Outcomes in RBC transfusion-dependent patients with Low-/Intermediate-1-risk myelodysplastic syndromes with isolated deletion 5q treated with lenalidomide: a subset analysis from the MDS-004 study

OBJECTIVE: A subset analysis of the randomised, 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). METHODS: Patients received lenalidomide 10 mg/d (days 1‐21; n = 47) or 5 mg/d (days 1‐28; n = 43) on 28‐d cycles or placebo (n = 45). From the placebo and lenalidomide 5 mg groups, 84% and 58% of patients, respectively, crossed over to lenalidomide 5 or 10 mg at 16 wk, respectively. RESULTS: Rates of red blood cell‐transfusion independence (RBC‐TI) ≥182 d were higher in the lenalidomide 10 mg (57.4%; P < 0.0001) and 5 mg (37.2%; P = 0.0001) groups vs. 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 d vs. non‐responders (P = 0.0072). The most common grade 3‐4 adverse event was myelosuppression. CONCLUSIONS: 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).