Obinutuzumab Plus Bendamustine Doubles Progression-Free Survival in Non-Hodgkin Lymphoma
CHICAGO–Obinutuzumab combined with bendamustine followed by obinutuzumab maintenance significantly improved progression-free survival compared with bendamustine alone in patients with rituximab-refractory indolent non-Hodgkin lymphoma (iNHL), data presented at the 2015 American Society of Clinical Oncology (ASCO) annual meeting have shown.
“Despite an increase in the number of chemotherapeutic options, advanced stage indolent NHL remains incurable,” said Laurie Sehn, MD, medical oncologist at the BC Cancer Agency and Clinical Associate Professor at the University of British Columbia in Vancouver, BC, Canada.
“Addition of rituximab to chemotherapy during induction followed by maintenance has significantly improved outcomes in patients with indolent NHL; however, patients with disease that is refractory to a rituximab-containing therapy have limited options.”
For the open-label, phase 3 GADOLIN trial, researchers randomly assigned 396 patients with CD20+ rituximab-refractory iNHL to receive bendamustine 120 mg/m2 alone on days 1 and 2 for 6 cycles, or bendamustine 90 mg/m2 on days 1 and 2 for 6 cycles plus obinutuzumab 1,000 mg on days 1, 8, and 15 of cycle 1 and day 1 of cycles 2 through 6.
“Patient characteristics were balanced between arms. The median age was 63 years,” Dr. Sehn added.
Results showed that median IRF-assessed progression-free survival was 14.9 months in the bendamustine alone arm compared with not yet reached in the obinutuzumab plus bendamustine arm (HR=0.55; 95% CI: 0.4, 0.74; P=0.00011), while median investigator-assessed progression-free survival was 14 months for bendamustine alone and 29 months for obinutuzumab plus bendamustine (HR=0.52; 95% CI: 0.39, 0.70; P<0.0001), “indicating more than a doubling in progression-free survival in the combination arm,” Dr. Sehn noted.
In regard to safety, patients in the bendamustine group experienced fewer grade 3 or higher adverse events compared with those in the combination arm.
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Patients in the combination arm experienced a higher rate of grade 3 to 4 neutropenia and infusion-related reactions, but a lower rate ofgrade 3 or higher thrombocytopenia, anemia, and pneumonia than patients in the bendamustine alone arm.
Dr. Sehn concluded, “There was no difference in the response rates between treatment arms; however, the bendamustine dose was higher in the monotherapy arm. Importantly, no new safety signals were observed.”
Obinutuzumab (Gazyva) was initially approved by the U.S. Food and Drug Administration in 2013 for the treatment of patients with previously untreated chronic lymphocytic leukemia in combination with chlorambucil.
- Sehn LH, Chua NS, Mayer J, et al. GADOLIN: Primary results from a phase III study of obinutuzumab plus bendamustine compared with bendamustine alone in patients with rituximab-refractory indolent non-Hodgkin lymphoma. J Clin Oncol. 2015;33:(suppl; abstr LBA8502).