Bortezomib in Combination with Conventional Chemotherapeutic Agents for Multiple Myeloma Compared with Bortezomib Alone

Background: Recent studies have demonstrated synergy between bortezomib and a number of conventional cytotoxic agents. This study examined whether or not the speed of the response, progression and safety from a combination treatment of bortezomib with common chemotherapeutic drugs is superior to bortezomib monotherapy. Methods: Fifty-seven patients with relapsed, refractory multiple myeloma (MM) who had received at least two cycles of treatment including bortezomib were enrolled in this study. The median age was 56 (35–79) years and 49.1 % were male. Thirty-two patients were treated with bortezomib alone and 25 were treated with chemotherapeutic agents that were given in combination with bortezomib. The monoclonal immunoglobulin (mIg) or free light chain (FLC) concentrations were determined in the sera before and after two cycles of bortezomib treat-ment. The adverse events were assessed and graded according to the NCI Common Toxicity Criteria (version 2.0). Results: Thirty-one of the 57 patients (54.4%) attained an early objective response (EOR) after the second bortezomib treatment, defined as a 50 % decrease in the serum mIg or FLC concentration. Improvements in the response were observed when commo