OBJECTIVETo evaluate the efficacy and safety of bortezomib retreatment in 76 patients with relapsed/refractory multiple myeloma (MM), who previously responded to bortezomib.

METHODSRetrospective analysis of 76 MM patients, who had achieved at least a partial response (PR) on initial bortezomib therapy in our hospital from May 2006 to August 2011, received bortezomib retreatment when they relapsed or progressed.

RESULTSThe overall response rate (ORR) was 60.5%, among them 6.5% patients achieved CR, 5.8% patients achieved very good partial response (VGPR), 38.2% patients achieved PR. Then we further stratified all patients into 3 groups according to the response of initial bortezomib therapy, including CR group, VGPR group and PR group. After bortezomib retreatment, the ORR of the 3 groups was 84.6%, 73.1% and 43.2%, respectively. According to the response of bortezomib retreatment, the patients were divided into 2 groups: group 1 who at least achieved PR, group 2 who showed no response. The median progression-free survival (PFS) after bortezomib retreatment for group 1 and 2 was 7(1-39) and 5(1-14) months, respectively (P>0.05), while the median overall survival (OS) after bortezomib retreatment was 16(2-64) and 8(1-28) months, respectively (P<0.05). Adverse events (AE) were identified in 88% patients during bortezomib retreatment, including neutropenia, diarrhea and thrombocytopenia, only 9.2%(7 patients) reached Ⅲ-Ⅳ grade of AE. Severe peripheral neuropathy occurred in only one patient.

CONCLUSIONBortezomib retreatment regimen is demonstrated a higher response rate in patients who achieved deeper response in initial treatment, with no more adverse events.