Long-term outcome in relapsed and refractory multiple myeloma treated with thalidomide. Balancing efficacy and side-effects.

A total of 303 MM patients were retrospectively reviewed to evaluate long-term efficacy and toxicity of thalidomide alone or in combination with steroids. Overall response rate was 57% (CR/VGPR 12%). Median TTP, PFS and OS were 13.4 months, 20.6 months, and 26.2 months, respectively. PFS and OS were significantly different according to response (p < 0.0001), with better outcome in patients achieving CR/VGPR (PFS and OS 35.4 months and 63 months, respectively). PFS and OS of patients achieving SD or PR were overlapping (p = 0.3). The addition of steroids significantly increased the response rate (p = 0.01). The most clinically relevant complications were neuropathy (40%), constipation (26%), thromboembolic events (7%). Thalidomide was reduced for toxicity in 68 patients (24%) and permanently discontinued in 36 (12%). In conclusion, thalidomide produces high response rate in relapsed/refractory MM. The best outcome is observed in patients with good quality response, but even patients with suboptimal response may obtain durable survival.