LUGANO, SWITZERLAND – For patients with relapsed or refractory follicular lymphoma, a pairing of lenalidomide (Revlimid) and obinutuzumab (Gazyva) appeared to be especially useful among patients who had disease progression within 24 months, based on results from a Lymphoma Academic Research Organisation trial.
Among 86 patients who were enrolled in a phase II trial and were assessable for efficacy, overall response rates (ORR) with the combination therapy, nicknamed “GALEN,” were 80.2% by 1999 International Working Group criteria, and 74.4% according to the 2007 IWG criteria, reported Franck Morschhauser, MD, PhD, of the University of Lille, France.
Neil Osterweil/Frontline Medical News
Dr. Franck Morschhauser
The rationale for this combination is the known synergy between lenalidomide and rituximab in relapsed refractory non-Hodgkin lymphomas and in the frontline setting for patients with follicular lymphoma. Obinutuzumab, a follow-on to rituximab, is a unique type II glycoengineered monoclonal antibody directed against CD20, but with increased antibody-dependent cell-mediated cytotoxicity and increased direct cytotoxicity, compared with rituximab, he explained.
In the phase Ib part of the study, researchers settled on a dose of obinutuzumab 1000 mg and lenalidomide 20 mg. Obinutuzumab was administered on days 8, 15 and 22 and lenalidomide on days 1 to 21 of each 28 day cycle. Patients were evaluated for response after three cycles and at the end of induction (after completion of 4 to 6 cycles).
The maintenance phase consisted of obinutuzumab on day 1 of every other cycle beginning with cycle 1, and lenalidomide on days 1 through 22 for cycles 7 through 18. From cycles 19 through 24, obinutuzumab was given alone on the first day of every 56-day cycle.
The overall response rate (ORR) at the end of induction according to the IWG 1999 criteria, the primary endpoint, was 80.2%, including 39.5% complete or unconfirmed complete responses.
When the same patients were assessed according to 2007 IWG criteria, the ORR rate was slightly lower, at 74.4%, but the complete or unconfirmed complete response rate was slightly higher, at 44.2%.
An analysis of responses by time to relapse showed that the ORR among 24 patients with disease progression within 24 months was 70.8%, including 33.3% complete or unconfirmed complete responses by the 1999 criteria, and 66.7% with 54.2% complete or unconfirmed complete responses by the 2007 criteria.
ORR among the 64 patients with disease progression after more than 24 months was 83.9% with 41.9% complete or unconfirmed complete responses by 1999 criteria, and 77.4% with 40.3% complete or unconfirmed complete responses by 2007 criteria. The differences between the groups with disease progression within 24 months and later relapse groups were not significant.
A subanalysis by refractory status, however, showed that the 63 nonrefractory patients fared significantly better, with 87.3% ORR and 41.3% complete or unconfirmed complete responses by 1999 criteria, and 81.0% with 49.2% complete or unconfirmed complete response rate by 2007 determinations, compared with respective rates among 23 refractory patients of 60.9%/34.8% complete or unconfirmed complete response rate and 56.5% with 30.4% complete or unconfirmed complete responses (P = .0212 by 1999 criteria, and P = .022 by 2007 criteria).
After a median follow-up of 18 months, 1-year progression-free survival (PFS) among all patients was 75.5%, and 1-year overall survival (OS) was 88.8%.
There were no significant differences in either progression-free survival or overall survival by time to relapse. Although there appeared to be a nonsignificant trend toward worse outcomes among patients with refractory vs. nonrefractory disease, there was a significantly lower 1-year overall survival rate among refractory patients, at 71.5% compared with 95% for nonrefractory patients (censored logrank P = .0098).
Dr. Morschhauser said that the combination had no unexpected toxicities. Hematologic toxicities of grade 3 or greater included neutropenia in 28.4%, thrombocytopenia in 11.4%, and anemia and lymphopenia in 3.4% each.
The most common nonhematologic toxicities of all grades included infections in 62.5% of patients (grade 3 or greater in 6.8%), and asthenia in 52.3% of patients (grade 3 or greater in 2.3%). The only other grade 3 or greater toxicities were peripheral neuropathy in 1.1%, and infusion related rash in 3.4%.
Additional follow-up will be need for evaluation of the full impact of maintenance on outcomes, he added.
The study was funded by Celgene and Roche. Dr. Morschhauser disclosed receiving honoraria from and serving on advisory boards for both companies.