Lenalidomide and Dexamethasone in Patients with Relapsed or Refractory Multiple Myeolma

San Diego—A regimen of lenalidomide plus dexamethasone proved safe and effective in patients with relapsed or refractory multiple myeolma, according to a retrospective analysis of 2 randomized, double-blind, phase 3 trials presented in a poster session at the ASH meeting. Of the 353 patients in the studies, 18% had progression-free survival (PFS) for ≥2 years. The authors also concluded that there were few adverse events found in the population. The results were included in a poster titled Long-Term Outcomes and Safety of Continuous Len+Dex Treatment in Patients with Relapsed/Refractory Multiple Myeloma. A previous analysis of the trials found that patients taking lenalidomide plus dexamethasone had a median overall survival of 38.0 months compared with 31.6 months for patients taking placebo plus dexamethasone (P=.045). In this analysis, the authors were interested in long-term outcomes of the studies and wanted to examine the qualities of patients who had PFS for ≥2 years. The analysis included all of the patients in the 2 trials who achieved PFS for ≥2 years. The median follow-up was 48 months, and the data cutoff for the trials were July 23, 2008, and March 2, 2008, respectively. Compared with all patients included in the studies, patients who had ≥2 years of PFS were younger (70% were <65 years of age vs 54%), had lower ß2-microglobulin levels (43% had levels <2.5 mg/L vs 24%), had higher creatinine clearance at baseline (median of 85.0 vs 77.5 mL/min), and had fewer prior therapies (48% received ≥2 prior therapies vs 60%). Each of the 64 patients with PFS for ≥2 years achieved at least a partial response, including 67% who achieved at least a very good response and 50% who achieved complete response. Of all patients in the studies, 60% achieved at least a partial response, including 23% who achieved at least a very good response and 16% who achieved complete response. The median time to first response was 2.8 months in all patients as well as in the group that achieved PFS for ≥2 years. In patients with PFS for ≥2 years, the median PFS and median overall survival were not reached. In patients with PFS for <2 years, the median PFS was 6.6 months and the median overall survival was 29.4 months. According to a multivariate Cox regression analysis, the baseline hemoglobin level (P=.027), ß2-microglobulin level (P=.002), and number of prior antimyeloma therapies (P=.032) were prognostic in patients with PFS of ≥2 years. The number of grade 3 or 4 adverse events was similar in the total study population and the group with PFS of ≥2 years, although the percentage of patients who discontinued the studies due to adverse events was smaller in patients with PFS of ≥2 years compared with the overall study population (12.5% vs 18.7%). This study was funded by Celgene Corporation.