Abatacept added to routine prophylaxis for acute graft-vs-host disease (GVHD) reduced incidence of severe GVHD at 100 days in children with transfusion-dependent beta-thalassemia, according to research published in Transplantation.
Myeloablative preparative regimens improve durable engraftment from allogeneic hematopoietic stem cell transplant (HSCT) in patients with beta-thalassemia major. However, patients are still at high risk of severe GVHD, even with matched sibling donors.
Current preparative regimens include busulfan, fludarabine and thiotepa with calcineurin inhibitor and corticosteroids. The study authors added abatacept to the standard GVHD prophylaxis regimen. Abatacept is a human cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibody that attenuates T-cell activation.
The retrospective review included data from 32 patients with a median age of 6.6 years who underwent HSCT. A total of 24 patients received 4 doses of abatacept as prophylaxis in addition to standard care.
A total of 4 patients receiving abatacept had acute GVHD, compared with 6 patients who received only standard prophylaxis (P =.005). All 4 patients in the abatacept cohort had grade I skin GVHD. 4 patients win the standard prophylaxis group had grade III-IV steroid-refractory GVHD by day 100. A total of 6 patients in the abatacept cohort had chronic GVHD, while 2 patients in the standard care cohort had chronic GVHD, but the difference was not significant.
About half of patients who underwent transplantation with an unrelated donor developed chronic GVHD. The authors planned to address this risk in future studies with extended doses of abatacept.
At a median follow-up of 853 days, all patients who received abatacept are alive and thalassemia-free. A total of 5 (62.5%) patients in the standard prophylaxis cohort are alive and thalassemia-free at a median follow up of 1931 days.
Patients in both cohorts experienced viral reactivation, and the authors noted viral reactivation is a concern with abatacept.
The authors concluded that the results show that adding abatacept to standard prophylaxis reduces day 100 severe acute GVHD and maintains donor engraftment. The study is limited by its retrospective nature and small sample size.
Khandelwal P, Yeh RF, Yu L, et al. Graft-versus-host disease prophylaxis with abatacept reduces severe acute graft-versus-host disease in allogeneic hematopoietic stem cell transplant for beta-thalassemia major with busulfan, fludarabine, and thiotepa. Transplantation. 2021;105(4):891-896. doi:10.1097/TP.0000000000003327