Trevogrumab

updated

Trevogrumab (REGN1033) is an investigational Regeneron antibody that blocks myostatin, tested with semaglutide in the phase 2 COURAGE trial to limit lean mass loss during weight loss. Every COURAGE result so far comes from company press releases, with no peer-reviewed paper in PubMed as of 11 October 2026. The releases report less lean mass loss with trevogrumab, no strength or function result, and no regulator has approved the drug.

Anti-myostatin (GDF8) monoclonal antibody

  • Trevogrumab, development code REGN1033, is a fully human monoclonal antibody that blocks myostatin (GDF8).
  • No regulator has approved it; Regeneron states its safety and efficacy have not been evaluated by any regulatory authority.
  • COURAGE, a randomized phase 2 trial that enrolled 1,005 people, has results only in company press releases.
  • At 26 weeks, the company reported lean mass falling 6.5% on semaglutide alone versus 3.3% and 3.8% with trevogrumab 200 mg or 400 mg added.
  • No strength or physical function result has been reported.
  • Two deaths occurred in the arm that also added garetosmab; Regeneron stated it has not identified a causal association.

What is trevogrumab, and is it approved?

Trevogrumab (REGN1033) is an investigational Regeneron antibody that blocks myostatin. No regulator has approved it, and the 2026 US approval of garetosmab, the second antibody in one COURAGE arm, is for a rare bone disease only.

The ClinicalTrials.gov record for COURAGE lists REGN1033 as another name for trevogrumab. It is a fully human monoclonal antibody that blocks myostatin, also called GDF8. As a biologic it has no small-molecule record: PubChem name lookups for trevogrumab and REGN1033 returned no compound on 11 October 2026, and no formula, molecular weight or CAS number applies.

openFDA Drugs@FDA queries for trevogrumab and for REGN1033 each returned no application on 11 October 2026. Regeneron's releases of 17 September 2025 and 1 October 2026 each state that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

Garetosmab, given with trevogrumab in one COURAGE arm, is a separate antibody. FDA lists it as PASATRU (garetosmab-grts) under BLA 761508, with an original approval status date of 19 August 2026, to reduce new heterotopic ossification lesions and flare-ups in adults with fibrodysplasia ossificans progressiva. That approval does not cover trevogrumab or any use in obesity.

COURAGE registry: 1,005 enrolled, no posted results

Trial registry record

ClinicalTrials.gov record NCT06299098, COURAGE (sponsor study R1033-OB-2288). Randomized, quadruple-masked phase 2 study of trevogrumab, garetosmab and semaglutide.

Enrolled 1,005 people (actual). Part A in healthy adults aged 18 to 55; Parts B and C in adults aged 18 to 80 with obesity and no history of diabetes. Trevogrumab is given subcutaneously in Parts B and C, garetosmab intravenously and semaglutide subcutaneously. Primary outcomes are percent change in total lean mass, total fat mass and body weight at week 26 (Part B) and week 52 (Part C). Start 13 March 2024, primary completion 16 June 2026, estimated completion 21 October 2026, active not recruiting; no posted results.

Participants / model
Healthy adults aged 18 to 55 (BMI 18 to 32) and adults aged 18 to 80 with obesity (BMI at least 30) and no history of diabetes
Treatment
Subcutaneous trevogrumab, intravenous garetosmab and subcutaneous semaglutide
Follow-up
Primary outcomes at week 26 (Part B) and week 52 (Part C)
Study design
Randomized, quadruple-masked phase 2 trial registry record
Funding
Sponsor: Regeneron (sponsor study R1033-OB-2288)

The registry lists REGN1033 as another name for trevogrumab and REGN2477 as garetosmab.

Read the original source
Mouse study: REGN1033 raised muscle size, mass and force

Animal study

Latres E et al. Skelet Muscle. 2015;5:34. PMID 26457176.

Chronic REGN1033 treatment increased muscle fiber size, muscle mass and force, prevented muscle loss from immobilization, glucocorticoid treatment or hindlimb unweighting, and in aged mice raised muscle mass and strength and improved treadmill performance. REGN1033 is a fully human monoclonal antibody that blocks myostatin (GDF8); PubChem name lookups for trevogrumab and REGN1033 returned no compound on 11 October 2026.

Participants / model
Mice, including aged mice
Treatment
Chronic REGN1033 treatment; route and dose not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study with in vitro binding and cell assays
Funding
Sponsor authors (Regeneron)

Mouse data. The strength and treadmill gains have not been shown in people.

