ACE-083 | Pen

ACE-083 is a peptide positioned for controlled research settings where localized myostatin/activin pathway inhibition is being studied in relation to target-muscle hypertrophy, strength/function readouts, and muscle composition biomarkers (e.g., contractile fraction).

Supports

1. Local myostatin/activin ligand trapping in injected muscle tissue (model-dependent)
2. Targeted muscle volume increases and compartment-specific hypertrophy endpoints
3. Strength and functional performance readouts in focal weakness paradigms
4. Muscle composition shifts (contractile muscle fraction vs fat fraction markers)
5. Safety monitoring for localized growth-factor modulation (injection-site tolerability signals)

Description

ACE-083 is an investigational, locally acting recombinant fusion protein engineered from a follistatin-based ligand trap design. It is studied for binding myostatin (GDF8) and related TGF-β family ligands involved in limiting skeletal muscle growth. By concentrating activity within the injected muscle, ACE-083 has been used to test whether focal hypertrophy can be achieved without widespread systemic exposure.

In preclinical studies, ACE-083 produced localized increases in muscle size and, in certain models, improvements in force-related endpoints. In human clinical research (including healthy volunteer studies and phase 2 programs in neuromuscular conditions), ACE-083 has consistently shown the ability to increase muscle volume in targeted muscles, while functional improvements have been more variable and endpoint-dependent.

ACE-083 is presented for research context only. Effects and interpretation depend on muscle selection, baseline disease physiology, endpoint sensitivity, treatment duration, and how functional outcomes are measured in controlled protocols.

Clinical Status

ACE-083 has been evaluated in human studies (including randomized phase 2 trials) focusing on changes in muscle volume and related imaging/biomarker endpoints in conditions with focal or asymmetric weakness. While pharmacodynamic effects on muscle volume have been demonstrated, functional endpoint outcomes have not consistently met prespecified targets across programs. ACE-083 is not described as having regulatory approval for therapeutic use in the provided source text.

Evidence type:
Human RCT ✔ | Observational ✔ | Animal ✔ | In vitro ✔ | Regulatory approval ☐

Mechanism of Action

ACE-083 is designed as a follistatin-based ligand trap that binds myostatin and other negative regulators of skeletal muscle growth, reducing their availability to signal through activin type II receptor complexes. In experimental designs, this “ligand sequestration” approach is used to study derepression of muscle growth constraints in a localized, muscle-targeted manner.

Because follistatin-based traps can engage multiple ligands beyond myostatin, mechanistic interpretation often considers broader pathway biology (e.g., activins and related growth factors) as well as local tissue remodeling signals. Clinical programs have therefore relied heavily on imaging-based muscle volume endpoints (and composition metrics) alongside strength/function readouts to map pharmacodynamic effects to measurable performance outcomes.

Benefits

• Localized muscle hypertrophy:
  Studied for producing targeted increases in muscle volume at the injected site, enabling focal hypertrophy mapping in controlled protocols.
• Muscle composition endpoint shifts:
  Clinical studies assess whether increases are driven by contractile muscle fraction versus non-contractile components, supporting mechanistic interpretation.
• Strength/function hypothesis testing:
  Used to test whether focal hypertrophy translates into measurable gains in muscle strength or task performance within defined outcome frameworks.
• Reduced systemic exposure model:
  Local administration is investigated as a way to concentrate pharmacodynamic effects in selected muscles rather than producing broad, body-wide changes.
• Neuromuscular disease research context:
  Evaluated in clinical research for conditions with focal weakness (e.g., CMT and FSHD), focusing on muscle volume as a sensitive pharmacodynamic endpoint.
• Pathway deconvolution tool:
  Supports research into myostatin/activin ligand redundancy and the relationship between hypertrophy, muscle composition, and functional outputs.

Research Data

Stack Suggestions

In extended experimental designs, ACE-083 is sometimes paired with:

• CJC-1295 (No-DAC) → to co-study GH/IGF-axis biomarker shifts alongside focal hypertrophy endpoints
• IGF-1 LR3 → to compare downstream anabolic signaling markers with myostatin-pathway blockade designs
• TB-500 (Thymosin Beta-4 fragment) → to explore tissue remodeling and recovery-related readouts in parallel models

Stacks discussed are for experimental design only, not safety/efficacy guidance.

Possible Side Effects

ACE 083 is an innovative medicinal product used to treat various muscular diseases. This medicine stimulates muscle growth, enhancing the efficacy of local genetic growth factors.

Like any medicine, medicinal product, and supplement, the administration of ACE083 can also cause some side effects. These manifest as headaches, mild pain, or redness around the injection site, and a feeling of fatigue. These side effects are not dangerous and usually disappear within a few days as symptoms of the body,s adaptation.

ACE-083 is safe for use, as long as the recommended dosage is respected.

Scientific References

• Locally acting ACE-083 increases muscle volume in healthy volunteers — Human RCT
• Follistatin-based ligand trap ACE-083 induces localized hypertrophy of skeletal muscle with functional improvement in models of neuromuscular disease — Animal/In vitro
• Randomized Phase 2 Study of ACE-083 in Patients With Charcot-Marie-Tooth Disease — Human RCT
• Randomized phase 2 study of ACE-083 in facioscapulohumeral muscular dystrophy (FSHD) — Human RCT
• ClinicalTrials.gov: Study of ACE-083 in Patients With Facioscapulohumeral Muscular Dystrophy (NCT02927080) — Clinical registry
• ClinicalTrials.gov: Study of ACE-083 in Patients With Charcot-Marie-Tooth Disease (NCT03124459) — Clinical registry
• Acceleron press release filing: Topline Phase 2 results in FSHD (ACE-083) — Regulatory/Company
• Acceleron press release: Topline Phase 2 results in CMT (ACE-083) — Regulatory/Company
• Results of a Phase 2 Double-Blind Placebo-Controlled Study of ACE-083 in Patients With Charcot-Marie-Tooth Disease (conference report) — Human RCT
• Impact of Genetic and Pharmacologic Inhibition of Myostatin in Musculoskeletal and Metabolic Biology — Review

Cautions

• For educational and scientific context only; not intended to diagnose, treat, cure, or prevent any disease.
• If you are pregnant, nursing, have a medical condition, or use prescription medication, consult a qualified professional.
• Discontinue use if sensitivity occurs.