Polatuzumab Vedotin for Relapsed/Refractory Diffuse Large B-Cell Lymphoma

In a recent clinical trial, therapies that included polatuzumab vedotin demonstrated efficacy in the treatment of patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Results were reported in the Journal of Clinical Oncology.

This phase 1b/2 trial (ClinicalTrials.gov Identifier: NCT02257567) examined outcomes with polatuzumab vedotin in combination therapies for patients with R/R DLBCL who were ineligible for transplantation or who had undergone any prior unsuccessful autologous stem cell transplantation.

In the phase 1b safety run-in portion of the trial, 6 patients were treated with polatuzumab vedotin plus bendamustine and rituximab (pola-BR). In phase 1b/2 safety and expansion analyses, 27 patients were assigned to receive polatuzumab vedotin plus bendamustine and obinutuzumab (pola-BG). The phase 2 randomized cohort consisted of 1 arm (40 patients) that received pola-BR and a comparator arm (40 patients) that received bendamustine with rituximab (BR).

The phase 2 primary end point was the end-of-treatment complete response (CR) rate, as assessed by an independent review committee (IRC).

Among the patients receiving pola-BG, the IRC-assessed CR rate was 29.6%. For the phase 2 pola-BR treatment arm, this rate was 40.0%, and for the BR-treated arm it was 17.5% (P =.026).

After median follow-up of 27.0 months, patients receiving pola-BG had a 10.8-month median overall survival (OS). After median follow-up of 22.3 months, patients in the phase 2 pola-BR arm reported a median OS of 12.4 months and the BR arm reported a median OS of 4.7 months (hazard ratio, 0.42; 95% CI, 0.24-0.75; P =.002).

After median follow-up of 22.3 months, median IRC-assessed progression-free survival for the phase 2 pola-BR arm was 9.5 months, compared with 3.7 months for the control arm (hazard ratio, 0.36; 95% CI, 0.21-0.63; P <.001).

Grade 3 to 4 neutropenia, thrombocytopenia, and anemia were more common with patients receiving pola-BR compared with patients receiving BR in phase 2 analyses. Patients in the pola-BR arm had 9 fatal adverse events, compared with 11 in the BR arm.

“Pola-BR represents a novel, effective therapeutic regimen to address the unmet need of patients with transplantation-ineligible R/R DLBCL,” the researchers concluded.

Reference

1. Sehn LH, Herrera AF, Flowers CR, et al. Polatuzumab vedotin in relapsed or refractory diffuse large B-cell lymphoma [published online November 6, 2019]. J Clin Oncol. doi:10.1200/JCO.19.00172

This article originally appeared on Hematology Advisor