Luspatercept + Darbepoetin in MDS

This is a single arm open-label Phase II trial of luspatercept and darbepoetin alfa in non-mutated SF3B1 , lower-risk, RBC transfusion dependent MDS participants with an endogenous erythropoietin (EPO) level \< 500 IU/L. Each participant will be treated with luspatercept in combination with darbepoetin alfa every 21 days (three weeks). Both agents will be administered on day 1 of each 21-day (three weeks) cycle. Based on the individual participant's response to combination therapy of luspatercept and darbepoetin alfa, the doses of luspatercept and/or darbepoetin alfa can be either decreased or increased.