Efficacy of retreatment with immunomodulatory drugs (IMiDs) in patients receiving IMiDs for initial therapy of newly diagnosed multiple myeloma.

The efficacy of retreatment with immunomodulatory drugs (IMiDs) among patients with multiple myeloma who received this class of drugs for initial therapy is unknown. We studied 140 patients who received either thalidomide-dexamethasone (81; 58%) or lenalidomide-dexamethasone (59; 42%) as first-line therapy of multiple myeloma followed by repeat IMiD (thalidomide [34; 24%] or lenalidomide [106; 76%]) as one of the salvage regimens. A median of 2 treatments (range, 1-6), including a stem cell transplant in 105 patients (75%), were administered before IMiD-based salvage therapy. The median time from diagnosis to repeat exposure to IMiD was 28 months. Among the 113 evaluable patients, 50 (44%) achieved at least a partial response, and 63 (56%) achieved less than a partial response to repeat IMiD. Response rates with lenalidomide retreatment were higher than with repeat administration of thalidomide.