Does obinutuzumab have a leg up over rituximab for treating follicular lymphoma?
A strict reading of the efficacy records of the two anti-CD20 antibodies when they went head-to-head suggests that obinutuzumab (Gazyva) edged out rituximab (Rituxan), but a broader view leaves the door open for rituximab as a still viable option depending on a patient’s status and priorities, experts said at the conference held by Imedex.
For the roughly 80% of patients with follicular lymphoma (indolent non-Hodgkin lymphoma) who die with their disease rather than from it, management needs to focus on quality of life issues as much as on efficacy, said John P. Leonard, M.D
., professor of medicine at Weill Cornell Medicine, New York.
While conceding that quality of life correlates with progression-free survival (PFS), he stressed that it also correlates with treatment toxicities, treatment duration, and disease-related side effects.
Trial results have indicated that patients with newly diagnosed follicular lymphoma are reasonably treated with rituximab alone, or with rituximab plus bendamustine, without need for maintenance therapy, Dr. Leonard said.
In contrast, GALLIUM
, a phase III trial that compared rituximab against obinutuzumab, used a maintenance phase of monotherapy with each of these two drugs following an induction phase when each of the drugs was combined with chemotherapy.
“If you use this approach [tested in GALLIUM] you need to use maintenance therapy,” and it was in GALLIUM that the most dramatic efficacy advantage for obinutuzumab over rituximab appeared, in the form of longer PFS although, so far, without demonstrated advantage in overall survival. The GALLIUM results, reported in December 2016 at the American Society of Hematology meeting, showed a 3-year PFS rate of 80% among patients treated with obinutuzumab and 73% among those treated with rituximab, a hazard ratio of 0.66 in favor of obinutuzumab that was statistically significant (P
= .001) for the study’s primary endpoint (Blood. 2016 Dec 4;abstract 6
“If you follow this study, you commit the patient to maintenance. We need to talk with patients about the pros and cons of maintenance, the pros and cons of chemotherapy, and the pros and cons of single agent therapy” with one of these anti-CD20 antibodies, Dr. Leonard said. “Right now, I think it’s unclear which antibody is best,” he concluded.