ACE-031

updated

ACE-031 (ramatercept) is a dimeric fusion protein of the activin receptor type IIB and human IgG1 Fc, not a peptide, and it has never been approved. One subcutaneous dose raised total body lean mass 3.3% in 48 healthy postmenopausal women, but the Duchenne program was stopped for epistaxis and telangiectasias, and a 2025 analysis of 14 black market products found none contained the Fc fusion protein.

Activin receptor type IIB Fc fusion protein (myostatin pathway inhibitor)

  • ACE-031 (ramatercept) is a dimeric fusion protein of the human activin receptor type IIB extracellular domain and the Fc part of human IgG1. It is not a peptide.
  • Drugs@FDA queries for ACE-031 and ramatercept returned no matching application on 9 October 2026. A 2025 paper states it has not been pharmaceutically approved and is sold as a research chemical on the black market.
  • In 48 healthy postmenopausal women, one subcutaneous dose of 3 mg/kg raised total body lean mass 3.3% by DXA and thigh muscle volume 5.1% by MRI at day 29 (P=0.03 for each).
  • The Duchenne trial stopped after the second dosing regimen: epistaxis in 5 of 9 boys at 1.0 mg/kg every 2 weeks versus 0 of 6 on placebo, and telangiectasia in 5 of 9 versus 0 of 6. No serious adverse events were reported.
  • A second healthy-volunteer study (NCT00952887, 70 women) has no posted results and no located publication, and the Duchenne extension study (NCT01239758, 11 subjects) was terminated.
  • In a 2025 analysis of 14 black market ACE-031 products, 2 contained no relevant protein and 12 contained full-length human activin receptor IIB, not the Fc fusion protein.

What is ACE-031, and has anyone approved it?

ACE-031 (ramatercept) is a dimeric fusion protein of the human activin receptor type IIB extracellular domain and the Fc part of human IgG1, not a peptide. It has never been approved: Drugs@FDA queries on 9 October 2026 returned no matching application.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein and means there is no small-molecule identity record to cite. Any vendor product described as an "ACE-031 peptide" or "ACE-031 fragment" is by definition not the dimeric Fc fusion protein that every clinical study on this page used.

openFDA Drugs@FDA substance-name queries for ACE-031 and for ramatercept each returned no matching application on 9 October 2026. ACE-031 has never been approved. A 2025 analytical paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. The registered healthy-volunteer studies were sponsored by Acceleron Pharma.

2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source
Drugs@FDA queries, 9 October 2026: no matching application

Regulatory record

U.S. Food and Drug Administration. openFDA Drugs@FDA substance-name queries for ACE-031 and for ramatercept, run on 9 October 2026.

openFDA Drugs@FDA substance-name queries for ACE-031 and for ramatercept each returned no matching application on 9 October 2026. ACE-031 has never been approved.

Participants / model
Regulator database, not a population
Treatment
Exact substance-name searches
Follow-up
Searches run on 9 October 2026
Study design
FDA API query
Funding
not stated in the source

This is a US-scoped statement; the analytical paper cited separately makes a broader statement that ACE-031 has not been pharmaceutically approved.

Read the original source

What did the study in healthy volunteers find?

In 48 healthy postmenopausal women given a single subcutaneous dose, total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03) at day 29 in the 3 mg/kg group. That is one dose, one population and one dose level reaching significance. A second healthy-volunteer study in 70 women was never reported.

A double-blind placebo-controlled study randomized 48 healthy postmenopausal women 3 to 1 to a single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg or placebo. At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

The sellers' statement that ACE-031 increased lean mass in healthy volunteers is accurate and narrower than it sounds: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

The registry record NCT00755638 describes this as a phase 1 single escalating dose safety and tolerability study of ACE-031 (ActRIIB-IgG1) in healthy postmenopausal volunteers, sponsored by Acceleron Pharma, with actual enrollment of 48, started in September 2008 and completed in July 2009, with no posted results.

A second healthy-volunteer study exists and was never reported. NCT00952887 is a phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women, sponsored by Acceleron Pharma, with actual enrollment of 70, started in August 2009 and completed in February 2011, with no posted results. A PubMed search on 9 October 2026 for ACE-031 restricted to human records returned 10 items, of which only two are human trial reports: the single-dose healthy volunteer study and the Duchenne trial. The repeat-dose data in 70 women have not been published in the records reviewed.

Healthy volunteers: 48 postmenopausal women, one dose, lean mass +3.3% at day 29

Randomized controlled trial

Attie KM et al. Muscle Nerve. 2013;47(3):416-23. PMID 23169607.

