Thalidomide, dexamethasone, Doxil and Velcade (ThaDD-V) followed by consolidation/maintenance therapy in patients with relapsed-refractory multiple myeloma.

In newly diagnosed multiple myeloma (MM), three/four-drug combinations as induction therapy seem to be more effective compared with two-drug associations in terms of response rate and duration of remission. Moreover, there is an emergent body of evidences that consolidation/maintenance therapy improves the quality of response and remission duration. However, the impact of these strategies in relapsed/refractory MM (r-rMM) is still unknown. This phase II study explored the four-drug combination of thalidomide, dexamethasone, pegylated liposomal doxorubicin (pLD), and bortezomib (ThaDD-V) as induction followed by consolidation therapy based on bortezomib-dexamethasone and thalidomide-dexamethasone and maintenance therapy with thalidomide in r-rMM patients. The primary end points of this study were best response and toxicity of the planned therapy. Forty-six patients were enrolled. At the end of therapy, the best response was as follows: 37% complete response (CR), 34.5% VGPR, and 4.5% PR with an ORR of 76%. Patients receiving ≤ 2 prior regimens had a CR rate significantly higher than those heavily treated (41% vs 0%; p=0.010). With a median follow-up of 31 months, median time to progression (TTP) and OS were 18.5 months and 40 months, respectively. By a 6-month landmark analysis, patients who completed the protocol had a significantly longer TTP compared with those who did not because of toxicity (not reached vs 7 months; p<0.0001). After the dose intensity of bortezomib was reduced due to an excess of peripheral neuropathy (PN), grade 3 PN occurred in 7.5% of patients. ThaDD-V followed by consolidation-maintenance therapy seems to be very effective in patients with r-rMM provided that this procedure is used early on relapse when very deep responses seem to be the rule.