RESUMO
Abatacept plus calcineurin inhibitors/methotrexate (CNI/MTX) is the first FDA-approved regimen for acute graft-versus-host disease (aGVHD) prophylaxis during unrelated-donor hematopoietic cell transplantation (URD-HCT). We investigated its impact in URD-HCT patients using Center for International Blood and Marrow Transplant Research data for 7/8-human leukocyte antigen (HLA)-mismatched (MMUD) or 8/8-HLA-matched (MUD) URD-HCT recipients between 2011-2018. Primary outcomes included day-180, 1-year, and 2-year overall survival (OS) and relapse-free survival (RFS) for abatacept+CNI/MTX vs CNI/MTX, CNI/MTX+antithymocyte globulin (ATG), and post-transplant cyclophosphamide-based prophylaxis (PT-Cy); other outcomes included aGVHD, chronic GVHD, non-relapse mortality, and relapse. For 7/8-MMUDs, day-180 OS (primary endpoint supporting FDA approval) was significantly higher for abatacept+CNI/MTX vs CNI/MTX (98%vs75%; p=0.0028). Two-year OS was significantly higher for abatacept+CNI/MTX vs CNI/MTX (83%vs55%; p=0.0036), CNI/MTX+ATG (83%vs46%; p=0.0005) and similar to PT-Cy (80%vs68%; p=0.2325). Two-year RFS was significantly higher for abatacept+CNI/MTX vs CNI/MTX (74%vs49%; p=0.0098) and CNI/MTX+ATG (77%vs35%; p=0.0002), and similar vs PT-Cy (72%vs56%; p=0.1058). For 8/8-MUDs, 2-year OS was similar with abatacept+CNI/MTX vs CNI/MTX (70%vs62%; p=0.2569), CNI/MTX+ATG (75%vs64%; p=0.1048), and PT-Cy (74%vs69%; p=0.5543). Two-year RFS for abatacept+CNI/MTX was numerically higher vs CNI/MTX (63%vs52%; p=0.1497) with an improved hazard ratio (HR: 0.46 [0.25-0.86]), and vs CNI/MTX+ATG (66%vs55%; p=0.1193; HR: 0.39 [0.21-0.73]). Two-year RFS was similar vs PT-Cy (68%vs57%; p=0.2356; HR: 0.54 [0.26-1.11]). For both 7/8-MMUD and 8/8-MUD recipients, abatacept+CNI/MTX prophylaxis improved survival outcomes vs CNI/MTX and CNI/MTX+ATG; outcomes were similar to PT-Cy-based regimens. Abatacept+CNI/MTX has potential to facilitate unrelated donor pool expansion for HCT.
RESUMO
Background: Belatacept, a selective T-cell costimulation blocker, was associated with improved survival and renal function but also with a risk of posttransplant lymphoproliferative disorder (PTLD) in adult kidney transplant recipients in phase 3 trials. This registry examined long-term safety in Epstein-Barr virus (EBV)-seropositive kidney transplant recipients treated with belatacept. Methods: This US-based, prospective, voluntary, multicenter registry (Evaluating Nulojix Long-Term Safety in Transplant [ENLiST]) included adult EBV-seropositive kidney-only transplant recipients treated de novo (within 14 d of transplantation) with belatacept. Primary objectives were to estimate incidence rates of confirmed PTLD, central nervous system (CNS) PTLD, and progressive multifocal encephalopathy (PML). The minimum follow-up was 2 y. Results: Of 985 enrolled transplant recipients, 933 EBV-seropositive patients received belatacept, with 523 (56.1%) receiving concomitant tacrolimus at transplant (for up to 12 mo). By study end, 3 cases of non-CNS PTLD (incidence rate, 0.08/100 person-years), 1 case of CNS PTLD (0.03/100 person-years), and no cases of PML had been reported. Two patients with non-CNS PTLD received concomitant belatacept and tacrolimus and 1 received belatacept and lymphocyte-depleting therapy. Incidence rates were comparable between patients who received concomitant belatacept and tacrolimus and those who did not receive tacrolimus (0.09/100 person-years and 0.07/100 person-years, respectively; P = 0.96). Two of 4 patients with PTLD died, and 2 were alive at the end of the study. Cumulatively, 131 graft losses or deaths were reported by study end. Conclusions: Our results from the ENLiST registry, a large, prospective real-world study, showed that the incidence rates of PTLD and CNS PTLD in belatacept-treated EBV-seropositive transplant recipients were consistent with findings from previous phase 3 trials.