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The Incidence of Screen Failures Among African American Patients in Clinical Trials Due to Low White Blood Cell Counts








The Incidence of Screen Failures Among African American Patients in Clinical Trials Due to Low White Blood Cell Counts


Matthew Baker


Stanford University






31 July 2023


Up to two-thirds of African American individuals carry the benign rs2814778-CC genotype that lowers total white blood cell (WBC) count. Although this reduction in WBC is unlikely to have clinical significance, the low WBC can lead to exclusion from clinical trials. This is particularly true for clinical trials involving immunosuppressive treatments, which often include exclusion criteria for a WBC below a certain threshold. African Americans are already underrepresented in clinical trials, and this circumstance may further disadvantage African American patients from participating in clinical research. In clinical practice, if an African American patient in need of an immunosuppressive treatment presents with a low WBC that has been stable over many years, they are typically still given that treatment, with the understanding that their WBC is low due to a benign cause. Thus, genotyping is typically not necessary in clinical practice. However, for clinical trials, these patients are excluded, which leads to a lack of representation. The goal of this study is to determine if a significant number of African American patients are excluded from clinical trials due to a low WBC. If so, in the future it may be possible to institute genotyping in clinical trials, which may allow for the inclusion of patients with the rs2814778-CC genotype despite having a low WBC.



