2. Diagnosis of Myelodysplastic syndrome (MDS) according to WHO classification with refractory anemia with excess blasts (subtype RAEB-1 or RAEB-2), or considered high-risk by the Revised International Prognostic Scoring System (IPSS-R), that is recurrent or refractory, or the subject is intolerant to established therapy known to provide clinical benefit for their condition (i.e., subjects must not be candidates for regimens known to provide clinical benefit), according to the treating physician and with approval of the Medical Monitor.