Think duration, not dose, when managing bleeding with non–factor replacements

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– Clinicians should prioritize treatment duration with factors or bypassing agents – not dose level – when managing breakthrough bleeds in patients with hemophilia who are on non–factor replacement therapy, according to a leading expert.

Will Pass/MDedge News
Dr. Andreas Tiede

Duration of treatment is more strongly associated with thromboembolism than dose magnitude, said Andreas Tiede, MD, PhD, head of hemostaseology at Hannover (Germany) Medical School in Germany, noting that recommendations vary by non–factor replacement agent.

These remarks were part of a presentation about novel agents for treatment of hemophilia with inhibitors delivered at the annual congress of the European Association for Haemophilia and Allied Disorders.

“Concomitant use of factor products, both factor VIII and IX, and the bypassing agents, have usually preceded thromboembolic events in clinical trials [for non–factor replacement therapies] so this [topic] is crucial,” Dr. Tiede said.

Other experts recommend lower doses and shorter treatment durations. “I think that’s reasonable, but with some question mark behind the low doses,” he said. “I think it depends a little bit on the interaction between the non–factor replacement therapy and the bypassing agent in your patient.”

With a busy pipeline of non–factor replacement agents for hemophilia, such interactions are becoming increasingly relevant for clinicians and their patients.

Emicizumab, for instance, which is now approved for hemophilia with or without inhibitors, has synergistic activity with activated prothrombin complex concentrates (APCC). This was demonstrated by an emicizumab prophylaxis trial in which five out of eight patients with breakthrough bleeding who were treated with APPC at a dose higher than 100 IU/kg per day for more than 24 hours developed thrombotic microangiopathy. (N Engl J Med. 2017;377:809-18).

Other patients who received multiple infusions of APCC developed skin necrosis, cavernous vein thrombosis, and thrombophlebitis. Consequently, it is now recommended that APCC be avoided in patients taking emicizumab, and if unavoidable, given at the lowest dose possible. However, Dr. Tiede advised that this recommendation for APCC should not be extrapolated to encompass all factors and bypassing agents, based on existing data.

“Regarding higher or lower doses for initial treatment, I would be a little bit more careful,” he said. “That obviously depends on [whether] there is a synergistic effect with the non–factor replacement therapy and the bypassing agent. Synergistic effects have clearly been shown for the interaction of emicizumab and APCC, but when it comes to the interaction between emicizumab and VIIa, I’m not so sure. I don’t think that we have enough evidence to recommend lower doses of VIIa.”

Dr. Tiede also suggested that lower doses of factor VIII are probably unnecessary. “At high doses or high concentrations of factor VIII, emicizumab’s low affinity to the targets will not result in any significant action anymore,” he said. “So I think we have to wait for more data from basic research and also more clinical data.”

Regarding concern for duration of therapy, Dr. Tiede explained that, when treating breakthrough bleeding in a patient on non–factor replacement therapy, “the patient’s hemostatic protection level will never fall to zero, as it would have done in a patient treated previously, on demand with bypassing agents only.” Since hemostatic protection levels never return to zero, it is easier to enter the thromboembolic danger zone.

This risk was recently demonstrated by an emerging non-factor replacement therapy. In a phase 3 trial for fitusiran – a small interfering RNA therapy that targets antithrombin – a patient with hemophilia A developed a breakthrough bleed and 31-46 IU/kg of factor VIII was given, resulting in fatal cerebral sinus thrombosis. After a temporary hold, the study restarted with new limits on factor and bypassing agent doses.

Dr. Tiede reported financial relationships with Bayer, Biotest, CSL Behring, Novo Nordisk, Pfizer, and other companies.

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– Clinicians should prioritize treatment duration with factors or bypassing agents – not dose level – when managing breakthrough bleeds in patients with hemophilia who are on non–factor replacement therapy, according to a leading expert.

Will Pass/MDedge News
Dr. Andreas Tiede

Duration of treatment is more strongly associated with thromboembolism than dose magnitude, said Andreas Tiede, MD, PhD, head of hemostaseology at Hannover (Germany) Medical School in Germany, noting that recommendations vary by non–factor replacement agent.

These remarks were part of a presentation about novel agents for treatment of hemophilia with inhibitors delivered at the annual congress of the European Association for Haemophilia and Allied Disorders.

“Concomitant use of factor products, both factor VIII and IX, and the bypassing agents, have usually preceded thromboembolic events in clinical trials [for non–factor replacement therapies] so this [topic] is crucial,” Dr. Tiede said.

Other experts recommend lower doses and shorter treatment durations. “I think that’s reasonable, but with some question mark behind the low doses,” he said. “I think it depends a little bit on the interaction between the non–factor replacement therapy and the bypassing agent in your patient.”

With a busy pipeline of non–factor replacement agents for hemophilia, such interactions are becoming increasingly relevant for clinicians and their patients.

Emicizumab, for instance, which is now approved for hemophilia with or without inhibitors, has synergistic activity with activated prothrombin complex concentrates (APCC). This was demonstrated by an emicizumab prophylaxis trial in which five out of eight patients with breakthrough bleeding who were treated with APPC at a dose higher than 100 IU/kg per day for more than 24 hours developed thrombotic microangiopathy. (N Engl J Med. 2017;377:809-18).

Other patients who received multiple infusions of APCC developed skin necrosis, cavernous vein thrombosis, and thrombophlebitis. Consequently, it is now recommended that APCC be avoided in patients taking emicizumab, and if unavoidable, given at the lowest dose possible. However, Dr. Tiede advised that this recommendation for APCC should not be extrapolated to encompass all factors and bypassing agents, based on existing data.

“Regarding higher or lower doses for initial treatment, I would be a little bit more careful,” he said. “That obviously depends on [whether] there is a synergistic effect with the non–factor replacement therapy and the bypassing agent. Synergistic effects have clearly been shown for the interaction of emicizumab and APCC, but when it comes to the interaction between emicizumab and VIIa, I’m not so sure. I don’t think that we have enough evidence to recommend lower doses of VIIa.”

Dr. Tiede also suggested that lower doses of factor VIII are probably unnecessary. “At high doses or high concentrations of factor VIII, emicizumab’s low affinity to the targets will not result in any significant action anymore,” he said. “So I think we have to wait for more data from basic research and also more clinical data.”

Regarding concern for duration of therapy, Dr. Tiede explained that, when treating breakthrough bleeding in a patient on non–factor replacement therapy, “the patient’s hemostatic protection level will never fall to zero, as it would have done in a patient treated previously, on demand with bypassing agents only.” Since hemostatic protection levels never return to zero, it is easier to enter the thromboembolic danger zone.

This risk was recently demonstrated by an emerging non-factor replacement therapy. In a phase 3 trial for fitusiran – a small interfering RNA therapy that targets antithrombin – a patient with hemophilia A developed a breakthrough bleed and 31-46 IU/kg of factor VIII was given, resulting in fatal cerebral sinus thrombosis. After a temporary hold, the study restarted with new limits on factor and bypassing agent doses.

Dr. Tiede reported financial relationships with Bayer, Biotest, CSL Behring, Novo Nordisk, Pfizer, and other companies.

 

– Clinicians should prioritize treatment duration with factors or bypassing agents – not dose level – when managing breakthrough bleeds in patients with hemophilia who are on non–factor replacement therapy, according to a leading expert.

Will Pass/MDedge News
Dr. Andreas Tiede

Duration of treatment is more strongly associated with thromboembolism than dose magnitude, said Andreas Tiede, MD, PhD, head of hemostaseology at Hannover (Germany) Medical School in Germany, noting that recommendations vary by non–factor replacement agent.

These remarks were part of a presentation about novel agents for treatment of hemophilia with inhibitors delivered at the annual congress of the European Association for Haemophilia and Allied Disorders.

“Concomitant use of factor products, both factor VIII and IX, and the bypassing agents, have usually preceded thromboembolic events in clinical trials [for non–factor replacement therapies] so this [topic] is crucial,” Dr. Tiede said.

Other experts recommend lower doses and shorter treatment durations. “I think that’s reasonable, but with some question mark behind the low doses,” he said. “I think it depends a little bit on the interaction between the non–factor replacement therapy and the bypassing agent in your patient.”

With a busy pipeline of non–factor replacement agents for hemophilia, such interactions are becoming increasingly relevant for clinicians and their patients.

Emicizumab, for instance, which is now approved for hemophilia with or without inhibitors, has synergistic activity with activated prothrombin complex concentrates (APCC). This was demonstrated by an emicizumab prophylaxis trial in which five out of eight patients with breakthrough bleeding who were treated with APPC at a dose higher than 100 IU/kg per day for more than 24 hours developed thrombotic microangiopathy. (N Engl J Med. 2017;377:809-18).

Other patients who received multiple infusions of APCC developed skin necrosis, cavernous vein thrombosis, and thrombophlebitis. Consequently, it is now recommended that APCC be avoided in patients taking emicizumab, and if unavoidable, given at the lowest dose possible. However, Dr. Tiede advised that this recommendation for APCC should not be extrapolated to encompass all factors and bypassing agents, based on existing data.

“Regarding higher or lower doses for initial treatment, I would be a little bit more careful,” he said. “That obviously depends on [whether] there is a synergistic effect with the non–factor replacement therapy and the bypassing agent. Synergistic effects have clearly been shown for the interaction of emicizumab and APCC, but when it comes to the interaction between emicizumab and VIIa, I’m not so sure. I don’t think that we have enough evidence to recommend lower doses of VIIa.”

Dr. Tiede also suggested that lower doses of factor VIII are probably unnecessary. “At high doses or high concentrations of factor VIII, emicizumab’s low affinity to the targets will not result in any significant action anymore,” he said. “So I think we have to wait for more data from basic research and also more clinical data.”

Regarding concern for duration of therapy, Dr. Tiede explained that, when treating breakthrough bleeding in a patient on non–factor replacement therapy, “the patient’s hemostatic protection level will never fall to zero, as it would have done in a patient treated previously, on demand with bypassing agents only.” Since hemostatic protection levels never return to zero, it is easier to enter the thromboembolic danger zone.

This risk was recently demonstrated by an emerging non-factor replacement therapy. In a phase 3 trial for fitusiran – a small interfering RNA therapy that targets antithrombin – a patient with hemophilia A developed a breakthrough bleed and 31-46 IU/kg of factor VIII was given, resulting in fatal cerebral sinus thrombosis. After a temporary hold, the study restarted with new limits on factor and bypassing agent doses.

Dr. Tiede reported financial relationships with Bayer, Biotest, CSL Behring, Novo Nordisk, Pfizer, and other companies.

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Three neglected numbers in the CBC: The RDW, MPV, and NRBC count

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Three neglected numbers in the CBC: The RDW, MPV, and NRBC count

The complete blood cell count (CBC) is one of the most frequently ordered laboratory tests in both the inpatient and outpatient settings. Not long ago, the CBC required peering through a microscope and counting the red blood cells, white blood cells, and platelets. These 3 numbers are still the primary purpose of the test.

Now, with automated counters, the CBC report also contains other numbers that delineate characteristics of each cell type. For example:

The mean corpuscular volume is the average volume of red blood cells. Providers use it to classify anemia as either microcytic, normocytic, or macrocytic, each with its own differential diagnosis.

The differential white blood cell count provides absolute counts and relative percentages of each type of leukocyte. For example, the absolute neutrophil count is an important measure of immunocompetence.

But other values in the CBC may be overlooked, even though they can provide important information. Here, we highlight 3 of them:

  • The red blood cell distribution width (RDW)
  • The mean platelet volume (MPV)
  • The nucleated red blood cell (NRBC) count.

In addition to describing their diagnostic utility, we also discuss emerging evidence of their potential prognostic significance in hematologic and nonhematologic disorders. By incorporating an awareness of their value in clinical practice, providers can maximize the usefulness of the CBC.

RED BLOOD CELL DISTRIBUTION WIDTH

Figure 1. A: Example of a normal red blood cell distribution width (RDW) of 13.5% (red line) in a patient with a normal complete blood cell count. B: Example of an increased RDW of 28.8% in a patient with iron deficiency shortly after initiation of iron supplementation.

The RDW is a measure of variation (anisocytosis) in the size of the circulating red cells. The term “width” is misleading, as the value is not derived from the width of the red blood cell, but rather from the width of the distribution curve of the corpuscular volume (Figure 1). Therefore, a normal RDW means that the cells are all about the same size, while a high RDW means they vary widely in size.

The RDW can be calculated either as a coefficient of variation, with a reference range of 11% to 16% depending on the laboratory, or, less often, as a standard deviation, with a reference range of 39 to 46 fL.

The RDW can differentiate between causes of anemia

A high RDW is often found in nutritional deficiencies of iron, vitamin B12, and folate. This information is helpful in differentiating the cause of microcytic anemia, as a high RDW suggests iron-deficiency anemia while a normal RDW suggests thalassemia.1 In iron deficiency, the RDW often rises before the mean corpuscular volume falls, serving as an early diagnostic clue.

The RDW can also be high after recent hemorrhage or rapid hemolysis, as the acute drop in hemoglobin results in increased production of reticulocytes, which are larger than mature erythrocytes.

Because a range of disorders can elevate the RDW, reviewing the peripheral blood smear is an important next step in the diagnostic evaluation, specifically looking for reticulocytes, microspherocytes, and other abnormal red blood cells contributing to the RDW elevation.

A normal RDW is less diagnostically useful. It indicates the red blood cells are of uniform size, but they may be uniformly small or large depending on how long the anemia has persisted. Since red cells circulate for only about 120 days, patients who have severe iron-deficiency anemia for months to years are expected to have a normal rather than a high RDW, as their red cells of normal size have all been replaced by microcytes.

A low RDW is not consistently associated with any hematologic disorder.

RDW may have prognostic value

Emerging data suggest that the RDW may also have prognostic value in nonhematologic diseases. In a retrospective study of 15,852 adult participants in the Third National Health and Nutrition Examination Survey (1988–1994), a higher RDW was associated with a higher risk of death, with the all-cause mortality rate increasing by 23% for every 1% increment in RDW.2

This correlation is particularly prominent in cardiac disorders. In 2 large retrospective studies of patients with symptomatic heart failure, a higher RDW was a strong predictor of morbidity and death (hazard ratio 1.17 per 1-standard deviation increase, P < .001), even stronger than more commonly used variables such as ejection fraction, New York Heart Association functional class, and renal function.3

In a retrospective analysis of 4,111 patients with myocardial infarction, the degree of RDW elevation correlated with the risk of repeat nonfatal myocardial infarction, coronary death, new symptomatic heart failure, and stroke.4

It is hypothesized that high RDW may reflect poor cell membrane integrity from altered cholesterol content, which in turn has deleterious effects on multiple organ systems and is therefore associated with adverse outcomes.5

Currently, using the RDW to assess prognosis remains investigational, and how best to interpret it in daily practice requires further study.

 

 

MEAN PLATELET VOLUME

The MPV, ie, the average size of platelets, is reported in femtoliters (fL). Because the MPV varies depending on the instrument used, each laboratory has a unique reference range, usually about 8 to 12 fL. The MPV must be interpreted in conjunction with the platelet count; the product of the MPV and platelet count is called the total platelet mass.

Using the MPV to find the cause of thrombocytopenia

The MPV can be used to help narrow the differential diagnosis of thrombocytopenia. For example, it is high in thrombocytopenia resulting from peripheral destruction, as in immune thrombocytopenic purpura. This is because as platelets are lost, thrombopoietin production increases and new, larger platelets are released from healthy megakaryocytes in an attempt to increase the total platelet mass.

Figure 2. Giant platelets (thin arrows), normal sized platelets (dotted arrows), and a nucleated red blood cell (thick arrow) in a patient with myelofibrosis and extensive extramedullary hematopoiesis.

