Multicenter, Open-Label, Phase II Study of Bendamustine and Rituximab Followed by 90-Yttrium (Y) Ibritumomab Tiuxetan for Untreated Follicular Lymphoma (Fol-BRITe).

Purpose: Bendamustine and rituximab (BR) has been established as a superior frontline therapy over R-CHOP in the treatment of follicular lymphoma (FL). Yttrium-90 Ibritumomab tiuxetan (90YIT) is an effective consolidation strategy after chemotherapy induction. This prospective, single-arm, multicenter, phase II trial evaluated the response rate, progression-free survival (PFS), and tolerability of BR followed by consolidation with 90YIT in patients with untreated FL. Patients and

Methods: The study included grade 1 to 3a FL patients aged ≥18 years, chemotherapy-naïve, and requiring treatment for stage II-IV disease. Study treatment included an initial rituximab treatment, followed by four cycles of BR. Patients were eligible for consolidation with 90YIT, 6 to 12 weeks after BR, if they obtained at least a partial response after induction had adequate count recovery and bone marrow infiltration < 25%.

Results: Thirty-nine patients were treated. Eighty-two percent had an intermediate or high-risk Follicular Lymphoma International Prognostic Index score, and 6 of 39 (15%) were grade 3a. The response rate was 94.8%, and the complete response(CR)/CR unconfirmed (CRu) rate was 77% in the intention-to-treat analysis. The conversion rate from PR to CR/Cru after 90YIT was 81%. After median follow-up of 45 months, the PFS was 0.71 (95% confidence interval, 0.57-0.89).

Conclusions: This report demonstrates that four cycles of BR followed by consolidation with 90YIT achieve high response rates that are durable. In addition, consolidation with 90YIT results in a high conversion rate of PR to CR/CRu. A short course of BR followed by 90YIT is a safe and effective regimen for frontline treatment of FL.