At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

Participants / model
48 healthy postmenopausal women
Treatment
A single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg, or placebo
Follow-up
Single dose, measured at day 29
Study design
Double-blind placebo-controlled phase 1 trial, randomized 3 to 1
Funding
not stated in the source

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

Read the original source
Registry NCT00755638: phase 1 single dose, 48 enrolled, no posted results

Trial registry record

ClinicalTrials.gov. NCT00755638, phase 1 single escalating dose safety and tolerability study of ACE-031 (ActRIIB-IgG1) in healthy postmenopausal volunteers.

NCT00755638 is a phase 1 single escalating dose safety and tolerability study of ACE-031 (ActRIIB-IgG1) in healthy postmenopausal volunteers, sponsor Acceleron Pharma, actual enrollment 48, started in September 2008 and completed in July 2009, with no posted results.

Participants / model
48 healthy postmenopausal volunteers
Treatment
Subcutaneous ACE-031
Follow-up
September 2008 to July 2009
Study design
Registered safety and tolerability outcomes; no posted results
Funding
not stated in the source

The registration supports that the study existed; the published report supplies the result.

Read the original source
Registry NCT00952887: phase 1 repeat dose, 70 enrolled, no posted results, no located publication

Trial registry record

ClinicalTrials.gov. NCT00952887, phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women.

NCT00952887 is a phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women, sponsor Acceleron Pharma, actual enrollment 70, started in August 2009 and completed in February 2011, with no posted results. A PubMed search on 9 October 2026 for ACE-031 restricted to human records returned 10 items, of which only two are human trial reports (the single-dose healthy volunteer study and the Duchenne trial).

Participants / model
70 healthy postmenopausal women
Treatment
Multiple escalating subcutaneous doses
Follow-up
August 2009 to February 2011
Study design
Registered safety, tolerability, PK and PD outcomes; no posted results and no located publication
Funding
not stated in the source

The repeat-dose data in 70 women have not been published in the records reviewed.

Read the original source
Searches, 9 October 2026: 4 registry records, all the fusion protein; no fragment study in any species

PubMed search record

PubMed search run on 9 October 2026: ACE-031 AND humans MeSH term, 10 items. ClinicalTrials.gov intervention-scoped search for ACE-031, 4 records, run the same day.

A ClinicalTrials.gov intervention-scoped search for ACE-031 returned 4 records, all of them the Acceleron fusion protein: two phase 1 studies in healthy postmenopausal women and two phase 2 Duchenne studies. A PubMed search for ACE-031 restricted to human records returned 10 items, of which the only human trial reports are the single-dose healthy volunteer study and the Duchenne trial. No study in any species tests a short peptide fragment marketed as ACE-031.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Searches run on 9 October 2026
Study design
Registry and literature searches
Funding
not stated in the source

A search result shows what the databases returned on that date. It is not proof that no unindexed study exists.

Read the original source

What happened in the Duchenne trial, and why did it stop?

The trial of subcutaneous ACE-031 in ambulatory boys with Duchenne muscular dystrophy was stopped after the second dosing regimen because of epistaxis and telangiectasias. In the registry results, epistaxis occurred in 5 of 9 boys at 1.0 mg/kg every 2 weeks versus 0 of 6 on placebo, and telangiectasia in 5 of 9 versus 0 of 6. No serious adverse events were reported, and the efficacy trends were not statistically significant.

ACE-031 was given subcutaneously every 2 to 4 weeks to ambulatory boys with Duchenne muscular dystrophy in a randomized, double-blind, placebo-controlled, ascending-dose trial whose primary objective was safety. The study was stopped after the second dosing regimen due to potential safety concerns of epistaxis and telangiectasias. ACE-031 was not associated with serious or severe adverse events. There was a trend, not statistically significant, for maintenance of 6-minute walk test distance versus a decline on placebo, and trends for increased lean body mass and bone mineral density and reduced fat mass. The Duchenne evidence is a stopped safety study with non-significant efficacy trends, not a demonstration of benefit.

The posted registry results for NCT01099761 give the numbers behind the termination. It randomized 24 boys: 9 to ACE-031 0.5 mg/kg every 4 weeks, 9 to 1.0 mg/kg every 2 weeks and 6 to placebo, for 12 weeks, with a planned 2.5 mg/kg cohort that was never enrolled because the study was terminated. The registry gives the reason for stopping as "Based on preliminary safety data." Reported events above the 5% threshold were epistaxis in 5 of 9 at 1.0 mg/kg every 2 weeks, 1 of 9 at 0.5 mg/kg every 4 weeks and 0 of 6 on placebo; telangiectasia in 5 of 9, 0 of 9 and 0 of 6; injection site erythema in 6 of 9, 3 of 9 and 3 of 6; and headache in 3 of 9, 1 of 9 and 1 of 6. Serious adverse events were 0 in every arm. The vascular signal is dose-related and clear even in 24 children.