In contrast, the MPV is low in patients with thrombocytopenia due to megakaryocyte hypoplasia, as malfunctioning megakaryocytes cannot maintain the total platelet mass, and any platelets produced remain small. This distinction can be obscured in the setting of splenomegaly, as larger platelets are more easily sequestered in the spleen and the MPV may therefore be low or normal.

The MPV can also be used to differentiate congenital thrombocytopenic disorders, which can be characterized by either a high MPV (eg, gray platelet syndrome, Bernard-Soulier syndrome) or a low MPV (eg, Wiskott-Aldrich syndrome) (Figure 2).

MPV may have prognostic value

Evidence suggests that the MPV also has potential prognostic value, particularly in vascular disease, as larger platelets are hypothesized to have increased hemostatic potential.

In a large meta-analysis of patients with coronary artery disease, a high MPV was associated with worse outcomes; the risk of death or myocardial infarction was 17% higher in those with a high MPV (the threshold ranged from 8.4 to 11.7 fL in the different studies) than in those with a low MPV.6

In a study of 213 patients with non-ST-segment elevation myocardial infarction, the risk of significant coronary artery disease was 4.18 times higher in patients with a high MPV and a high troponin level than in patients with a normal MPV and a high troponin.7 The authors suggested that a high MPV may help identify patients at highest risk of significant coronary artery disease who would benefit from invasive studies (ie, coronary angiography).

This correlation has also been observed in other forms of vascular disease. In 261 patients who underwent carotid angioplasty and stenting, an MPV higher than 10.1 fL was associated with a risk of in-stent restenosis more than 3 times higher.8

The MPV has also been found to be higher in patients with type 2 diabetes than in controls, particularly in those with microvascular complications such as retinopathy or microalbuminuria.9

Conversely, in patients with cancer, a low MPV appears to be associated with a poor prognosis. In a retrospective analysis of 236 patients with esophageal cancer, those who had an MPV of 7.4 fL or less had significantly shorter overall survival than patients with an MPV higher than 7.4 fL.10

A low MPV has also been associated with an increased risk of venous thromoboembolism in patients with cancer. In a prospective observational cohort study of 1,544 patients, the 2-year probability of venous thromboembolism was 9% in patients with an MPV less than 10.8 fL, compared with 5.5% in those with higher MPV values. The 2-year overall survival rate was also higher in patients with high MPV than in those with low MPV, at 64.7% vs 55.7%, respectively (P = .001).11

But the MPV is far from a perfect clinical metric. Since its measurement is subject to significant laboratory variation, an abnormal value should always be confirmed with evaluation of a peripheral blood smear. Furthermore, it is unclear why a high MPV portends poor prognosis in patients without cancer, whereas the opposite is true in patients with cancer. Therefore, its role in prognostication remains investigational, and further studies are essential to determine its appropriate usefulness in clinical practice.12

NUCLEATED RED BLOOD CELL COUNT

NRBCs are immature red blood cell precursors not present in the circulation of healthy adults. During erythropoiesis, the common myeloid progenitor cell first differentiates into a proerythroblast; subsequently, the chromatin in the nucleus of the proerythroblast gradually condenses until it becomes an orthochromatic erythroblast, also known as a nucleated red cell (Figure 2). Once the nucleus is expelled, the cell is known as a reticulocyte, which ultimately becomes a mature erythrocyte.

Healthy newborns have circulating NRBCs that rapidly disappear within a few weeks of birth. However, NRBCs can return to the circulation in a variety of disease states.

Causes of NRBCs

Brisk hemolysis or rapid blood loss can cause NRBCs to be released into the blood as erythropoiesis increases in an attempt to compensate for acute anemia.

Damage or stress to the bone marrow also causes NRBCs to be released into the peripheral blood, as is often the case in hematologic diseases. In a study of 478 patients with hematologic diseases, the frequency of NRBC positivity at diagnosis was highest in patients with chronic myeloid leukemia (100%), acute leukemia (62%), and myelodysplastic syndromes (45%).13 NRBCs also appeared at higher frequencies during chemotherapy in other hematologic conditions, such as hemophagocytic lymphohistiocytosis.

The mechanism by which NRBCs are expelled from the bone marrow is unclear, though studies have suggested that inflammation or hypoxia or both cause increased hematopoietic stress, resulting in the release of immature red cells. Increased concentrations of inflammatory cytokines (interleukin 6 and interleukin 3) and erythropoietin in the plasma and decreased arterial oxygen partial tension have been reported in patients with circulating NRBCs.14,15

Because they are associated with hematologic disorders, the finding of NRBCs should prompt evaluation of a peripheral smear to assess for abnormalities in other cell lines.

The NRBC count and prognosis

In critically ill patients, peripheral NRBCs can also indicate life-threatening conditions.

In a study of 421 adult intensive care patients, the in-hospital mortality rate was 42% in those with peripheral NRBCs vs 5.9% in those without them.16 Further, the higher the NRBC count and the more days that NRBCs were reported in the CBC, the higher the risk of death.

In adults with acute respiratory distress syndrome, the finding of any NRBCs in the peripheral blood was an independent risk factor for death, and an NRBC count higher than 220 cells/µL was associated with a more than 3-fold higher risk of death.17

Daily screening in patients in surgical intensive care units revealed that NRBCs appeared an average of 9 days before death, consistent with an early marker of impending decline.18

In another study,19 the risk of death within 90 days of hospital discharge was higher in NRBC-positive patients, reaching 21.9% in those who had a count higher than 200 cells/µL. The risk of unplanned hospital readmission within 30 days was also increased.

Leukoerythroblastosis

The combination of NRBCs and immature white blood cells (eg, myelocytes, metamyelocytes) is called leukoerythroblastosis.

Leukoerythroblastosis is classically seen in myelophthisic anemias in which hematopoietic cells in the marrow are displaced by fibrosis, tumor, or other space-occupying processes, but it can also occur in any situation of acute marrow stress, including critical illness.

In addition, leukoerythroblastosis appears in a rare complication of sickle cell hemoglobinopathies: bone marrow necrosis with fat embolism syndrome.20,21 As the marrow necroses, fat emboli are released in the systemic circulation causing micro- and macrovascular occlusions and multiorgan failure. The largest case series in the literature reports 58 patients with bone marrow necrosis with fat embolism syndrome.22

At our institution, we have seen 18 patients with this condition in the past 8 years, with the frequency of diagnosis increasing with heightened awareness of the disorder. We have found that leukoerythroblastosis is often an early marker of this unrecognized syndrome and can prompt emergency red cell exchange, which is considered to be lifesaving in this condition.22

These examples and many others show that the presence of NRBCs in the CBC can serve as an important clinical warning.

OLD TESTS CAN STILL BE USEFUL

The CBC provides much more than simple cell counts; it is a rich collection of information related to each blood cell. These days, with new diagnostic tests and prognostic tools based on molecular analysis, it is important to not overlook the value of the tests clinicians have been ordering for generations.

The RDW, MPV, and NRBC count will not likely provide definitive or flawless diagnostic or prognostic information, but when understood and used correctly, they provide readily available, cost-effective, and useful data that can supplement and guide clinical decision-making. By understanding the CBC more fully, providers can maximize the truly complete nature of this routine laboratory test.

References
  1. Lima CS, Reis AR, Grotto HZ, Saad ST, Costa FF. Comparison of red cell distribution width and a red cell discriminant function incorporating volume dispersion for distinguishing iron deficiency from beta thalassemia trait in patients with microcytosis. Sao Paulo Med J 1996; 114(5):1265–1269. pmid:9239926
  2. Perlstein TS, Weuve J, Pfeffer MA, Beckman JA. Red blood cell distribution width and mortality risk in a community-based prospective cohort. Arch Intern Med 2009; 169(6):588–594. doi:10.1001/archinternmed.2009.55
  3. Felker GM, Allen LA, Pocock SJ, et al; CHARM Investigators. Red cell distribution width as a novel prognostic marker in heart failure: data from the CHARM Program and the Duke Databank. J Am Coll Cardiol 2007; 50(1):40–47. doi:10.1016/j.jacc.2007.02.067
  4. Tonelli M, Sacks F, Arnold M, Moye L, Davis B, Pfeffer M; for the Cholesterol and Recurrent Events (CARE) Trial Investigators. Relation between red blood cell distribution width and cardiovascular event rate in people with coronary disease. Circulation 2008; 117(2):163–168. doi:10.1161/CIRCULATIONAHA.107.727545
  5. Goldstein MR, Mascitelli L, Pezzetta F. Is red cell distribution width a marker of overall membrane integrity? [Letter] Arch Intern Med 2009; 169(16):1539–1540. doi:10.1001/archinternmed.2009.275
  6. Sansanaydhu N, Numthavaj P, Muntham D, et al. Prognostic effect of mean platelet volume in patients with coronary artery disease. A systematic review and meta-analysis. Thromb Haemost 2015; 114(6):1299–1309. doi:10.1160/TH15-04-0280
  7. Taskesen T, Sekhon H, Wroblewski I, et al. Usefulness of mean platelet volume to predict significant coronary artery disease in patients with non-ST-elevation acute coronary syndromes. Am J Cardiol 2017; 119(2):192–196. doi:10.1016/j.amjcard.2016.09.042
  8. Dai Z, Gao J, Li S, et al. Mean platelet volume as a predictor for restenosis after carotid angioplasty and stenting. Stroke 2018; 49(4):872–876. doi:10.1161/STROKEAHA.117.019748
  9. Papanas N, Symeonidis G, Maltezos E, et al. Mean platelet volume in patients with type 2 diabetes mellitus. Platelets 2004; 15(8):475–478. doi:10.1080/0953710042000267707
  10. Shen W, Cui MM, Wang X, Wang RT. Reduced mean platelet volume is associated with poor prognosis in esophageal cancer. Cancer Biomark 2018; 22(3):559–563. doi:10.3233/CBM-181231
  11. Riedl J, Kaider A, Reitter EM, et al. Association of mean platelet volume with risk of venous thromboembolism and mortality in patients with cancer. Results from the Vienna Cancer and Thrombosis Study (CATS). Thromb Haemost 2014; 111(4):670–678. doi:10.1160/TH13-07-0603
  12. Tsiara S, Elisaf M, Jagroop IA, Mikhailidis DP. Platelets as predictors of vascular risk: is there a practical index of platelet activity? Clin Appl Thromb Hemost 2003; 9(3):177–190. pmid:14507105
  13. Danise P, Maconi M, Barrella F, et al. Evaluation of nucleated red blood cells in the peripheral blood of hematological diseases. Clin Chem Lab Med 2011; 50(2):357–360. doi:10.1515/CCLM.2011.766
  14. Stachon A, Bolulul O, Holland-Letz T, Krieg M. Association between nucleated red blood cells in blood and the levels of erythropoietin, interleukin 3, interleukin 6, and interleukin 12p70. Shock 2005; 24(1):34–39. pmid:15988318
  15. Kuert S, Holland-Letz T, Friese J, Stachon A. Association of nucleated red blood cells in blood and arterial oxygen partial tension. Clin Chem Lab Med 2011; 49(2):257–263. doi:10.1515/CCLM.2011.041
  16. Stachon A, Holland-Letz T, Krieg M. In-hospital mortality of intensive care patients with nucleated red blood cells in blood. Clin Chem Lab Med 2004; 42(8):933–938. doi:10.1515/CCLM.2004.151
  17. Menk M, Giebelhäuser L, Vorderwülbecke G, et al. Nucleated red blood cells as predictors of mortality in patients with acute respiratory distress syndrome (ARDS): an observational study. Ann Intensive Care 2018; 8(1):42. doi:10.1186/s13613-018-0387-5
  18. Stachon A, Kempf R, Holland-Letz T, Friese J, Becker A, Krieg M. Daily monitoring of nucleated red blood cells in the blood of surgical intensive care patients. Clin Chim Acta 2006; 366(1–2):329–335. doi:10.1016/j.cca.2005.11.022
  19. Purtle SW, Horkan CM, Moromizato T, Gibbons FK, Christopher KB. Nucleated red blood cells, critical illness survivors and postdischarge outcomes: a cohort study. Crit Care 2017; 21(1):154. doi:10.1186/s13054-017-1724-z
  20. May J, Sullivan JC, LaVie D, LaVie K, Marques MB. Inside out: bone marrow necrosis and fat embolism complicating sickle-beta+ thalassemia. Am J Med 2016; 129(12):e321–e324. doi:10.1016/j.amjmed.2016.05.027
  21. Gangaraju R, Reddy VV, Marques MB. Fat embolism syndrome secondary to bone marrow necrosis in patients with hemoglobinopathies. South Med J 2016; 109(9):549–553. doi:10.14423/SMJ.0000000000000520
  22. Tsitsikas DA, Gallinella G, Patel S, Seligman H, Greaves P, Amos RJ. Bone marrow necrosis and fat embolism syndrome in sickle cell disease: increased susceptibility of patients with non-SS genotypes and a possible association with human parvovirus B19 infection. Blood Rev 2014; 28(1):23–30. doi:10.1016/j.blre.2013.12.002
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Jori E. May, MD
Department of Medicine, University of Alabama, Birmingham

Marisa B. Marques, MD
Department of Pathology, University of Alabama, Birmingham

Vishnu V.B. Reddy, MD
Department of Pathology, University of Alabama, Birmingham

Radhika Gangaraju, MD
Department of Medicine, University of Alabama, Birmingham

Address: Jori E. May, MD, Department of Medicine, University of Alabama, 1720 2nd Avenue South, NP 2565, Birmingham, AL 35294; jemay@uabmc.edu

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Cleveland Clinic Journal of Medicine - 86(3)
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Legacy Keywords
complete blood cell count, CBC, red cell distribution width, RDW, mean platelet volume, MPV, nucleated red blood cell count, NRBC, anemia, thrombocytopenia, iron deficiency, thalassemia, blood test, prognosis, leukoerythroblastosis, Jori May, Marisa Marques, Vishnu Reddy, Radhika Gangaraju
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Jori E. May, MD
Department of Medicine, University of Alabama, Birmingham

Marisa B. Marques, MD
Department of Pathology, University of Alabama, Birmingham

Vishnu V.B. Reddy, MD
Department of Pathology, University of Alabama, Birmingham

Radhika Gangaraju, MD
Department of Medicine, University of Alabama, Birmingham

Address: Jori E. May, MD, Department of Medicine, University of Alabama, 1720 2nd Avenue South, NP 2565, Birmingham, AL 35294; jemay@uabmc.edu

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Jori E. May, MD
Department of Medicine, University of Alabama, Birmingham

Marisa B. Marques, MD
Department of Pathology, University of Alabama, Birmingham

Vishnu V.B. Reddy, MD
Department of Pathology, University of Alabama, Birmingham

Radhika Gangaraju, MD
Department of Medicine, University of Alabama, Birmingham

Address: Jori E. May, MD, Department of Medicine, University of Alabama, 1720 2nd Avenue South, NP 2565, Birmingham, AL 35294; jemay@uabmc.edu

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The complete blood cell count (CBC) is one of the most frequently ordered laboratory tests in both the inpatient and outpatient settings. Not long ago, the CBC required peering through a microscope and counting the red blood cells, white blood cells, and platelets. These 3 numbers are still the primary purpose of the test.

Now, with automated counters, the CBC report also contains other numbers that delineate characteristics of each cell type. For example:

The mean corpuscular volume is the average volume of red blood cells. Providers use it to classify anemia as either microcytic, normocytic, or macrocytic, each with its own differential diagnosis.

The differential white blood cell count provides absolute counts and relative percentages of each type of leukocyte. For example, the absolute neutrophil count is an important measure of immunocompetence.

