Meta-analysis of the efficacy and safety of bortezomib re-treatment in patients with multiple myeloma.

INTRODUCTION Bortezomib is administered for a finite course; thus, patients might remain sensitive to bortezomib-based therapy at relapse. We report a meta-analysis of bortezomib-based retreatment in relapsed/refractory myeloma. PATIENTS AND METHODS A systematic literature review identified studies of bortezomib-based retreatment in relapsed/refractory myeloma. Proportions of bortezomib-refractory patients and additional prognostic factors were extracted and used in weighted stratified analyses of TTP and OS. Random-effect pooled estimates were calculated for overall response rate (ORR) and rates of common AEs. RESULTS Twenty-three studies (n = 1051 patients) were identified. Bortezomib was administered intravenously in all studies. Across studies in which data were available, pooled, weighted average ORR was 39.1% (95% confidence interval, 30.8%-47.4%), and pooled, weighted average median TTP and OS were 7.5 and 16.6 months, respectively. Patients with fewer previous therapies (≤ 4) and relapsed (not refractory) patients achieved higher ORRs, of 43.4% and 57.2%, respectively. Random-effects meta-regression analysis confirmed that relapsed patients were associated with a higher ORR by 28 to 41 percentage points versus refractory patients. In relapsed patients, median TTP and OS were 8.5 and 19.7 months, respectively. Common Grade 3/4 AEs included thrombocytopenia (35%), neutropenia (15%), anemia (14%), pneumonia (10%), and peripheral neuropathy (3%). CONCLUSION Based on these findings, bortezomib retreatment is well tolerated and appears efficacious in relapsed patients. In an era of new and emerging treatment options for relapsed and/or refractory myeloma, these data indicate that bortezomib retreatment might be a highly effective option in previously treated patients.