[The efficacy and safety analysis of bortezomib retreatment in 76 patients with relapsed/refractory multiple myeloma].

OBJECTIVE: To evaluate the efficacy and safety of bortezomib retreatment in 76 patients with relapsed/refractory multiple myeloma (MM), who previously responded to bortezomib.
METHODS: Retrospective 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.
RESULTS: The 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.
CONCLUSION: Bortezomib retreatment regimen is demonstrated a higher response rate in patients who achieved deeper response in initial treatment, with no more adverse events.