But other values in the CBC may be overlooked, even though they can provide important information. Here, we highlight 3 of them:

  • The red blood cell distribution width (RDW)
  • The mean platelet volume (MPV)
  • The nucleated red blood cell (NRBC) count.

In addition to describing their diagnostic utility, we also discuss emerging evidence of their potential prognostic significance in hematologic and nonhematologic disorders. By incorporating an awareness of their value in clinical practice, providers can maximize the usefulness of the CBC.

RED BLOOD CELL DISTRIBUTION WIDTH

Figure 1. A: Example of a normal red blood cell distribution width (RDW) of 13.5% (red line) in a patient with a normal complete blood cell count. B: Example of an increased RDW of 28.8% in a patient with iron deficiency shortly after initiation of iron supplementation.

The RDW is a measure of variation (anisocytosis) in the size of the circulating red cells. The term “width” is misleading, as the value is not derived from the width of the red blood cell, but rather from the width of the distribution curve of the corpuscular volume (Figure 1). Therefore, a normal RDW means that the cells are all about the same size, while a high RDW means they vary widely in size.

The RDW can be calculated either as a coefficient of variation, with a reference range of 11% to 16% depending on the laboratory, or, less often, as a standard deviation, with a reference range of 39 to 46 fL.

The RDW can differentiate between causes of anemia

A high RDW is often found in nutritional deficiencies of iron, vitamin B12, and folate. This information is helpful in differentiating the cause of microcytic anemia, as a high RDW suggests iron-deficiency anemia while a normal RDW suggests thalassemia.1 In iron deficiency, the RDW often rises before the mean corpuscular volume falls, serving as an early diagnostic clue.

The RDW can also be high after recent hemorrhage or rapid hemolysis, as the acute drop in hemoglobin results in increased production of reticulocytes, which are larger than mature erythrocytes.

Because a range of disorders can elevate the RDW, reviewing the peripheral blood smear is an important next step in the diagnostic evaluation, specifically looking for reticulocytes, microspherocytes, and other abnormal red blood cells contributing to the RDW elevation.

A normal RDW is less diagnostically useful. It indicates the red blood cells are of uniform size, but they may be uniformly small or large depending on how long the anemia has persisted. Since red cells circulate for only about 120 days, patients who have severe iron-deficiency anemia for months to years are expected to have a normal rather than a high RDW, as their red cells of normal size have all been replaced by microcytes.

A low RDW is not consistently associated with any hematologic disorder.

RDW may have prognostic value

Emerging data suggest that the RDW may also have prognostic value in nonhematologic diseases. In a retrospective study of 15,852 adult participants in the Third National Health and Nutrition Examination Survey (1988–1994), a higher RDW was associated with a higher risk of death, with the all-cause mortality rate increasing by 23% for every 1% increment in RDW.2

This correlation is particularly prominent in cardiac disorders. In 2 large retrospective studies of patients with symptomatic heart failure, a higher RDW was a strong predictor of morbidity and death (hazard ratio 1.17 per 1-standard deviation increase, P < .001), even stronger than more commonly used variables such as ejection fraction, New York Heart Association functional class, and renal function.3

In a retrospective analysis of 4,111 patients with myocardial infarction, the degree of RDW elevation correlated with the risk of repeat nonfatal myocardial infarction, coronary death, new symptomatic heart failure, and stroke.4

It is hypothesized that high RDW may reflect poor cell membrane integrity from altered cholesterol content, which in turn has deleterious effects on multiple organ systems and is therefore associated with adverse outcomes.5

Currently, using the RDW to assess prognosis remains investigational, and how best to interpret it in daily practice requires further study.

 

 

MEAN PLATELET VOLUME

The MPV, ie, the average size of platelets, is reported in femtoliters (fL). Because the MPV varies depending on the instrument used, each laboratory has a unique reference range, usually about 8 to 12 fL. The MPV must be interpreted in conjunction with the platelet count; the product of the MPV and platelet count is called the total platelet mass.

Using the MPV to find the cause of thrombocytopenia

The MPV can be used to help narrow the differential diagnosis of thrombocytopenia. For example, it is high in thrombocytopenia resulting from peripheral destruction, as in immune thrombocytopenic purpura. This is because as platelets are lost, thrombopoietin production increases and new, larger platelets are released from healthy megakaryocytes in an attempt to increase the total platelet mass.

Figure 2. Giant platelets (thin arrows), normal sized platelets (dotted arrows), and a nucleated red blood cell (thick arrow) in a patient with myelofibrosis and extensive extramedullary hematopoiesis.

In contrast, the MPV is low in patients with thrombocytopenia due to megakaryocyte hypoplasia, as malfunctioning megakaryocytes cannot maintain the total platelet mass, and any platelets produced remain small. This distinction can be obscured in the setting of splenomegaly, as larger platelets are more easily sequestered in the spleen and the MPV may therefore be low or normal.

The MPV can also be used to differentiate congenital thrombocytopenic disorders, which can be characterized by either a high MPV (eg, gray platelet syndrome, Bernard-Soulier syndrome) or a low MPV (eg, Wiskott-Aldrich syndrome) (Figure 2).

MPV may have prognostic value

Evidence suggests that the MPV also has potential prognostic value, particularly in vascular disease, as larger platelets are hypothesized to have increased hemostatic potential.

In a large meta-analysis of patients with coronary artery disease, a high MPV was associated with worse outcomes; the risk of death or myocardial infarction was 17% higher in those with a high MPV (the threshold ranged from 8.4 to 11.7 fL in the different studies) than in those with a low MPV.6

In a study of 213 patients with non-ST-segment elevation myocardial infarction, the risk of significant coronary artery disease was 4.18 times higher in patients with a high MPV and a high troponin level than in patients with a normal MPV and a high troponin.7 The authors suggested that a high MPV may help identify patients at highest risk of significant coronary artery disease who would benefit from invasive studies (ie, coronary angiography).

This correlation has also been observed in other forms of vascular disease. In 261 patients who underwent carotid angioplasty and stenting, an MPV higher than 10.1 fL was associated with a risk of in-stent restenosis more than 3 times higher.8

The MPV has also been found to be higher in patients with type 2 diabetes than in controls, particularly in those with microvascular complications such as retinopathy or microalbuminuria.9

Conversely, in patients with cancer, a low MPV appears to be associated with a poor prognosis. In a retrospective analysis of 236 patients with esophageal cancer, those who had an MPV of 7.4 fL or less had significantly shorter overall survival than patients with an MPV higher than 7.4 fL.10

A low MPV has also been associated with an increased risk of venous thromoboembolism in patients with cancer. In a prospective observational cohort study of 1,544 patients, the 2-year probability of venous thromboembolism was 9% in patients with an MPV less than 10.8 fL, compared with 5.5% in those with higher MPV values. The 2-year overall survival rate was also higher in patients with high MPV than in those with low MPV, at 64.7% vs 55.7%, respectively (P = .001).11

But the MPV is far from a perfect clinical metric. Since its measurement is subject to significant laboratory variation, an abnormal value should always be confirmed with evaluation of a peripheral blood smear. Furthermore, it is unclear why a high MPV portends poor prognosis in patients without cancer, whereas the opposite is true in patients with cancer. Therefore, its role in prognostication remains investigational, and further studies are essential to determine its appropriate usefulness in clinical practice.12

NUCLEATED RED BLOOD CELL COUNT

NRBCs are immature red blood cell precursors not present in the circulation of healthy adults. During erythropoiesis, the common myeloid progenitor cell first differentiates into a proerythroblast; subsequently, the chromatin in the nucleus of the proerythroblast gradually condenses until it becomes an orthochromatic erythroblast, also known as a nucleated red cell (Figure 2). Once the nucleus is expelled, the cell is known as a reticulocyte, which ultimately becomes a mature erythrocyte.

Healthy newborns have circulating NRBCs that rapidly disappear within a few weeks of birth. However, NRBCs can return to the circulation in a variety of disease states.

Causes of NRBCs

Brisk hemolysis or rapid blood loss can cause NRBCs to be released into the blood as erythropoiesis increases in an attempt to compensate for acute anemia.

Damage or stress to the bone marrow also causes NRBCs to be released into the peripheral blood, as is often the case in hematologic diseases. In a study of 478 patients with hematologic diseases, the frequency of NRBC positivity at diagnosis was highest in patients with chronic myeloid leukemia (100%), acute leukemia (62%), and myelodysplastic syndromes (45%).13 NRBCs also appeared at higher frequencies during chemotherapy in other hematologic conditions, such as hemophagocytic lymphohistiocytosis.

The mechanism by which NRBCs are expelled from the bone marrow is unclear, though studies have suggested that inflammation or hypoxia or both cause increased hematopoietic stress, resulting in the release of immature red cells. Increased concentrations of inflammatory cytokines (interleukin 6 and interleukin 3) and erythropoietin in the plasma and decreased arterial oxygen partial tension have been reported in patients with circulating NRBCs.14,15

Because they are associated with hematologic disorders, the finding of NRBCs should prompt evaluation of a peripheral smear to assess for abnormalities in other cell lines.

The NRBC count and prognosis

In critically ill patients, peripheral NRBCs can also indicate life-threatening conditions.

In a study of 421 adult intensive care patients, the in-hospital mortality rate was 42% in those with peripheral NRBCs vs 5.9% in those without them.16 Further, the higher the NRBC count and the more days that NRBCs were reported in the CBC, the higher the risk of death.

In adults with acute respiratory distress syndrome, the finding of any NRBCs in the peripheral blood was an independent risk factor for death, and an NRBC count higher than 220 cells/µL was associated with a more than 3-fold higher risk of death.17

Daily screening in patients in surgical intensive care units revealed that NRBCs appeared an average of 9 days before death, consistent with an early marker of impending decline.18

In another study,19 the risk of death within 90 days of hospital discharge was higher in NRBC-positive patients, reaching 21.9% in those who had a count higher than 200 cells/µL. The risk of unplanned hospital readmission within 30 days was also increased.

Leukoerythroblastosis

The combination of NRBCs and immature white blood cells (eg, myelocytes, metamyelocytes) is called leukoerythroblastosis.

Leukoerythroblastosis is classically seen in myelophthisic anemias in which hematopoietic cells in the marrow are displaced by fibrosis, tumor, or other space-occupying processes, but it can also occur in any situation of acute marrow stress, including critical illness.

In addition, leukoerythroblastosis appears in a rare complication of sickle cell hemoglobinopathies: bone marrow necrosis with fat embolism syndrome.20,21 As the marrow necroses, fat emboli are released in the systemic circulation causing micro- and macrovascular occlusions and multiorgan failure. The largest case series in the literature reports 58 patients with bone marrow necrosis with fat embolism syndrome.22

At our institution, we have seen 18 patients with this condition in the past 8 years, with the frequency of diagnosis increasing with heightened awareness of the disorder. We have found that leukoerythroblastosis is often an early marker of this unrecognized syndrome and can prompt emergency red cell exchange, which is considered to be lifesaving in this condition.22

These examples and many others show that the presence of NRBCs in the CBC can serve as an important clinical warning.

OLD TESTS CAN STILL BE USEFUL

The CBC provides much more than simple cell counts; it is a rich collection of information related to each blood cell. These days, with new diagnostic tests and prognostic tools based on molecular analysis, it is important to not overlook the value of the tests clinicians have been ordering for generations.

The RDW, MPV, and NRBC count will not likely provide definitive or flawless diagnostic or prognostic information, but when understood and used correctly, they provide readily available, cost-effective, and useful data that can supplement and guide clinical decision-making. By understanding the CBC more fully, providers can maximize the truly complete nature of this routine laboratory test.

The complete blood cell count (CBC) is one of the most frequently ordered laboratory tests in both the inpatient and outpatient settings. Not long ago, the CBC required peering through a microscope and counting the red blood cells, white blood cells, and platelets. These 3 numbers are still the primary purpose of the test.

Now, with automated counters, the CBC report also contains other numbers that delineate characteristics of each cell type. For example:

The mean corpuscular volume is the average volume of red blood cells. Providers use it to classify anemia as either microcytic, normocytic, or macrocytic, each with its own differential diagnosis.

The differential white blood cell count provides absolute counts and relative percentages of each type of leukocyte. For example, the absolute neutrophil count is an important measure of immunocompetence.

But other values in the CBC may be overlooked, even though they can provide important information. Here, we highlight 3 of them:

  • The red blood cell distribution width (RDW)
  • The mean platelet volume (MPV)
  • The nucleated red blood cell (NRBC) count.

In addition to describing their diagnostic utility, we also discuss emerging evidence of their potential prognostic significance in hematologic and nonhematologic disorders. By incorporating an awareness of their value in clinical practice, providers can maximize the usefulness of the CBC.

RED BLOOD CELL DISTRIBUTION WIDTH

Figure 1. A: Example of a normal red blood cell distribution width (RDW) of 13.5% (red line) in a patient with a normal complete blood cell count. B: Example of an increased RDW of 28.8% in a patient with iron deficiency shortly after initiation of iron supplementation.

The RDW is a measure of variation (anisocytosis) in the size of the circulating red cells. The term “width” is misleading, as the value is not derived from the width of the red blood cell, but rather from the width of the distribution curve of the corpuscular volume (Figure 1). Therefore, a normal RDW means that the cells are all about the same size, while a high RDW means they vary widely in size.

The RDW can be calculated either as a coefficient of variation, with a reference range of 11% to 16% depending on the laboratory, or, less often, as a standard deviation, with a reference range of 39 to 46 fL.

The RDW can differentiate between causes of anemia

A high RDW is often found in nutritional deficiencies of iron, vitamin B12, and folate. This information is helpful in differentiating the cause of microcytic anemia, as a high RDW suggests iron-deficiency anemia while a normal RDW suggests thalassemia.1 In iron deficiency, the RDW often rises before the mean corpuscular volume falls, serving as an early diagnostic clue.

The RDW can also be high after recent hemorrhage or rapid hemolysis, as the acute drop in hemoglobin results in increased production of reticulocytes, which are larger than mature erythrocytes.

Because a range of disorders can elevate the RDW, reviewing the peripheral blood smear is an important next step in the diagnostic evaluation, specifically looking for reticulocytes, microspherocytes, and other abnormal red blood cells contributing to the RDW elevation.

A normal RDW is less diagnostically useful. It indicates the red blood cells are of uniform size, but they may be uniformly small or large depending on how long the anemia has persisted. Since red cells circulate for only about 120 days, patients who have severe iron-deficiency anemia for months to years are expected to have a normal rather than a high RDW, as their red cells of normal size have all been replaced by microcytes.

A low RDW is not consistently associated with any hematologic disorder.

RDW may have prognostic value

Emerging data suggest that the RDW may also have prognostic value in nonhematologic diseases. In a retrospective study of 15,852 adult participants in the Third National Health and Nutrition Examination Survey (1988–1994), a higher RDW was associated with a higher risk of death, with the all-cause mortality rate increasing by 23% for every 1% increment in RDW.2

This correlation is particularly prominent in cardiac disorders. In 2 large retrospective studies of patients with symptomatic heart failure, a higher RDW was a strong predictor of morbidity and death (hazard ratio 1.17 per 1-standard deviation increase, P < .001), even stronger than more commonly used variables such as ejection fraction, New York Heart Association functional class, and renal function.3

In a retrospective analysis of 4,111 patients with myocardial infarction, the degree of RDW elevation correlated with the risk of repeat nonfatal myocardial infarction, coronary death, new symptomatic heart failure, and stroke.4

It is hypothesized that high RDW may reflect poor cell membrane integrity from altered cholesterol content, which in turn has deleterious effects on multiple organ systems and is therefore associated with adverse outcomes.5

Currently, using the RDW to assess prognosis remains investigational, and how best to interpret it in daily practice requires further study.

