Pomalidomide and its clinical potential for relapsed or refractory multiple myeloma: an update for the hematologist.

Multiple myeloma is a common plasma cell neoplasm that is incurable with conventional therapy. The treatment paradigm of multiple myeloma is not standardized and is evolving. The advent of novel drugs, including the proteasome inhibitor bortezomib and the immunomodulatory agents, has resulted in increased median survival. Unfortunately, all patients eventually relapse and require further therapy. Pomalidomide is the newest immunomodulatory drug, created by chemical modification of thalidomide with the intention of increasing therapeutic activity while limiting toxicity. Its mechanism of action is incompletely understood but involves anti-angiogenic effects, immunomodulation, an effect on the myeloma tumor microenvironment, and the protein cereblon. It is more potent than thalidomide and lenalidomide. In phase II studies, it has shown significant activity in patients with relapsed and refractory multiple myeloma, including patients who are heavily pretreated, have disease refractory to lenalidomide and bortezomib, and those with high-risk cytogenetic or molecular markers. It is generally well tolerated, with adverse effects including fatigue, neutropenia, neuropathy, and thromboembolic disease. Pomalidomide is a promising new agent in the expanding arsenal of antimyeloma drugs. In this review, we discuss the clinical experience to date with pomalidomide in multiple myeloma.