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"Title": "NOVARTIS-CAIN457A2220", "Description": "A Randomized, Double-blind, Placebo Controlled, Multicenter Dose Ranging Study of Subcutaneously Administered AIN457, Assessing Psoriasis Area and Severity Index (PASI) Response in Patients With Moderate to Severe Chronic Plaque-type Psoriasis" },{ "PostingID": 3956, "Title": "NOVARTIS-CAIN457A2302", "Description": "A Randomized, Double-blind, Placebo Controlled, Multicenter Study of Subcutaneous Secukinumab to Demonstrate Efficacy After Twelve Weeks of Treatment, and to Assess the Safety, Tolerability and Long-term Efficacy up to One Year in Subjects With Moderate to Severe Chronic Plaque-type Psoriasis" },{ "PostingID": 3957, "Title": "NOVARTIS-CAIN457A2303", "Description": "A Randomized, Double-blind, Double-dummy, Placebo Controlled, Multicenter Study of Subcutaneous Secukinumab to Demonstrate Efficacy After Twelve Weeks of Treatment, Compared to Placebo and Etanercept, and to Assess the Safety, Tolerability and Long-term Efficacy up to One Year in Subjects With Moderate to Severe Chronic Plaque-type Psoriasis" },{ "PostingID": 4070, "Title": "NOVARTIS-CAIN457A2308", "Description": "A randomized, double-blind, placebo controlled, multicenter study of subcutaneous secukinumab in prefilled syringes to demonstrate efficacy after twelve weeks of treatment, and to assess the safety, tolerability, usability and long-term efficacy in subjects with chronic plaque-type psoriasis" },{ "PostingID": 4071, "Title": "NOVARTIS-CAIN457A2309", "Description": "A randomized, double-blind, placebo controlled, multicenter study of subcutaneous secukinumab in autoinjectors to demonstrate efficacy after twelve weeks of treatment, and to assess the safety, tolerability, usability and long-term efficacy in subjects with chronic plaque-type psoriasis" },{ "PostingID": 4183, "Title": "NOVARTIS-CAIN457F2306", "Description": "A Randomized, Double-blind, Placebo-controlled, Multicenter Study of Secukinumab to Demonstrate the Efficacy at 24 Weeks and to Assess the Long Term Safety, Tolerability and Efficacy up to 2 Years in Patients With Active Psoriatic Arthritis" },{ "PostingID": 5006, "Title": "NOVARTIS-CAIN457F2305", "Description": "A Randomized, Double-blind, Placebo-controlled, Multicenter Study of Secukinumab to Demonstrate the 16 Week Efficacy and to Assess the Long Term Safety, Tolerability and Efficacy up to 2 Years in Patients With Active Ankylosing Spondylitis" },{ "PostingID": 14488, "Title": "GSK-HGS1006-C1115", "Description": "A Phase 3, Multi-Center, Randomized, Double-Blind, Placebo-Controlled, 52-Week Study to Evaluate the Efficacy and Safety of Belimumab (HGS1006) Administered Subcutaneously (SC) to Subjects with Systemic Lupus Erythematosus (SLE)" },{ "PostingID": 14532, "Title": "GSK-BEL115470", "Description": "A Phase 4, Multi-Center, Randomized, Open-Label Study to Evaluate the Effect of BENLYSTA™ (belimumab; HGS1006) on Vaccine Responses in Subjects with Systemic Lupus Erythematosus (SLE)" },{ "PostingID": 19688, "Title": "NOVARTIS-CAIN457F2336", "Description": "A phase III, randomized, double-blind, placebo-controlled multicenter study of subcutaneous secukinumab (150 mg) in pre-filled syringe, with or without loading regimen, to demonstrate efficacy, safety and tolerability up to 2 years in patients with active psoriatic arthritis (FUTURE 4)" },{ "PostingID": 19800, "Title": "GSK-BEL115466", "Description": "A Phase 3, Multi-Center, Multinational, Randomized, Double-Blind, Study to Evaluate the Efficacy and Safety of Belimumab (HGS1006) in Combination with Azathioprine for the Maintenance of Remission in Wegener's Granulomatosis and Microscopic Polyangiitis" },{ "PostingID": 19986, "Title": "NOVARTIS-CACZ885N2301", "Description": "A Randomized, Double-blind, Placebo Controlled Study of Canakinumab in Patients With Hereditary Periodic Fevers (TRAPS, HIDS, or crFMF), With Subsequent Randomized Withdrawal/Dosing Frequency Reduction and Open-label Long-term Treatment Epochs" },{ "PostingID": 20264, "Title": "NOVARTIS-CAIN457A2317", "Description": "A 52-week, multicenter, randomized, double-blind study of subcutaneous secukinumab to demonstrate efficacy as assessed by Psoriasis Area and Severity Index at 16 weeks of treatment compared to ustekinumab and to assess long-term safety, tolerability and efficacy in subjects with moderate to severe plaque psoriasis (CLEAR)" },{ "PostingID": 20265, "Title": "NOVARTIS-CAIN457A2326", "Description": "A 52-week, randomized, double-blind study of secukinumab (300 mg) compared to ustekinumab in subjects with moderate to severe plaque psoriasis" },{ "PostingID": 20266, "Title": "NOVARTIS-CAIN457A2312", "Description": "A randomized, double-blind, placebo-controlled, multicenter study to demonstrate the efficacy at 16 weeks of secukinumab 150 and 300 mg s.c. and to assess safety, tolerability and long-term efficacy up to 132 weeks in subjects with moderate to severe palmoplantar psoriasis" },{ "PostingID": 20267, "Title": "NOVARTIS-CAIN457A2313", "Description": "A randomized, double-blind, placebo-controlled, multicenter, study to demonstrate the efficacy at 16 weeks of secukinumab 150 and 300 mg s.c. and to assess safety, tolerability and long-term efficacy up to 132 weeks in subjects with moderate to severe nail psoriasis" },{ "PostingID": 20576, "Title": "NOVARTIS-CVAY736X2201", "Description": "A single dose, double-blind, placebo-controlled, parallel study to assess the pharmacodynamics, pharmacokinetics and safety and tolerability of VAY736 in patients with primary Sjoegren's syndrome" },{ "PostingID": 20622, "Title": "NOVARTIS-CAIN457F2302/E1", "Description": "A randomized, double-blind, placebo-controlled study of secukinumab to demonstrate the efficacy at 24 weeks and to assess the safety, tolerability and long term efficacy up to 2 years in patients with active rheumatoid arthritis who have an inadequate response to anti-TNF¿ agents (CAIN457F2302) and a three year extension study to evaluate the long term efficacy, safety and tolerability of secukinumab in patients with active rheumatoid arthritis (CAIN457F2302E1)" },{ "PostingID": 20744, "Title": "GSK-201755", "Description": "A Phase IIb, Double-Blind, Placebo-Controlled, Dose-Adaptive, Study of the Efficacy and Safety of GSK3196165 in Combination with Methotrexate Therapy, in Subjects with Active Moderate-Severe Rheumatoid Arthritis Despite Treatment with Methotrexate" },{ "PostingID": 20745, "Title": "GSK-205180", "Description": "A Phase IIa, Double-Blind, Mechanistic Study of GSK3196165 in Combination with Methotrexate Therapy in Subjects with Active Rheumatoid Arthritis Despite Treatment with DMARDs" },{ "PostingID": 20827, "Title": "GSK-203168", "Description": "A multicenter, randomized, double-blind (sponsor-unblinded), placebo-controlled study to investigate the safety and tolerability, pharmacokinetics, pharmacodynamics, and efficacy of GSK2982772 in subjects with moderate to severe rheumatoid arthritis" },{ "PostingID": 20877, "Title": "NOVARTIS-CAIN457F2366", "Description": "A randomized, double-blind, active control, multicenter study to evaluate the efficacy at week 52 of secukinumab monotherapy compared with adalimumab monotherapy in patients with active psoriatic arthritis" },{ "PostingID": 20882, "Title": "NOVARTIS-CAIN457AUS01", "Description": "A randomized, double-blind, placebo-controlled, parallel-group, multicenter study to demonstrate the efficacy of subcutaneous secukinumab 300 mg as assessed by the Psoriasis Scalp Severity Index (PSSI) at 12 weeks of treatment, compared to placebo, and to assess safety and tolerability up to 24 weeks in adult subjects with moderate to severe scalp psoriasis" },{ "PostingID": 21009, "Title": "GSK-116027", "Description": "An Open-label, Non-randomized, 52-Week Study to Evaluate Treatment Holidays and Rebound Phenomenon After Treatment With Belimumab 10 mg/kg in Systemic Lupus Erythematosus Subjects" }]

Statistical Analysis Plan