Abstract P119

Inclusion of Brentuximab vedotin in salvage regimens before transplant benefits relapsed/refractory Hodgkin lymphoma patients in a real-world setting - a multicenter study in Portugal

Background: Hodgkin lymphoma (HL) is curable with frontline therapy in 70-80% of patients (pts). Nonetheless, in those who relapse or are primary refractory (PRD), the best salvage regimen to allow autologous stem cell transplantation (ASCT) in the era of checkpoint inhibitors (CPI) and brentuximab vedotin (BV) is not well defined.

Methods: We performed a retrospective multicenter study in a cohort of pts with relapsed/refractory HL (r/r HL) from 11 centers receiving salvage therapy between 2019 and 2022 with intention to proceed to ASCT. Data were collected from pt records. The primary endpoint was event-free survival (EFS) measured from the beginning of each salvage: EFS1 for the 1st and EFS2 for the 2nd salvage. Secondary endpoints were the proportion of transplanted pts, response rate (according to Lugano criteria) and overall survival (OS). Outcomes were accessed according to different salvage regimens including chemotherapy (CHT), BV-based [BV monotherapy, BV + chemotherapy (BV-CHT)] and CPI based regimens. Kaplan-Meier estimates were used to describe time-to-event endpoints and groups compared by the log rank test. Cox regression models were applied to assess survival associations.

Results: We included 149 pts [median age 36 years (20-68), 59% males, 53% PRD] - Table 1. At first salvage, 118 pts received CHT and 31 received BV-based regimens (90.3% with CHT). When adjusting for the presence of B-symptoms, PRD, extra-nodal disease and ASCT, median EFS1 was significantly longer for pts treated with BV-based regimens compared to CHT (12 vs 8 months, respectively; HR 0.47, 95%CI 0.288-0.814, p=0.007). Half of the pts in each group proceeded to ASCT. PRD pts had a significant benefit from BV-based compared with CHT (median EFS1 12 months vs 5 months, p=0.045). Sixty-nine pts needed a 2nd salvage therapy: 20 received BV, 34 BV-CHT and 15 CPI-based regimens. There was no difference in EFS2 between these groups. However, BV-CHT doubled the proportion of pts proceeding to ASCT compared to BV alone and CPI-based regimens (67% vs 35% vs 33% respectively, p=0.021). There was 1 toxic death in BV-CHT group (infection-related) and 1 in the CPI-based group (myocarditis).

Conclusion: In this cohort of r/r HL pts, BV-based regimens as 1st salvage, led to a significant improvement in EFS1 compared with CHT. This benefit was greater in high-risk PRD pts. Comparative trials are needed to clarify the most adequate salvage regimens in this highly curable tumor.