 

 

MEAN PLATELET VOLUME

The MPV, ie, the average size of platelets, is reported in femtoliters (fL). Because the MPV varies depending on the instrument used, each laboratory has a unique reference range, usually about 8 to 12 fL. The MPV must be interpreted in conjunction with the platelet count; the product of the MPV and platelet count is called the total platelet mass.

Using the MPV to find the cause of thrombocytopenia

The MPV can be used to help narrow the differential diagnosis of thrombocytopenia. For example, it is high in thrombocytopenia resulting from peripheral destruction, as in immune thrombocytopenic purpura. This is because as platelets are lost, thrombopoietin production increases and new, larger platelets are released from healthy megakaryocytes in an attempt to increase the total platelet mass.

Figure 2. Giant platelets (thin arrows), normal sized platelets (dotted arrows), and a nucleated red blood cell (thick arrow) in a patient with myelofibrosis and extensive extramedullary hematopoiesis.

In contrast, the MPV is low in patients with thrombocytopenia due to megakaryocyte hypoplasia, as malfunctioning megakaryocytes cannot maintain the total platelet mass, and any platelets produced remain small. This distinction can be obscured in the setting of splenomegaly, as larger platelets are more easily sequestered in the spleen and the MPV may therefore be low or normal.

The MPV can also be used to differentiate congenital thrombocytopenic disorders, which can be characterized by either a high MPV (eg, gray platelet syndrome, Bernard-Soulier syndrome) or a low MPV (eg, Wiskott-Aldrich syndrome) (Figure 2).

MPV may have prognostic value

Evidence suggests that the MPV also has potential prognostic value, particularly in vascular disease, as larger platelets are hypothesized to have increased hemostatic potential.

In a large meta-analysis of patients with coronary artery disease, a high MPV was associated with worse outcomes; the risk of death or myocardial infarction was 17% higher in those with a high MPV (the threshold ranged from 8.4 to 11.7 fL in the different studies) than in those with a low MPV.6

In a study of 213 patients with non-ST-segment elevation myocardial infarction, the risk of significant coronary artery disease was 4.18 times higher in patients with a high MPV and a high troponin level than in patients with a normal MPV and a high troponin.7 The authors suggested that a high MPV may help identify patients at highest risk of significant coronary artery disease who would benefit from invasive studies (ie, coronary angiography).

This correlation has also been observed in other forms of vascular disease. In 261 patients who underwent carotid angioplasty and stenting, an MPV higher than 10.1 fL was associated with a risk of in-stent restenosis more than 3 times higher.8

The MPV has also been found to be higher in patients with type 2 diabetes than in controls, particularly in those with microvascular complications such as retinopathy or microalbuminuria.9

Conversely, in patients with cancer, a low MPV appears to be associated with a poor prognosis. In a retrospective analysis of 236 patients with esophageal cancer, those who had an MPV of 7.4 fL or less had significantly shorter overall survival than patients with an MPV higher than 7.4 fL.10

A low MPV has also been associated with an increased risk of venous thromoboembolism in patients with cancer. In a prospective observational cohort study of 1,544 patients, the 2-year probability of venous thromboembolism was 9% in patients with an MPV less than 10.8 fL, compared with 5.5% in those with higher MPV values. The 2-year overall survival rate was also higher in patients with high MPV than in those with low MPV, at 64.7% vs 55.7%, respectively (P = .001).11

But the MPV is far from a perfect clinical metric. Since its measurement is subject to significant laboratory variation, an abnormal value should always be confirmed with evaluation of a peripheral blood smear. Furthermore, it is unclear why a high MPV portends poor prognosis in patients without cancer, whereas the opposite is true in patients with cancer. Therefore, its role in prognostication remains investigational, and further studies are essential to determine its appropriate usefulness in clinical practice.12

NUCLEATED RED BLOOD CELL COUNT

NRBCs are immature red blood cell precursors not present in the circulation of healthy adults. During erythropoiesis, the common myeloid progenitor cell first differentiates into a proerythroblast; subsequently, the chromatin in the nucleus of the proerythroblast gradually condenses until it becomes an orthochromatic erythroblast, also known as a nucleated red cell (Figure 2). Once the nucleus is expelled, the cell is known as a reticulocyte, which ultimately becomes a mature erythrocyte.

Healthy newborns have circulating NRBCs that rapidly disappear within a few weeks of birth. However, NRBCs can return to the circulation in a variety of disease states.

Causes of NRBCs

Brisk hemolysis or rapid blood loss can cause NRBCs to be released into the blood as erythropoiesis increases in an attempt to compensate for acute anemia.

Damage or stress to the bone marrow also causes NRBCs to be released into the peripheral blood, as is often the case in hematologic diseases. In a study of 478 patients with hematologic diseases, the frequency of NRBC positivity at diagnosis was highest in patients with chronic myeloid leukemia (100%), acute leukemia (62%), and myelodysplastic syndromes (45%).13 NRBCs also appeared at higher frequencies during chemotherapy in other hematologic conditions, such as hemophagocytic lymphohistiocytosis.

The mechanism by which NRBCs are expelled from the bone marrow is unclear, though studies have suggested that inflammation or hypoxia or both cause increased hematopoietic stress, resulting in the release of immature red cells. Increased concentrations of inflammatory cytokines (interleukin 6 and interleukin 3) and erythropoietin in the plasma and decreased arterial oxygen partial tension have been reported in patients with circulating NRBCs.14,15

Because they are associated with hematologic disorders, the finding of NRBCs should prompt evaluation of a peripheral smear to assess for abnormalities in other cell lines.

The NRBC count and prognosis

In critically ill patients, peripheral NRBCs can also indicate life-threatening conditions.

In a study of 421 adult intensive care patients, the in-hospital mortality rate was 42% in those with peripheral NRBCs vs 5.9% in those without them.16 Further, the higher the NRBC count and the more days that NRBCs were reported in the CBC, the higher the risk of death.

In adults with acute respiratory distress syndrome, the finding of any NRBCs in the peripheral blood was an independent risk factor for death, and an NRBC count higher than 220 cells/µL was associated with a more than 3-fold higher risk of death.17

Daily screening in patients in surgical intensive care units revealed that NRBCs appeared an average of 9 days before death, consistent with an early marker of impending decline.18

In another study,19 the risk of death within 90 days of hospital discharge was higher in NRBC-positive patients, reaching 21.9% in those who had a count higher than 200 cells/µL. The risk of unplanned hospital readmission within 30 days was also increased.

Leukoerythroblastosis

The combination of NRBCs and immature white blood cells (eg, myelocytes, metamyelocytes) is called leukoerythroblastosis.

Leukoerythroblastosis is classically seen in myelophthisic anemias in which hematopoietic cells in the marrow are displaced by fibrosis, tumor, or other space-occupying processes, but it can also occur in any situation of acute marrow stress, including critical illness.

In addition, leukoerythroblastosis appears in a rare complication of sickle cell hemoglobinopathies: bone marrow necrosis with fat embolism syndrome.20,21 As the marrow necroses, fat emboli are released in the systemic circulation causing micro- and macrovascular occlusions and multiorgan failure. The largest case series in the literature reports 58 patients with bone marrow necrosis with fat embolism syndrome.22

At our institution, we have seen 18 patients with this condition in the past 8 years, with the frequency of diagnosis increasing with heightened awareness of the disorder. We have found that leukoerythroblastosis is often an early marker of this unrecognized syndrome and can prompt emergency red cell exchange, which is considered to be lifesaving in this condition.22

These examples and many others show that the presence of NRBCs in the CBC can serve as an important clinical warning.

OLD TESTS CAN STILL BE USEFUL

The CBC provides much more than simple cell counts; it is a rich collection of information related to each blood cell. These days, with new diagnostic tests and prognostic tools based on molecular analysis, it is important to not overlook the value of the tests clinicians have been ordering for generations.

The RDW, MPV, and NRBC count will not likely provide definitive or flawless diagnostic or prognostic information, but when understood and used correctly, they provide readily available, cost-effective, and useful data that can supplement and guide clinical decision-making. By understanding the CBC more fully, providers can maximize the truly complete nature of this routine laboratory test.

References
  1. Lima CS, Reis AR, Grotto HZ, Saad ST, Costa FF. Comparison of red cell distribution width and a red cell discriminant function incorporating volume dispersion for distinguishing iron deficiency from beta thalassemia trait in patients with microcytosis. Sao Paulo Med J 1996; 114(5):1265–1269. pmid:9239926
  2. Perlstein TS, Weuve J, Pfeffer MA, Beckman JA. Red blood cell distribution width and mortality risk in a community-based prospective cohort. Arch Intern Med 2009; 169(6):588–594. doi:10.1001/archinternmed.2009.55
  3. Felker GM, Allen LA, Pocock SJ, et al; CHARM Investigators. Red cell distribution width as a novel prognostic marker in heart failure: data from the CHARM Program and the Duke Databank. J Am Coll Cardiol 2007; 50(1):40–47. doi:10.1016/j.jacc.2007.02.067
  4. Tonelli M, Sacks F, Arnold M, Moye L, Davis B, Pfeffer M; for the Cholesterol and Recurrent Events (CARE) Trial Investigators. Relation between red blood cell distribution width and cardiovascular event rate in people with coronary disease. Circulation 2008; 117(2):163–168. doi:10.1161/CIRCULATIONAHA.107.727545
  5. Goldstein MR, Mascitelli L, Pezzetta F. Is red cell distribution width a marker of overall membrane integrity? [Letter] Arch Intern Med 2009; 169(16):1539–1540. doi:10.1001/archinternmed.2009.275
  6. Sansanaydhu N, Numthavaj P, Muntham D, et al. Prognostic effect of mean platelet volume in patients with coronary artery disease. A systematic review and meta-analysis. Thromb Haemost 2015; 114(6):1299–1309. doi:10.1160/TH15-04-0280
  7. Taskesen T, Sekhon H, Wroblewski I, et al. Usefulness of mean platelet volume to predict significant coronary artery disease in patients with non-ST-elevation acute coronary syndromes. Am J Cardiol 2017; 119(2):192–196. doi:10.1016/j.amjcard.2016.09.042
  8. Dai Z, Gao J, Li S, et al. Mean platelet volume as a predictor for restenosis after carotid angioplasty and stenting. Stroke 2018; 49(4):872–876. doi:10.1161/STROKEAHA.117.019748
  9. Papanas N, Symeonidis G, Maltezos E, et al. Mean platelet volume in patients with type 2 diabetes mellitus. Platelets 2004; 15(8):475–478. doi:10.1080/0953710042000267707
  10. Shen W, Cui MM, Wang X, Wang RT. Reduced mean platelet volume is associated with poor prognosis in esophageal cancer. Cancer Biomark 2018; 22(3):559–563. doi:10.3233/CBM-181231
  11. Riedl J, Kaider A, Reitter EM, et al. Association of mean platelet volume with risk of venous thromboembolism and mortality in patients with cancer. Results from the Vienna Cancer and Thrombosis Study (CATS). Thromb Haemost 2014; 111(4):670–678. doi:10.1160/TH13-07-0603
  12. Tsiara S, Elisaf M, Jagroop IA, Mikhailidis DP. Platelets as predictors of vascular risk: is there a practical index of platelet activity? Clin Appl Thromb Hemost 2003; 9(3):177–190. pmid:14507105
  13. Danise P, Maconi M, Barrella F, et al. Evaluation of nucleated red blood cells in the peripheral blood of hematological diseases. Clin Chem Lab Med 2011; 50(2):357–360. doi:10.1515/CCLM.2011.766
  14. Stachon A, Bolulul O, Holland-Letz T, Krieg M. Association between nucleated red blood cells in blood and the levels of erythropoietin, interleukin 3, interleukin 6, and interleukin 12p70. Shock 2005; 24(1):34–39. pmid:15988318
  15. Kuert S, Holland-Letz T, Friese J, Stachon A. Association of nucleated red blood cells in blood and arterial oxygen partial tension. Clin Chem Lab Med 2011; 49(2):257–263. doi:10.1515/CCLM.2011.041
  16. Stachon A, Holland-Letz T, Krieg M. In-hospital mortality of intensive care patients with nucleated red blood cells in blood. Clin Chem Lab Med 2004; 42(8):933–938. doi:10.1515/CCLM.2004.151
  17. Menk M, Giebelhäuser L, Vorderwülbecke G, et al. Nucleated red blood cells as predictors of mortality in patients with acute respiratory distress syndrome (ARDS): an observational study. Ann Intensive Care 2018; 8(1):42. doi:10.1186/s13613-018-0387-5
  18. Stachon A, Kempf R, Holland-Letz T, Friese J, Becker A, Krieg M. Daily monitoring of nucleated red blood cells in the blood of surgical intensive care patients. Clin Chim Acta 2006; 366(1–2):329–335. doi:10.1016/j.cca.2005.11.022
  19. Purtle SW, Horkan CM, Moromizato T, Gibbons FK, Christopher KB. Nucleated red blood cells, critical illness survivors and postdischarge outcomes: a cohort study. Crit Care 2017; 21(1):154. doi:10.1186/s13054-017-1724-z
  20. May J, Sullivan JC, LaVie D, LaVie K, Marques MB. Inside out: bone marrow necrosis and fat embolism complicating sickle-beta+ thalassemia. Am J Med 2016; 129(12):e321–e324. doi:10.1016/j.amjmed.2016.05.027
  21. Gangaraju R, Reddy VV, Marques MB. Fat embolism syndrome secondary to bone marrow necrosis in patients with hemoglobinopathies. South Med J 2016; 109(9):549–553. doi:10.14423/SMJ.0000000000000520
  22. Tsitsikas DA, Gallinella G, Patel S, Seligman H, Greaves P, Amos RJ. Bone marrow necrosis and fat embolism syndrome in sickle cell disease: increased susceptibility of patients with non-SS genotypes and a possible association with human parvovirus B19 infection. Blood Rev 2014; 28(1):23–30. doi:10.1016/j.blre.2013.12.002
References
  1. Lima CS, Reis AR, Grotto HZ, Saad ST, Costa FF. Comparison of red cell distribution width and a red cell discriminant function incorporating volume dispersion for distinguishing iron deficiency from beta thalassemia trait in patients with microcytosis. Sao Paulo Med J 1996; 114(5):1265–1269. pmid:9239926
  2. Perlstein TS, Weuve J, Pfeffer MA, Beckman JA. Red blood cell distribution width and mortality risk in a community-based prospective cohort. Arch Intern Med 2009; 169(6):588–594. doi:10.1001/archinternmed.2009.55
  3. Felker GM, Allen LA, Pocock SJ, et al; CHARM Investigators. Red cell distribution width as a novel prognostic marker in heart failure: data from the CHARM Program and the Duke Databank. J Am Coll Cardiol 2007; 50(1):40–47. doi:10.1016/j.jacc.2007.02.067
  4. Tonelli M, Sacks F, Arnold M, Moye L, Davis B, Pfeffer M; for the Cholesterol and Recurrent Events (CARE) Trial Investigators. Relation between red blood cell distribution width and cardiovascular event rate in people with coronary disease. Circulation 2008; 117(2):163–168. doi:10.1161/CIRCULATIONAHA.107.727545
  5. Goldstein MR, Mascitelli L, Pezzetta F. Is red cell distribution width a marker of overall membrane integrity? [Letter] Arch Intern Med 2009; 169(16):1539–1540. doi:10.1001/archinternmed.2009.275
  6. Sansanaydhu N, Numthavaj P, Muntham D, et al. Prognostic effect of mean platelet volume in patients with coronary artery disease. A systematic review and meta-analysis. Thromb Haemost 2015; 114(6):1299–1309. doi:10.1160/TH15-04-0280
  7. Taskesen T, Sekhon H, Wroblewski I, et al. Usefulness of mean platelet volume to predict significant coronary artery disease in patients with non-ST-elevation acute coronary syndromes. Am J Cardiol 2017; 119(2):192–196. doi:10.1016/j.amjcard.2016.09.042
  8. Dai Z, Gao J, Li S, et al. Mean platelet volume as a predictor for restenosis after carotid angioplasty and stenting. Stroke 2018; 49(4):872–876. doi:10.1161/STROKEAHA.117.019748
  9. Papanas N, Symeonidis G, Maltezos E, et al. Mean platelet volume in patients with type 2 diabetes mellitus. Platelets 2004; 15(8):475–478. doi:10.1080/0953710042000267707
  10. Shen W, Cui MM, Wang X, Wang RT. Reduced mean platelet volume is associated with poor prognosis in esophageal cancer. Cancer Biomark 2018; 22(3):559–563. doi:10.3233/CBM-181231
  11. Riedl J, Kaider A, Reitter EM, et al. Association of mean platelet volume with risk of venous thromboembolism and mortality in patients with cancer. Results from the Vienna Cancer and Thrombosis Study (CATS). Thromb Haemost 2014; 111(4):670–678. doi:10.1160/TH13-07-0603
  12. Tsiara S, Elisaf M, Jagroop IA, Mikhailidis DP. Platelets as predictors of vascular risk: is there a practical index of platelet activity? Clin Appl Thromb Hemost 2003; 9(3):177–190. pmid:14507105
  13. Danise P, Maconi M, Barrella F, et al. Evaluation of nucleated red blood cells in the peripheral blood of hematological diseases. Clin Chem Lab Med 2011; 50(2):357–360. doi:10.1515/CCLM.2011.766
  14. Stachon A, Bolulul O, Holland-Letz T, Krieg M. Association between nucleated red blood cells in blood and the levels of erythropoietin, interleukin 3, interleukin 6, and interleukin 12p70. Shock 2005; 24(1):34–39. pmid:15988318
  15. Kuert S, Holland-Letz T, Friese J, Stachon A. Association of nucleated red blood cells in blood and arterial oxygen partial tension. Clin Chem Lab Med 2011; 49(2):257–263. doi:10.1515/CCLM.2011.041
  16. Stachon A, Holland-Letz T, Krieg M. In-hospital mortality of intensive care patients with nucleated red blood cells in blood. Clin Chem Lab Med 2004; 42(8):933–938. doi:10.1515/CCLM.2004.151
  17. Menk M, Giebelhäuser L, Vorderwülbecke G, et al. Nucleated red blood cells as predictors of mortality in patients with acute respiratory distress syndrome (ARDS): an observational study. Ann Intensive Care 2018; 8(1):42. doi:10.1186/s13613-018-0387-5
  18. Stachon A, Kempf R, Holland-Letz T, Friese J, Becker A, Krieg M. Daily monitoring of nucleated red blood cells in the blood of surgical intensive care patients. Clin Chim Acta 2006; 366(1–2):329–335. doi:10.1016/j.cca.2005.11.022
  19. Purtle SW, Horkan CM, Moromizato T, Gibbons FK, Christopher KB. Nucleated red blood cells, critical illness survivors and postdischarge outcomes: a cohort study. Crit Care 2017; 21(1):154. doi:10.1186/s13054-017-1724-z
  20. May J, Sullivan JC, LaVie D, LaVie K, Marques MB. Inside out: bone marrow necrosis and fat embolism complicating sickle-beta+ thalassemia. Am J Med 2016; 129(12):e321–e324. doi:10.1016/j.amjmed.2016.05.027
  21. Gangaraju R, Reddy VV, Marques MB. Fat embolism syndrome secondary to bone marrow necrosis in patients with hemoglobinopathies. South Med J 2016; 109(9):549–553. doi:10.14423/SMJ.0000000000000520
  22. Tsitsikas DA, Gallinella G, Patel S, Seligman H, Greaves P, Amos RJ. Bone marrow necrosis and fat embolism syndrome in sickle cell disease: increased susceptibility of patients with non-SS genotypes and a possible association with human parvovirus B19 infection. Blood Rev 2014; 28(1):23–30. doi:10.1016/j.blre.2013.12.002
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Three neglected numbers in the CBC: The RDW, MPV, and NRBC count
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Three neglected numbers in the CBC: The RDW, MPV, and NRBC count
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complete blood cell count, CBC, red cell distribution width, RDW, mean platelet volume, MPV, nucleated red blood cell count, NRBC, anemia, thrombocytopenia, iron deficiency, thalassemia, blood test, prognosis, leukoerythroblastosis, Jori May, Marisa Marques, Vishnu Reddy, Radhika Gangaraju
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complete blood cell count, CBC, red cell distribution width, RDW, mean platelet volume, MPV, nucleated red blood cell count, NRBC, anemia, thrombocytopenia, iron deficiency, thalassemia, blood test, prognosis, leukoerythroblastosis, Jori May, Marisa Marques, Vishnu Reddy, Radhika Gangaraju
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  • The RDW can help differentiate the cause of anemia: eg, a high RDW suggests iron-deficiency anemia, while a normal RDW suggests thalassemia. Studies also suggest that a high RDW may be associated with an increased rate of all-cause mortality and may predict a poor prognosis in several cardiac diseases.
  • The MPV can be used in the evaluation of thrombocytopenia. Furthermore, emerging evidence suggests that high MPV is associated with worse outcomes in cardiovascular disorders.
  • An elevated NRBC count may predict poor outcomes in a number of critical care settings. It can also indicate a serious underlying hematologic disorder.
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The tests that we order define us

