ABBA CORD: dCBT w/ Abatacept for aGVHD Prophylaxis

Description

Cord blood (CB) is a valuable alternative graft source for patients with hematologic malignancies in need of allogeneic transplantation who lack human leukocyte antigen (HLA)-matched adult donors. In Black, Asian, Hispanic populations, the chance of finding a HLA matched donor is 23%, 41%, and 46%, respectively. CB allows for greater HLA difference between donor and recipient, and increases the availability of donors, and therefore transplant, to these populations. Retrospective analyses and prospective trials demonstrate that recipients of double CB transplant (dCBT) have a grade II-IV acute graft versus host disease (aGVHD) rate of 45-90% and grade III-IV aGVHD rates up to 24%. This high aGVHD rate is likely due to the HLA-disparities between donor and recipient, which also drives a robust graft versus leukemia response8. Anti-thymocyte globin has been used in dCBT to reduce the incidence of aGVHD, but is no longer recommended due to delayed immune-reconstitution of the CB grafts. The ABA2 trial demonstrated efficacy and safety of abatacept as prophylaxis for aGVHD in HLA-mismatched unrelated donors (MMUD), significantly reducing the rate both of grade III-IV aGVHD and grade II-IV aGVHD in 7/8 MMUD when compared to historical controls. Our hypothesis is that abatacept will be safe and effective in reducing aGVHD rates in dCBT.