Induction therapy in multiple myeloma.

In most hematologic malignancies the role of induction treatment is to achieve complete remission (CR). In multiple myeloma this has been possible only with the introduction of high-dose therapy plus autologous stem-cell transplantation (ASCT). In the context of ASCT there is a statistical relationship between CR or very good partial remission (VGPR) achievement and progression-free survival or overall survival. High-dose therapy consists of 3 to 6 courses of a dexamethasone alone or combined with vincristine-adriamycin (VAD) to reduce the tumor burden and the plasma cell infiltration followed by 1 or 2 courses of high-dose melphalan plus ASCT. This treatment induces 20% to 40% CR and 40% to 55% CR/VGPR. The introduction of novel agents in the induction treatment is changing this scenario. The combinations of dexamethasone with thalidomide, bortezomib or lenalidomide increase the CR/VGPR rates compared to dexamethasone or VAD. Triple combinations are currently being evaluated, but preliminary results with not more than 3 or 4 cycles show post-ASCT CR/VGPR rates of 60% to 75% In elderly patients who are not candidates for ASCT, combinations of melphalan-prednisone with a novel agent (thalidomide, bortezomib or lenalidomide) yield CR/VGPR rates that are quite comparable to those achieved in younger patients with ASCT. Prolonged treatment with the combination of lenalidomide plus dexamethasone can be administered safely and appears to induce very high (up to 70%) CR/VGPR rates as well.