Evolving role of novel agents for maintenance therapy in myeloma.

Maintenance therapy after remission achievement is a question still open in multiple myeloma (MM). Steroids and interferon-alpha failed to demonstrate a clear benefit in term of survival. Thalidomide, lenalidomide, and bortezomib have shown to be effective and safe drugs for the treatment of both newly diagnosed and relapsed MM, leading to explore their efficacy also in maintenance setting. Thalidomide seems to be a good choice for patients with low-risk MM and for those who achieved less than very good partial remission after induction treatment. Lenalidomide and bortezomib are still under investigation and a longer follow-up is needed for confirming their role as maintenance treatment. As shown by recent clinical trials, thalidomide and bortezomib are more indicated as consolidation agent, increasing the complete remission/very good partial remission rate. Considering their toxicity profile, first of all peripheral neuropathy and, in case of thalidomide, the lack of correlation between cumulative dose and outcome, a limited administration is suggested. In contrast, lenalidomide showed a low toxicity profile and a benefit from prolonged treatment, making the drug one of the best choices for maintenance treatment.