The extension study stopped too. NCT01239758, an extension study of ACE-031 in subjects with Duchenne muscular dystrophy, enrolled 11 and was terminated, with the registry reason given as "This study was terminated based on preliminary safety data." No results are posted. Two of the four registered ACE-031 studies were terminated, and the two that completed have never posted results.

Duchenne trial: stopped after the second regimen for epistaxis and telangiectasias

Randomized controlled trial

Campbell C et al. Muscle Nerve. 2017;55(4):458-464. PMID 27462804.

The study was stopped after the second dosing regimen due to potential safety concerns of epistaxis and telangiectasias. ACE-031 was not associated with serious or severe adverse events. There was a trend, not statistically significant, for maintenance of 6-minute walk test distance versus a decline on placebo, and trends for increased lean body mass and bone mineral density and reduced fat mass.

Participants / model
Ambulatory boys with Duchenne muscular dystrophy; number not stated in the source
Treatment
Subcutaneous ACE-031 every 2 to 4 weeks, or placebo
Follow-up
not stated in the source
Study design
Randomized, double-blind, placebo-controlled, ascending-dose trial; primary objective was safety
Funding
not stated in the source

The Duchenne evidence is a stopped safety study with non-significant efficacy trends, not a demonstration of benefit.

Read the original source
Registry NCT01099761: 24 boys, epistaxis 5 of 9 and telangiectasia 5 of 9 at the higher regimen

Trial registry record

ClinicalTrials.gov. NCT01099761, phase 2 study of ACE-031 in boys with Duchenne muscular dystrophy, with posted results.

NCT01099761 randomized 24 boys: 9 to ACE-031 0.5 mg/kg every 4 weeks, 9 to 1.0 mg/kg every 2 weeks and 6 to placebo, with a planned 2.5 mg/kg cohort that was never enrolled because the study was terminated. The registry gives the reason for stopping as "Based on preliminary safety data." Reported events above the 5% threshold: epistaxis in 5 of 9 at 1.0 mg/kg every 2 weeks, 1 of 9 at 0.5 mg/kg every 4 weeks and 0 of 6 on placebo; telangiectasia in 5 of 9, 0 of 9 and 0 of 6; injection site erythema in 6 of 9, 3 of 9 and 3 of 6; headache in 3 of 9, 1 of 9 and 1 of 6. Serious adverse events were 0 in every arm.

Participants / model
24 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031, 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks, or placebo
Follow-up
12 weeks
Study design
Registry record with posted results; outcomes were adverse reactions and clinical laboratory adverse reactions
Funding
not stated in the source

The vascular signal is dose-related and clear even in 24 children.

Read the original source
Registry NCT01239758: Duchenne extension, 11 enrolled, terminated, no results

Trial registry record

ClinicalTrials.gov. NCT01239758, extension study of ACE-031 in subjects with Duchenne muscular dystrophy.

NCT01239758, an extension study of ACE-031 in subjects with Duchenne muscular dystrophy, enrolled 11 and was terminated, with the registry reason given as "This study was terminated based on preliminary safety data." No results are posted. Two of the four registered ACE-031 studies were terminated, and the two that completed have never posted results.

Participants / model
11 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031
Follow-up
not stated in the source
Study design
Registered adverse events and laboratory parameters; no posted results
Funding
not stated in the source

The extension study stopped on the same kind of preliminary safety data as the main Duchenne study.

Read the original source

Is the sellers' claim accurate, and does a vendor fragment do anything?

Both factual points are accurate: the original biologic was studied in Duchenne muscular dystrophy and raised lean mass in healthy volunteers. No study in any species tests a short peptide fragment marketed as ACE-031, so the sellers' statement that its effect in humans is unknown is correct and, if anything, understated.

Sellers say the original biologic was studied in Duchenne muscular dystrophy and raised lean mass in healthy volunteers, and that whether a vendor peptide fragment does anything in humans is unknown. Both factual halves are accurate.

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. The Duchenne study was stopped for epistaxis and telangiectasias, and its efficacy trends were not statistically significant.

A ClinicalTrials.gov intervention-scoped search for ACE-031 returned 4 records on 9 October 2026, all of them the Acceleron fusion protein: two phase 1 studies in healthy postmenopausal women and two phase 2 Duchenne studies. A PubMed search for ACE-031 restricted to human records returned 10 items, of which the only human trial reports are the single-dose healthy volunteer study and the Duchenne trial. No study in any species tests a short peptide fragment marketed as ACE-031, so the sellers' own statement that its effect in humans is unknown is correct and, if anything, understated: there is no evidence in any species, and the product analysis in the next section indicates the vials do not contain the trial molecule.

Searches, 9 October 2026: 4 registry records, all the fusion protein; no fragment study in any species

PubMed search record

PubMed search run on 9 October 2026: ACE-031 AND humans MeSH term, 10 items. ClinicalTrials.gov intervention-scoped search for ACE-031, 4 records, run the same day.

