Up to now, high-dose therapy supported by autologous stem-cell transplantation (ASCT) is considered standard of care for first-line therapy in patients with symptomatic multiple myeloma (MM). The role of bortezomib, a proteasome inhibitor, as consolidation or maintenance therapy after ASCT in patients with newly diagnosed MM is currently investigated in clinical trials. Bortezomib is already approved as monotherapy and in patients with progressive MM or as combination therapy as first-line treatment for transplant-ineligible patients in Europe.
Two recent phase III trials assessed the efficacy and safety of bortezomib within a transplant setting. In both trials, bortezomib was incorporated in the induction regimen prior to ASCT, followed by post-transplant bortezomib as consolidation therapy in one trial and as prolonged maintenance therapy after ASCT in the second trial. Although response rates were better in the bortezomib-containing arm compared to the control arm throughout the course of the studies, its role in the post-transplant setting remains unclear.
Currently there are multiple effective therapeutic options available for the treatment of MM. In order to prolong overall survival and to improve or at least maintain quality of life, the main task will be to determine the most effective sequence and combination of these therapeutic strategies.