Myostatin, also called GDF-8, is a protein that inhibits muscle growth. It is produced naturally in the body and its production increases with age. Myostatin is required in the body to stop muscles from growing too large. Various induced or natural conditions leading to myostatin deficiency result in increased muscle mass and strength in normal animals and have been shown to treat or prevent a range of muscle wasting conditions.

Studies in mouse models of Duchenne show reduced fibrosis and adipose tissue replacement in muscles of mice treated with myostatin inhibitors.

      In August 2018, Pfizer terminated the development of Domagrozumab, a myostatin inhibitor, after the drug did not meet primary efficacy endpoint in a phase 2 clinical trial. The trial was terminated due to safety. The data gathered from this trial is of high quality and Pfizer hope to use it to help develop new therapies for DMD. 

      In November 2019, Roche discontinued their phase 2 study into mysotatin inhibitors, as interim data showed that it was unlikely to meet its primary endpoint. For more information, please click here