Actively Recruiting
Safety Evaluation of Belimumab in People With Idiopathic CD4 Lymphopenia and Autoantibodies (Phoebe)
Led by National Institute of Allergy and Infectious Diseases (NIAID) ยท Updated on 2026-04-20
20
Participants Needed
1
Research Sites
N/A
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are studying idiopathic CD4 lymphopenia (ICL), a condition where people have persistently low levels of CD4 white blood cells, which help fight infections. This condition can be linked with autoimmunity, infections, and certain cancers, but its cause is unclear and no approved treatments exist. The study aims to evaluate the safety of belimumab, a drug approved for lupus that targets certain immune cells, to understand its effects in people with ICL who have autoantibodies. Participants will receive belimumab through intravenous infusions over about six months. The treatment schedule includes 3 doses every 2 weeks followed by 5 doses every 4 weeks. Before and during treatment, participants will have medical exams, blood and urine tests, and may undergo leukapheresis to collect white blood cells. After the treatment period, they will have follow-up visits at 8, 16, and 24 weeks to monitor health and immune function. Throughout the study, participants will be closely monitored with physical exams, laboratory tests, and questionnaires about mental health. Researchers will track adverse events related to belimumab and measure immune cell counts and autoantibody levels. After completing this study, participants will continue follow-up in a related NIH protocol. The entire study duration includes treatment and extended observation to assess safety and immune changes.
CONDITIONS
Brief Title
Safety of Belimumab in People With Idiopathic CD4 Lymphopenia and Autoantibodies (Phoebe)
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Aged 18 to 70 years
- Enrolled in study 09-I-0102
- Documented diagnosis of idiopathic CD4 lymphopenia with CD4 count below 300 cells/microliter on at least two measurements 6 weeks apart and within the past 90 days
- Evidence of autoantibody positivity such as ANA or antilymphocyte antibodies
- Female participants of childbearing potential must agree to use adequate contraception from day 0 until 4 months after the last belimumab dose
- Able to give informed consent
- Willing to allow samples to be stored for future research
You will not qualify if you...
- Prior receipt of belimumab, except for limited prior doses with re-enrollment conditions
- Allergy to any component of belimumab
- HIV infection or other recognized immune deficiency
- Current moderate or severe acute illness or progressive serious infection related to ICL
- Untreated hepatitis B or C
- Active tuberculosis infection
- Serum creatinine greater than 1.5 times the upper limit of normal
- Hemoglobin less than 8 g/dL
- Elevated liver enzymes above twice the upper limit of normal
- Serum IgG less than 400 mg/L
- Current use of systemic glucocorticosteroids except nasal spray, inhaler, or topical steroids
- Recent cancer diagnosis or autoimmune treatment requiring chemotherapy, immunomodulators, or radiation within past 6 months
- Severe depression
- Recent infections requiring new medications within past 60 days
- Receipt of any vaccination within past 30 days
- Pregnant or breastfeeding
- Behavioral or substance use issues that affect study participation
- Concomitant diagnosis of SLE is allowed if criteria met without immunosuppressive treatments affecting lymphopenia
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 6 months
Participants receive belimumab 10 mg/kg by intravenous infusion following the schedule approved for systemic lupus erythematosus: doses at study entry, 2 weeks, 4 weeks, then monthly for a total of 8 doses over 6 months. Clinical safety evaluations with immunologic and serologic testing are performed at all study visits.
8 infusion visits over 6 months
Duration - 6 months
Participants are followed for an additional 6 months after completing belimumab treatment to monitor safety and immunologic status with ongoing clinical and laboratory evaluations.
3 visits approximately every 2 months
Trial Site Locations
Total: 1 location
1
National Institutes of Health Clinical Center
Bethesda, Maryland, United States, 20892
Actively Recruiting
Research Team
I
Irini Sereti, M.D.
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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