ACE-031

ID: ace031

Aliases: ActRIIB-Fc, ActRIIB-IgG1, soluble activin receptor type IIB, activin receptor type IIB decoy

Type: compound

Route/form: subcutaneous injection in clinical studies; discontinued investigational biologic

Status: discontinued_investigational

Evidence level: human RCT

Best data tier: human controlled/review; exact-use indirect

Support scope: human, non-human/mechanistic

Source types: human_rct, human_trial, preclinical

Linked sources: 3

Broad outcomes: Fat loss / metabolic health, Muscle growth / performance / recovery, PEDs / AAS / thermogenics

Reading note: These are curation notes anchored to linked sources, not a clinical recommendation or protocol.

Targets / mechanism

• activin receptor type IIB ligand trap
• myostatin binding
• activin/myostatin pathway inhibition

Optimization domains

• myostatin
• activin signaling
• muscle
• muscle wasting
• Duchenne muscular dystrophy
• body composition

Research basis

• A single-dose healthy-volunteer study reported lean-mass and thigh-muscle-volume increases after high-dose ACE-031, and a DMD trial showed pharmacodynamic trends in lean mass, fat mass, and bone markers.
• It is a concrete ActRIIB/myostatin/activin-pathway compound to contrast with bimagrumab rather than a vague myostatin-inhibition idea.
• Marmoset data provide adjacent translational biology for muscle-size and pathway-engagement expectations.

Limits, risks, and missing evidence

• Clinical development was discontinued after vascular safety concerns in the DMD program, including epistaxis/telangiectasia signals.
• Myostatin/activin-pathway mass gains do not automatically prove strength, tendon adaptation, or long-term performance benefit.

Risk flags

• discontinued investigational
• biologic
• myostatin activin pathway
• vascular adverse events
• epistaxis telangiectasia
• unapproved context
• doping
• medical supervision
• lean mass not function

Linked papers, labels, and reviews

1. A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers
   human_trial / pubmed_ace031_healthy_volunteers_2013
   Double-blind placebo-controlled single-dose ACE-031 study in healthy postmenopausal women; lean mass and thigh muscle volume signals at the highest dose.
2. Myostatin inhibitor ACE-031 treatment of ambulatory boys with Duchenne muscular dystrophy: results of a randomized, placebo-controlled clinical trial
   human_rct / pubmed_ace031_dmd_trial_2017
   Randomized DMD trial; stopped after second dosing regimen because of potential safety concerns including epistaxis and telangiectasias.
3. ACE-031, a soluble activin type IIB receptor, increases muscle mass and strength in the common marmoset
   preclinical / plos_ace031_marmoset_2026
   Common marmoset preclinical study reporting lean-mass and muscle-strength effects.