Cyclophosphamide's Addition in Relapsed/Refractory Multiple Myeloma Patients With Biochemical Progression During Lenalidomide-Dexamethasone Treatment

Objective: The aim of this study was to evaluate the addition of cyclophosphamide in relapsed-refractory multiple myeloma patients (RRMM) who experienced biochemical relapse or progression without CRAB, during treatment with lenalidomide and dexamethasone (Rd), to slow down the progression in active relapse. Methods: This analysis included 31 patients with RRMM treated with Rd who received cyclophosphamide (CRd) at biochemical relapse. The CRd regimen was continued until disease progression. Results: The median number of CRd cycles administered was 8 (range: 1-35). A response was observed in 9 (29%) patients. After a median observation time of 11 months, the median overall survival (OS) from the beginning of CRd was 17.7 months. The median progression-free survival (PFS) from the beginning of CRd was 13.1 months. Conclusion: The addition of cyclophosphamide delays the progression in patients who present a biochemical relapse during Rd treatment. The response rate and the duration of PFS obtained with minimal toxicities and low costs induced us to setting up a randomized clinical trial.