Its mechanism involves binding to ligands such as GDF11 and activins via a modified extracellular domain of activin receptor type IIB (ActRIIB), effectively acting as a “ligand trap.” By inhibiting aberrant Smad2/3 signaling, luspatercept promotes late-stage erythroid maturation, addressing the ineffective erythropoiesis characteristics of MDS [49–51]. The gene discussed is ACVR2B; the disease is myelodysplastic syndrome.