Acceleron Initiates Phase 2 Study of ACE-536 to Treat Anemia in Patients with Myelodysplastic Syndromes

Acceleron Initiates Phase 2 Study of ACE-536 to Treat Anemia in Patients with Myelodysplastic Syndromes

Acceleron earns $10 million milestone payment from collaboration partner Celgene Corporation

Cambridge, Mass. – January 29, 2013 – Acceleron Pharma, Inc., a biopharmaceutical company developing protein therapeutics for cancer and orphan diseases, today announced the initiation of a phase 2 study of its investigational protein therapeutic, ACE-536, to treat anemia in patients with myelodysplastic syndromes (MDS).  MDS are a group of hematologic malignancies of the bone marrow that result in low levels of one or more types of blood cells resulting most commonly in severe and chronic anemia (low levels of red blood cells).  Acceleron is developing ACE-536 in a global collaboration with Celgene Corporation (NASDAQ: CELG).  Acceleron earned a $10 million milestone for initiating this phase 2 study and is still eligible to receive development, regulatory and commercial milestones of up to $200 million for the ACE-536 program.

"The anemia experienced by patients with MDS is clinically challenging because it is often unresponsive to administration of erythropoietin and many patients ultimately require red blood cell transfusions," said Professor Uwe Platzbecker, M.D., Director outpatient department of Hematology/Oncology at Universitatsklinikum Carl Gustav Carus in Dresden, Germany and coordinating principal investigator of the ACE-536 "PACE-MDS" phase 2 study.  "We are excited to explore ACE-536 as a potential new treatment for MDS patients in this phase 2 study".

"ACE-536 has the potential to make a significant impact on the treatment of anemia in MDS," said Matthew Sherman, M.D., Chief Medical Officer of Acceleron.  "Unlike erythropoietin, ACE-536 may target the specific defect in the erythropoietic maturation process in MDS patients and we are optimistic that it could become an important new therapeutic option for this underserved patient population."

About the Phase 2 Clinical Trial

The phase 2 clinical trial is designed to evaluate the safety, tolerability and efficacy of ACE-536 in patients with low-risk or intermediate-1 risk MDS.  Efficacy measures include increases in hemoglobin levels, reduction of red blood cell transfusion burden, and other hematologic parameters, as well as biomarkers of iron and bone metabolism.  For additional information on this clinical trial, please visit, identifier NCT01749514.

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 (red blood cell formation).  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 due to ineffective erythropoiesis, which is characterized by high endogenous levels of erythropoietin 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-beta superfamily involved in late stages of erythropoiesis.  ACE-536 promotes late-stage erythrocyte precursor cell differentiation, distinct from erythropoietin which acts during early, proliferative stages of erythropoiesis.  This mechanism of action to increase red blood cells has the potential to treat patients with anemia in diseases such as myelodysplastic syndromes (MDS) and beta-thalassemia that are inadequately managed with current therapy.  In a phase 1 clinical study of healthy volunteers, ACE-536 produced a dose-dependent increase in red blood cells and hemoglobin levels.  Acceleron and Celgene are jointly developing ACE-536 for diseases such as beta-thalassemia and myelodysplastic syndromes (MDS).

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


Acceleron Pharma:
Steve Ertel, 617-649-9234
Chief Business Officer

Maureen L. Suda (Media)
Suda Communications LLC

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