BENDAMUSTINE, RITUXIMAB, AND POLATUZUMAB VEDOTIN FOR RELAPSED OR REFRACTORY DIFFUSE LARGE B‐CELL LYMPHOMA: SINGLE‐CENTER REAL‐WORLD EXPERIENCE

Field: Medicine (Health Sciences)

Introduction: In a pivotal phase 2 randomized cohort, addition of polatuzumab vedotin (pola) to bendamustine and rituximab (BR) improved rate of complete response (CR), progression-free survival (PFS), and overall survival (OS) versus BR alone in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Our experience suggests many patients treated with BR-pola off-trial receive fewer cycles and have dose reductions or omissions of bendamustine potentially impacting response. Methods: We reviewed adults who received ≥ 1 dose of pola for R/R DLBCL at Memorial Sloan Kettering Cancer Center between June 2019 and September 2020. Patients who received pola in a clinical trial were excluded. We evaluated best response as assessed by investigator. PFS and OS were estimated by Kaplan Meier method. Results: Cohort characteristics and outcomes are described in Table 1 (n = 57). All patients had completed or discontinued pola-based treatment at analysis. Median age was 68 years. Patients received median 3 prior lines of therapy, including prior hematopoietic cell transplantation (HCT) in 25% and prior chimeric antigen receptor T-cell therapy (CAR-T) in 39%. Patients received median 3 cycles, with median dose delivered (as percent of US-approved dosing) of 100% for both rituximab and pola and 78% for bendamustine. Four patients (7%) completed 6 cycles. Thirteen patients (23%) proceeded to CAR-T. Among 38 patients who received a short course (1 to 3 cycles), 11 patients (29%) proceeded to CAR-T and 4 patients (11%) proceeded to HCT. At median follow-up of 5 months, CR was achieved in 16%; partial response (PR) was achieved in 33%. Median time to best response was 1.6 months. Median PFS and OS were 6 months and 6.3 months, respectively (Figure 1). Univariate analysis did not identify characteristics associated with response, although an association of lack of efficacy was noted in patients with double-hit DLBCL (0% of responders vs 20% of non-responders had double-hit; p = 0.051). Eleven patients (19%) did not receive bendamustine or only received bendamustine in cycle 1 (Table 2). Two patients (18%) in this subgroup responded (both PR; both received ≥ 1 dose of bendamustine). Five patients (63%) in this subgroup underwent subsequent CAR-T, 4 of whom did not receive bendamustine. Keywords: Aggressive B-cell non-Hodgkin lymphoma, Combination Therapies Conflicts of interests pertinent to the abstract L. Falchi Consultant or advisory role: Genmab Research funding: Roche, Genmab A. Kumar Consultant or advisory role: Celgene Research funding: Abbvie, Adaptive Biotechnologies, Celgene, Pharmacyclics, Seattle Genetics A. Noy Consultant or advisory role: Janssen, Pharmacyclics, Medscape, Targeted Oncology Research funding: Pharmacyclics, NIH, Raphael Pharma M L. Palomba Honoraria: Merck, Celgene, Juno, Pharmacyclics G. Salles Consultant or advisory role: Abbvie, Beigene, BMS/Celgene, Debiopharm, Genentech/Roche, Genmab, Incyte, Ipsen, Kite/Gilead, Milteniy, Morphosys, Novartis, Velosbio D. J. Straus Consultant or advisory role: Seattle Genetics Research funding: Seattle Genetics A. D. Zelenetz Consultant or advisory role: Genentech/Roche, Kite/Gilead, Quant Health, Astra Zeneca, Karyopharm, Adaptive Biotechnology, MorphoSys, Juno/Celgene/BMS, BeiGene, Verastem Research funding: MEI Pharma, Genentech/Roche, BeiGene, Adaptive Biotechnology C. L. Batlevi Honoraria: Dava Oncology Research funding: Janssen, Novartis, Epizyme, Xynomics