Immunochemotherapy and Maintenance With Obinutuzumab or Rituximab in Patients With Previously Untreated Marginal Zone Lymphoma in the Randomized GALLIUM Trial

The aim of this study was to explore the efficacy and safety of obinutuzumab (G)- versus rituximab (R)-chemotherapy in a subgroup of patients with previously untreated marginal zone lymphoma (MZL) in the phase III GALLIUM trial (NCT01332968). Patients had stage III/IV (or stage II with bulky disease), splenic, nodal, or extranodal MZL requiring treatment. Patients were randomized 1:1 to receive G- or R-chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone; cyclophosphamide, vincristine, and prednisone; or bendamustine, allocated at patient level). Patients with complete/partial response at the end of induction (EOI) received G/R maintenance. Investigator-assessed progression-free survival (PFS), other time-to-event endpoints, response, and safety were assessed. Overall, 195 patients with MZL were included in this analysis: G-chemotherapy (n = 99), R-chemotherapy (n = 96). Median observation time: 59.3 months. No meaningful difference was observed between arms for PFS (4-y PFS rates: G-chemotherapy, 72.6%; R-chemotherapy, 64.1%), other time-to-event endpoints, or EOI response rates (by computed tomography [CT; G-chemotherapy, 81.8%; R-chemotherapy, 81.3%] and positron emission tomography CT [G-chemotherapy, 79.2%; R-chemotherapy, 87.5%]). All patients experienced ≥1 adverse event (AE). G-chemotherapy was associated with a higher incidence of grade 3–5 (86.1% versus 77.4%), grade 5 (14.9% versus 9.7%), and serious (66.3% versus 51.6%) AEs versus R-chemotherapy. Both arms had a higher incidence of grade 3–5 and serious AEs than patients with follicular lymphoma (GALLIUM), with G-chemotherapy being less tolerable than R-chemotherapy. Based on the observed tolerability of G-chemotherapy versus R-chemotherapy, and the comparable efficacy of G-chemotherapy and R-chemotherapy in this analysis, G-chemotherapy cannot be recommended as first-line treatment for MZL.