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The tests that we order define us

This issue of the Journal includes 3 articles related to clinical testing. Each focuses on a different content area of clinical medicine and each has a different higher arching message.

May et al discuss one of the most common laboratory tests we order, the complete blood cell count, and how to interpret and unlock additional information that we often overlook.

Singh et al explain the utility and limitations of assessing hepatic fibrosis in patients with known liver disease using specialized and increasingly available imaging techniques in patients with common diseases that may progress to liver failure.

Using several clinical scenarios, Suresh explores the limitations of serologic testing in patients with a potential “autoimmune” or systemic inflammatory syndrome (which, based on new consultations I see in my rheumatology clinic, seems to be virtually everyone who has experienced pain or fatigue).

The Journal also continues our ongoing series on Smart Testing that has focused on tests and testing strategies that have a strong evidence basis to support or discourage their utilization in specific settings. But in most real-life clinical scenarios, relatively little directly applicable evidence can be brought to bear on our decision process with a specific patient. Hence the ongoing need for each of us to refine our clinical reasoning skills, and to recognize the continuing challenges facing the incorporation of artificial intelligence and algorithmic practice into the management of the individual patient sitting or lying in front of us.

The challenge is to balance input from Watson, “Dr. Google,” our accumulated anecdotal and group experience, and specific data from the patient’s physical examination and provided history. All these sources are valuable, and I believe that how we thoughtfully and purposefully weigh and incorporate this information into practice defines us as the clinicians we are.

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This issue of the Journal includes 3 articles related to clinical testing. Each focuses on a different content area of clinical medicine and each has a different higher arching message.

May et al discuss one of the most common laboratory tests we order, the complete blood cell count, and how to interpret and unlock additional information that we often overlook.

Singh et al explain the utility and limitations of assessing hepatic fibrosis in patients with known liver disease using specialized and increasingly available imaging techniques in patients with common diseases that may progress to liver failure.

Using several clinical scenarios, Suresh explores the limitations of serologic testing in patients with a potential “autoimmune” or systemic inflammatory syndrome (which, based on new consultations I see in my rheumatology clinic, seems to be virtually everyone who has experienced pain or fatigue).

The Journal also continues our ongoing series on Smart Testing that has focused on tests and testing strategies that have a strong evidence basis to support or discourage their utilization in specific settings. But in most real-life clinical scenarios, relatively little directly applicable evidence can be brought to bear on our decision process with a specific patient. Hence the ongoing need for each of us to refine our clinical reasoning skills, and to recognize the continuing challenges facing the incorporation of artificial intelligence and algorithmic practice into the management of the individual patient sitting or lying in front of us.

The challenge is to balance input from Watson, “Dr. Google,” our accumulated anecdotal and group experience, and specific data from the patient’s physical examination and provided history. All these sources are valuable, and I believe that how we thoughtfully and purposefully weigh and incorporate this information into practice defines us as the clinicians we are.

This issue of the Journal includes 3 articles related to clinical testing. Each focuses on a different content area of clinical medicine and each has a different higher arching message.

May et al discuss one of the most common laboratory tests we order, the complete blood cell count, and how to interpret and unlock additional information that we often overlook.

Singh et al explain the utility and limitations of assessing hepatic fibrosis in patients with known liver disease using specialized and increasingly available imaging techniques in patients with common diseases that may progress to liver failure.

Using several clinical scenarios, Suresh explores the limitations of serologic testing in patients with a potential “autoimmune” or systemic inflammatory syndrome (which, based on new consultations I see in my rheumatology clinic, seems to be virtually everyone who has experienced pain or fatigue).

The Journal also continues our ongoing series on Smart Testing that has focused on tests and testing strategies that have a strong evidence basis to support or discourage their utilization in specific settings. But in most real-life clinical scenarios, relatively little directly applicable evidence can be brought to bear on our decision process with a specific patient. Hence the ongoing need for each of us to refine our clinical reasoning skills, and to recognize the continuing challenges facing the incorporation of artificial intelligence and algorithmic practice into the management of the individual patient sitting or lying in front of us.

The challenge is to balance input from Watson, “Dr. Google,” our accumulated anecdotal and group experience, and specific data from the patient’s physical examination and provided history. All these sources are valuable, and I believe that how we thoughtfully and purposefully weigh and incorporate this information into practice defines us as the clinicians we are.

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The tests that we order define us
Display Headline
The tests that we order define us
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complete blood cell count, CBC, liver fibrosis, hepatic fibrosis, autoimmune disease, inflammation, smart testing, Brian Mandell
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Barriers to CAR T use in the spotlight at first European meeting

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The high cost of chimeric antigen receptor (CAR) T-cell therapy largely limits its use to the sickest patients and prohibits experimentation in “less-diseased” populations, outcomes data suggest.

For that reason, and because bone marrow units are profit centers and CAR T-cell therapy reimbursement remains problematic, CAR T in the United States is “effectively being used as a bridge to transplant” – at a cost of more than $1 million per dose, economist Duane Schulthess told attendees at a recent, first-of-its-kind joint European CAR T-cell meeting in Paris, which was cosponsored by the European Hematology Association (EHA) and the European Society for Blood and Marrow Transplantation (EBMT).

“This is the way clinical practice is evolving right now; the price is not allowing enough experimentation for CAR T to flow up and be used in the less-diseased population,” said Mr. Schulthess, managing director of Vital Transformation, a consulting company based in Wezembeek-Oppem, Belgium.

In Europe, there is a slightly different problem in that health technology assessment bodies (HTAs) “have to figure out what they want to do” given the 2018 approvals of the first CAR T therapies there, he said, explaining that the data he presented was from a study commissioned by the Dutch government to help determine “what [CAR T] looks like from an effectiveness standpoint while they’re trying to figure out how much it’s worth and what they should pay.”

“Increasingly these are the big issues,” Mr. Schulthess said.

In August, the European Commission approved tisagenlecleucel (Kymriah) and axicabtagene ciloleucel (Yescarta) on the recommendation of the European Medicines Agency. Kymriah was approved for pediatric and young adult patients up to age 25 years with refractory B-cell acute lymphoblastic leukemia in relapse after transplant or in second or later relapse, as well as for adults patients with relapsed/refractory diffuse large B-cell lymphoma after failing at least two lines of systemic therapy, and Yescarta was approved for the latter and for the treatment of primary refractory mediastinal large B-cell lymphoma after at least two lines of systemic therapy.

The approvals have researchers and clinicians there clamoring for information about the therapy, which is revolutionizing the field of hematologic malignancies, according to Christian Chabannon, MD, PhD, chair of the EBMT Cellular Therapy & Immunobiology Working Party and vice-chair of the EBMT Scientific Council.

“An increasing number of European institutions are starting to administer this new category of medicinal products and increasingly contribute to ongoing clinical protocols and preclinical studies,” Dr. Chabannon said in an interview, explaining the urgency in planning the 1st European CAR T Cell Meeting just 6 months after the CAR T approvals in Europe.

EHA and EBMT brought together patient advocates, young investigators, and experts from across the globe to present the latest relevant information and data on topics ranging from current trials and experience, CAR T implementation and management, the preclinical and clinical pipelines, various CAR T applications, industry perspectives, and relevant economic issues, he said.

The latter is where Mr. Schulthess came in.

His research involved patient-level treatment pathway data from a database of more than 3 million patients treated with either allogeneic hematopoietic stem cell transplant (allo-HCT) or CAR T therapy across 5 years of experience. The data showed up to 85% response rates for each in the first-line setting. He and his colleagues then looked at therapy choices for those who failed to respond to second-line therapies and at how decisions were made regarding transplant and CAR T therapy – and specifically whether CAR T can be a substitute for transplant.

Ultimately, they looked at 29 allo-HCT recipients and 14 CAR T therapy recipients for a head-to-head comparison of the two treatments and performed an in-depth cost-efficacy analysis using a novel “visual pathology” methodology to account for limitations in the data.

The 3-year relapse-free survival probability was nearly 68% in the transplant recipients and 46% with CAR T.

“Now why is that? [Because] ... these populations are not the same; the CAR T population has a much higher disease burden,” Mr. Schulthess said. “So what we’re seeing [among] actual clinical doctors doing this for real – they are defaulting to bone marrow transplants, except in those cases where they do not have enough time or the patient does not respond. Then and only then are they giving CAR T.”



And that comes back to the fact that bone marrow units make money, he said.

CAR T is costly, and reimbursement can be problematic; these are disincentives for doctors to use CAR T therapy, at least in the United States, and while this is currently “being worked out,” the choice more often is “giving bone marrow transplant first and seeing what happens,” Mr. Schulthess said.

In Europe, that creates “a tough choice” for the HTAs, he said, noting that, in the absence of evidence of CAR T being curative in the subpopulation of patients with high disease burden who fail transplant and given the high cost, there is a push to determine at what point it begins to make sense economically.

“We think that you gain efficiency at ... roughly $277,000 [per dose] because [at that cost] you can do more CAR Ts than you can do bone marrow transplants. [CAR T] is less invasive, it’s lighter touch, it’s more efficient,” he said. “So if we were to see an efficiency cost of between $222,000 and $277,000, we think that works.”

Another recent study came to similar conclusions based on quality assessments, he said (J Clin Oncol. 2018 Sep 13. doi: 10.1200/JCO.2018.79.0642).

“We think that’s where this is going to end up, so we think that, if someone starts producing this for a couple hundred thousand bucks, then – certainly in Europe – it will make sense for this to start drifting up and being used as a substitute [to transplant],” he added.

Mr. Schulthess was one of scores of experts and investigators who presented at the EHA/EBMT joint meeting, which included numerous U.S. pioneers in the field and young European investigators, among others, Dr. Chabannon said.

Attesting to the enthusiasm in Europe regarding CAR T, Dr. Chabannon said that there were “more requests for registration than the venue could safely accommodate, a long waiting list, and a high number of individuals on the waiting list who registered for the live streaming” of the event.

“The field of CAR T cells is growing at a fast pace since the first clinical successes reported in the early 2010s, and one can wonder whether the expectations are not in excess of what reality will deliver,” he said. “Nevertheless, CAR T cells represent an essential innovation, not an incremental progress in biomedical sciences. They combine new mechanisms of action, clinical activity in advanced malignancies (and possibly beyond the field of cancer), transfer of manufacturing of human cell-based therapeutics to the industry, and potentially the first commercial success for a gene therapy.”