A ClinicalTrials.gov intervention-scoped search for ACE-031 returned 4 records, all of them the Acceleron fusion protein: two phase 1 studies in healthy postmenopausal women and two phase 2 Duchenne studies. A PubMed search for ACE-031 restricted to human records returned 10 items, of which the only human trial reports are the single-dose healthy volunteer study and the Duchenne trial. No study in any species tests a short peptide fragment marketed as ACE-031.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Searches run on 9 October 2026
Study design
Registry and literature searches
Funding
not stated in the source

A search result shows what the databases returned on that date. It is not proof that no unindexed study exists.

Read the original source
Healthy volunteers: 48 postmenopausal women, one dose, lean mass +3.3% at day 29

Randomized controlled trial

Attie KM et al. Muscle Nerve. 2013;47(3):416-23. PMID 23169607.

At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

Participants / model
48 healthy postmenopausal women
Treatment
A single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg, or placebo
Follow-up
Single dose, measured at day 29
Study design
Double-blind placebo-controlled phase 1 trial, randomized 3 to 1
Funding
not stated in the source

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

Read the original source
Duchenne trial: stopped after the second regimen for epistaxis and telangiectasias

Randomized controlled trial

Campbell C et al. Muscle Nerve. 2017;55(4):458-464. PMID 27462804.

The study was stopped after the second dosing regimen due to potential safety concerns of epistaxis and telangiectasias. ACE-031 was not associated with serious or severe adverse events. There was a trend, not statistically significant, for maintenance of 6-minute walk test distance versus a decline on placebo, and trends for increased lean body mass and bone mineral density and reduced fat mass.

Participants / model
Ambulatory boys with Duchenne muscular dystrophy; number not stated in the source
Treatment
Subcutaneous ACE-031 every 2 to 4 weeks, or placebo
Follow-up
not stated in the source
Study design
Randomized, double-blind, placebo-controlled, ascending-dose trial; primary objective was safety
Funding
not stated in the source

The Duchenne evidence is a stopped safety study with non-significant efficacy trends, not a demonstration of benefit.

Read the original source
2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source

What is actually in vials sold as ACE-031?

A 2025 analysis of 14 black market ACE-031 products found that only 12 contained an ACVR2B-immunoreactive protein, and those 12 contained full-length human activin receptor IIB rather than ACE-031. The other 2 contained no relevant protein. The material on sale was not the studied drug.

A 2025 analysis of 14 black market ACE-031 products found that only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa, and the products also contained many other proteins.

So 2 of 14 products contained no relevant protein, and the other 12 contained a different molecule from the one in the trials. This is the direct answer to the vendor peptide-fragment question: the material on sale was not the studied drug.

2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source

How does ACE-031 work, and what happens to it in the body?

ACE-031 binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. After a single subcutaneous dose in 48 healthy postmenopausal women, AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days.

ACE-031 is a dimeric fusion protein of a fragment of the human activin receptor type IIB extracellular domain and the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle.

In the single-dose study in 48 healthy postmenopausal women, doses ranged from 0.02 to 3 mg/kg subcutaneously. Mean AUC and Cmax rose linearly with dose, and mean half-life was 10 to 15 days. Tmax is not given in the sources reviewed, and the repeat-dose pharmacokinetics from the 70-woman study were never published.

2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source
Healthy volunteers: 48 postmenopausal women, one dose, lean mass +3.3% at day 29

Randomized controlled trial

Attie KM et al. Muscle Nerve. 2013;47(3):416-23. PMID 23169607.

At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

Participants / model
48 healthy postmenopausal women
Treatment
A single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg, or placebo
Follow-up
Single dose, measured at day 29
Study design
Double-blind placebo-controlled phase 1 trial, randomized 3 to 1
Funding
not stated in the source

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

Read the original source
Registry NCT00952887: phase 1 repeat dose, 70 enrolled, no posted results, no located publication

Trial registry record

ClinicalTrials.gov. NCT00952887, phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women.

NCT00952887 is a phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women, sponsor Acceleron Pharma, actual enrollment 70, started in August 2009 and completed in February 2011, with no posted results. A PubMed search on 9 October 2026 for ACE-031 restricted to human records returned 10 items, of which only two are human trial reports (the single-dose healthy volunteer study and the Duchenne trial).

Participants / model
70 healthy postmenopausal women
Treatment
Multiple escalating subcutaneous doses
Follow-up
August 2009 to February 2011
Study design
Registered safety, tolerability, PK and PD outcomes; no posted results and no located publication
Funding
not stated in the source

The repeat-dose data in 70 women have not been published in the records reviewed.

Read the original source

What safety signals did the studies show?

