7002 Background: ESAs, the first line treatments of anemia in non del 5q lower risk MDS, yield only 40-50% responses. LEN gives RBC transfusion independence (TI) in about 25% of ESA resistant (or relapsing) TD lower risk MDS without del 5q (Raza, Blood, 2008), and a gene expression signature can predict response (Ebert, Plos Med 2008). We randomized in this patient population LEN alone and LEN+EPO. Methods: In this prospective multicenter open-label phase II study (NCT01718379), lower risk MDS patients without del 5q, with TD (≥4 RBC units during the previous 8 weeks (w)) with ESA resistance or relapse after a response were randomized between LEN alone, 10mg/d x 21 d/4 w (L arm) or LEN (same schedule) + EPO beta, 60 000 U/w (LE arm). The primary endpoint was erythroid response (HI-E, IWG 2006 criteria) after 4 treatment cycles. Secondary objectives included identification of biomarkers of response. Results: Between July 2010 and June 2012, 132 patients (pts, 66 / arm), median age 73 (range 46-88), M/F: 88...