Abstract P132

Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed/Refractory Classical Hodgkin Lymphoma in the Brentuximab Era: Updated Single-Center Experience

Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a potentially curative option for patients with relapsed/refractory classical Hodgkin lymphoma (R/R cHL) after failure of salvage therapy and high-dose chemotherapy. PD-1 inhibitor-based salvage regimens have shown high response rates in clinical trials and real-world cohorts, but their use is constrained by limited regulatory approval and restricted reimbursement in many real-world settings. Consequently, many patients still proceed to allo-HSCT after brentuximab vedotin (BV)-based therapy with limited exposure to PD-1 inhibitors.

Methods: This retrospective single-center study included 19 consecutive patients with R/R cHL who underwent allo-HSCT. Demographic characteristics, time from diagnosis to allo-HSCT, prior therapies, and survival outcomes were updated as of June 15, 2026. Prior treatment exposure included autologous HSCT (auto-HSCT), BV-containing therapy, and BV plus nivolumab before allo-HSCT. Overall survival (OS) was estimated using the Kaplan-Meier method.

Results: The median age at allo-HSCT was 29.6 years (range, 20.3-42.9), and the median time from diagnosis to allo-HSCT was 4.9 years (range, 0.7-11.8). Prior auto-HSCT had been performed in 16 patients (84.2%). BV-based therapy before allo-HSCT was administered in 10 patients (52.6%), including 8 treated with BV alone and 2 with BV plus nivolumab. With a median follow-up of 23.2 months, the estimated 1-, 3-, and 5-year OS rates were 78.3% (95% CI, 59.4-97.2), 60.4% (95% CI, 37.3-83.5), and 31.1% (95% CI, 4.2-58.0), respectively (Figure 1). Ten deaths were recorded: 6 were associated with disease relapse/progression and 4 with graft-versus-host disease (GvHD)-related complications.

Conclusions: In this updated single-center cohort, allo-HSCT provided meaningful survival despite extensive exposure to auto-HSCT and BV-based regimens, with only limited pre-transplant use of PD-1 inhibitors reflecting real-world access barriers. Long-term OS remained modest, with mortality driven by both relapse and GvHD-related complications, underscoring the need to optimize disease control before transplant and reduce post-transplant toxicity.