Epistaxis and telangiectasias ended the Duchenne trial after the second dosing regimen: epistaxis in 5 of 9 and telangiectasia in 5 of 9 boys at 1.0 mg/kg every 2 weeks versus 0 of 6 on placebo, with no serious adverse events in any arm. Injection site erythema also occurred, and the extension study was terminated on preliminary safety data.

In the Duchenne trial, epistaxis and telangiectasias led to termination after the second dosing regimen. In the registry results, epistaxis occurred in 5 of 9 boys at 1.0 mg/kg every 2 weeks, 1 of 9 at 0.5 mg/kg every 4 weeks and 0 of 6 on placebo, and telangiectasia in 5 of 9, 0 of 9 and 0 of 6. Serious adverse events were 0 in every arm. The vascular signal is dose-related. Its mechanism is not established in the sources reviewed, so it is described here as an observed signal and not explained.

Injection site erythema occurred in the 48-woman single-dose study and in 6 of 9, 3 of 9 and 3 of 6 boys across the Duchenne arms. The extension study was terminated based on preliminary safety data. The 70-woman repeat-dose study has no posted results and no located publication, so repeated-dose safety in healthy people is unreported in the records reviewed.

Vendor vials add a separate concern. In the 2025 analysis of 14 black market products, 2 contained no relevant protein and 12 contained full-length activin receptor IIB, not the Fc fusion protein, and the products also contained many other proteins. No safety data exist for products sold as ACE-031.

Duchenne trial: stopped after the second regimen for epistaxis and telangiectasias

Randomized controlled trial

Campbell C et al. Muscle Nerve. 2017;55(4):458-464. PMID 27462804.

The study was stopped after the second dosing regimen due to potential safety concerns of epistaxis and telangiectasias. ACE-031 was not associated with serious or severe adverse events. There was a trend, not statistically significant, for maintenance of 6-minute walk test distance versus a decline on placebo, and trends for increased lean body mass and bone mineral density and reduced fat mass.

Participants / model
Ambulatory boys with Duchenne muscular dystrophy; number not stated in the source
Treatment
Subcutaneous ACE-031 every 2 to 4 weeks, or placebo
Follow-up
not stated in the source
Study design
Randomized, double-blind, placebo-controlled, ascending-dose trial; primary objective was safety
Funding
not stated in the source

The Duchenne evidence is a stopped safety study with non-significant efficacy trends, not a demonstration of benefit.

Read the original source
Registry NCT01099761: 24 boys, epistaxis 5 of 9 and telangiectasia 5 of 9 at the higher regimen

Trial registry record

ClinicalTrials.gov. NCT01099761, phase 2 study of ACE-031 in boys with Duchenne muscular dystrophy, with posted results.

NCT01099761 randomized 24 boys: 9 to ACE-031 0.5 mg/kg every 4 weeks, 9 to 1.0 mg/kg every 2 weeks and 6 to placebo, with a planned 2.5 mg/kg cohort that was never enrolled because the study was terminated. The registry gives the reason for stopping as "Based on preliminary safety data." Reported events above the 5% threshold: epistaxis in 5 of 9 at 1.0 mg/kg every 2 weeks, 1 of 9 at 0.5 mg/kg every 4 weeks and 0 of 6 on placebo; telangiectasia in 5 of 9, 0 of 9 and 0 of 6; injection site erythema in 6 of 9, 3 of 9 and 3 of 6; headache in 3 of 9, 1 of 9 and 1 of 6. Serious adverse events were 0 in every arm.

Participants / model
24 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031, 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks, or placebo
Follow-up
12 weeks
Study design
Registry record with posted results; outcomes were adverse reactions and clinical laboratory adverse reactions
Funding
not stated in the source

The vascular signal is dose-related and clear even in 24 children.

Read the original source
Registry NCT01239758: Duchenne extension, 11 enrolled, terminated, no results

Trial registry record

ClinicalTrials.gov. NCT01239758, extension study of ACE-031 in subjects with Duchenne muscular dystrophy.

NCT01239758, an extension study of ACE-031 in subjects with Duchenne muscular dystrophy, enrolled 11 and was terminated, with the registry reason given as "This study was terminated based on preliminary safety data." No results are posted. Two of the four registered ACE-031 studies were terminated, and the two that completed have never posted results.

Participants / model
11 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031
Follow-up
not stated in the source
Study design
Registered adverse events and laboratory parameters; no posted results
Funding
not stated in the source

The extension study stopped on the same kind of preliminary safety data as the main Duchenne study.

Read the original source
Healthy volunteers: 48 postmenopausal women, one dose, lean mass +3.3% at day 29

Randomized controlled trial

Attie KM et al. Muscle Nerve. 2013;47(3):416-23. PMID 23169607.

