Durable long‐term remission in high‐risk relapse refractory lymphoma—20 years’ experience of allogeneic haemopoietic stem cell transplant in singapore

Background: Allogeneic hematopoietic stem cell transplantation (AlloHSCT) is a curative option for those who have high risk relapsed/refractory lymphoma in the era of novel and cellular therapies including CAR-T cell. There is a paucity of data evaluating the long term outcomes of AlloHSCT in Asian lymphoma patients. We performed a retrospective analysis of 20 years to evaluate the prognostic factors and outcomes of AlloHSCT for lymphoma patients in Singapore. Methods: We evaluated 121 lymphoma patients (both non-Hodgkin (NHL) and Hodgkin lymphoma (HL)) from two major transplant centres in Singapore who had AlloHSCT over a 20-year period (2003–2022). Results: The 121 patients have a median age of 41 (range 16–71). Diagnoses include B-NHL (N = 41, diffuse large B cell lymphoma n = 21, follicular lymphoma n = 2, mantle cell lymphoma n = 6, primary mediastinal B cell lymphoma n = 5, chronic lymphocytic leukemia n = 7), T-NHL (N = 38, peripheral T cell lymphoma n = 32, other T-NHL n = 6), NK T cell (N = 24) and HL (N = 18). 84% received reduced intensity conditioning (RIC), and 27.3% had a previous transplant. Donor types include matched sibling donor (N = 54), matched unrelated donor (N = 35), Haplo-identical donors (N = 23) and Cord blood (N = 9). With a median duration of follow up of 56 months (range 0–232 months), the 4-year progression free survival (PFS) and overall survival (OS) were 38% and 45% respectively. The non-relapse mortality was 11.6% at day 100 and 24% at 1 year. The cumulative incidence of acute graft-versus-host disease (GvHD) was 36.4% with 5 patients having grade IV acute GvHD. On univariate analysis, patients who were in complete remission (CR) at the time of AlloHSCT and those who have been given RIC had improved OS. Subset analyses showed that the outcomes of AlloHSCT for relapsed/refractory Hodgkin lymphoma were the most favourable (4-year PFS and OS at 61.2% and 62% respectively), whereas patients with T-NHL, B-NHL and NK T cell lymphoma had lower survival rates (4-year PFS 35%, 44%, 19%; 4-year OS 52%, 43%, 30% respectively). Keyword: Stem Cell Transplant No conflicts of interests pertinent to the abstract.