A subset analysis of the randomized, phase 3, MDS-004 study to evaluate outcomes in patients with International Prognostic Scoring System (IPSS)-defined Low-/Intermediate (Int)-1-risk myelodysplastic syndromes (MDS) with isolated del(5q).
Patients received lenalidomide 10 mg/day (days 1-21; n = 47) or 5 mg/day (days 1-28; n = 43) on 28-day cycles, or placebo (n = 45). From the placebo and lenalidomide 5 mg groups, 84% and 58% of patients, respectively, crossed over to lenalidomide 5 mg or 10 mg at 16 weeks, respectively.
Rates of red blood cell-transfusion independence (RBC-TI) ≥182 days were higher in the lenalidomide 10 mg (57.4%; P < 0.0001) and 5 mg (37.2%; P = 0.0001) groups versus placebo (2.2%). Cytogenetic response rates (major + minor responses) were 56.8% (P < 0.0001), 23.1% (P = 0.0299), and 0%, respectively. Two-year cumulative risk of acute myeloid leukaemia progression was 12.6%, 17.4%, and 16.7% in the lenalidomide 10 mg, 5 mg, and placebo groups, respectively. In a 6-month landmark analysis, overall survival was longer in lenalidomide-treated patients with RBC-TI ≥182 days versus non-responders (P = 0.0072). The most common grade 3-4 adverse event was myelosuppression.
These data support the clinical benefits and acceptable safety profile of lenalidomide in transfusion-dependent patients with IPSS-defined Low-/Int-1-risk MDS with isolated del(5q). The study is registered at www.ClinicalTrials.gov, identifier NCT00179621.