At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

Participants / model
48 healthy postmenopausal women
Treatment
A single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg, or placebo
Follow-up
Single dose, measured at day 29
Study design
Double-blind placebo-controlled phase 1 trial, randomized 3 to 1
Funding
not stated in the source

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

Read the original source
Registry NCT00952887: phase 1 repeat dose, 70 enrolled, no posted results, no located publication

Trial registry record

ClinicalTrials.gov. NCT00952887, phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women.

NCT00952887 is a phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women, sponsor Acceleron Pharma, actual enrollment 70, started in August 2009 and completed in February 2011, with no posted results. A PubMed search on 9 October 2026 for ACE-031 restricted to human records returned 10 items, of which only two are human trial reports (the single-dose healthy volunteer study and the Duchenne trial).

Participants / model
70 healthy postmenopausal women
Treatment
Multiple escalating subcutaneous doses
Follow-up
August 2009 to February 2011
Study design
Registered safety, tolerability, PK and PD outcomes; no posted results and no located publication
Funding
not stated in the source

The repeat-dose data in 70 women have not been published in the records reviewed.

Read the original source
2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source

Why does ACE-031 sit in D tier?

The fusion protein has real pharmacodynamic data from one dose in 48 postmenopausal women, but development went badly: the Duchenne trial stopped for a dose-related vascular signal, its extension was terminated and the repeat-dose study was never published. Failed development plus that signal fits D, and vendor vials were not the studied molecule.

The fusion protein has genuine human pharmacodynamic data: 3.3% lean mass and 5.1% thigh muscle volume after one subcutaneous dose in 48 healthy postmenopausal women. That is the strongest thing anyone can say about it.

Everything downstream went badly. The Duchenne program was stopped after the second dosing regimen for epistaxis in 5 of 9 and telangiectasia in 5 of 9 boys at 1.0 mg/kg every 2 weeks against 0 of 6 on placebo. The extension study was terminated for preliminary safety data, the 70-woman repeat-dose study was never published, and no application appears in the FDA record. No serious adverse event or death was reported in the posted results.

The sellers' claim is accurate on both of its factual halves. What it leaves out is the stopped Duchenne program and the product analysis: of 14 black market products, none contained the Fc fusion protein, and 12 contained full-length activin receptor IIB instead.

Healthy volunteers: 48 postmenopausal women, one dose, lean mass +3.3% at day 29

Randomized controlled trial

Attie KM et al. Muscle Nerve. 2013;47(3):416-23. PMID 23169607.

At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

Participants / model
48 healthy postmenopausal women
Treatment
A single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg, or placebo
Follow-up
Single dose, measured at day 29
Study design
Double-blind placebo-controlled phase 1 trial, randomized 3 to 1
Funding
not stated in the source

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

Read the original source
Registry NCT01099761: 24 boys, epistaxis 5 of 9 and telangiectasia 5 of 9 at the higher regimen

Trial registry record

ClinicalTrials.gov. NCT01099761, phase 2 study of ACE-031 in boys with Duchenne muscular dystrophy, with posted results.

NCT01099761 randomized 24 boys: 9 to ACE-031 0.5 mg/kg every 4 weeks, 9 to 1.0 mg/kg every 2 weeks and 6 to placebo, with a planned 2.5 mg/kg cohort that was never enrolled because the study was terminated. The registry gives the reason for stopping as "Based on preliminary safety data." Reported events above the 5% threshold: epistaxis in 5 of 9 at 1.0 mg/kg every 2 weeks, 1 of 9 at 0.5 mg/kg every 4 weeks and 0 of 6 on placebo; telangiectasia in 5 of 9, 0 of 9 and 0 of 6; injection site erythema in 6 of 9, 3 of 9 and 3 of 6; headache in 3 of 9, 1 of 9 and 1 of 6. Serious adverse events were 0 in every arm.

Participants / model
24 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031, 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks, or placebo
Follow-up
12 weeks
Study design
Registry record with posted results; outcomes were adverse reactions and clinical laboratory adverse reactions
Funding
not stated in the source

The vascular signal is dose-related and clear even in 24 children.

Read the original source
Registry NCT01239758: Duchenne extension, 11 enrolled, terminated, no results

Trial registry record

ClinicalTrials.gov. NCT01239758, extension study of ACE-031 in subjects with Duchenne muscular dystrophy.

NCT01239758, an extension study of ACE-031 in subjects with Duchenne muscular dystrophy, enrolled 11 and was terminated, with the registry reason given as "This study was terminated based on preliminary safety data." No results are posted. Two of the four registered ACE-031 studies were terminated, and the two that completed have never posted results.

Participants / model
11 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031
Follow-up
not stated in the source
Study design
Registered adverse events and laboratory parameters; no posted results
Funding
not stated in the source

The extension study stopped on the same kind of preliminary safety data as the main Duchenne study.

