Acceleron and Celgene announced that the FDA has granted orphan drug designation for ACE-536 for the treatment of beta-thalassemia and for the treatment of myelodysplastic syndromes (MDS), two rare blood disorders characterized by severe and chronic anemia (low levels of red blood cells).

ACE-536 is a modified type 2 activin receptor fusion protein that acts as a ligand trap for members in the TGF-β superfamily involved in erythropoiesis. It regulates late-stage erythrocyte (red blood cell) precursor cell differentiation and maturation, distinct from erythropoietin (EPO) which stimulates the proliferation of early-stage erythrocyte precursor cells.

In a Phase 1 clinical study in healthy volunteers, ACE-536 produced dose-dependent increases in red blood cell counts and hemoglobin levels. ACE-536 is currently in Phase 2 clinical trials in patients with beta-thalassemia and in patients with myelodysplastic syndromes.

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