Salvage therapies in transplant-eligible relapsed classic Hodgkin lymphoma, are novel regimens better?
Authors: Desai Sanjal , Wang Yucai , Rosenthal Allison Claire , Reeder Craig B. , Inwards David James , Ayala Ernesto , Nowakowski Grzegorz S. , Tun Han W. , Paludo Jonas , Villasboas Jose Caetano , Porrata Luis F. , Alhaj Moustafa Muhamad , Kharfan-Dabaja Mohamed , Johnston Patrick B. , Ansell Stephen M. , Habermann Thomas Matthew , Micallef Ivana N. M. 
Published: June 2021

7530 Background: Clinical trials of novel salvage therapies (ST) have encouraging outcomes for relapsed/refractory classic Hodgkin lymphoma (R/R cHL) eligible for autologous stem cell transplant (ASCT). In this observational study, we report efficacies and outcomes of different ST in ASCT-eligible R/R cHL. Methods: Consecutive ASCT-eligible R/R cHL pts at 3 Mayo Clinic sites were included. Demographics and clinical variables at relapse were recorded by medical records review. Time to event endpoints were defined from relapse. Univariate associations were confirmed in multivariate models of age, sex, B symptoms, stage, bulky disease (BD, single mass > 6 cm) extra nodal disease (END), primary refractory disease (PRD) and early relapse (ER, within 1 year). Results: From Jan 2008 to May 2020, 207 ASCT-eligible pts with R/R cHL were included. Median age was 33 (24-43) years, 53% were male, 52% had advanced stage, 24% had BD, 36% had B symptoms, 41% had END, 11% had PRD and 43% had ER. All patients received ST and underwent ASCT; 43 (21%) received 2 ST, 14 (7%) 3 ST and 4 (0.5%) received 4 ST. 6 groups of ST were identified: ifosfamide, carboplatin and etoposide (ICE), bendamustine/brentuximab (BBV), brentuximab vedotin (BV), gemcitabine-based therapy (Gem), checkpoint inhibitor (CPI), and others. Table lists response to first line ST. BBV had significantly higher overall response rate (ORR) and complete response (CR) as first ST in univariate and multivariate models. 114 (79%) after ICE, 30 (97%) after BBV, 15 (56%) after BV, 25 (76%) after Gem, 8 (73%) after CPI and 15 (79%) after other ST underwent ASCT. Higher number of pts were bridged to ASCT after BBV than ICE (p<0.01). 110 (53%) went to ASCT in CR, 74 (36%) in partial response (PR) and 11% in progressive disease (PD). 43 received BV maintenance (BVm) after ASCT. Pts going to ASCT in PR or PD had significantly lower progression free survival (PFS) compared to pts in CR (2 yr PFS: 62%, 18% vs 77%, respectively, p<0.0001) in univariate and multivariate models. There was no difference in PFS and overall survival (OS) by type of ST. BVm was associated with higher PFS (HR 0.3 (CI95 0.2-0.8)) and higher number of ST was associated with lower OS (HR 2 (CI95 1.4-3)) in multivariate model (p<0.001). For pts transplanted in CR, there was no significant difference in PFS and OS by type of ST but higher number of ST predicted lower OS (HR 2.4 (CI95 1.2-3.5), p<0.01). Conclusions: Type of ST did not predict survival, response to and number of ST did. For pts with CR, number of ST not type of ST predicted survival. BBV had higher response rates, higher rates of bridge to ASCT, and may be a preferable ST than ICE. Large, randomized trials are needed to evaluate efficacy of BBV compared to ICE.[Table: see text]