Read the original source
Registry NCT00952887: phase 1 repeat dose, 70 enrolled, no posted results, no located publication

Trial registry record

ClinicalTrials.gov. NCT00952887, phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women.

NCT00952887 is a phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women, sponsor Acceleron Pharma, actual enrollment 70, started in August 2009 and completed in February 2011, with no posted results. A PubMed search on 9 October 2026 for ACE-031 restricted to human records returned 10 items, of which only two are human trial reports (the single-dose healthy volunteer study and the Duchenne trial).

Participants / model
70 healthy postmenopausal women
Treatment
Multiple escalating subcutaneous doses
Follow-up
August 2009 to February 2011
Study design
Registered safety, tolerability, PK and PD outcomes; no posted results and no located publication
Funding
not stated in the source

The repeat-dose data in 70 women have not been published in the records reviewed.

Read the original source
Drugs@FDA queries, 9 October 2026: no matching application

Regulatory record

U.S. Food and Drug Administration. openFDA Drugs@FDA substance-name queries for ACE-031 and for ramatercept, run on 9 October 2026.

openFDA Drugs@FDA substance-name queries for ACE-031 and for ramatercept each returned no matching application on 9 October 2026. ACE-031 has never been approved.

Participants / model
Regulator database, not a population
Treatment
Exact substance-name searches
Follow-up
Searches run on 9 October 2026
Study design
FDA API query
Funding
not stated in the source

This is a US-scoped statement; the analytical paper cited separately makes a broader statement that ACE-031 has not been pharmaceutically approved.

Read the original source
2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source

Studies and sources

2025 analysis of 14 black market ACE-031 products: none contained the Fc fusion protein

Chemical identity record

Reichel C et al. Drug Test Anal. 2025;17(10):1934-1946. PMID 40312924.

ACE-031, INN ramatercept, is a dimeric fusion protein consisting of a fragment of the human activin receptor type IIB (ACVR2B) extracellular domain linked to the Fc part of human IgG1. It binds myostatin and related ligands and thereby removes their inhibitory signal on muscle. The paper states plainly that ACE-031 has not been pharmaceutically approved and is sold as a research chemical on the black market. In an analysis of 14 black market ACE-031 products, only 12 contained an ACVR2B-immunoreactive protein at all. Mass spectrometry and immunoblotting showed those 12 contained the full-length human activin receptor IIB rather than ACE-031, and treatment with IdeS protease, which cleaves IgG, failed to cleave them, confirming the absence of an Fc fusion. The main band ran at about 58.4 kDa and the products also contained many other proteins. A PubChem compound lookup for ACE-031 and for ramatercept returned no CID on 9 October 2026, which is expected for a recombinant protein.

Participants / model
14 black market products analyzed in the laboratory
Treatment
Vials sold as ACE-031
Follow-up
Not applicable
Study design
Analytical study using SDS-PAGE, Western blot, mass spectrometry and IdeS digestion
Funding
not stated in the source

Any vendor product described as an ACE-031 peptide or ACE-031 fragment is by definition not the dimeric Fc fusion protein that every clinical study used. There is no small-molecule identity record to cite.

Read the original source
Healthy volunteers: 48 postmenopausal women, one dose, lean mass +3.3% at day 29

Randomized controlled trial

Attie KM et al. Muscle Nerve. 2013;47(3):416-23. PMID 23169607.

At day 29 in the 3 mg/kg group, mean total body lean mass rose 3.3% by DXA (P=0.03) and thigh muscle volume rose 5.1% by MRI (P=0.03). Mean AUC and Cmax rose linearly with dose and mean half-life was 10 to 15 days. Adverse events included injection site erythema.

Participants / model
48 healthy postmenopausal women
Treatment
A single subcutaneous dose of ACE-031 from 0.02 to 3 mg/kg, or placebo
Follow-up
Single dose, measured at day 29
Study design
Double-blind placebo-controlled phase 1 trial, randomized 3 to 1
Funding
not stated in the source

The lean mass result is narrow: one subcutaneous dose, 48 postmenopausal women, one dose level reaching significance, measured at 29 days. No study in men, no study in trained people and no strength endpoint was found.

Read the original source
Registry NCT00755638: phase 1 single dose, 48 enrolled, no posted results

Trial registry record

ClinicalTrials.gov. NCT00755638, phase 1 single escalating dose safety and tolerability study of ACE-031 (ActRIIB-IgG1) in healthy postmenopausal volunteers.

NCT00755638 is a phase 1 single escalating dose safety and tolerability study of ACE-031 (ActRIIB-IgG1) in healthy postmenopausal volunteers, sponsor Acceleron Pharma, actual enrollment 48, started in September 2008 and completed in July 2009, with no posted results.

