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Withdrawn Phase 1Phase 2 Interventional

Safety and Efficacy of Abatacept for Treating Chronic Cytopenia in Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) Haploinsufficiency

ClinicalTrials.gov ID: NCT03733067

Public ClinicalTrials.gov record NCT03733067. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 8, 2026, 10:05 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

Phase 1/2 Randomized, Double-Blind, Placebo-Controlled Study of Safety and Efficacy of Abatacept for Treating Chronic Cytopenia in Cytotoxic T-lymphocyte Antigen 4 (CTLA4) Haploinsufficiency

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

Background: CTLA4 stands for cytotoxic T-lymphocyte antigen-4. It is a protein the body makes naturally to check its immune system from attacking itself. Some people don t produce enough CTLA4 protein, causing problems due to overactive immune system such as big spleens, repeated lung infections, breathing problems, stomach and intestine symptoms as well as inflamed brain and nerve problems. Many have problems with their bone marrow causing low numbers of blood cells like platelets, red blood cells or white blood cells, which is called cytopenia. Researchers want to see if the drug abatacept can treat cytopenias by replacing the missing protein CTLA4. Objective: To see if abatacept is safe and helps treat cytopenias caused by CTLA4 deficiency. Eligibility: People ages 8-65 years who have CTLA4 deficiency with cytopenia Design: Participants will be screened with medical history, medication review, physical exam and blood and urine tests. They will continue their current medications and may start taking antibiotics daily. Participants will receive either abatacept or placebo through a vein for 6 months. The study team will not know if you are receiving the study drug or the placebo Women who can become pregnant must agree to use birth control measures. Men who get someone pregnant during the study will be asked to collect information and have the partner contact the study team. Participants will undergo the following procedures before starting the study and at the completion: * radiology scans of body and brain * heart and lung function tests * Bone marrow examination by a needle inserted into the hip bone to remove a small amount of tissue to study. * Participants may have a small camera on a long, thin tool passed down the throat into the stomach and small intestine for evaluation of their gut. * Questionnaires about their disease, symptoms and quality of life Over 6 months, participants will have regular study visits and get 8 doses of the study drug or a placebo by intravenous injection. They will repeat some of the same tests done earlier at the end of the study at assess response. About 1 month after the last study drug visit, participants will have a final study visit. Some participants may join a treatment extension for the study drug abatacept with no placebo. They will sign a separate consent form for this.

Study identification

NCT ID
NCT03733067
Recruitment status
Withdrawn
Study type
Interventional
Phase
Phase 1, Phase 2
Enrollment
Not listed

Conditions and interventions

Interventions

Drug · Other

Eligibility (public fields only)

Age range
8 Years to 65 Years
Sex
All
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Nov 29, 2023
Primary completion
Nov 29, 2023
Completion
Nov 29, 2023
Last update posted
Dec 3, 2023

2023

United States locations

U.S. sites
1
U.S. states
1
U.S. cities
1
Facility City State ZIP Site status
National Institutes of Health Clinical Center Bethesda Maryland 20892

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT03733067, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Dec 3, 2023 · Synced Sep 8, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT03733067 live on ClinicalTrials.gov.

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