Safety in Patients Receiving Maintenance Rituximab for Follicular Lymphoma: Results from Phase IIIb MAXIMA Trial.

Background: The clinical benefit of improved PFS and OS for rituximab maintenance in follicular lymphoma (FL) has been reported in five randomized trials. The primary objective of the current study is to extend the safety database for rituximab maintenance following a wide range of induction therapies. The study also examines the safety profile associated with rapid-infusion of rituximab.

Methods: The sample size of this single-arm trial has been calculated to detect at least one rare event with a true incidence of 0.32% with 80% power. Patients with first line or relapsed/refractory FL achieving a response after rituximab containing induction therapy were eligible to receive rituximab at the standard dose for follicular lymphoma of 375 mg/m² every eight weeks for a maximum of 2 years. Primary study endpoint is safety. Secondary endpoints being PFS, EFS, TTNL, and OS.

Results: 526 patients with FL have been enrolled at clinical cut-off for whom demographic data is available: Median age of the patient population is 57 years [range: 29 to 86], with 43% being male. Seventy-four percent of patients had their first lymphoma treatment prior to enrollment, while the remaining 24% of patients had up to 4 previous treatments; 71% entered the study in CR/CRu. Data on a total of 2004 infusions was available. Except for one patient who received rituximab at standard infusion speed and suffered from a TIA no SAEs were recorded within 24h of the maintenance infusion, including those patients who received rituximab via a rapid infusion protocol. A total of 31 SAEs were recorded in the 484 patients that received at least one infusion, all but one were considered unrelated. One patient with previously known cardiac arrythmias died 13 days after the 4th infusion of unknown causes. Three patients died of progressive lymphoma, another patient died due to refractory ITP. Hematologic toxicity occured in 13 patients, with one grade 5 event (ITP) and 12 grade 3/4 events, one resulting in febrile neutropenia. Data on efficicacy will be presented.

Conclusions: Rituximab maintenance q 8 weeks in FL after rituximab containing induction therapy can be safely administered, regardless if a rapid-infusion protocol is used or not.