Acceleron's rare blood disease drug flies high in phase 3

Acceleron Pharma and partner Celgene unveiled 24-week data Thursday showing that luspatercept hit its primary and secondary endpoints in a phase 3 trial of patients with chronic anemia associated with a rare blood disease.

Luspatercept reduced the need for red blood cell transfusions for at least eight consecutive weeks in patients with myelodysplastic syndromes (MDS) and chronic anemia, for whom erythropoietin-stimulating agent (ESA) drugs do not, or no longer work, the companies said in a statement.

Considered a type of blood cancer, myelodysplastic syndromes occur when the blood-forming cells in the bone marrow become abnormal. This leads to depleted numbers of one of more types of blood cells, according to the American Cancer Society. Luspatercept is designed to foster the production of red blood cells by targeting transforming growth factor-beta (TGF-beta) proteins involved in red cell differentiation and maturation.

In addition to the primary endpoint, luspatercept also met its secondary endpoints, which included reducing the need for blood transfusions for at least 12 consecutive weeks. The data will be presented at a "future medical meeting in 2018," the companies said.

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“This result from the phase III MEDALIST trial demonstrates the potential clinical benefit of luspatercept as an erythroid maturation agent for the treatment of chronic anemia in patients with low-to-intermediate risk MDS,” said Jay Backstrom, M.D., Chief Medical Officer for Celgene.

The companies plan to file luspatercept for approval in the U.S. and Europe in the first half of 2019 and to test the drug in MDS patients who have not yet been treated with ESA meds. The drug is also in a late-stage trial in beta-thalassemia.

Acceleron and Celgene have been working on the TGF-beta program since 2008, initially focusing on another candidate called sotatercept that has been superseded by luspatercept and was recently taken back in-house by Acceleron as a therapy for pulmonary artery hypertension.