Read the original source
openFDA, 11 October 2026: no application for trevogrumab or REGN1033

Regulatory record

U.S. Food and Drug Administration, openFDA Drugs@FDA API. Queries for trevogrumab and for REGN1033 run on 11 October 2026, each returning no application. Regeneron press releases of 17 September 2025 and 1 October 2026 state that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

No application was returned for trevogrumab or REGN1033. Regeneron states that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Queries run on 11 October 2026
Study design
Dated US approval-record search, with a company regulatory statement
Funding
not stated in the source

The database search covers the United States; the company statement covers other regulators.

Read the original source
PASATRU label, version effective 14 August 2026: garetosmab for FOP

FDA prescribing information

DailyMed, U.S. National Library of Medicine. PASATRU (garetosmab-grts) injection for intravenous infusion, 300 mg/5 mL single-dose vial, prescribing information, label version effective 14 August 2026. Set ID 0d5cec96-b02b-4f1d-bc66-51e62ce04e3c. openFDA lists BLA 761508 with an original approval status date of 19 August 2026.

PASATRU is indicated to reduce formation of new heterotopic ossification lesions and clinician-assessed flare-ups in adults with fibrodysplasia ossificans progressiva. Warnings cover embryo-fetal toxicity (contraindicated in pregnancy), skin and soft tissue infections and epistaxis. Adverse reactions in at least 10% were abscess, acne, increased hair growth, madarosis, oral ulcers and epistaxis.

Participants / model
Adults with fibrodysplasia ossificans progressiva
Treatment
PASATRU intravenous infusion, 300 mg/5 mL single-dose vial
Follow-up
Label version effective 14 August 2026
Study design
FDA prescribing information and FDA application record
Funding
not stated in the source

This label is for garetosmab only. It does not cover trevogrumab or any use in obesity.

Read the original source

What did the COURAGE trial report at 26 weeks?

In company-reported results, lean mass fell 6.5% on semaglutide alone versus 3.3% and 3.8% with trevogrumab 200 mg or 400 mg added, and 2.0% when garetosmab was also added. These figures come from a press release, not a peer-reviewed paper, and no strength or function result was reported.

COURAGE (NCT06299098) is a randomized, quadruple-masked phase 2 study that enrolled 1,005 people. Part A enrolled healthy adults aged 18 to 55, and Parts B and C adults aged 18 to 80 with obesity (BMI at least 30) and no history of diabetes. Registered primary outcomes are percent change in total lean mass, total fat mass and body weight at week 26 (Part B) and week 52 (Part C). Primary completion was 16 June 2026, the estimated study completion is 21 October 2026, and the registry shows no posted results.

Regeneron's release of 17 September 2025, presented at EASD, reports 26-week results for semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152), or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass by DXA changed -6.5%, -3.3%, -3.8% and -2.0%. Lean mass made up 33.0% of total weight lost on semaglutide alone, 16.8% and 18.1% in the two trevogrumab arms, and 7.4% in the triplet arm. Fat mass changed -15.7%, -17.3%, -19.1% and -27.1%, and body weight -10.6%, -9.9%, -11.1% and -13.4%.

The release marks the lean mass differences in all three combination arms at p below 0.001, the fat mass difference at p below 0.05 for the 400 mg arm and below 0.001 for the triplet, and body weight at p below 0.001 for the triplet only. The p-values were not corrected for multiplicity, and the analysis excluded data after treatment stopped. The company's phrase that about half of lean mass loss was prevented summarizes the two trevogrumab-only arms. No strength or physical function result is reported.

COURAGE registry: 1,005 enrolled, no posted results

Trial registry record

ClinicalTrials.gov record NCT06299098, COURAGE (sponsor study R1033-OB-2288). Randomized, quadruple-masked phase 2 study of trevogrumab, garetosmab and semaglutide.

Enrolled 1,005 people (actual). Part A in healthy adults aged 18 to 55; Parts B and C in adults aged 18 to 80 with obesity and no history of diabetes. Trevogrumab is given subcutaneously in Parts B and C, garetosmab intravenously and semaglutide subcutaneously. Primary outcomes are percent change in total lean mass, total fat mass and body weight at week 26 (Part B) and week 52 (Part C). Start 13 March 2024, primary completion 16 June 2026, estimated completion 21 October 2026, active not recruiting; no posted results.

