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Biomarker and Safety Study of Clozapine in Patients With Benign Ethnic Neutropenia (BEN)

NCT02404155 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 274

Last updated 2023-01-31

Study results available
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Summary

Clozapine (CLZ) is the most effective antipsychotic for treatment-refractory schizophrenia (SZ). Despite the overwhelming evidence of superior efficacy, CLZ is infrequently prescribed in the US, at a considerably lower rate than the estimated prevalence of treatment-resistant SZ, especially for African-Americans (AA). Recent evidence suggests that low Absolute Neutrophil Counts (ANC), either at baseline or during treatment are a significant barrier to CLZ use in AA patients in the US, where guidelines mandate CLZ discontinuation if ANC drops below 1500 cells/mm3. The investigators group has found that discontinuation of CLZ in AA patients is over twice that in European-American (EA) patients (N\~400; 42% vs.19%, P=0.041) and initiation rates are 50% lower. In a Statewide study (N=1875), the investigators reported that discontinuation was more frequently due to neutropenia in the AA sample, though no AA had developed agranulocytosis (8 cases in EA). Benign Ethnic Neutropenia (BEN) in people of African ancestry, including AAs, identifies a group (50% of AA) with low ANCs but no increased risk of agranulocytosis or infection. Low baseline or in-treatment fluctuations requiring CLZ discontinuation under current prescribing guidelines are common in CLZ-treated persons with BEN. In the investigators recent pilot study of N=12 AA patients with BEN, treatment was safely and successfully continued with CLZ despite low baseline ANC (outside current guidelines). Recent evidence implicates a polymorphism in the Duffy Antigen Receptor Chemokine (DARC) gene in the pathophysiology of BEN. In homozygotes (FY-/-) for the DARC null allele, mean within-subject neutrophil counts are reduced, resulting in sporadic ANC \<1500 cells/mm3 in 10-15% of people with the allele. In population studies, the FY-/- genotype is found in 0.01% of EAs, 99.3% of sub-Saharan Africans (SSA), and 68% of AAs. Further, a missense DARC mutation has been reported to interact with the DARC FY-/- in determining low WBC in AAs. Normal patterns of week-to-week fluctuation in ANC levels in individuals of African ancestry with BEN and the DARC null genotype are not known, and no published research has examined variation in ANC in African ancestry CLZ-treated SZ patients with BEN and the DARC null genotype (FY-/-). Such data are also lacking on individuals with BEN without the DARC null genotype. Conducting such research will generate genetic marker and safety data that could be used to expand access to CLZ for AA patients who otherwise are eligible to receive this superior treatment option.

Conditions

Interventions

DRUG

Clozapine

Sponsors & Collaborators

  • University of Maryland, Baltimore

    lead OTHER

Principal Investigators

  • Deanna L Kelly, Pharm.D, BCPP · Principal Investigator

Study Design

Allocation
NA
Purpose
TREATMENT
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Max Age
64 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2015-07-31
Primary Completion
2021-10-26
Completion
2021-10-26

Countries

  • United States

Study Locations

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Drugs
Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT02404155 on ClinicalTrials.gov