Acceleron Receives Two FDA Orphan Designations for ACE-536

Acceleron Receives Two FDA Orphan Designations for ACE-536
ACE-536 granted rare disease designation for the treatment of beta-thalassemia and for the treatment of myelodysplastic syndromes (MDS)

Cambridge, Mass. – March 26, 2013 - Acceleron Pharma, Inc., a biopharmaceutical company developing protein therapeutics for cancer and orphan diseases, today announced that the United States Food and Drug Administration (FDA) granted orphan 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).  Patients with beta-thalassemia and MDS suffer from ineffective erythropoiesis, a defect in which red blood cell precursors are prevented from maturing into healthy, functional red blood cells resulting in severe anemia.  Anemia in these patients is often unresponsive to current therapies and many patients are ultimately dependent on frequent red blood cell transfusions.  ACE-536 is an investigational protein therapeutic that increases red blood cells through a novel mechanism and is being developed by Acceleron as part of a global collaboration with Celgene Corporation (NASDAQ: CELG).

"ACE-536 has shown the potential to address a significant unmet medical need in the treatment of these rare hematological disorders," said Matthew Sherman, M.D., Chief Medical Officer of Acceleron.  "We are excited about the prospect of bringing a new therapeutic option to these underserved patient populations and continue to work closely with our clinical investigators on both of our recently initiated phase 2 clinical studies of ACE-536, one in patients with beta-thalassemia and a second in patients with MDS."

Orphan designation is granted by the FDA Office of Orphan Products Development to advance the evaluation and development of safe and effective therapies for the treatment of rare diseases or conditions affecting fewer than 200,000 people in the U.S.  Under the Orphan Drug Act, the FDA may provide grant funding towards clinical trial costs, tax advantages, FDA user-fee benefits, and seven years of market exclusivity in the United States following marketing approval by the FDA.  The granting of an orphan designation request does not alter the standard regulatory requirements and process for obtaining marketing approval. For more information about orphan designation, please visit the FDA website at www.fda.gov

About Beta-Thalassemia

Beta-thalassemia is a rare, inherited disease involving mutations in the beta globin gene leading to defective hemoglobin production and serious anemia.  In beta-thalassemia patients, there is an over production of red blood cell (RBC) precursors in the bone marrow that fail to properly mature into functional RBCs, a condition referred to as "ineffective erythropoiesis."  This often leads to bone deformities, decreased bone mineral density and bone strength, and pathologic fractures.    Beyond the severe anemia and bone effects, many patients also suffer from multiple organ dysfunction, largely due to excess iron deposits, known as "iron overload", resulting from the ineffective erythropoiesis and the repeated RBC transfusions to address the anemia.  Iron overload can lead to heart failure, liver fibrosis, and diabetes, among other consequences.  Current treatment for beta-thalassemia includes regular RBC transfusions and daily iron chelation therapy, which is associated with toxicities.    

About Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematologic malignancies of the bone marrow commonly leading to severe and chronic anemia due to ineffective erythropoiesis.  The National Cancer Institute estimates that more than 10,000 people are diagnosed with MDS in the United States each year.  Patients with MDS have a hypercellular bone marrow with various dysplastic changes of the cells that are also seen in peripheral blood, resulting in cytopenias (low blood cell counts) and an increased risk of progression to acute myeloid leukemia (AML).  Nearly all MDS patients suffer from anemia.  The anemia in MDS is characterized by high endogenous levels of erythropoietin (EPO) driving an abundance of early stage red blood cell precursors and an inability of these precursor cells to properly differentiate into healthy, functional red blood cells.  Many patients are therefore unresponsive to the administration of erythropoietin to correct the resulting anemia and instead require red blood cell transfusions, which can increase the risk of infection and iron-overload related toxicities.   

About ACE-536

ACE-536 is a modified type II activin receptor fusion protein that acts as a ligand trap for members in the TGF-β superfamily involved in erythropoiesis.  ACE-536 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 diseases of ineffective erythropoiesis, such as myelodysplastic syndromes (MDS) and beta-thalassemia, in which there is an over-production of early-stage erythrocyte precursors in the bone marrow, administration of erythropoietin does not correct the underlying cause of the anemia.  By promoting the differentiation of the precursor cells into mature RBCs, ACE-536 has the potential to treat the anemia in MDS and beta-thalassemia patients.  In a phase 1 clinical study in healthy volunteers, ACE-536 produced dose-dependent increases in red blood cell counts and hemoglobin levels.  Acceleron and Celgene are jointly developing ACE-536.  ACE-536 is currently in phase 2 clinical trials in patients with beta-thalassemia and in patients with myelodysplastic syndromes.  For more information, please visit www.clinicaltrials.gov.

About Acceleron
Acceleron is a privately-held biopharmaceutical company committed to discover, develop, manufacture and commercialize novel protein therapeutics for orphan diseases and cancer. Acceleron's scientific approach takes advantage of its unique insight to discover first-in-class therapies based on the TGF-β protein superfamily. Acceleron utilizes proven biotherapeutic technologies and capitalizes on the company's internal GMP manufacturing capability to advance its therapeutic programs rapidly and efficiently. The investors in Acceleron include Advanced Technology Ventures, Alkermes, Avalon Ventures, Bessemer Ventures, Celgene, Flagship Ventures, MPM BioEquities, OrbiMed Advisors, Polaris Ventures, QVT Financial, Sutter Hill Ventures and Venrock. For further information on Acceleron, please visit www.acceleronpharma.com.