 demonstrate that additional research is needed to define whether TMB needs to be combined with other markers in an algorithm or matrix to guide decision making or whether we should focus entirely on identifying better biomarkers of immunogenicity.
PD-L1 expression and overall survival
Federico Cappuzzo, MD, and colleagues reported a subset analysis of IMpower131, a randomized, phase 3 trial of chemotherapy plus or minus atezolizumab as first-line therapy in 1,021 patients with stage IV squamous NSCLC. Patients were randomized to arm A (atezolizumab plus carboplatin plus paclitaxel), arm B (atezolizumab plus carboplatin plus nab-paclitaxel) or arm C (carboplatin plus nab-paclitaxel). Investigator-assessed progression-free survival, reported at the 2018 annual meeting of the American Society of Clinical Oncology, showed a small (about 21 days), but statistically significant, improvement in median progression-free survival in arm B versus arm C. The progression-free survival benefit was seen in all PD-L1-positive subgroups. At WCLC 2019, he reported the final overall survival results of arms B versus C.
Median overall survival in the intent-to-treat population was 14.2 months with atezolizumab versus 13.5 months without it (HR, 0.88). Patients with high PD-L1 expression (14% and 13% of patients in the groups, respectively), experienced dramatic, clinically important improvement in overall survival with atezolizumab plus chemotherapy, compared with chemotherapy alone (median of 23.4 vs. 10.2 months; HR, 0.48).
In IMpower 131, PD-L1-high expression was defined as TC3 or IC3 – expression on greater than 50% of tumor cells or greater than 10% of immune cells. Patients were also categorized as PD-L1 positive (TC 1/2/3 or IC 1/2/3 – expression of PD-L1 on 1% or greater of tumor cells or immune cells) or PD-LI negative (TC 0 or IC 0 – expression on less than 1% of cells). The PD-L1-positive and negative subsets did not demonstrate improved overall survival with atezolizumab.
How these results influence clinical practice
As noted above, in NSCLC patients (regardless of histology), we need biomarkers that predict benefit from ICIs alone and additive benefit when ICIs are combined with other, potentially toxic therapies. In the subset analysis of IMpower 131, despite clinically relevant differences in overall survival for the “PD-L1-high” patients, the PD-L1-positive patients did not benefit, so PD-L1 tumor proportion score remains an imperfect biomarker.
To put this report in its proper context, it will be important to analyze the details of the final manuscript of IMpower 131, particularly the comparison of arms A plus B versus C and the proportion of arm C patients who ultimately received an ICI in the second- or later-line setting. In the meantime, clinicians will select their ICI and chemotherapy regimen of choice, utilizing PD-L1 expression as an “eyebrow raiser,” but not an exclusionary criteria – as they did prior to WCLC 2019.
Dr. Lyss has been a community-based medical oncologist and clinical researcher for more than 35 years, practicing in St. Louis. His clinical and research interests are in the prevention, diagnosis, and treatment of breast and lung cancers and in expanding access to clinical trials to medically underserved populations.
In this edition of “How I will treat my next patient,” I highlight three studies presented at the World Conference on Lung Cancer (WCLC 2019) regarding the use of tissue biomarkers to predict benefit when immune checkpoint inhibitors (ICIs) are combined with chemotherapy in the treatment of stage IV non–small cell lung cancer (NSCLC) patients.
TMB in nonsquamous NSCLC
Marina C. Garassino, MD, and colleagues examined tumor mutation burden (TMB) to predict benefit from pembrolizumab in the KEYNOTE-189 study. KEYNOTE-189 was a double-blind comparison of first-line chemotherapy plus either pembrolizumab or placebo in 616 patients with stage IV nonsquamous NSCLC who were randomized 2:1 to the treatment arms.
Overall, adding pembrolizumab to pemetrexed and platinum significantly improved overall survival (hazard ratio, 0.49), progression-free survival (HR, 0.52), and overall response rate (47.6% vs. 18.9%). Benefit was observed in all analyzed subgroups, including patients with programmed death-ligand 1 (PD-L1) of less than 1%, 1%-49%, and 50% or greater.