Participants / model
48 healthy postmenopausal volunteers
Treatment
Subcutaneous ACE-031
Follow-up
September 2008 to July 2009
Study design
Registered safety and tolerability outcomes; no posted results
Funding
not stated in the source

The registration supports that the study existed; the published report supplies the result.

Read the original source
Registry NCT00952887: phase 1 repeat dose, 70 enrolled, no posted results, no located publication

Trial registry record

ClinicalTrials.gov. NCT00952887, phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women.

NCT00952887 is a phase 1 multiple escalating dose safety, tolerability, PK and PD study of ACE-031 in healthy postmenopausal women, sponsor Acceleron Pharma, actual enrollment 70, started in August 2009 and completed in February 2011, with no posted results. A PubMed search on 9 October 2026 for ACE-031 restricted to human records returned 10 items, of which only two are human trial reports (the single-dose healthy volunteer study and the Duchenne trial).

Participants / model
70 healthy postmenopausal women
Treatment
Multiple escalating subcutaneous doses
Follow-up
August 2009 to February 2011
Study design
Registered safety, tolerability, PK and PD outcomes; no posted results and no located publication
Funding
not stated in the source

The repeat-dose data in 70 women have not been published in the records reviewed.

Read the original source
Duchenne trial: stopped after the second regimen for epistaxis and telangiectasias

Randomized controlled trial

Campbell C et al. Muscle Nerve. 2017;55(4):458-464. PMID 27462804.

The study was stopped after the second dosing regimen due to potential safety concerns of epistaxis and telangiectasias. ACE-031 was not associated with serious or severe adverse events. There was a trend, not statistically significant, for maintenance of 6-minute walk test distance versus a decline on placebo, and trends for increased lean body mass and bone mineral density and reduced fat mass.

Participants / model
Ambulatory boys with Duchenne muscular dystrophy; number not stated in the source
Treatment
Subcutaneous ACE-031 every 2 to 4 weeks, or placebo
Follow-up
not stated in the source
Study design
Randomized, double-blind, placebo-controlled, ascending-dose trial; primary objective was safety
Funding
not stated in the source

The Duchenne evidence is a stopped safety study with non-significant efficacy trends, not a demonstration of benefit.

Read the original source
Registry NCT01099761: 24 boys, epistaxis 5 of 9 and telangiectasia 5 of 9 at the higher regimen

Trial registry record

ClinicalTrials.gov. NCT01099761, phase 2 study of ACE-031 in boys with Duchenne muscular dystrophy, with posted results.

NCT01099761 randomized 24 boys: 9 to ACE-031 0.5 mg/kg every 4 weeks, 9 to 1.0 mg/kg every 2 weeks and 6 to placebo, with a planned 2.5 mg/kg cohort that was never enrolled because the study was terminated. The registry gives the reason for stopping as "Based on preliminary safety data." Reported events above the 5% threshold: epistaxis in 5 of 9 at 1.0 mg/kg every 2 weeks, 1 of 9 at 0.5 mg/kg every 4 weeks and 0 of 6 on placebo; telangiectasia in 5 of 9, 0 of 9 and 0 of 6; injection site erythema in 6 of 9, 3 of 9 and 3 of 6; headache in 3 of 9, 1 of 9 and 1 of 6. Serious adverse events were 0 in every arm.

Participants / model
24 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031, 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks, or placebo
Follow-up
12 weeks
Study design
Registry record with posted results; outcomes were adverse reactions and clinical laboratory adverse reactions
Funding
not stated in the source

The vascular signal is dose-related and clear even in 24 children.

Read the original source
Registry NCT01239758: Duchenne extension, 11 enrolled, terminated, no results

Trial registry record

ClinicalTrials.gov. NCT01239758, extension study of ACE-031 in subjects with Duchenne muscular dystrophy.

NCT01239758, an extension study of ACE-031 in subjects with Duchenne muscular dystrophy, enrolled 11 and was terminated, with the registry reason given as "This study was terminated based on preliminary safety data." No results are posted. Two of the four registered ACE-031 studies were terminated, and the two that completed have never posted results.

Participants / model
11 boys with Duchenne muscular dystrophy
Treatment
Subcutaneous ACE-031
Follow-up
not stated in the source
Study design
Registered adverse events and laboratory parameters; no posted results
Funding
not stated in the source

The extension study stopped on the same kind of preliminary safety data as the main Duchenne study.

Read the original source

Why is ACE-031 in D tier?

D fits a compound with failed development and a dose-related safety signal. The fusion protein raised lean mass in healthy women after one dose, but the Duchenne trial and its extension were stopped on preliminary safety data, with epistaxis and telangiectasia clustering at the higher regimen, and the repeat-dose study was never published. No serious adverse event was reported in the posted results, and a vendor fragment has no study in any species.