Surveys conducted by various professional associations, including EBMT, have clearly identified the potential for clinical successes that CAR T cells represent and the tremendous challenges raised by these innovations, he said, noting that “these include fulfilling specific educational needs.”

Therefore, EBMT and EHA have already announced that a second edition of the meeting is planned for Jan. 30 – Feb. 1, 2020, he noted.

Mr. Schulthess reported that his research was funded by the Dutch government.

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The high cost of chimeric antigen receptor (CAR) T-cell therapy largely limits its use to the sickest patients and prohibits experimentation in “less-diseased” populations, outcomes data suggest.

For that reason, and because bone marrow units are profit centers and CAR T-cell therapy reimbursement remains problematic, CAR T in the United States is “effectively being used as a bridge to transplant” – at a cost of more than $1 million per dose, economist Duane Schulthess told attendees at a recent, first-of-its-kind joint European CAR T-cell meeting in Paris, which was cosponsored by the European Hematology Association (EHA) and the European Society for Blood and Marrow Transplantation (EBMT).

“This is the way clinical practice is evolving right now; the price is not allowing enough experimentation for CAR T to flow up and be used in the less-diseased population,” said Mr. Schulthess, managing director of Vital Transformation, a consulting company based in Wezembeek-Oppem, Belgium.

In Europe, there is a slightly different problem in that health technology assessment bodies (HTAs) “have to figure out what they want to do” given the 2018 approvals of the first CAR T therapies there, he said, explaining that the data he presented was from a study commissioned by the Dutch government to help determine “what [CAR T] looks like from an effectiveness standpoint while they’re trying to figure out how much it’s worth and what they should pay.”

“Increasingly these are the big issues,” Mr. Schulthess said.

In August, the European Commission approved tisagenlecleucel (Kymriah) and axicabtagene ciloleucel (Yescarta) on the recommendation of the European Medicines Agency. Kymriah was approved for pediatric and young adult patients up to age 25 years with refractory B-cell acute lymphoblastic leukemia in relapse after transplant or in second or later relapse, as well as for adults patients with relapsed/refractory diffuse large B-cell lymphoma after failing at least two lines of systemic therapy, and Yescarta was approved for the latter and for the treatment of primary refractory mediastinal large B-cell lymphoma after at least two lines of systemic therapy.

The approvals have researchers and clinicians there clamoring for information about the therapy, which is revolutionizing the field of hematologic malignancies, according to Christian Chabannon, MD, PhD, chair of the EBMT Cellular Therapy & Immunobiology Working Party and vice-chair of the EBMT Scientific Council.

“An increasing number of European institutions are starting to administer this new category of medicinal products and increasingly contribute to ongoing clinical protocols and preclinical studies,” Dr. Chabannon said in an interview, explaining the urgency in planning the 1st European CAR T Cell Meeting just 6 months after the CAR T approvals in Europe.

EHA and EBMT brought together patient advocates, young investigators, and experts from across the globe to present the latest relevant information and data on topics ranging from current trials and experience, CAR T implementation and management, the preclinical and clinical pipelines, various CAR T applications, industry perspectives, and relevant economic issues, he said.

The latter is where Mr. Schulthess came in.

His research involved patient-level treatment pathway data from a database of more than 3 million patients treated with either allogeneic hematopoietic stem cell transplant (allo-HCT) or CAR T therapy across 5 years of experience. The data showed up to 85% response rates for each in the first-line setting. He and his colleagues then looked at therapy choices for those who failed to respond to second-line therapies and at how decisions were made regarding transplant and CAR T therapy – and specifically whether CAR T can be a substitute for transplant.

Ultimately, they looked at 29 allo-HCT recipients and 14 CAR T therapy recipients for a head-to-head comparison of the two treatments and performed an in-depth cost-efficacy analysis using a novel “visual pathology” methodology to account for limitations in the data.

The 3-year relapse-free survival probability was nearly 68% in the transplant recipients and 46% with CAR T.

“Now why is that? [Because] ... these populations are not the same; the CAR T population has a much higher disease burden,” Mr. Schulthess said. “So what we’re seeing [among] actual clinical doctors doing this for real – they are defaulting to bone marrow transplants, except in those cases where they do not have enough time or the patient does not respond. Then and only then are they giving CAR T.”



And that comes back to the fact that bone marrow units make money, he said.

CAR T is costly, and reimbursement can be problematic; these are disincentives for doctors to use CAR T therapy, at least in the United States, and while this is currently “being worked out,” the choice more often is “giving bone marrow transplant first and seeing what happens,” Mr. Schulthess said.

In Europe, that creates “a tough choice” for the HTAs, he said, noting that, in the absence of evidence of CAR T being curative in the subpopulation of patients with high disease burden who fail transplant and given the high cost, there is a push to determine at what point it begins to make sense economically.

“We think that you gain efficiency at ... roughly $277,000 [per dose] because [at that cost] you can do more CAR Ts than you can do bone marrow transplants. [CAR T] is less invasive, it’s lighter touch, it’s more efficient,” he said. “So if we were to see an efficiency cost of between $222,000 and $277,000, we think that works.”

Another recent study came to similar conclusions based on quality assessments, he said (J Clin Oncol. 2018 Sep 13. doi: 10.1200/JCO.2018.79.0642).

“We think that’s where this is going to end up, so we think that, if someone starts producing this for a couple hundred thousand bucks, then – certainly in Europe – it will make sense for this to start drifting up and being used as a substitute [to transplant],” he added.

Mr. Schulthess was one of scores of experts and investigators who presented at the EHA/EBMT joint meeting, which included numerous U.S. pioneers in the field and young European investigators, among others, Dr. Chabannon said.

Attesting to the enthusiasm in Europe regarding CAR T, Dr. Chabannon said that there were “more requests for registration than the venue could safely accommodate, a long waiting list, and a high number of individuals on the waiting list who registered for the live streaming” of the event.

“The field of CAR T cells is growing at a fast pace since the first clinical successes reported in the early 2010s, and one can wonder whether the expectations are not in excess of what reality will deliver,” he said. “Nevertheless, CAR T cells represent an essential innovation, not an incremental progress in biomedical sciences. They combine new mechanisms of action, clinical activity in advanced malignancies (and possibly beyond the field of cancer), transfer of manufacturing of human cell-based therapeutics to the industry, and potentially the first commercial success for a gene therapy.”

Surveys conducted by various professional associations, including EBMT, have clearly identified the potential for clinical successes that CAR T cells represent and the tremendous challenges raised by these innovations, he said, noting that “these include fulfilling specific educational needs.”

Therefore, EBMT and EHA have already announced that a second edition of the meeting is planned for Jan. 30 – Feb. 1, 2020, he noted.

Mr. Schulthess reported that his research was funded by the Dutch government.

 

The high cost of chimeric antigen receptor (CAR) T-cell therapy largely limits its use to the sickest patients and prohibits experimentation in “less-diseased” populations, outcomes data suggest.

For that reason, and because bone marrow units are profit centers and CAR T-cell therapy reimbursement remains problematic, CAR T in the United States is “effectively being used as a bridge to transplant” – at a cost of more than $1 million per dose, economist Duane Schulthess told attendees at a recent, first-of-its-kind joint European CAR T-cell meeting in Paris, which was cosponsored by the European Hematology Association (EHA) and the European Society for Blood and Marrow Transplantation (EBMT).

“This is the way clinical practice is evolving right now; the price is not allowing enough experimentation for CAR T to flow up and be used in the less-diseased population,” said Mr. Schulthess, managing director of Vital Transformation, a consulting company based in Wezembeek-Oppem, Belgium.

In Europe, there is a slightly different problem in that health technology assessment bodies (HTAs) “have to figure out what they want to do” given the 2018 approvals of the first CAR T therapies there, he said, explaining that the data he presented was from a study commissioned by the Dutch government to help determine “what [CAR T] looks like from an effectiveness standpoint while they’re trying to figure out how much it’s worth and what they should pay.”

“Increasingly these are the big issues,” Mr. Schulthess said.

In August, the European Commission approved tisagenlecleucel (Kymriah) and axicabtagene ciloleucel (Yescarta) on the recommendation of the European Medicines Agency. Kymriah was approved for pediatric and young adult patients up to age 25 years with refractory B-cell acute lymphoblastic leukemia in relapse after transplant or in second or later relapse, as well as for adults patients with relapsed/refractory diffuse large B-cell lymphoma after failing at least two lines of systemic therapy, and Yescarta was approved for the latter and for the treatment of primary refractory mediastinal large B-cell lymphoma after at least two lines of systemic therapy.

The approvals have researchers and clinicians there clamoring for information about the therapy, which is revolutionizing the field of hematologic malignancies, according to Christian Chabannon, MD, PhD, chair of the EBMT Cellular Therapy & Immunobiology Working Party and vice-chair of the EBMT Scientific Council.

“An increasing number of European institutions are starting to administer this new category of medicinal products and increasingly contribute to ongoing clinical protocols and preclinical studies,” Dr. Chabannon said in an interview, explaining the urgency in planning the 1st European CAR T Cell Meeting just 6 months after the CAR T approvals in Europe.

EHA and EBMT brought together patient advocates, young investigators, and experts from across the globe to present the latest relevant information and data on topics ranging from current trials and experience, CAR T implementation and management, the preclinical and clinical pipelines, various CAR T applications, industry perspectives, and relevant economic issues, he said.

The latter is where Mr. Schulthess came in.

His research involved patient-level treatment pathway data from a database of more than 3 million patients treated with either allogeneic hematopoietic stem cell transplant (allo-HCT) or CAR T therapy across 5 years of experience. The data showed up to 85% response rates for each in the first-line setting. He and his colleagues then looked at therapy choices for those who failed to respond to second-line therapies and at how decisions were made regarding transplant and CAR T therapy – and specifically whether CAR T can be a substitute for transplant.

Ultimately, they looked at 29 allo-HCT recipients and 14 CAR T therapy recipients for a head-to-head comparison of the two treatments and performed an in-depth cost-efficacy analysis using a novel “visual pathology” methodology to account for limitations in the data.

The 3-year relapse-free survival probability was nearly 68% in the transplant recipients and 46% with CAR T.

“Now why is that? [Because] ... these populations are not the same; the CAR T population has a much higher disease burden,” Mr. Schulthess said. “So what we’re seeing [among] actual clinical doctors doing this for real – they are defaulting to bone marrow transplants, except in those cases where they do not have enough time or the patient does not respond. Then and only then are they giving CAR T.”



And that comes back to the fact that bone marrow units make money, he said.

CAR T is costly, and reimbursement can be problematic; these are disincentives for doctors to use CAR T therapy, at least in the United States, and while this is currently “being worked out,” the choice more often is “giving bone marrow transplant first and seeing what happens,” Mr. Schulthess said.

In Europe, that creates “a tough choice” for the HTAs, he said, noting that, in the absence of evidence of CAR T being curative in the subpopulation of patients with high disease burden who fail transplant and given the high cost, there is a push to determine at what point it begins to make sense economically.

“We think that you gain efficiency at ... roughly $277,000 [per dose] because [at that cost] you can do more CAR Ts than you can do bone marrow transplants. [CAR T] is less invasive, it’s lighter touch, it’s more efficient,” he said. “So if we were to see an efficiency cost of between $222,000 and $277,000, we think that works.”

Another recent study came to similar conclusions based on quality assessments, he said (J Clin Oncol. 2018 Sep 13. doi: 10.1200/JCO.2018.79.0642).

“We think that’s where this is going to end up, so we think that, if someone starts producing this for a couple hundred thousand bucks, then – certainly in Europe – it will make sense for this to start drifting up and being used as a substitute [to transplant],” he added.

Mr. Schulthess was one of scores of experts and investigators who presented at the EHA/EBMT joint meeting, which included numerous U.S. pioneers in the field and young European investigators, among others, Dr. Chabannon said.

Attesting to the enthusiasm in Europe regarding CAR T, Dr. Chabannon said that there were “more requests for registration than the venue could safely accommodate, a long waiting list, and a high number of individuals on the waiting list who registered for the live streaming” of the event.

“The field of CAR T cells is growing at a fast pace since the first clinical successes reported in the early 2010s, and one can wonder whether the expectations are not in excess of what reality will deliver,” he said. “Nevertheless, CAR T cells represent an essential innovation, not an incremental progress in biomedical sciences. They combine new mechanisms of action, clinical activity in advanced malignancies (and possibly beyond the field of cancer), transfer of manufacturing of human cell-based therapeutics to the industry, and potentially the first commercial success for a gene therapy.”

Surveys conducted by various professional associations, including EBMT, have clearly identified the potential for clinical successes that CAR T cells represent and the tremendous challenges raised by these innovations, he said, noting that “these include fulfilling specific educational needs.”

Therefore, EBMT and EHA have already announced that a second edition of the meeting is planned for Jan. 30 – Feb. 1, 2020, he noted.

Mr. Schulthess reported that his research was funded by the Dutch government.

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FDA: Safety signal emerged with higher dose of tofacitinib in RA study

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A safety signal of pulmonary embolism and increased mortality has emerged in a postmarketing trial of tofacitinib (Xeljanz) in patients with rheumatoid arthritis, the Food and Drug Administration reported.

The trial’s Data Safety and Monitoring Board identified the signal in patients taking a 10-mg dose of tofacitinib twice daily, the FDA said in a safety announcement.

Pfizer, the trial’s sponsor, took “immediate action” to transition patients in the ongoing trial from the 10-mg, twice-daily dose to 5 mg twice daily, which is the approved dose for adult patients with moderate to severe rheumatoid arthritis, the agency said. The 10-mg, twice-daily dose is approved only in the dosing regimen for patients with ulcerative colitis. Xeljanz is also approved to treat psoriatic arthritis. The 11-mg, once-daily dose of Xeljanz XR that is approved to treat rheumatoid arthritis and psoriatic arthritis was not tested in the trial.

The ongoing study was designed to assess risks of cardiovascular events, cancer, and opportunistic infections with tofacitinib 10 mg twice daily or 5 mg twice daily versus the risks in a control group treated with a tumor necrosis factor (TNF) inhibitor, according to the statement.



Patients had to be 50 years of age or older and have at least one cardiovascular risk factor to be eligible for the study, which was required by the agency in 2012 when it approved tofacitinib, the statement says.

The FDA is reviewing trial data and working with Pfizer to better understand the safety signal, its effect on patients, and how tofacitinib should be used, Janet Woodcock, MD, director of the FDA’s Center for Drug Evaluation and Research, said in a news release. The trial will continue and is expected to be completed by the end of 2019.

“The agency will take appropriate action, as warranted, to ensure patients enrolled in this and other trials are protected and that health care professionals and clinical trial researchers understand the risks associated with this use,” she added.



Health care professionals should follow tofacitinib prescribing information, monitor patients for the signs and symptoms of pulmonary embolism, and advise patients to seek medical attention immediately if they experience those signs and symptoms, according to the statement.

“We are communicating now, given the serious nature of the safety issue, to ensure that patients taking tofacitinib are aware that the FDA still believes the benefits of taking tofacitinib for its approved uses continue to outweigh the risks,” Dr. Woodcock said in the release.

While not approved in rheumatoid arthritis, the 10-mg, twice-daily dose of tofacitinib is approved in the dosing regimen for patients with ulcerative colitis, the release says.

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A safety signal of pulmonary embolism and increased mortality has emerged in a postmarketing trial of tofacitinib (Xeljanz) in patients with rheumatoid arthritis, the Food and Drug Administration reported.

The trial’s Data Safety and Monitoring Board identified the signal in patients taking a 10-mg dose of tofacitinib twice daily, the FDA said in a safety announcement.

