Combination treatment with lenalidomide plus obinutuzumab resulted in an overall response rate of 79% among patients with CD20-positive relapsed or refractory follicular lymphoma enrolled in the phase II GALEN study. High rates of response were seen even in patients with early relapse, according to Frank Morschhauser, MD, of Centre Hospitalier Regional Universitaire de Lille, France, and colleagues.
The study, the results of which were published in Lancet Haematology, included 89 patients aged 18 years or older with ECOG performance status of 0–2 who had received at least one prior dose of rituximab.
“Results of this study evaluating the activity and safety of combining lenalidomide with obinutuzumab for induction therapy and using lenalidomide for maintenance provide supporting evidence to expand immunomodulatory treatment options for previously treated patients with relapsed or refractory follicular lymphoma, including subgroups of patients with disease progression within 24 months of initial diagnosis and refractory disease,” the study authors .
The combination of lenalidomide plus rituximab is currently approved for the treatment of patients with relapsed or refractory follicular lymphoma. However, studies of obinutuzumab have shown that, compared with rituximab, obinutuzumab “has lower complement-dependent cytotoxicity, but greater antibody-dependent cellular cytotoxicity and phagocytosis, and direct B-cell killing effects”.
Patients in the study were treated with oral lenalidomide plus IV infused obinutuzumab as induction therapy. Patients who achieved at least partial response could continue with 1 year of maintenance lenalidomide plus obinutuzumab, followed by an additional year with obinutuzumab alone.
Of the 89 patients enrolled, 86 were evaluable for efficacy and 88 for safety.
With the median follow-up of 2.6 years, overall response at end of induction was 79%. At 2 years, event-free survival was 62%, progression-free survival was 65% and overall survival was 87%. More than one-third (38%) of patients achieved complete response.
A post-hoc analysis showed similar outcomes for response and survival in patients with disease progression within 24 months of initial diagnosis, compared with those with later relapse.
Common adverse events included asthenia (61%), neutropenia (43%), bronchitis (41%), diarrhea (40%), and muscle spasms (39%). Neutropenia was the most common grade 3 or worse adverse events. There was one death due to treatment-related febrile neutropenia, which occurred in 5% of patients.
“Randomized trials of new immunomodulatory regimens, such as GALEN or using GALEN as a backbone, versus lenalidomide plus rituximab, are warranted,” the researchers concluded.
In an accompanying editorial, Gottfried von Keudell, and Anas Younes, of Memorial Sloan Kettering Cancer Center in New York, wrote that without a randomized trial the relevance of the regimen in the GALEN trial to clinical practice is unclear.
“Despite the differences in patients’ characteristics, response assessment methods, and duration of therapy, there appears to be no significant advantage of using obinutuzumab plus lenalidomide over rituximab plus lenalidomide,” they wrote. “Even so, the future of patients with follicular lymphoma has never been brighter, with an abundance of agents in development that will probably continue to improve their outcomes, while hopefully maintaining a good quality of life.”