Durable Responses with Bortezomib in Patients with Relapsed or Refractory Mantle Cell Lymphoma (MCL): Updated Time-to-Event Analyses of the Multicenter PINNACLE Study.

Abstract

Background: We previously reported substantial activity with single-agent bortezomib (VELCADE®; Vc) in patients (pts) with relapsed or refractory MCL in the PINNACLE study (JCO 2006 ; 24:4867–74), which resulted in approval of Vc for MCL pts following ≥1 prior therapy. All pts have now completed treatment. Here we report updated time-to-event data in all pts, and by response category, with extended follow-up.Methods: 155 pts (median age 65 yrs; 55%/41%/4% with 1/2/≥3 prior therapies; 77% Stage IV MCL; 55% positive bone marrow) received Vc 1.3 mg/m2 on days 1, 4, 8, and 11 of 21-day cycles; of these, 141 were response-evaluable. Response and progression were determined by modified International Workshop Response Criteria using independent radiology review.Results: After a median follow-up of 26.4 mo, 55 pts (35%) remained in follow-up; 93 (60%) had died, 2 (1%) had withdrawn consent, and 5 (3%) were lost to follow-up. Pts received a median of 4 treatment cycles (range 1–21; 8 in responding pts). Median time to first response was 1.3 months. Median duration of response (DOR) was 9.2 mo in all responders and has not been reached in pts achieving CR/CRu. Median time to progression (TTP), time to next therapy (TTNT; first Vc dose to start of next therapy), and overall survival (OS) are shown in the table for all pts and by response.Survival rate at 12-mo was 69% overall and 91% in responding pts. In pts refractory to their last therapy (no response or response with TTP <6 mo; n=58), median DOR was 5.9 mo, median TTP was 3.9 mo, median TTNT was 4.6 mo, and median survival was 17.3 mo. Safety profile was similar to previously reported; most common grade ≥3 AEs were peripheral neuropathy (13%), fatigue (12%), and thrombocytopenia (11%). The most common AE resulting in Vc discontinuation was peripheral neuropathy (10%). Twelve (8%) pts died on-study, including 5 (3%) considered related to Vc.Conclusions: Vc provides durable responses plus prolonged time off-therapy and survival in responding pts, suggesting substantial clinical benefit in relapsed/refractory MCL.Median TTP, TTNT, and OS (months) in all pts and by responseAll pts (N=155)Responders (N=45)CR/CRu (N=11)PR (N=34)SD (N=52)PD (N=34)TTP6.712.4NE9.16.91.2TTNT7.414.323.913.37.02.3OS23.535.436.035.127.813.7NE, not estimable