Pfizer, the trial’s sponsor, took “immediate action” to transition patients in the ongoing trial from the 10-mg, twice-daily dose to 5 mg twice daily, which is the approved dose for adult patients with moderate to severe rheumatoid arthritis, the agency said. The 10-mg, twice-daily dose is approved only in the dosing regimen for patients with ulcerative colitis. Xeljanz is also approved to treat psoriatic arthritis. The 11-mg, once-daily dose of Xeljanz XR that is approved to treat rheumatoid arthritis and psoriatic arthritis was not tested in the trial.

The ongoing study was designed to assess risks of cardiovascular events, cancer, and opportunistic infections with tofacitinib 10 mg twice daily or 5 mg twice daily versus the risks in a control group treated with a tumor necrosis factor (TNF) inhibitor, according to the statement.



Patients had to be 50 years of age or older and have at least one cardiovascular risk factor to be eligible for the study, which was required by the agency in 2012 when it approved tofacitinib, the statement says.

The FDA is reviewing trial data and working with Pfizer to better understand the safety signal, its effect on patients, and how tofacitinib should be used, Janet Woodcock, MD, director of the FDA’s Center for Drug Evaluation and Research, said in a news release. The trial will continue and is expected to be completed by the end of 2019.

“The agency will take appropriate action, as warranted, to ensure patients enrolled in this and other trials are protected and that health care professionals and clinical trial researchers understand the risks associated with this use,” she added.



Health care professionals should follow tofacitinib prescribing information, monitor patients for the signs and symptoms of pulmonary embolism, and advise patients to seek medical attention immediately if they experience those signs and symptoms, according to the statement.

“We are communicating now, given the serious nature of the safety issue, to ensure that patients taking tofacitinib are aware that the FDA still believes the benefits of taking tofacitinib for its approved uses continue to outweigh the risks,” Dr. Woodcock said in the release.

While not approved in rheumatoid arthritis, the 10-mg, twice-daily dose of tofacitinib is approved in the dosing regimen for patients with ulcerative colitis, the release says.

 

A safety signal of pulmonary embolism and increased mortality has emerged in a postmarketing trial of tofacitinib (Xeljanz) in patients with rheumatoid arthritis, the Food and Drug Administration reported.

The trial’s Data Safety and Monitoring Board identified the signal in patients taking a 10-mg dose of tofacitinib twice daily, the FDA said in a safety announcement.

Pfizer, the trial’s sponsor, took “immediate action” to transition patients in the ongoing trial from the 10-mg, twice-daily dose to 5 mg twice daily, which is the approved dose for adult patients with moderate to severe rheumatoid arthritis, the agency said. The 10-mg, twice-daily dose is approved only in the dosing regimen for patients with ulcerative colitis. Xeljanz is also approved to treat psoriatic arthritis. The 11-mg, once-daily dose of Xeljanz XR that is approved to treat rheumatoid arthritis and psoriatic arthritis was not tested in the trial.

The ongoing study was designed to assess risks of cardiovascular events, cancer, and opportunistic infections with tofacitinib 10 mg twice daily or 5 mg twice daily versus the risks in a control group treated with a tumor necrosis factor (TNF) inhibitor, according to the statement.



Patients had to be 50 years of age or older and have at least one cardiovascular risk factor to be eligible for the study, which was required by the agency in 2012 when it approved tofacitinib, the statement says.

The FDA is reviewing trial data and working with Pfizer to better understand the safety signal, its effect on patients, and how tofacitinib should be used, Janet Woodcock, MD, director of the FDA’s Center for Drug Evaluation and Research, said in a news release. The trial will continue and is expected to be completed by the end of 2019.

“The agency will take appropriate action, as warranted, to ensure patients enrolled in this and other trials are protected and that health care professionals and clinical trial researchers understand the risks associated with this use,” she added.



Health care professionals should follow tofacitinib prescribing information, monitor patients for the signs and symptoms of pulmonary embolism, and advise patients to seek medical attention immediately if they experience those signs and symptoms, according to the statement.

“We are communicating now, given the serious nature of the safety issue, to ensure that patients taking tofacitinib are aware that the FDA still believes the benefits of taking tofacitinib for its approved uses continue to outweigh the risks,” Dr. Woodcock said in the release.

While not approved in rheumatoid arthritis, the 10-mg, twice-daily dose of tofacitinib is approved in the dosing regimen for patients with ulcerative colitis, the release says.

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Ultrasound method predicts liver complications in pediatric transplant

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– An ultrasound method for assessing liver stiffness might be useful for predicting which pediatric patients will develop a life-threatening complication of hematopoietic stem cell transplantation.

Andrew D. Bowser/MDedge News
Dr. Sherwin S. Chan

Shear wave elastography values predicted severe hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) at least 4 days before standard diagnostic criteria in most patients treated in a small, prospective, two-center study, Sherwin S. Chan, MD, PhD, said at the Transplantation & Cellular Therapy Meetings.

Early identification of SOS/VOD using elastography could be beneficial in light of data showing that timing is critical in the administration of defibrotide, a treatment recommended for severe and very severe patients, according to Dr. Chan, vice chair of radiology for the University of Missouri at Kansas City.

“If you’re able to initiate it early, you can really increase day 100 survival,” Dr. Chan said in an oral presentation.

The data presented included 54 pediatric patients undergoing transplantation at one of two institutions.

At one site, the patients underwent shear wave elastography evaluation 10 days before the conditioning regimen began, and again at 5 and 14 days after the transplant. At the other site, patients with suspected SOS/VOD were enrolled and underwent elastography every other day for up to 10 exams.

Those are very different imaging protocols, Dr. Chan acknowledged in his presentation, noting that the studies started independently and data were pooled as investigators at the two institutions became aware of one another’s work.

A total of 16 patients, or 30%, developed SOS/VOD, Dr. Chan reported. Of those 16 cases, 12 (75%) were severe or very severe by the recent European Society for Blood and Marrow Transplantation (EBMT) criteria.

Increased shear wave elastography velocity was the best predictor of severe SOS/VOD, according to Dr. Chan, with a cutoff value of 1.65 m/s being 92% sensitive and 67% specific for severe SOS/VOD.

That threshold was passed at least 4 days before severe grading or death in 9 out of the 12 severe cases, he added.

Accordingly, a prospective, multicenter trial has been initiated at a number of U.S. centers to investigate whether the findings of this study are generalizable to other patient populations, Dr. Chan said at the meeting held by the American Society of Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At this meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy.

That prospective, multicenter trial is supported by Jazz Pharmaceuticals, according to Dr. Chan, who reported consulting with Jazz Pharmaceuticals in his disclosure statement.

SOURCE: Chan SS et al. TCT 2019, Abstract 55.

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– An ultrasound method for assessing liver stiffness might be useful for predicting which pediatric patients will develop a life-threatening complication of hematopoietic stem cell transplantation.

Andrew D. Bowser/MDedge News
Dr. Sherwin S. Chan

Shear wave elastography values predicted severe hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) at least 4 days before standard diagnostic criteria in most patients treated in a small, prospective, two-center study, Sherwin S. Chan, MD, PhD, said at the Transplantation & Cellular Therapy Meetings.

Early identification of SOS/VOD using elastography could be beneficial in light of data showing that timing is critical in the administration of defibrotide, a treatment recommended for severe and very severe patients, according to Dr. Chan, vice chair of radiology for the University of Missouri at Kansas City.

“If you’re able to initiate it early, you can really increase day 100 survival,” Dr. Chan said in an oral presentation.

The data presented included 54 pediatric patients undergoing transplantation at one of two institutions.

At one site, the patients underwent shear wave elastography evaluation 10 days before the conditioning regimen began, and again at 5 and 14 days after the transplant. At the other site, patients with suspected SOS/VOD were enrolled and underwent elastography every other day for up to 10 exams.

Those are very different imaging protocols, Dr. Chan acknowledged in his presentation, noting that the studies started independently and data were pooled as investigators at the two institutions became aware of one another’s work.

A total of 16 patients, or 30%, developed SOS/VOD, Dr. Chan reported. Of those 16 cases, 12 (75%) were severe or very severe by the recent European Society for Blood and Marrow Transplantation (EBMT) criteria.

Increased shear wave elastography velocity was the best predictor of severe SOS/VOD, according to Dr. Chan, with a cutoff value of 1.65 m/s being 92% sensitive and 67% specific for severe SOS/VOD.

That threshold was passed at least 4 days before severe grading or death in 9 out of the 12 severe cases, he added.

Accordingly, a prospective, multicenter trial has been initiated at a number of U.S. centers to investigate whether the findings of this study are generalizable to other patient populations, Dr. Chan said at the meeting held by the American Society of Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At this meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy.

That prospective, multicenter trial is supported by Jazz Pharmaceuticals, according to Dr. Chan, who reported consulting with Jazz Pharmaceuticals in his disclosure statement.

SOURCE: Chan SS et al. TCT 2019, Abstract 55.

– An ultrasound method for assessing liver stiffness might be useful for predicting which pediatric patients will develop a life-threatening complication of hematopoietic stem cell transplantation.

Andrew D. Bowser/MDedge News
Dr. Sherwin S. Chan

Shear wave elastography values predicted severe hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) at least 4 days before standard diagnostic criteria in most patients treated in a small, prospective, two-center study, Sherwin S. Chan, MD, PhD, said at the Transplantation & Cellular Therapy Meetings.

Early identification of SOS/VOD using elastography could be beneficial in light of data showing that timing is critical in the administration of defibrotide, a treatment recommended for severe and very severe patients, according to Dr. Chan, vice chair of radiology for the University of Missouri at Kansas City.

“If you’re able to initiate it early, you can really increase day 100 survival,” Dr. Chan said in an oral presentation.

The data presented included 54 pediatric patients undergoing transplantation at one of two institutions.

At one site, the patients underwent shear wave elastography evaluation 10 days before the conditioning regimen began, and again at 5 and 14 days after the transplant. At the other site, patients with suspected SOS/VOD were enrolled and underwent elastography every other day for up to 10 exams.

Those are very different imaging protocols, Dr. Chan acknowledged in his presentation, noting that the studies started independently and data were pooled as investigators at the two institutions became aware of one another’s work.

A total of 16 patients, or 30%, developed SOS/VOD, Dr. Chan reported. Of those 16 cases, 12 (75%) were severe or very severe by the recent European Society for Blood and Marrow Transplantation (EBMT) criteria.

Increased shear wave elastography velocity was the best predictor of severe SOS/VOD, according to Dr. Chan, with a cutoff value of 1.65 m/s being 92% sensitive and 67% specific for severe SOS/VOD.

That threshold was passed at least 4 days before severe grading or death in 9 out of the 12 severe cases, he added.

Accordingly, a prospective, multicenter trial has been initiated at a number of U.S. centers to investigate whether the findings of this study are generalizable to other patient populations, Dr. Chan said at the meeting held by the American Society of Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At this meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy.

That prospective, multicenter trial is supported by Jazz Pharmaceuticals, according to Dr. Chan, who reported consulting with Jazz Pharmaceuticals in his disclosure statement.

SOURCE: Chan SS et al. TCT 2019, Abstract 55.

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ICYMI: Rivaroxaban reduces VTE incidence in ambulatory cancer patients

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While treatment with rivaroxaban did not significantly reduce venous thromboembolism incidence in high-risk ambulatory patients with cancer over the entire course of a 180-day intervention period (6.0% vs. 8.8% in controls; hazard ratio, 0.66; 95% confidence interval, 0.40-1.09), it did reduce major bleeding incidence while patients were on treatment (2.0% vs. 6.4%; HR, 0.40; 95% CI, 0.20 0.80), according to results from the multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3b CASSINI trial published in the New England Journal of Medicine (2019 Feb 20. doi: 10.1056/NEJMoa1814630).

We reported this story at the annual meeting of the American Society of Hematology before it was published in the journal. Find our coverage at the link below.

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While treatment with rivaroxaban did not significantly reduce venous thromboembolism incidence in high-risk ambulatory patients with cancer over the entire course of a 180-day intervention period (6.0% vs. 8.8% in controls; hazard ratio, 0.66; 95% confidence interval, 0.40-1.09), it did reduce major bleeding incidence while patients were on treatment (2.0% vs. 6.4%; HR, 0.40; 95% CI, 0.20 0.80), according to results from the multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3b CASSINI trial published in the New England Journal of Medicine (2019 Feb 20. doi: 10.1056/NEJMoa1814630).

We reported this story at the annual meeting of the American Society of Hematology before it was published in the journal. Find our coverage at the link below.

While treatment with rivaroxaban did not significantly reduce venous thromboembolism incidence in high-risk ambulatory patients with cancer over the entire course of a 180-day intervention period (6.0% vs. 8.8% in controls; hazard ratio, 0.66; 95% confidence interval, 0.40-1.09), it did reduce major bleeding incidence while patients were on treatment (2.0% vs. 6.4%; HR, 0.40; 95% CI, 0.20 0.80), according to results from the multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3b CASSINI trial published in the New England Journal of Medicine (2019 Feb 20. doi: 10.1056/NEJMoa1814630).

We reported this story at the annual meeting of the American Society of Hematology before it was published in the journal. Find our coverage at the link below.

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FROM THE NEW ENGLAND JOURNAL OF MEDICINE

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Supplementary compression doesn’t improve DVT odds in critically ill

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– In critically ill patients receiving pharmacologic thromboprophylaxis, adjunct intermittent pneumatic compression (IPC) had no effect on the rates of lower-limb deep vein thrombosis (DVT), according to a new trial.

Jim Kling/MDedge News
Dr. Yaseen M. Arabi

“I was surprised. My hypothesis was that it would work,” said lead author Yaseen M. Arabi, MD, chairman of the intensive care department at King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.

Many physicians routinely carry out the practice on the assumption that IPC should lead to better blood flow and further cut DVT risk. The procedure carries few risks, aside from patient discomfort. “The main issue is that it’s not needed. It might be useful in patients who are not receiving heparin or low-molecular-weight heparin,” said Dr. Arabi, who presented the results of the study at the Critical Care Congress sponsored by the Society of Critical Care Medicine. The study was simultaneously published online in the New England Journal of Medicine.

Unfractionated or low-molecular-weight heparin reduces the risk of DVT by about 50%, but about 5%-20% of critically ill patients will develop DVT in spite of treatment, and mechanical thromboprophylaxis reduces DVT risk, compared with no prophylaxis. Some researchers have attempted to address whether adjunct intermittent pneumatic compression could further reduce DVT risk, but their studies were marked by a lack of controls, unoptimized pharmacologic regimens, and other limitations.

The trial included 2,003 adults from 20 sites in Saudi Arabia, Canada, Australia, and India, who were expected to have an intensive care unit stay of at least 72 hours. They were randomized to receive IPC combined with pharmacologic thromboprophylaxis (pneumatic compression group) or pharmacologic thromboprophylaxis alone (control).

 

 

The proportion of patients receiving unfractionated heparin versus low-molecular-weight heparin was similar between the two groups, with about 58% treated with unfractionated heparin.

A total of 3.9% of patients in the pneumatic compression group experienced incident proximal DVT, compared with 4.2% of controls (relative risk, 0.93; P =.74). A total of 3.4% experienced prevalent proximal DVT, compared with 2.7% of controls (RR, 1.29; 95% confidence interval, 0.78-2.12). There was no significant difference in the incidence of any lower-limb DVT (9.6% vs. 8.4%; RR, 1.14; 95% CI, 0.86-1.51).

There was no difference between the two groups in a composite outcome that included pulmonary embolism or all prevalent and incident lower-limb DVT (RR, 1.11; 95% CI, 0.85-1.44), and there were no between-group differences with respect to lower-limb skin injury or ischemia.

The results should change practice among those who still provide adjunct intermittent pneumatic compression, however surprising physicians may find these new results to be, according to Dr. Arabi: “People believed strongly that (adjunct IPC) should work, but you need to be evidence based, and here it showed no difference. But that’s why we do studies, right?”

