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.