ACE-031 (Ramatercept)
discontinuedAlso known as: Ramatercept, ActRIIB-Fc
**Mechanism of Action** ACE-031 (Ramatercept) is a soluble fusion protein comprising the extracellular domain of activin receptor type IIB (ActRIIB) linked to the Fc region of human IgG. It functions as a decoy receptor, binding and sequestering myostatin (GDF-8) and other TGF-β superfamily ligands (e.g., activin A, GDF-11). By preventing these ligands from activating endogenous ActRIIB receptors, ACE-031 inhibits downstream Smad2/3 signaling, thereby blocking the negative regulation of muscle growth. This results in increased muscle mass and reduced muscle wasting in preclinical models. **Key Research Findings** In a Phase II trial for Duchenne muscular dystrophy (DMD), ACE-031 demonstrated dose-dependent increases in lean body mass and muscle volume over 12 weeks. However, the trial was halted due to safety concerns, including transient nosebleeds (epistaxis), telangiectasias, and potential effects on bone metabolism (e.g., reduced bone mineral density). Preclinical studies also showed that ActRIIB blockade can impair bone formation and increase fracture risk, likely due to cross-inhibition of bone-protective ligands like activin A. Despite initial promise, the adverse event profile led to discontinuation of clinical development. **Clinical Relevance** ACE-031 was investigated as a potential therapy for muscle-wasting conditions, particularly DMD, where myostatin inhibition was hypothesized to preserve muscle function. However, the emergence of vascular and bone-related toxicities highlighted the challenge of targeting the ActRIIB pathway without disrupting its pleiotropic roles in non-muscle tissues. The discontinuation of ACE-031 underscores the need for more selective myostatin inhibitors or combination strategies to mitigate off-target effects. Currently, no further clinical trials are active. For research purposes only — not medical advice.
Key data
Research & studies
Of 14 tested black market ACE-031 products, 12 contained an ACVR2B-immunoreactive protein.; The 12 positive products contained many additional proteins beyond the main compound (ca. 58.4 kDa).; Mass spectrometry and immunoblotting revealed the products contained full-length human activin receptor IIB, not ACE-031.; In rat serum, BM ACE-031 was detectable up to 48 hours after a 10 mg/kg dose, though the human detection window may differ.
ACE-031 was not associated with serious or severe adverse events, but the study was stopped due to epistaxis and telangiectasias.; A non-significant trend for maintenance of 6-minute walk test distance was seen in ACE-031 groups versus placebo decline.; Trends for increased lean body mass and bone mineral density, and reduced fat mass were noted with ACE-031.; Non-muscle-related adverse events contributed to the decision to discontinue the study.
ACE-031 was generally well-tolerated with adverse events including injection site erythema.; Mean ACE-031 AUC and Cmax increased linearly with dose; mean half-life was 10-15 days.; At 3 mg/kg, total body lean mass increased by 3.3% and thigh muscle volume by 5.1% at day 29.; Serum biomarkers suggested improvements in bone and fat metabolism.
Frequently asked questions
What is ACE-031 (Ramatercept)?
**Mechanism of Action** ACE-031 (Ramatercept) is a soluble fusion protein comprising the extracellular domain of activin receptor type IIB (ActRIIB) linked to the Fc region of human IgG. It functions as a decoy receptor, binding and sequestering myostatin (GDF-8) and other TGF-β superfamily ligands (e.g., activin A, GD
How does ACE-031 (Ramatercept) work?
Soluble ActRIIB-Fc decoy receptor that sequesters myostatin and related ligands; trialed in muscular dystrophy before discontinuation.
What is the research status of ACE-031 (Ramatercept)?
ACE-031 (Ramatercept) is currently classified as discontinued, with 12 research references on record. This is for research purposes only and is not medical advice.
Related peptides
Mechanically activated IGF-1 splice variant that activates muscle satellite cells for repair and hypertrophy.
Truncated IGF-1 variant with high local potency and short half-life, studied for site-specific muscle growth.
Activin-binding glycoprotein that antagonizes myostatin (GDF-8) to release the brake on skeletal muscle growth.
Long-acting IGF-1 analog with reduced IGFBP binding, prolonging activation of the IGF-1 receptor to drive muscle hypertrophy.
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