Bortezomib plus dexamethasone is highly effective in relapsed and refractory myeloma patients but responses are short-lived

Objectives: Bortezomib has proven to be effective as single agent in myeloma patients. Aim of this study was to evaluate the efficacy and toxicity of bortezomib in combination with dexamethasone in a cohort of multiple myeloma (MM) relapsed/refractory patients treated in a single center. Patients and Methods: In this single center study, 70 patients were treated with bortezomib alone (9) or in combination with dexamethasone (61). Results: Forty-one patients (59%) achieved at least a partial response (PR), including 7% complete response (CR), 36% very good partial response (VGPR) reaching the best response within four cycles. The duration of response was significantly longer for patients achieving CR/VGPR than for those achieving PR (7.3 vs. 3.8 months, P = 0.03). Likewise, time to progression, time to alternative treatment, and treatment free interval were significantly better for patients obtaining CR/VGPR (6.8, 9.4, 6.5 months respectively) as compared with PR (4.9, 6.3, 2 months respectively). The only dose-limiting toxicity was peripheral neuropathy (PN), which occurred in 38/70 patients (55%) and was of grade 3-4 in 12 (17%). PN led to a dose reduction or treatment discontinuation in 17 (24%) patients. Complete resolution or improvement of PN occurred in 29/38 (76%) after a median time of 100 d (range: 17-202). Conclusions: Bortezomib in combination with dexamethasone is highly effective in relapsed/refractory MM producing an impressive rate of CR/VGPR, but responses are short-lived.