Post-Transplantation Cyclophosphamide and Abatacept Graft-Versus-Host-Disease Prophylaxis Shows Improved Outcomes in North American Adult T-Cell Leukemia/Lymphoma

• Published in: Blood 2024-11, Vol.144 (Supplement 1), p.7367-7367
• Main Authors: Nguyen, Julie, Bazarbachi, Abdul-Hamid, Pradhan, Kith, Yan, John, Cordover, Emma, Reef, Daniel K, Patel, Riya, Al Hamed, Rama, Thakkar, Astha, Rahman, Shafia, Herrera, Diego Adrianzen, Quinn, Ryann, Castro, Alyssa de, Gillick, Kailyn, Mustafa, Jennat, Khatun, Fariha, Lombardo, Amanda, Townsend, Latoya S, Abreu, Michelly, Chambers, Nicole, Elkind, Richard, Shi, Yang, Wang, Yanhua, Derman, Olga, Gritsman, Kira, Steidl, Ulrich, Goldfinger, Mendel, Kornblum, Noah, Shastri, Aditi, Mantzaris, Ioannis, Bachier Rodriguez, Lizamarie, Moavero, Brittany, Verceles, Jhannine, Czavar, Angela, Shapiro, Lauren, Wang, Trent, Ramos, Juan Carlos, Shah, Nishi, Gupta, Ridhi, Konopleva, Marina, Braunschweig, Ira, Verma, Amit, Ye, B. Hilda, Janakiram, Murali, Cooper, Dennis L, Sica, R. Alejandro
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2024-207521

Background: Adult T-cell leukemia/lymphoma (ATLL) is a T-cell malignancy driven by the human T-cell lymphotropic virus type I (HTLV-1) that is associated with a dismal prognosis. Allogeneic stem-cell transplantation (Allo-SCT) has shown promising results but is associated with serious complications such as graft-versus-host disease (GVHD). Moreover, as a disease that disproportionately affects minorities, which are underrepresented in the National Marrow Donor Program (NMDP), there are significant barriers to access this potentially curative modality. Post-transplantation cyclophosphamide (PTCy) and abatacept (aba) have dramatically improved outcomes and greatly increased access to transplantation by enabling utilization of mismatched donors. Patients and Methods: This is a retrospective single center analysis with 23 HTLV-1-associated North American ATLL patients (NA-ATLL) that underwent Allo-SCT from 2012 to 2024. Two cohorts were analyzed based on the use of PTCy and abatacept (Cohort A: No PTCy/Aba except for PTCy in haploidentical donors, Cohort B: PTCy + Aba regardless of HLA match). Variables collected in each cohort include age, sex, ethnicity, CMV/HTLV1 serologies, ECOG Performance Status (ECOG), Karnofsky Performance Status (KPS), diagnosis date, disease subtype, number of prior therapy lines, status at transplant, transplant date, donor sex, CMV/HTLV1 serologies, stem cell source, donor type, in-vivo T-cell depletion, engraftment, conditioning regimen, GVHD prophylaxis, maximum acute and chronic GVHD grade, relapse date when applicable, and main cause of death. Kaplan Meier estimates were used for overall survival (OS), progression-free survival (PFS), and GVHD-free, relapse-free survival (GRFS). Differences in time-to-event distributions between groups were checked with a log rank test. Patients who relapsed before 90 days were not included in these analyses. Results: Twenty-three patients met eligibility criteria, 29-74 years old, 18 Black patients and 5 Hispanic. Cohort A had a median follow-up of 443 days and Cohort B had a median follow-up of 238 days. In Cohort A (n=16), 9 patients (56.2%) had acute ATLL and 7 (43.8%) lymphomatous. 8 (50.0%) patients were transplanted in first completed remission (CR1), and 13 (81.2%) had ECOG ≤1 and 12 (75.0%) had KPS ≥90. 7 patients had matched related donors (MRD), 1 match unrelated (MUD), 6 haploidentical (haplo), and 2 mismatched unrelated (MMUD). Donors were CMV positive in 10 cases and HTLV-1 positi