FS-EEE-mFc

FS-EEE-mFc is an engineered, long-acting recombinant fusion protein consisting of a modified human follistatin (FS315) fused to a mouse IgG1 Fc domain. Developed by Shire (now Takeda), it serves as a mouse surrogate for the human therapeutic candidate FS-EEE-hFc. The molecule features three specific glutamate mutations (K76E, K81E, and K82E) within the follistatin heparin-binding domain, which significantly reduce its affinity for heparin and heparan sulfate proteoglycans. This modification prevents sequestration to the vascular endothelium, resulting in a longer systemic half-life compared to native follistatin. FS-EEE-mFc functions as a potent dual antagonist of myostatin (GDF-8) and activin A. By inhibiting these negative regulators of muscle mass, the drug promotes skeletal muscle hypertrophy and exerts anti-inflammatory and anti-fibrotic effects, making it a candidate for the treatment of Duchenne muscular dystrophy (DMD).

Other names

engineered follistatin-mouse Fc fusionFS-EEE-mouse Fc