Low-dose lenalidomide and dexamethasone therapy after melphalan-prednisolone induction in elderly patients with newly diagnosed multiple myeloma.

Lenalidomide (Len) and dexamethasone (dex) therapy is a standard therapy in patients with multiple myeloma. Elderly or unfit patients may reduce Len or dex doses to prevent toxicities that lead to treatment discontinuation. However, there have been few studies evaluating the efficacy and safety of lower doses of Len and dex. We conducted a phase II study of 1.5-year low-dose Len and dex therapy following melphalan and prednisolone (MP), the number of which cycles was determined by a response within 9 cycles. The Len dose was 10 mg daily and the dex dose was 20 mg weekly, which were continued for 1.5 years. Twenty-one patients were enrolled. The median number of cycles of MP was 3 (range, 2-9). The overall response rate was 81% and a very good partial response or better was achieved in 33.3% of patients. The median follow-up time for survivors was 70.5 months (range, 42-83 months), the median progression-free survival (PFS) was 27 months (95% CI, 21-33 months), and the median overall survival was not reached. Grade 3 or 4 adverse events were observed in 28.6% of patients. In conclusion, the low-dose Len and dex therapy safely achieved comparable efficacies to the standard-dose regimen in elderly patients with newly diagnosed multiple myeloma. UMIN000007889.