Participants / model
Healthy adults aged 18 to 55 (BMI 18 to 32) and adults aged 18 to 80 with obesity (BMI at least 30) and no history of diabetes
Treatment
Subcutaneous trevogrumab, intravenous garetosmab and subcutaneous semaglutide
Follow-up
Primary outcomes at week 26 (Part B) and week 52 (Part C)
Study design
Randomized, quadruple-masked phase 2 trial registry record
Funding
Sponsor: Regeneron (sponsor study R1033-OB-2288)

The registry lists REGN1033 as another name for trevogrumab and REGN2477 as garetosmab.

Read the original source
Regeneron release, 17 September 2025: 26-week lean mass, fat and weight

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025.

Semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152) or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass change by DXA: -6.5% (SE 0.5), -3.3% (0.5), -3.8% (0.5) and -2.0% (0.6). Lean mass as a share of total weight loss: 33.0%, 16.8%, 18.1% and 7.4%. Fat mass: -15.7%, -17.3%, -19.1% and -27.1%. Body weight: -10.6%, -9.9%, -11.1% and -13.4%. P-values were not corrected for multiplicity, and the efficacy estimand excludes data after treatment discontinuation. No strength or physical function result is reported.

Participants / model
Adults with obesity (BMI at least 30) in a randomized phase 2 trial
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

About half of lean mass loss prevented is the company's summary of the two trevogrumab-only arms. Here lower dose refers to the 200 mg arm.

Read the original source

What did the 52-week results with 25 mg and 75 mg show?

At 52 weeks, the company reported lean mass falling 7.3% on semaglutide alone, 5.8% with trevogrumab 25 mg and 4.2% with 75 mg, with less loss of thigh muscle volume on MRI. Weight loss was not meaningfully greater. These are different doses from the 200 mg arm of the 26-week release, even though both releases call their arms lower dose.

Regeneron's release of 1 October 2026 compares trevogrumab 25 mg or 75 mg plus semaglutide 2.4 mg with semaglutide alone for 52 weeks, and states the results are in press at The Lancet. Lean mass by DXA changed -6.7% and -7.3% at weeks 26 and 52 on semaglutide alone, -4.7% and -5.8% with 25 mg, and -3.3% and -4.2% with 75 mg. The release calls this 29.9% and 20.5% preservation for 25 mg, and 50.7% and 42.5% for 75 mg, relative to semaglutide alone.

In people with evaluable MRI data, absolute change in fat-free thigh muscle volume at weeks 26 and 52 was -0.88 and -1.03 on semaglutide alone, -0.32 and -0.29 with 25 mg, and -0.24 and -0.32 with 75 mg. The release gives no units and no count of evaluable participants. It reports muscle preservation of 63.6% and 71.8% with 25 mg and 72.7% and 68.9% with 75 mg, and says lower-dose trevogrumab did not meaningfully enhance weight loss.

The two releases use lower dose for different arms: 200 mg in the September 2025 release and 25 mg and 75 mg in the October 2026 release. The October release does not report the 26-week maintenance phase, in which trevogrumab was compared with placebo after semaglutide was stopped.

Regeneron release, 1 October 2026: 25 mg and 75 mg over 52 weeks

Regulatory record

Regeneron Pharmaceuticals. Phase 2 COURAGE trial results on lean mass with trevogrumab, 52-week and MRI data. Company news release, Regeneron investor relations, 1 October 2026.

Lean mass change by DXA at weeks 26 and 52: -6.7% and -7.3% with semaglutide alone, -4.7% and -5.8% with 25 mg (29.9% and 20.5% preservation), and -3.3% and -4.2% with 75 mg (50.7% and 42.5%). MRI fat-free muscle volume change at weeks 26 and 52: -0.88 and -1.03, -0.32 and -0.29, and -0.24 and -0.32, with no units or evaluable count given. Reported muscle preservation 63.6% and 71.8% (25 mg) and 72.7% and 68.9% (75 mg). Lower-dose trevogrumab did not meaningfully enhance weight loss. 77% of trevogrumab participants had at least one adverse event versus 82% on placebo.

Participants / model
Adults with obesity in the lower-dose portion of a randomized phase 2 trial; MRI substudy subset
Treatment
Semaglutide 2.4 mg with trevogrumab 25 or 75 mg; route not stated in the release
Follow-up
52 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed; stated to be in press at The Lancet
Funding
Sponsor: Regeneron

Here lower dose means 25 and 75 mg, not the 200 mg arm of the September 2025 release. The maintenance phase after semaglutide was stopped is not reported.

