Abstract P131

Results of allogeneic stem cell transplantation in Hodgkin lymphoma – long term experience.

Goal: Retrospective analysis of allogeneic stem cell transplantation (allo-SCT) in relapsed/refractory Hodgkin lymphoma (R/R HL). Methods: Retrospective analysis of patients who underwent allo-SCT between the years 2013-2023 at 2 transplant centers. Data were calculated using NCSS software. The probabilities of OS and PFS were estimated using the Kaplan–Meier method and Cox regression analysis. Results: Among 32 patients with a median age of 42 years (22-52) were 19 men (60%) and 13 (40%) women. The median time from diagnosis to transplantation was 904 days. All patients received prior autologous transplant and brentuximab vedotin, 8 patients also nivolumab. Ten (31%) patients were in complete remission (CR) at the time of transplant. Twelve patients underwent matched related allo-SCT and 20 matched unrelated transplant. The preferred conditioning regimen was fludarabine and melphalan ±ATG (29 patients). The median time to neutrophil engraftment was 18 days, 13 days for platelets. All patients achieved complete chimerism at day 30. NRM at day 100 was 3%. The cumulative incidence of acute GVHD was 59%; 2 patients had grade III‐IV acute GVHD. Fifteen out of 30 evaluated patients developed chronic GVHD. According to the NIH scoring system 3 had NIH I, 7 NIH II and 5 NIH III. CR was achieved in 23 patients at day 100 after allo-SCT. Fourteen (43%) of them are in ongoing CR (median duration of follow-up 7.2 years; 0.7-8.7 years). One patient in remission died due to infectious complications. Eight patients relapsed after transplant. Nine patients did not achieve remission after allo-SCT. Of 17 relapsed/refractory patients after allo-SCT, 9 died due to the progression of the disease, 1 is alive with active lymphoma, and 7 are in remission after the following treatments: 3x nivolumab, 1x brentuximab vedotin+bendamustine, 1x radiotherapy,1x anti-CD20 monoclonal antibody, 1x 2nd haplo SCT). With a median duration follow-up of 6 years, 22 patients are alive (20 in ongoing CR). Five-year PFS is 49% with a median of 4,5 years and 5-year OS is 69%, the median was not reached. The donor type (related vs. unrelated) had no impact on PFS (p = 0.5827) and OS (p = 0.0983). The presence of cGVHD was not associated with worse OS (p = 0.7217). CR before (p = 0.0062) and after transplant (p = 0.0000) was statistically significant for better OS. Conclusion: R/R HL remains a therapeutic challenge despite the newer treatment options. Anal