Keros Therapeutics announced on August 20, 2025, that the U.S. Food and Drug Administration has granted Orphan Drug designation to KER-065 for the treatment of Duchenne muscular dystrophy (DMD). The designation marks a significant regulatory milestone for the clinical-stage biopharmaceutical company as it prepares to advance the investigational therapy into Phase 2 clinical trials.
"Receiving Orphan Drug designation for KER-065 highlights the significant unmet medical need for patients with DMD," said Jasbir S. Seehra, President and Chief Executive Officer of Keros. "This designation serves as a significant milestone for Keros as we advance KER-065 into a Phase 2 clinical trial in patients with DMD."
Regulatory Benefits and Market Positioning
The FDA grants Orphan Drug designation to investigational therapies addressing rare medical diseases or conditions that affect fewer than 200,000 people in the United States. This designation provides several potential benefits, including tax credits for qualified clinical testing, waiver or partial payment of FDA application fees, and seven years of market exclusivity if approved.
The designation could enhance Keros' market positioning and operational strategy in developing treatments for rare diseases, providing both financial incentives and competitive advantages in the DMD treatment landscape.
KER-065 Mechanism and Design
KER-065 is a novel ligand trap comprised of a modified ligand-binding domain derived from activin receptor type IIA and activin receptor type IIB that is fused to the portion of the human antibody known as the Fc domain. The therapeutic is designed to act as a ligand trap and inhibit the biological effects of myostatin and activin A, two ligands that signal through activin receptors.
The mechanism aims to increase skeletal muscle regeneration, increase muscle size and strength, reduce body fat, reduce fibrosis of the skeletal muscle, and increase bone strength. Keros is developing KER-065 for the treatment of neuromuscular diseases, with an initial focus on DMD.
Duchenne Muscular Dystrophy Disease Background
DMD is the most common form of muscular dystrophy and results in muscle degeneration and premature death. The disease results from the lack of functional dystrophin protein that helps promote myofiber stability, caused by a gene mutation. The lack of dystrophin, an important structural component of muscle cells, causes muscle cells to have increased susceptibility to damage and to progressively die.
The absence of dystrophin in muscle cells leads to significant cell damage and ultimately causes muscle cell death and the replacement of muscle with fibrotic and fatty tissue. The replacement of muscle fibers with fatty and fibrotic tissue leads to progressive loss of muscle strength and function leading to immobility and respiratory and cardiac complications.
In DMD patients, heart muscle cells progressively die and are replaced with scar tissue. This cardiomyopathy eventually leads to heart failure, which is currently the leading cause of death among those with DMD. The National Organization for Rare Disorders estimates that approximately one in every 3,500 male births is affected by DMD worldwide.
Company Focus and Pipeline
Keros Therapeutics is a clinical-stage biopharmaceutical company focused on developing and commercializing novel therapeutics to treat a wide range of patients with disorders that are linked to dysfunctional signaling of the transforming growth factor-beta (TGF-β) family of proteins. The company positions itself as a leader in understanding the role of the TGF-β family of proteins, which are master regulators of the growth, repair and maintenance of tissues including blood, bone, skeletal muscle, adipose and heart tissue.
In addition to KER-065, Keros' most advanced product candidate is elritercept, which is being developed for the treatment of cytopenias, including anemia and thrombocytopenia, in patients with myelodysplastic syndrome and in patients with myelofibrosis.
