Impact of Pretransplant Salvage Therapies on Outcome of Hodgkin Lymphoma Patients Performing Allogeneic Transplant

Background: Allogeneic transplant is an effective salvage therapy in patients with Hodgkin lymphoma (HL) relapsed or refractory (R/R) to previous treatments. In recent years, immunotherapies (conjugated antibody and checkpoint inhibitors [CPI]) showed interesting results and were used as bridge therapies to allotransplant. Aim: The aim of this retrospective study in Lazio region was to evaluate the impact of these new therapies on outcome after allogeneic hematopoietic stem cell transplantation (allo-SCT) in comparison with standard chemotherapies used in the past. Methods: We selected all consecutive patients with diagnosis of HL transplanted in four hematology transplant units, and we collected data obtained from patients' records concerning all the treatments before allo-SCT. Results: A total of 56 patients were enrolled in this study. All patients underwent allo-SCT for R/R HL. Seventeen patients (30%) received chemotherapy prior to allo-SCT (group B); they were treated between 2008 and 2015; and 39 patients (70%) received brentuximab vedotin (BV), CPI, or both before allo-SCT as a bridge to transplant (group A); they were treated between 2012 and 2020. Twenty-five patients were treated with BV alone, 2 with CPI alone, and 12 first with BV and then with CPI. No patient received concomitant BV and CPI. At 5 years from allo-SCT, overall survival (OS) was 59% and progression-free survival (PFS) was 65%. No statistical differences in OS or PFS were observed between patients in groups A and B. Relapse was significantly associated with a lower survival. The only factor associated with a reduced risk of relapse was development of any grade acute graft versus host disease (GVHD) (p > 0.02). Conclusions: This regional real-world experience shows the changes that have taken place in the last 10 years in R/R HL using new drugs to render a patient eligible for allo-SCT. This strategy appears to guarantee an impressive disease control with an increased risk of complications, for example, aGVHD, that appear to nullify this advantage at least in part.