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.

Two new myostatin inhibitors are currently in the clinical stage of development for Duchenne.

Clinical stage

Pfizer

PF-06252616 (Domagrozumab): Phase 2.

  • Currently a phase 2 clinical trial is underway.
  • 113 male participants between ages 6 and 15 years were recruited.
  • Subjects receive a monthly IV infused dose of either PF-06252616 or a placebo, and undergo safety evaluations.
  • This study is taking place across 60 study locations, including several in the UK.

Roche

BMS-986089: Phase 1/2 trial.

  • Compound originally developed by Bristol-Myers Squibb, now licenced to Roche.
  • This study is currently active and is primarily testing the safety and tolerability of the drug over 24 weeks.
  • The study recruited 40 ambulant participants between ages 5 and 10 with any mutation for DMD. 
  • The study design compares patients taking the BMS-986089 to patients taking a placebo.
  • The study is taking place in several sites across the USA and Canada.