In 293 patients – less than 50% of the total participants in the trial – with evaluable TMB data, TMB as a continuous variable showed no significant association with overall survival, progression-free survival, or overall response rate. There was no cut point at which TMB predicted outcome from treatment.
Similarly, Corey Langer, MD, and colleagues presented an exploratory analysis of the randomized, phase 2 KEYNOTE-021 trial (open label, pembrolizumab plus chemotherapy in 70 stage IV nonsquamous NSCLC patients). There was no association between tissue TMB and overall survival, progression-free survival, or overall response rate. In patients with tissue TMB greater than 175 mutations/exome and less than 175 mutations/exome, the overall response rate was 71% and 61%, respectively.
Both presenters recommended that tissue TMB not yet be used in therapeutic decision making.
How these results influence clinical practice
TMB has been associated with response to ICIs, but there is little information regarding whether TMB predicts for response to chemotherapy, either given alone or with ICIs. Logistical issues have limited the clinical utility of TMB. There are a variety of methodologies to measure TMB and no consensus on the ideal cut point for defining benefit from ICI therapy.
While TMB remains a marker of interest, the two presentations at WCLC 2019 demonstrate that additional research is needed to define whether TMB needs to be combined with other markers in an algorithm or matrix to guide decision making or whether we should focus entirely on identifying better biomarkers of immunogenicity.
PD-L1 expression and overall survival
Federico Cappuzzo, MD, and colleagues reported a subset analysis of IMpower131, a randomized, phase 3 trial of chemotherapy plus or minus atezolizumab as first-line therapy in 1,021 patients with stage IV squamous NSCLC. Patients were randomized to arm A (atezolizumab plus carboplatin plus paclitaxel), arm B (atezolizumab plus carboplatin plus nab-paclitaxel) or arm C (carboplatin plus nab-paclitaxel). Investigator-assessed progression-free survival, reported at the 2018 annual meeting of the American Society of Clinical Oncology, showed a small (about 21 days), but statistically significant, improvement in median progression-free survival in arm B versus arm C. The progression-free survival benefit was seen in all PD-L1-positive subgroups. At WCLC 2019, he reported the final overall survival results of arms B versus C.
Median overall survival in the intent-to-treat population was 14.2 months with atezolizumab versus 13.5 months without it (HR, 0.88). Patients with high PD-L1 expression (14% and 13% of patients in the groups, respectively), experienced dramatic, clinically important improvement in overall survival with atezolizumab plus chemotherapy, compared with chemotherapy alone (median of 23.4 vs. 10.2 months; HR, 0.48).
In IMpower 131, PD-L1-high expression was defined as TC3 or IC3 – expression on greater than 50% of tumor cells or greater than 10% of immune cells. Patients were also categorized as PD-L1 positive (TC 1/2/3 or IC 1/2/3 – expression of PD-L1 on 1% or greater of tumor cells or immune cells) or PD-LI negative (TC 0 or IC 0 – expression on less than 1% of cells). The PD-L1-positive and negative subsets did not demonstrate improved overall survival with atezolizumab.
How these results influence clinical practice
As noted above, in NSCLC patients (regardless of histology), we need biomarkers that predict benefit from ICIs alone and additive benefit when ICIs are combined with other, potentially toxic therapies. In the subset analysis of IMpower 131, despite clinically relevant differences in overall survival for the “PD-L1-high” patients, the PD-L1-positive patients did not benefit, so PD-L1 tumor proportion score remains an imperfect biomarker.
To put this report in its proper context, it will be important to analyze the details of the final manuscript of IMpower 131, particularly the comparison of arms A plus B versus C and the proportion of arm C patients who ultimately received an ICI in the second- or later-line setting. In the meantime, clinicians will select their ICI and chemotherapy regimen of choice, utilizing PD-L1 expression as an “eyebrow raiser,” but not an exclusionary criteria – as they did prior to WCLC 2019.
Dr. Lyss has been a community-based medical oncologist and clinical researcher for more than 35 years, practicing in St. Louis. His clinical and research interests are in the prevention, diagnosis, and treatment of breast and lung cancers and in expanding access to clinical trials to medically underserved populations.