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Polatuzumab Vedotin Plus Bendamustine and Rituximab Shows Safety in R/R DLBCL
Data from a phase 2 study of polatuzumab vedotin plus bendamustine and rituximab found the combination to be efficacious and safe for patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL; Cancer Sci. 2021 Jul;112(7):2845-2854).
“Polatuzumab vedotin is a CD79b-targeted antibody-drug conjugate delivering a potent antimitotic agent to B cells,” explained Yasuhito Terui, Department of Hematology and Oncology, The Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan, and co-investigators.
The open-label, single-arm study enrolled 35 patients (median age 71) with R/R DLBCL who received ≥1 prior line of therapy and were eligible for an autologous stem cell transplantation (ASCT) or experienced treatment failure with a prior ASCT. Refractory disease was seen in 23 (66%) of patients, and 23 (66%) had ≥2 prior lines of therapy.
Patients received polatuzumab vedotin 1.8mg/kg, bendamustine 90mg/m2, and rituximab 375mg/ m2 every 3 weeks for up to 6 cycles.
The primary endpoint was complete response rate (CRR) at the end of treatment (EOT) by positron emission tomography-computed tomography (PET-CT) using modified Lugano Response Criteria. Secondary endpoints included efficacy, safety, and pharmacokinetics.
At the median follow up of 5.4 months, patients received a median of 5 treatment cycles. The CRR was 34.3 percent (95% CI, 19.1-52.2) at EOT. The overall response rate (ORR) was 42.9 percent, and the median progression-free survival (PFS) was 5.2 months (95% CI, 3.6-NA). The median overall survival (OS) was not met.
There were no fatal adverse events (AEs) observed. AEs of grade 3-4 were mostly hematological, including anemia (37%), neutropenia (31%), white blood cell count decrease (23%), thrombocytopenia/platelet count decreased/neutrophil count decreased (20% each), and febrile neutropenia (11%). AEs of grade 1-2 included peripheral neuropathy (14%).
“This study demonstrated the efficacy and safety of polatuzumab vedotin plus bendamustine and rituximab in Japanese patients with R/R DLBCL who were ineligible for ASCT,” concluded Dr Terui et al.—Emily Bader
