Polatuzumab vedotin plus bendamustine and rituximab in relapsed/refractory DLBCL: survival update and new extension cohort.

Polatuzumab vedotin plus bendamustine and rituximab (pola+BR) received regulatory approvals in relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) based on primary results from the randomized arms of the GO29365 study. Following the randomized phase, 106 additional patients received pola+BR in a single-arm extension cohort. We report updated results from the randomized arms, and results of the extension cohort. In this phase Ib/II study, patients with R/R DLBCL who were transplant-ineligible received up to six 21-day cycles of pola+BR or BR. The primary endpoint of the randomized arms was complete response (CR) rate at end of treatment. Primary objectives of the extension cohort were safety, pharmacokinetics, and efficacy of pola+BR. As of July 7, 2020, 192 patients with R/R DLBCL were enrolled into pola+BR cohorts (n=152 [safety run-in: n=6; randomized: n=40; extension cohort: n=106]) or the BR cohort (n=40). Significant survival benefit with pola+BR versus BR persisted in the randomized arms (median progression-free survival [PFS]: 9.2 vs 3.7 months, hazard ratio [HR]: 0.42, 95% confidence interval [CI] 0.25-0.71 months; median overall survival [OS]: 12.4 vs 4.7 months, HR: 0.42, 95% CI 0.24-0.72 months). In the extension cohort, the independent review committee (IRC)-assessed objective response rate was 41.5% and CR rate was 38.7%; median IRC-assessed PFS and OS were 6.6 months and 12.5 months, respectively. No new safety signals with pola+BR were identified. Pola+BR is an effective treatment option for patients with R/R DLBCL, with a well-characterized and manageable safety profile. ClinicalTrials.gov: NCT02257567.