Efficacy and safety of obinutuzumab in patients with previously untreated follicular lymphoma: a subgroup analysis of patients enrolled in Japan in the randomized phase III GALLIUM trial

GALLIUM is a global phase III study that demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) with obinutuzumab plus chemotherapy (G-chemo) versus rituximab plus chemotherapy (R-chemo) in previously untreated patients with follicular lymphoma (FL). In this single-country subgroup analysis, we explored patterns of efficacy and safety in patients enrolled in the GALLIUM study in Japan (Japanese subgroup). Patients were randomized to open-label induction treatment with G-chemo or R-chemo. Responders received maintenance monotherapy with their randomized antibody for up to 2years. The primary endpoint was investigator-assessed PFS. Overall, 123 patients with FL were randomized in the Japanese subgroup (G-chemo, n=65; R-chemo, n=58). The majority of patients received cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy (82.9 vs 33.1% in the global GALLIUM FL population). PFS at 3years was 89.9% (G-chemo) vs. 74.7% (R-chemo); hazard ratio 0.42; 95% confidence interval 0.15, 1.15; P=0.08. Higher rates of grade 3-5 adverse events (96.9 vs. 89.7%) and serious adverse events (35.4 vs. 22.4%) were observed with G-chemo vs R-chemo, respectively. Neutropenia was frequent in the Japanese subgroup (92.3% G-chemo; 79.3% R-chemo). Overall, the results in the Japanese subgroup were consistent with those in the global GALLIUM population.