Long-term results of response to therapy, time to progression, and survival with lenalidomide plus dexamethasone in newly diagnosed myeloma.

OBJECTIVE: To determine the long-term effects of a combined regimen of lenalidomide and dexamethasone (Rev-Dex) on time to progression, progression-free survival, and overall survival (OS) in patients with multiple myeloma. PATIENTS AND METHODS: From March 2004 through October 2004, 34 patients were registered for the study. They were treated with 25 mg/d of lenalidomide on days 1 through 21 of a 28-day cycle and 40 mg/d of dexamethasone on days 1 through 4, 9 through 12, and 17 through 20 of each cycle. After 4 cycles of therapy, patients were allowed to discontinue treatment to pursue autologous stem cell transplant (SCT). Treatment beyond 4 cycles was permitted at the physician s discretion.
RESULTS: Thirteen patients proceeded to SCT after initial therapy and were censored at that time point for purposes of calculation of response. Thirty-one patients achieved an objective response, defined as a partial response or better (91%; 95% confidence interval, 79%-98%), with a complete response plus very good partial response rate of 56%. The complete response plus very good partial response among the 21 patients who received Rev-Dex without SCT was 67%. The 2-year progression-free survival rates for patients proceeding to SCT and patients remaining on Rev-Dex were 83% and 59%, respectively; the OS rates were 92% and 90% at 2 years and 92% and 85% at 3 years, respectively. The 3-year OS rate for the whole cohort was 88%.
CONCLUSION: The Rev-Dex regimen is highly active in the treatment of newly diagnosed multiple myeloma. Responses are durable with a low progression rate at 2 years. Randomized trials that incorporate quality-of-life measures are needed to determine if this and other combination regimens are better used early in therapy or should be reserved for later interventions.