Safety of Belimumab in People With Idiopathic CD4 Lymphopenia and Autoantibodies (Phoebe)

NCT04097561 | Recruiting Phase 1 FDA Drug

• 2 other identifiers: 19014019-I-0140
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

Background: People with Idiopathic CD4 lymphopenia (ICL) have lower numbers of a type of white blood cell called CD4 cells. White blood cells fight against infections. Low levels of CD4 cells may make a person more likely to get sick. There are no approved treatments for ICL. Researchers think a drug called belimumab may be able to help in specific situations. Objective: To see if belimumab is safe for people with ICL. Eligibility: People ages 18-70 who have ICL and are participating in NIH protocol 09-I-0102 (EPIC) Design: Participants will be screened with: Medical and medication history Physical exam Questionnaire about mental health and depression Blood and urine tests Participants will have a baseline visit. This will include some repeats of the screening tests. They may also have leukapheresis: Blood will be taken from a needle in one arm and passed through a machine that separates out the white blood cells. The rest of the blood will be returned through a needle in the other arm. Participants will receive 8 doses of belimumab through IV: A needle will insert a thin plastic tube into an arm vein. Belimumab will be given through the IV line. The first 3 doses will be given every 2 weeks. The other 5 will be given once every 4 weeks. Participants will have a physical exam and blood and urine tests at each dosing visit. They will be monitored for up to 4 hours after the infusion. Participants will have 3 follow-up visits, at around 8, 16, and 24 weeks after the last dose of belimumab. They will have a physical exam and blood and urine tests. Once they finish this protocol and they will continue to be followed under 09-I-0102 (EPIC study).

Conditions

Idiopathic CD4 Lymphopenia

Keywords

CD8 Counts; B-Cell Activating Factor (BAFF); Heterogeneous Disorder; Autoimmune Disease

Outcome Measures

Primary Outcomes (1)

• Incidence of adverse events (AEs) that are possibly, probably, or definitely related to belimumab.

  Incidence of AEs that are possibly, probably, or definitely related to belimumab.

  Week 2 through Week 48

Secondary Outcomes (4)

• Evaluation of CD4 and CD8 counts at all study visits.

  All study visits

• Evaluation of natural killer (NK) and B-cell counts at all study visits.

  All study visits

• Evaluation of serum levels of BAFF at all study visits.

  All study visits

• Evaluation of any known clinical autoimmune disease (eg, hemolytic anemia) or positive autoantibodies such as ANA at all study time points.

  All study visits

Study Arms (1)

Single arm, open-label

EXPERIMENTAL

Belimumab 10 mg/kg once every 2 weeks for 3 doses, and then once every 4 weeks for 5 doses, delivered via 1-hour intravenous (IV) infusion.

Biological: Belimumab

Interventions

Belimumab BIOLOGICAL

Belimumab 10 mg/kg once every 2 weeks for 3 doses, and then once every 4 weeks for 5 doses, delivered via 1-hour intravenous (IV) infusion.

Single arm, open-label

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Individuals must meet all of the following criteria to be eligible for study participation:
• Aged 18-70 years.
• Enrolled in study 09-I-0102.
• Has a documented diagnosis of ICL, defined as the following:
• CD4 count \< 300 cells/microliter in at least 2 separate measurements 6 weeks apart at any point in the past, AND
• CD4 count \< 300 cells/microliter within previous 90 days.
• Evidence for autoantibody positivity (eg, ANA or in the research flow method looking for antilymphocyte antibodies).
• Female participants of childbearing potential must agree to use adequate contraception when engaging in sexual activities that can result in pregnancy, beginning at day 0 (or day 30 for hormonal contraception) until 4 months after the last dose of belimumab.
• Acceptable methods of contraception include the following:
• Hormonal contraception.
• Male or female condom.
• Diaphragm or cervical cap with a spermicide.
• Intrauterine device.
• Able to provide informed consent.
• Willing to allow samples to be stored for future research.

You may not qualify if:

• Individuals meeting any of the following criteria will be excluded from study participation:
• Prior receipt of belimumab. Exception: If an individual had been previously enrolled in this study and received up to 3 doses of belimumab but had to withdraw for reasons that were not related to safety or clinical concerns, they may be re-enrolled. In this case, at least 6 months must have passed from the last prior infusion and they will restart the protocol and drug administration from the beginning.
• Allergy to any component of belimumab formulation.
• HIV infection or other recognized congenital or acquired immunodeficiency.
• Current moderate or severe acute illness (eg, febrile illness, seizure, myocardial infarction, cerebrovascular accident, pulmonary embolism) or progressive serious infection related to ICL that, in the opinion of the principal investigator, would make the participant unsuitable for the study. Pre-existing infections that have been stable both clinically and with laboratory (eg, cryptococcal antigen titer or histoplasma antigen level) and radiographic evaluations on maintenance therapy over at least a year will be eligible.
• Untreated hepatitis B or C (acute or chronic).
• Active tuberculosis infection.
• Serum creatinine \> 1.5 times the upper limit of normal (ULN).
• Hemoglobin \< 8 g/dL.
• Alanine transaminase or aspartate transaminase \> 2 times ULN.
• Serum IgG \< 400 mg/L.
• Current use of systemic glucocorticosteroids, with the exception of corticosteroid nasal spray or inhaler and topical steroids.
• Severe depression. Psychiatry may be consulted prior to final eligibility decision.
• Infections (recently acquired or exacerbation of a chronic infection) that required new medications for management within the past 60 days.
• Receipt of any vaccination within the past 30 days.

Sponsors & Collaborators

• National Institute of Allergy and Infectious Diseases (NIAID): lead

Study Sites (1)

National Institutes of Health Clinical Center

Bethesda, Maryland, 20892, United States

RECRUITING

Related Links

• NIH Clinical Center Detailed Web Page

MeSH Terms

Conditions

T-Lymphocytopenia, Idiopathic CD4-Positive; Autoimmune Diseases

Interventions

belimumab

Condition Hierarchy (Ancestors)

Lymphopenia; Leukopenia; Cytopenia; Hematologic Diseases; Hemic and Lymphatic Diseases; Leukocyte Disorders; Immunologic Deficiency Syndromes; Immune System Diseases

Study Officials

• Irini Sereti, M.D.

  National Institute of Allergy and Infectious Diseases (NIAID)

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Irini Sereti, M.D.

CONTACT

(301) 496-5533; isereti@niaid.nih.gov

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: NIH
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 19, 2019
• First Posted: September 20, 2019
• Study Start: January 13, 2020
• Primary Completion (Estimated): March 25, 2027
• Study Completion (Estimated): March 25, 2027
• Last Updated: April 20, 2026

Record last verified: 2026-04-14

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)