Lenalidomide, melphalan, prednisone and thalidomide (RMPT) for relapsed/refractory multiple myeloma

This multicenter, open-label, non-comparative phase II trial evaluated the safety and efficacy of salvage therapy with lenalidomide, melphalan, prednisone and thalidomide (RMPT) in patients with relapsed/refractory multiple myeloma (MM). Oral lenalidomide (10 mg/day) was administered on days 1-21, and oral melphalan (0.18 mg/kg) and oral prednisone (2 mg/kg) on days 1-4 of each 28-day cycle. Thalidomide was administered at 50 mg/day or 100 mg/day on days 1-28; six cycles were administered in total. Maintenance included lenalidomide 10 mg/day on days 1-21, until unacceptable adverse events or disease progression. Aspirin (100 mg/day) was given as thromboprophylaxis. A total of 44 patients with relapsed/refractory MM were enrolled and 75% achieved at least a partial response (PR), including 32% very good PR (VGPR) and 2% complete response (CR). The 1-year progression-free survival (PFS) was 51% and the 1-year overall survival (OS) from study entry was 72%. Grade 4 hematologic adverse events included neutropenia (18%), thrombocytopenia (7%) and anemia (2%). Grade 3 non-hematologic adverse events were infections (14%), neurological toxicity (4.5%) and fatigue (7%). No grade 3/4 thromboembolic events or peripheral neuropathy were reported. In conclusion, RMPT is an active salvage therapy with good efficacy and manageable side effects. This study represents the basis for larger phase III randomized trials.