Extended vs Short-term Abatacept Dosing for Graft Versus Host Disease Prophylaxis

This is a multicenter randomized, double blind, Phase 2 trial for patients receiving transplants from 7 of 8 HLA matched donors, in which an extended dosing regimen of abatacept, and a short-term dosing regimen + placebo, when added to standard calcineurin inhibitor + methotrexate-based prophylaxis, will be compared for their ability to improve outcomes in patients with a minimum follow-up of one year post-transplant. All patients will receive 4 doses of abatacept (Days -1, +5, +14, +28). Prior to the fifth dose, patients will be randomly assigned to the 4-dose abatacept arm and receive 4 doses of placebo or 8-dose abatacept arm and receive 4 more doses of abatacept. The primary endpoint of the study will be severe AGVHD-free, severe CGVHD-free, relapse-free survival (SGRFS). The study will end when the last patient has reached 2 years after transplant. Results will first be calculated and the study unblinded when the last patient has reached one year post-transplant.

NCT Number	NCT04380740
Lead Sponsor	Boston Children's Hospital Collaborators: Bristol-Myers Squibb
Conditions	Graft Vs Host Disease
Enrollment	160 participants
Start Date	2022-03-30
Primary Completion	2027-05 (estimated)
Study Completion	2028-06 (estimated)
Updated on ClinicalTrials.gov	2026-05-11