Therapy with bortezomib plus lenalidomide for relapsed/refractory mantle cell lymphoma: final results of a phase II trial (CALGB 50501).

Cancer and Leukemia Group B designed a phase II trial of lenalidomide + bortezomib for relapsed/refractory mantle cell lymphoma (MCL). Induction therapy was lenalidomide (days 1-14) plus bortezomib (days 1/4/8/11), every 21 days for eight cycles. Complete/partial responders (CR, PR) received maintenance lenalidomide (days 1-14) and bortezomib (days 1/8), every 21 days. Primary endpoint was overall response rate; secondary endpoints were CR rate, progression-free (PFS), event-free (EFS) and overall survival (OS). Fifty-three eligible patients, median age 67 years, were accrued. Median number of cycles received was 4 (range, 1-82). Median followup was 46 (range, 12-67) months. Best response was CR 15%, PR 25%. 5/8 CR, and 4/13 PR patients received maintenance. Six CR and one PR patient remain in remission (median, 3.2 years). Thirty-three (62%) patients have died. One-year PFS, EFS and OS are 40%, 25% and 68%, respectively. This combination will not be pursued further.