Impact of Lenalidomide Treatment on Overall Survival in Patients With Lower-Risk, Transfusion-Dependent Myelodysplastic Syndromes

Background: For patients with lower-risk (LR) myelodysplastic syndromes (MDS), overall survival (OS) is rarely a primary clinical trial endpoint. Treatments such as lenalidomide can reduce red blood cell (RBC) transfusion burden (TB) and serum ferritin, but the long-term impact on OS remains undetermined.

Patients and methods: Data from 3 trials evaluating lenalidomide in patients with LR-MDS (the phase 2 MDS-003 and phase 3 MDS-004 trials in del[5q]; the phase 3 trial MDS-005 in non-del[5q] patients) were pooled. Predictors of OS were assessed by multivariate analysis using time-dependent models for TB and RBC transfusion independence (RBC-TI), and a landmark analysis of RBC-TI at 17 weeks. Separate analyses using MDS-004 and MDS-005 data determined the relationship between OS and serum ferritin.

Results: Median follow-up for MDS-003, MDS-004, and MDS-005 was 3.2, 3.0, and 1.7 years, respectively. In multivariate analyses, transfusion of ≥6 RBC units over 8 weeks was a significant predictor of shorter OS vs. 0 units in the time-dependent TB model (hazard ratio [HR] 4.65; 95% confidence interval [CI] 3.32-6.52; P < .0001). RBC-TI achievement was associated with prolonged OS in the time-dependent (HR 0.48; 95% CI 0.37-0.62; P < .0001) and landmark model (HR 0.57; 95% CI 0.44-0.75; P < .0001). Increased serum ferritin was associated with shorter OS (P < .0001).

Conclusion: This analysis of prospective trial data in patients with LR-MDS confirms lenalidomide may improve OS by reducing TB and serum ferritin. OS should be considered as an endpoint in future lower risk MDS clinical trials.