Efficacy and Tolerability of a 2-Year Rituximab Maintenance Therapy in Patients with Advanced Follicular Lymphoma after Induction of Response with Rituximab-Containing First Line-Regimens (HUSOM Study).

Follicular lymphoma is a lymphoid malignancy commonly showing slow progression which makes the treatment of the disease challenging. Rituximab monotherapy and rituximab added to standard chemotherapy has been proven to increase survival among patients with advanced stage of the disease. However, the benefit of a rituximab maintenance therapy after induction was still unclear at the time of the initiation of this study. HUSOM was a phase III open-label, single-arm, multi-centre study aimed to assess the efficacy and the safety of the 12 cycles of rituximab (375 mg/m2 every 8 weeks) maintenance therapy in patients had already presented partial or complete response to R-CVP or R-CHOP. Efficacy endpoints such as event-free survival and overall survival were estimated. Adverse events were recorded during the entire course of the study. A total number of 124 patients were enrolled by 15 Hungarian study sites. Out of these, 86 patients received 12 cycles of rituximab and 69 patients completed the 3-year follow-up phase as well. The probabilities of the event free survival and progression at 4.3 years were estimated to be 70.3% and 74.4%, respectively. The overall and the disease free survival at 4 years were estimated to be 90.7% and 87.9%, respectively. A total number of 85 adverse events were reported during the study out of which 5 AEs were considered to be related to the administration of rituximab. Analyses of the efficacy variables have revealed comparable results to those reported by controlled clinical trials (EORTC 20981, PRIMA) conducted in parallel with the HUSOM study.