Polatuzumab vedotin plus bendamustine and rituximab in relapsed/refractory diffuse large B-cell lymphoma: A phase III bridging study in Chinese patients.

Background: Patients with transplant-ineligible relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) have limited treatment options and poor outcomes.

Methods: This phase III study (NCT04236141) evaluated the efficacy and safety of polatuzumab vedotin plus bendamustine and rituximab (Pola+BR) versus BR in Chinese patients with transplant-ineligible R/R DLBCL to support regulatory submission in China. Patients were randomized 2:1 to receive Pola+BR or placebo+BR. The primary endpoint was complete response (CR) at the end of treatment (EOT) by positron emission tomography-computed tomography.

Results: Overall, 42 patients were analyzed (Pola+BR, n = 28; placebo+BR, n = 14). At data cutoff (July 12, 2021; median follow-up: 7.5 months), CR at EOT was 25.0% (7/28) with Pola+BR and 14.3% (2/14) with placebo+BR, 10.7% difference [95% confidence interval (CI): -19.0, 40.4]. The median investigator-assessed progression-free survival was 4.6 (95%CI: 3.1-6.4) months with Pola+BR and 2.0 (95% CI: 1.9-4.6) months with placebo+BR, with a 50% reduction in risk of progression or death (unstratified hazard ratio: 0.50; 95% CI: 0.24-1.05). The median overall survival was 10.6 [95% CI: 5.5-not evaluable (NE)] and 6.5 (95% CI: 6.0-NE) months, with a 45% reduction in risk of death. The incidence of Grade 3-4 adverse events was similar between Pola+BR (20/27 patients, 74.1%) and placebo+BR arms (11/14 patients, 78.6%).

Conclusions: Efficacy findings were consistent with results of the GO29365 study (NCT02257567); treatment with Pola+BR led to clinically meaningful improvements in response rates in Chinese patients with transplant-ineligible R/R DLBCL with no new safety signals.