Bortezomib, bendamustine, and rituximab in patients with relapsed or refractory follicular lymphoma: the phase II VERTICAL study.

Purpose: The aims of this multicenter study were to evaluate the response rate, progression-free survival, and toxicity of the combination of bortezomib, bendamustine, and rituximab in patients with follicular lymphoma whose disease was relapsed or refractory to prior treatment.
Patients and Methods: Patients received five 35-day cycles of bortezomib, bendamustine, and rituximab: bortezomib administered intravenously (IV) at a dose of 1.6 mg/m(2) on days 1, 8, 15, and 22, cycles one to five; bendamustine 50, 70, or 90 mg/m(2) IV over a 60-minute infusion on days 1 and 2, cycles one to five; and rituximab 375 mg/m(2) on days 1, 8, 15, and 22 of cycle one and day 1 of subsequent cycles. Patients were assessed using the International Workshop Response Criteria, with the primary end point of 60% complete response rate.
Results: Seventy-three patients were enrolled. During the dose-escalation phase, the maximum-tolerated dose for bendamustine was not reached; the 90 mg/m(2) dose level was expanded for the efficacy assessment, and a total of 63 patients received bendamustine 90 mg/m(2). In these 63 patients, the overall response rate was 88% (including 53% complete response). Median duration of response was 11.7 months (95% CI, 9.2 to 13.3). Median progression-free survival was 14.9 months (95% CI, 11.1 to 23.7). Toxicities were manageable; myelosuppression was the main toxicity (25% and 14% of patients experienced grade 3 to 4 neutropenia and grade 3 to 4 thrombocytopenia, respectively). Transient grade 3 to 4 neuropathy occurred in 11% of patients.
Conclusion: The combination of bortezomib, bendamustine, and rituximab is highly active in patients with follicular lymphoma who have received previous treatment.