Lenalidomide can induce long-term responses in patients with multiple myeloma relapsing after multiple chemotherapy lines, in particular after allogeneic transplant.

Evidence of long-term response to lenalidomide in heavily pretreated patients with multiple myeloma is lacking. This study sought to assess whether long-term responders exist, long-term responders' characteristics, and predictive factors of a long-term response. One hundred and four patients with multiple myeloma treated with lenalidomide and dexamethasone after ≥2 therapy lines (median, 3) were analyzed. Long-term response was defined as at least a partial response (≥PR) lasting ≥12 months. The overall response rate was 73%, and 80.3% of the responses were achieved within 5 months. The median response was 14.3 months. Patients evaluable for long-term response numbered 87, and a total of 47% were long-term responders. Compared to non-long-term responders, long-term responders had better overall survival, less light-chain multiple myeloma, and higher incidence of t(11;14). Previous allogeneic transplant (alloSCT) and the response quality predicted a long-term response. In conclusion, patients treated with lenalidomide can become long-term responders; alloSCT and response quality predict long-term response.