Treatment-related adverse events in patients with relapsed/refractory multiple myeloma

In the past decade we have seen four new agents approved by the US Food and Drug Administration for treatment of multiple myeloma: the proteasome inhibitor (PI) bortezomib (Velcade), the immunomodulatory agents lenalidomide (Revlimid) and thalidomide (Thalomid), and liposomal doxorubicin. These are commonly used in the treatment of relapsed/refractory (R/R) multiple myeloma (MM), but there is no universally accepted standard treatment. Salvage therapy must be tailored according to an individual patient's clinical profile, with the risks and potential effects of treatment-related adverse events being major determinants of the choice of therapy. Two novel agents in phase II studies to investigate their potential for the treatment of R/R MM are carfilzomib, a selective, irreversible next-generation PI, and pomalidomide, a next-generation thalidomide analog. This review will discuss the side-effect profiles of the currently approved immunomodulatory agents and bortezomib, as well as those of the newer agents, carfilzomib and pomalidomide.