Results of a phase 2 study of bortezomib in patients with relapsed or refractory indolent lymphoma.

This study evaluated the efficacy and safety of single-agent bortezomib in indolent B-cell lymphoma that had relapsed from or was refractory to rituximab. Sixty patients enrolled: 59 were treated with bortezomib 1.3 mg/m(2) on days 1, 4, 8, and 11 for up to eight 21-day cycles; responders could receive 4 additional cycles; maintenance was optional. Fifty-three evaluable patients completed more than 2 cycles. The median age was 70 years, 53% female, Ann Arbor stage III-IIIE (28%) and IV (65%); 43 patients (72%) had more than 2 prior regimens; and 6 patients went on to maintenance. Overall responses are as follows: 1 complete response (1.9%), 3 unconfirmed complete response (5.7%), 3 partial response (5.7%), 34 stable disease (64.2%), and 12 progressive disease (22.6%). Median time to response = 2.2 months (range, 1.2-5.3 months); duration of response = 7.9 months (2.8-21.3 months); 1-year survival was 73% and 2-year survival was 58%; median survival = 27.7 months (range, 1.4-30.9 months); median progression-free survival = 5.1 months (range, 0.2-27.7 months), median time to progression = 5.1 months (range, 0.2-27.7 months), and median event-free survival = 1.8 months (range, 0.2-27.7 months). Treatment-related grade 3 or 4 adverse events included: thrombocytopenia (20%), fatigue (10%), neutropenia (8.5%), and neuropathy and diarrhea (6.8% each). This study demonstrates that bortezomib has modest activity against marginal zone and follicular lymphoma; it has the potential for combination with other agents in low-grade lymphomas. Maintenance therapy should be explored further.