The study was funded by King Abdulaziz City for Science and Technology and King Abdullah International Medical Research Center. Dr. Arabi has no relevant financial conflicts.

SOURCE: Arabi Y et al. CCC48, Abstract 142. N Engl J Med Feb 18. doi: 10.1056/NEJMoa1816150.

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– In critically ill patients receiving pharmacologic thromboprophylaxis, adjunct intermittent pneumatic compression (IPC) had no effect on the rates of lower-limb deep vein thrombosis (DVT), according to a new trial.

Jim Kling/MDedge News
Dr. Yaseen M. Arabi

“I was surprised. My hypothesis was that it would work,” said lead author Yaseen M. Arabi, MD, chairman of the intensive care department at King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.

Many physicians routinely carry out the practice on the assumption that IPC should lead to better blood flow and further cut DVT risk. The procedure carries few risks, aside from patient discomfort. “The main issue is that it’s not needed. It might be useful in patients who are not receiving heparin or low-molecular-weight heparin,” said Dr. Arabi, who presented the results of the study at the Critical Care Congress sponsored by the Society of Critical Care Medicine. The study was simultaneously published online in the New England Journal of Medicine.

Unfractionated or low-molecular-weight heparin reduces the risk of DVT by about 50%, but about 5%-20% of critically ill patients will develop DVT in spite of treatment, and mechanical thromboprophylaxis reduces DVT risk, compared with no prophylaxis. Some researchers have attempted to address whether adjunct intermittent pneumatic compression could further reduce DVT risk, but their studies were marked by a lack of controls, unoptimized pharmacologic regimens, and other limitations.

The trial included 2,003 adults from 20 sites in Saudi Arabia, Canada, Australia, and India, who were expected to have an intensive care unit stay of at least 72 hours. They were randomized to receive IPC combined with pharmacologic thromboprophylaxis (pneumatic compression group) or pharmacologic thromboprophylaxis alone (control).

 

 

The proportion of patients receiving unfractionated heparin versus low-molecular-weight heparin was similar between the two groups, with about 58% treated with unfractionated heparin.

A total of 3.9% of patients in the pneumatic compression group experienced incident proximal DVT, compared with 4.2% of controls (relative risk, 0.93; P =.74). A total of 3.4% experienced prevalent proximal DVT, compared with 2.7% of controls (RR, 1.29; 95% confidence interval, 0.78-2.12). There was no significant difference in the incidence of any lower-limb DVT (9.6% vs. 8.4%; RR, 1.14; 95% CI, 0.86-1.51).

There was no difference between the two groups in a composite outcome that included pulmonary embolism or all prevalent and incident lower-limb DVT (RR, 1.11; 95% CI, 0.85-1.44), and there were no between-group differences with respect to lower-limb skin injury or ischemia.

The results should change practice among those who still provide adjunct intermittent pneumatic compression, however surprising physicians may find these new results to be, according to Dr. Arabi: “People believed strongly that (adjunct IPC) should work, but you need to be evidence based, and here it showed no difference. But that’s why we do studies, right?”

The study was funded by King Abdulaziz City for Science and Technology and King Abdullah International Medical Research Center. Dr. Arabi has no relevant financial conflicts.

SOURCE: Arabi Y et al. CCC48, Abstract 142. N Engl J Med Feb 18. doi: 10.1056/NEJMoa1816150.

– In critically ill patients receiving pharmacologic thromboprophylaxis, adjunct intermittent pneumatic compression (IPC) had no effect on the rates of lower-limb deep vein thrombosis (DVT), according to a new trial.

Jim Kling/MDedge News
Dr. Yaseen M. Arabi

“I was surprised. My hypothesis was that it would work,” said lead author Yaseen M. Arabi, MD, chairman of the intensive care department at King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.

Many physicians routinely carry out the practice on the assumption that IPC should lead to better blood flow and further cut DVT risk. The procedure carries few risks, aside from patient discomfort. “The main issue is that it’s not needed. It might be useful in patients who are not receiving heparin or low-molecular-weight heparin,” said Dr. Arabi, who presented the results of the study at the Critical Care Congress sponsored by the Society of Critical Care Medicine. The study was simultaneously published online in the New England Journal of Medicine.

Unfractionated or low-molecular-weight heparin reduces the risk of DVT by about 50%, but about 5%-20% of critically ill patients will develop DVT in spite of treatment, and mechanical thromboprophylaxis reduces DVT risk, compared with no prophylaxis. Some researchers have attempted to address whether adjunct intermittent pneumatic compression could further reduce DVT risk, but their studies were marked by a lack of controls, unoptimized pharmacologic regimens, and other limitations.

The trial included 2,003 adults from 20 sites in Saudi Arabia, Canada, Australia, and India, who were expected to have an intensive care unit stay of at least 72 hours. They were randomized to receive IPC combined with pharmacologic thromboprophylaxis (pneumatic compression group) or pharmacologic thromboprophylaxis alone (control).

 

 

The proportion of patients receiving unfractionated heparin versus low-molecular-weight heparin was similar between the two groups, with about 58% treated with unfractionated heparin.

A total of 3.9% of patients in the pneumatic compression group experienced incident proximal DVT, compared with 4.2% of controls (relative risk, 0.93; P =.74). A total of 3.4% experienced prevalent proximal DVT, compared with 2.7% of controls (RR, 1.29; 95% confidence interval, 0.78-2.12). There was no significant difference in the incidence of any lower-limb DVT (9.6% vs. 8.4%; RR, 1.14; 95% CI, 0.86-1.51).

There was no difference between the two groups in a composite outcome that included pulmonary embolism or all prevalent and incident lower-limb DVT (RR, 1.11; 95% CI, 0.85-1.44), and there were no between-group differences with respect to lower-limb skin injury or ischemia.

The results should change practice among those who still provide adjunct intermittent pneumatic compression, however surprising physicians may find these new results to be, according to Dr. Arabi: “People believed strongly that (adjunct IPC) should work, but you need to be evidence based, and here it showed no difference. But that’s why we do studies, right?”

The study was funded by King Abdulaziz City for Science and Technology and King Abdullah International Medical Research Center. Dr. Arabi has no relevant financial conflicts.

SOURCE: Arabi Y et al. CCC48, Abstract 142. N Engl J Med Feb 18. doi: 10.1056/NEJMoa1816150.

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ICYMI: Andexanet alfa reduces anti–factor Xa activity from apixaban, rivaroxaban

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Patients with acute major bleeding associated with factor Xa inhibitor usage who received andexanet alfa experienced a significant decrease in anti–factor Xa activity, with more than three-quarters of patients experiencing good or excellent hemostatic efficiency after 12 hours. That finding emerged from the multicenter, prospective, open-label, single-group ANNEXA-4 trial published in the New England Journal of Medicine (2019 Feb 11. doi: 10.1056/NEJMoa1814051).

We reported this story at the annual meeting of the American College of Cardiology before it was published in the journal. Find our coverage at the link below.

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Patients with acute major bleeding associated with factor Xa inhibitor usage who received andexanet alfa experienced a significant decrease in anti–factor Xa activity, with more than three-quarters of patients experiencing good or excellent hemostatic efficiency after 12 hours. That finding emerged from the multicenter, prospective, open-label, single-group ANNEXA-4 trial published in the New England Journal of Medicine (2019 Feb 11. doi: 10.1056/NEJMoa1814051).

We reported this story at the annual meeting of the American College of Cardiology before it was published in the journal. Find our coverage at the link below.

Patients with acute major bleeding associated with factor Xa inhibitor usage who received andexanet alfa experienced a significant decrease in anti–factor Xa activity, with more than three-quarters of patients experiencing good or excellent hemostatic efficiency after 12 hours. That finding emerged from the multicenter, prospective, open-label, single-group ANNEXA-4 trial published in the New England Journal of Medicine (2019 Feb 11. doi: 10.1056/NEJMoa1814051).

We reported this story at the annual meeting of the American College of Cardiology before it was published in the journal. Find our coverage at the link below.

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FROM THE NEW ENGLAND JOURNAL OF MEDICINE

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Inhibitor risk nears zero after 75 days in previously untreated hemophilia A

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For previously untreated patients (PUPs) with severe hemophilia A, the risk of developing factor VIII (FVIII) alloantibodies (inhibitors) becomes negligible after 75 exposure days, according to a recent study involving more than 1,000 infants.

Will Pass/ MDedge News
Dr. H. Marijke van den Berg

This finding answers a long-standing and important question in the management of hemophilia A, reported lead author H. Marijke van den Berg, MD, PhD, of University Medical Centre in Utrecht, The Netherlands.

Inhibitor development is the biggest safety concern facing infants with severe hemophilia A because it affects 25%-35% of the patient population, but no previous studies have adequately described the associated risk profile, she noted.

“Most studies until now collected data until about 50 [exposure days] and not that far beyond,” Dr. van den Berg said at the annual congress of the European Association for Haemophilia and Allied Disorders. “So we were interested to see the serum plateau in our large cohort.”

Such a plateau would represent the time point at which risk of inhibitor development approaches zero.

Dr. van den Berg and her colleagues followed 1,038 PUPs with severe hemophilia A from first exposure to FVIII onward. Data were from drawn from the PedNet Registry. From the initial group, 943 patients (91%) were followed until 50 exposure days, and 899 (87%) were followed until 75 exposure days.

Inhibitor development was defined by a minimum of two positive inhibitor titers. In addition to determining the point in time of inhibitor development, the investigators performed a survival analysis for inhibitor incidence and reported median ages at first exposure and at exposure day 75.

The results showed that 298 out of 300 instances of inhibitor development occurred within 75 exposure days, and no inhibitors developed between exposure day 75 and 150. The final two instances occurred at exposure day 249 and 262, both with a low titer.

Median age at first exposure was 1.1 years, compared with 2.3 years at exposure day 75.

These findings suggest that risk of inhibitors is “near zero” after 75 days and that risk is approaching zero just 1 year after first exposure to FVIII, she said.

The results from this study could affect the design of future clinical trials for PUPs.

“Our recommendation will be to continue frequent [inhibitor] testing until 75 exposure days,” Dr. van den Berg said.

The time frame involved is very short, so close monitoring should be feasible for investigators, she noted.

Dr. van den Berg said that additional data, including Kaplan-Meier curves, would “hopefully” be published in a journal soon.

Dr. van den Berg reported having no relevant financial disclosures.

SOURCE: van den Berg HM et al. EAHAD 2019, Abstract OR05.

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For previously untreated patients (PUPs) with severe hemophilia A, the risk of developing factor VIII (FVIII) alloantibodies (inhibitors) becomes negligible after 75 exposure days, according to a recent study involving more than 1,000 infants.

Will Pass/ MDedge News
Dr. H. Marijke van den Berg

This finding answers a long-standing and important question in the management of hemophilia A, reported lead author H. Marijke van den Berg, MD, PhD, of University Medical Centre in Utrecht, The Netherlands.

Inhibitor development is the biggest safety concern facing infants with severe hemophilia A because it affects 25%-35% of the patient population, but no previous studies have adequately described the associated risk profile, she noted.

“Most studies until now collected data until about 50 [exposure days] and not that far beyond,” Dr. van den Berg said at the annual congress of the European Association for Haemophilia and Allied Disorders. “So we were interested to see the serum plateau in our large cohort.”

Such a plateau would represent the time point at which risk of inhibitor development approaches zero.

Dr. van den Berg and her colleagues followed 1,038 PUPs with severe hemophilia A from first exposure to FVIII onward. Data were from drawn from the PedNet Registry. From the initial group, 943 patients (91%) were followed until 50 exposure days, and 899 (87%) were followed until 75 exposure days.

Inhibitor development was defined by a minimum of two positive inhibitor titers. In addition to determining the point in time of inhibitor development, the investigators performed a survival analysis for inhibitor incidence and reported median ages at first exposure and at exposure day 75.

The results showed that 298 out of 300 instances of inhibitor development occurred within 75 exposure days, and no inhibitors developed between exposure day 75 and 150. The final two instances occurred at exposure day 249 and 262, both with a low titer.

Median age at first exposure was 1.1 years, compared with 2.3 years at exposure day 75.

These findings suggest that risk of inhibitors is “near zero” after 75 days and that risk is approaching zero just 1 year after first exposure to FVIII, she said.

The results from this study could affect the design of future clinical trials for PUPs.

“Our recommendation will be to continue frequent [inhibitor] testing until 75 exposure days,” Dr. van den Berg said.

The time frame involved is very short, so close monitoring should be feasible for investigators, she noted.

Dr. van den Berg said that additional data, including Kaplan-Meier curves, would “hopefully” be published in a journal soon.

Dr. van den Berg reported having no relevant financial disclosures.

SOURCE: van den Berg HM et al. EAHAD 2019, Abstract OR05.

 

For previously untreated patients (PUPs) with severe hemophilia A, the risk of developing factor VIII (FVIII) alloantibodies (inhibitors) becomes negligible after 75 exposure days, according to a recent study involving more than 1,000 infants.

Will Pass/ MDedge News
Dr. H. Marijke van den Berg

This finding answers a long-standing and important question in the management of hemophilia A, reported lead author H. Marijke van den Berg, MD, PhD, of University Medical Centre in Utrecht, The Netherlands.

Inhibitor development is the biggest safety concern facing infants with severe hemophilia A because it affects 25%-35% of the patient population, but no previous studies have adequately described the associated risk profile, she noted.

“Most studies until now collected data until about 50 [exposure days] and not that far beyond,” Dr. van den Berg said at the annual congress of the European Association for Haemophilia and Allied Disorders. “So we were interested to see the serum plateau in our large cohort.”

Such a plateau would represent the time point at which risk of inhibitor development approaches zero.

Dr. van den Berg and her colleagues followed 1,038 PUPs with severe hemophilia A from first exposure to FVIII onward. Data were from drawn from the PedNet Registry. From the initial group, 943 patients (91%) were followed until 50 exposure days, and 899 (87%) were followed until 75 exposure days.

Inhibitor development was defined by a minimum of two positive inhibitor titers. In addition to determining the point in time of inhibitor development, the investigators performed a survival analysis for inhibitor incidence and reported median ages at first exposure and at exposure day 75.

The results showed that 298 out of 300 instances of inhibitor development occurred within 75 exposure days, and no inhibitors developed between exposure day 75 and 150. The final two instances occurred at exposure day 249 and 262, both with a low titer.

Median age at first exposure was 1.1 years, compared with 2.3 years at exposure day 75.

These findings suggest that risk of inhibitors is “near zero” after 75 days and that risk is approaching zero just 1 year after first exposure to FVIII, she said.

The results from this study could affect the design of future clinical trials for PUPs.

“Our recommendation will be to continue frequent [inhibitor] testing until 75 exposure days,” Dr. van den Berg said.

The time frame involved is very short, so close monitoring should be feasible for investigators, she noted.

Dr. van den Berg said that additional data, including Kaplan-Meier curves, would “hopefully” be published in a journal soon.

Dr. van den Berg reported having no relevant financial disclosures.

SOURCE: van den Berg HM et al. EAHAD 2019, Abstract OR05.

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REPORTING FROM EAHAD 2019

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Key clinical point: For previously untreated patients with severe hemophilia A, the risk of developing Factor VIII alloantibodies becomes negligible after 75 exposure days.Major finding: Less than 1% of infants with severe hemophilia A developed inhibitors after 75 exposure days.

Study details: An observational study involving 1,038 previously untreated patients with severe hemophilia A, of which 899 (87%) were followed until 75 exposure days.

Disclosures: Dr. van den Berg reported having no relevant financial disclosures.

Source: van den Berg HM et al. EAHAD 2019, Abstract OR05.

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