Management of double-refractory multiple myeloma.

Widespread use of the novel agents bortezomib and lenalidomide has improved outcomes in multiple myeloma (MM). Despite remarkable progress, patients will eventually relapse after exhausting treatment with these drugs. Management of myeloma that is refractory to both bortezomib and lenalidomide (double-refractory MM, DRMM) is complicated due to disease, patient, and treatment-related factors and new therapies for these patients are required. A review of the unique challenges of treating DRMM, recently FDA-approved therapeutic agents, and selected novel drugs under active clinical investigation, is presented below.