Myostatin Inhibitor (research class)
/ Heterogeneous class — soluble receptor decoys (ACE-031), monoclonal antibodies (domagrozumab, taldefgrobep), engineered peptide ligands. Vendor product chemistry is typically unspecified.ALIAS · Myostatin antagonist (generic) · GDF-8 inhibitor (research)
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Tier 3 by class. 'Myostatin inhibitor' as sold by research-chemical vendors is not a single defined molecule. The pharmacological class includes the failed ACE-031 program, the discontinued domagrozumab antibody (Pfizer DMD trial halted 2018), taldefgrobep alfa (Phase 3 in DMD), and garetosmab (anti-activin A). None are sold as the vendor-labelled 'research myostatin inhibitor peptide'.
Class mechanism: bind myostatin (GDF-8) and prevent its engagement with cell-surface ActRIIB on skeletal muscle, releasing the brake on muscle hypertrophy. The clinical translation has been substantially harder than the rodent data predicted — multiple Phase 2/3 programs have failed primary endpoints in muscular dystrophies, sarcopenia, and recovery indications.
Class evidence is mixed-to-negative in late-stage human trials. ACE-031 halted for safety; domagrozumab Phase 2 in DMD missed primary endpoint and was terminated; bimagrumab Phase 2 in sporadic IBM showed muscle volume gains without functional benefit; taldefgrobep Phase 3 in DMD ongoing as of 2025. Rodent muscle-mass effects do not translate cleanly to human function.
Class concerns: ActRIIB-decoy molecules carry vascular off-target risk (ACE-031 epistaxis/telangiectasia signal); monoclonal antibodies have variable injection-site / immunogenicity profiles. Vendor research peptides have no human safety data.
Regulatory status
- FDA status:
- Not FDA-approved
The vendor-sold 'myostatin inhibitor research peptide' has no defined sequence in published literature, no PK data, and no biological characterisation independent of the seller's marketing claims. Cannot be assumed pharmacologically equivalent to any of the named clinical-stage molecules.