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A312.5

ACE-031 Research

Mostly mechanism / observational

5 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most ACE-031 studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from medium-quality randomised trials published 2001–2026.

Based on 5 studies · 2 RCTs

Confidence

Low confidence

By outcome

Lean body mass & muscle growthA single human study showed increased lean mass, but the Phase 2 trial was halted for bleeding/vascular safety; muscle gains are largely from animals. · Not established (development halted)
Mostly mechanism / observational3 studies
Muscle strength & powerA single human study showed increased lean mass, but the Phase 2 trial was halted for bleeding/vascular safety; muscle gains are largely from animals. · Not established (development halted)
Too few graded studies1 study
Therapeutic & clinical
Too few graded studies1 study
Safety profile
Too few graded studies1 study

Steady research

1 study in the last 5 years

200120132026

1RCT2017

Campbell C, McMillan HJ, Mah JK, Tarnopolsky M, Selby K, McClure T · Muscle Nerve (2017)

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2RCT2013

Attie KM, Borgstein NG, Yang Y, Condon CH, Wilson DM, Pearsall AE · Muscle Nerve (2013)

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3Animal2010

In plain English: By the end of treatment, mean body weight of the ACE-031 group was 16% greater than that of the control group, and wet weights of soleus, plantaris, gastrocnemius, and extensor digitorum longus muscles increased by 33, 44, 46 and 26%, respectively.

Cadena SM, Tomkinson KN, Monnell TE, Spaits MS, Kumar R, Underwood KW, Pearsall RS, Lachey JL. · J Appl Physiol (1985) (2010)

Foundational preclinical efficacy study: C57BL/6 mice treated with ACE-031 or vehicle for 28 days
Mean body weight was 16% greater than controls; individual muscle wet weights increased 26-46%
Muscle growth occurred independent of fibre type — distinct from myostatin-only inhibition, which predominantly targets type II fibres; fibre cross-sectional area rose in both type I and II fibres

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4Animal2026

In plain English: Marmosets administered ACE-031 were greater at euthanasia compared to baseline; this was not observed in the vehicle-treated controls.

Cadena SM, Bogdanovich S, Khurana TS, Pullen A, Pearsall RS, Curran E, Faucette R, Lane J, Seehra J, Lachey JL, Mizener AD, Pistilli EE. · PLoS One (2026)

Non-human-primate efficacy study: marmosets given ACE-031 or vehicle for 14 weeks, with body composition tracked weekly and muscle assessed terminally
Significant time × treatment interaction for lean body mass — ACE-031 animals gained lean mass while controls did not
Biceps brachii showed increased cross-sectional area of both type I and type II fibres; EDL muscle showed increased absolute and specific force production

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5Animal2001

In plain English: Independent transgenic mouse lines for each construct exhibited dramatic increases in muscle mass comparable to those seen in myostatin knockout mice.

Lee SJ, McPherron AC. · Proc Natl Acad Sci U S A (2001)

Mechanistic foundation: purified myostatin binds the activin type II receptors ActRIIB (and, less, ActRIIA), and this binding is inhibited by follistatin and the myostatin propeptide
Transgenic mice expressing follistatin or a dominant-negative ActRIIB in muscle showed dramatic hypertrophy comparable to myostatin-knockout mice
Establishes ActRIIB as the receptor that ACE-031's soluble decoy is designed to mimic and block — the scientific basis for the whole approach

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View in Research Library

ACE-031 Research

Mostly mechanism / observational

Myostatin inhibitor ACE-031 treatment of ambulatory boys with Duchenne muscular dystrophy: Results of a randomized, placebo-controlled clinical trial.

A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers.

Administration of a soluble activin type IIB receptor promotes skeletal muscle growth independent of fiber type.

ACE-031, a soluble activin type IIB receptor, increases muscle mass and strength in the common marmoset (Callithrix jacchus).

Regulation of myostatin activity and muscle growth.