Clinical effectiveness of DNA methyltransferase inhibitors and lenalidomide in older patients with refractory anemia with ring sideroblasts: a population-based study in the United States.

Existing studies regarding the role of DNA methyltransferase inhibitors (DNMTi) and lenalidomide in refractory anemia with ring sideroblasts (RARS) are limited. Using the surveillance, epidemiology, and end results-medicare database, we assembled a population-based cohort of older adults diagnosed with non-del(5q) lower-risk myelodysplastic syndromes during 2007-2015. Of 2167 patients, 30% had RARS. About 16% of RARS and non- ring sideroblasts (RS) patients received DNMTi. RARS patients were more likely to receive lenalidomide (11.1% vs. 7.1%, p < 0.01). Among patients who were transfusion-dependent at treatment initiation, 55.6% of those treated with DNMTi only and 42.5% treated with lenalidomide only achieved red blood cell transfusion independence (RBC-TI) for a median duration of 21 and 12 weeks, respectively. RS status did not impact rate of RBC-TI. RARS patients had a significantly better survival, and the median survival of RARS patients varied by treatment group. In this population-based study of older RARS patients, DNMTi and lenalidomide were clinically active.