Pomalidomide: new immunomodulatory agent with potent antiproliferative effects.

New treatment options are urgently needed for patients with relapsed multiple myeloma (MM) who are refractory to thalidomide, lenalidomide, and bortezomib therapy. Pomalidomide, a second-generation immunomodulatory agent, has been shown to exert direct antiproliferative actions on MM cells, effects on the bone-marrow microenvironment, and immunomodulation. In phase I clinical trials, pomalidomide has demonstrated promising response rates in patients with relapsed and/or refractory MM, with manageable toxicity. In phase II trials pomalidomide, 2-4 mg/daily, given continuously or on days 1-21 of a 28-day cycle, in combination with dexamethasone, has been associated with high quality and durable clinical responses in patients who are refractory to lenalidomide, bortezomib, or both. Pomalidomide appears to be well tolerated; hematologic toxicities are the most commonly reported adverse events and peripheral neuropathy is rare. Phase III trials are currently underway to determine the optimal dose and combination regimen of pomalidomide in the treatment of MM.