Scholar Rock (NASDAQ: SRRK) announced that the FDA has granted Fast Track and Orphan Drug designations to apitegromab for the treatment of facioscapulohumeral muscular dystrophy (FSHD), a progressive hereditary neuromuscular disease characterized by muscle atrophy, weakness, and functional decline.

The Cambridge, Mass.-based biopharmaceutical company also announced that participant dosing has begun in the Phase 2 FORGE clinical trial, which evaluates apitegromab as a monotherapy in adults with genetically confirmed FSHD.

FORGE is a randomized, double-blind, placebo-controlled, multi-center trial designed to enroll approximately 60 participants, who will be randomized one-to-one to receive apitegromab 10 mg/kg or placebo intravenously every four weeks for 52 weeks. The primary endpoint is percent change from baseline in total lean muscle volume as measured by MRI at Week 52.

Fast Track designation is granted to investigational therapies intended to treat serious or life-threatening conditions that have the potential to address significant unmet medical needs, with the aim of expediting development and review.

According to a statement from the company, preclinical data from the FLExDUX4 FSHD mouse model showed that a murine form of apitegromab increased muscle mass, strength, and endurance.

Apitegromab is an investigational fully human monoclonal antibody designed to inhibit myostatin activation. Scholar Rock previously studied the therapy in spinal muscular atrophy, where it was used in combination with SMN-targeted treatments.