Lenalidomide in lower-risk myelodysplastic syndromes with karyotypes other than deletion 5q and refractory to erythropoiesis-stimulating agents.

Lenalidomide (LEN) has been shown to yield red blood cell (RBC) transfusion independence in about 25% of lower risk myelodysplastic syndromes (MDS) without del(5q), but its efficacy in patients clearly refractory to erythropoiesis-stimulating agents (ESA) is not known. We report on 31 consecutive lower-risk non-del(5q) MDS patients with anaemia refractory to ESA and treated with LEN in a compassionate programme, 20 of whom also received an ESA. An erythroid response was obtained in 15 patients (48%), including 10 of the 27 (37%) previously transfusion-dependent (RBC-TD) patients, who became transfusion-independent (RBC-TI). Nine of the responders relapsed, whereas 6 (40%) were still responding and transfusion-free after 11(+)-31(+) months. Median response duration was 24 months. The erythroid response rate was lower in refractory cytopenia with multilineage dysplasia (27% vs. 60%) and tended to be higher in patients treated with LEN + ESA (55% vs. 36%). Response duration was significantly longer in responders who obtained RBC-TI and in patients treated with LEN after primary resistance to ESA. The main toxicity of LEN was cytopenias. We confirm that, in a patient population of lower risk MDS without del 5q clearly resistant to ESA, LEN is an interesting second line therapeutic option. Its combination with ESAs in this context warrants prospective studies.