Read the original source
Regeneron release, 17 September 2025: 26-week lean mass, fat and weight

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025.

Semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152) or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass change by DXA: -6.5% (SE 0.5), -3.3% (0.5), -3.8% (0.5) and -2.0% (0.6). Lean mass as a share of total weight loss: 33.0%, 16.8%, 18.1% and 7.4%. Fat mass: -15.7%, -17.3%, -19.1% and -27.1%. Body weight: -10.6%, -9.9%, -11.1% and -13.4%. P-values were not corrected for multiplicity, and the efficacy estimand excludes data after treatment discontinuation. No strength or physical function result is reported.

Participants / model
Adults with obesity (BMI at least 30) in a randomized phase 2 trial
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

About half of lean mass loss prevented is the company's summary of the two trevogrumab-only arms. Here lower dose refers to the 200 mg arm.

Read the original source

What did the first study in healthy volunteers find?

In 82 healthy people, combining an anti-GDF8 antibody with an anti-activin A antibody gave greater muscle growth than either alone, with fat reductions. The abstract gives no doses or effect sizes, so the effect of the anti-GDF8 antibody alone cannot be read from it.

A two-part randomized, placebo-controlled phase 1 trial enrolled 82 healthy people (48 in the single-dose part and 34 in the multiple-dose part): postmenopausal women aged 45 to 70 and men aged 35 to 60, BMI 18 to 32. The registry title for NCT02943239 names REGN2477 (garetosmab) alone and with REGN1033. The combination gave greater muscle growth by MRI than either antibody alone, with reductions in fat, was generally well tolerated, and no participant tested positive for anti-drug antibodies.

The abstract gives no doses, effect sizes or per-arm numbers. The authors are Regeneron employees or former employees, except one at a New Zealand clinical research site.

Phase 1: 82 healthy people, combination gave more muscle growth

Randomized controlled trial

Gonzalez Trotter D et al. Nat Commun. 2025;16(1):4376. PMID 40360471.

Combining an anti-GDF8 antibody with an anti-activin A antibody gave greater muscle growth than either alone, with increases in muscle accompanied by reductions in fat. The combination was generally well tolerated and no participant tested positive for anti-drug antibodies. The abstract gives no doses, effect sizes or per-arm numbers.

Participants / model
82 healthy people: postmenopausal women aged 45 to 70 and men aged 35 to 60, BMI 18 to 32; 48 in the single-dose part and 34 in the multiple-dose part
Treatment
Single and multiple doses of REGN2477 (garetosmab) alone and with REGN1033; route not stated in the abstract
Follow-up
not stated in the source
Study design
Two-part randomized, placebo-controlled phase 1 trial (NCT02943239)
Funding
Authors are Regeneron employees or former employees, except one at a New Zealand clinical research site

The size of the anti-GDF8 effect alone cannot be read from the abstract.

Read the original source

What came of the earlier REGN1033 studies?

ClinicalTrials.gov lists four completed phase 1 studies, a completed 253-person phase 2 study in people aged 70 and older with sarcopenia, and a withdrawn study in inclusion body myositis. The sarcopenia study has no posted results, and its outcome was not found in any record reviewed.

The completed phase 1 studies are NCT01507402 (n=76), NCT01720576 (n=60), NCT01910220 (n=125) and NCT02741739 (n=28). The phase 2 sarcopenia study, NCT01963598, enrolled 253 people aged 70 and older, used percent change in DXA lean body mass at week 12 as its primary endpoint, and was completed in February 2015 with no results posted. A phase 2 study in inclusion body myositis (NCT03710941) was withdrawn with no participants.

PubMed searches on 11 October 2026 found 2 records for trevogrumab, both narrative reviews listing it as a pipeline agent, and 4 for REGN1033: two mouse studies, a review of cachexia biologics and a cachexia conference summary. A search for SAR391786 returned none, and a search combining these names and anti-myostatin antibody with sarcopenia and randomized returned none. No peer-reviewed report of a human trevogrumab efficacy trial was found.

PubMed search, 11 October 2026: no peer-reviewed human efficacy trial

PubMed search record

PubMed searches run on 11 October 2026: trevogrumab (2 records), REGN1033 (4 records), SAR391786 (0 records), and trevogrumab OR REGN1033 OR SAR391786 OR anti-myostatin antibody AND sarcopenia AND randomized (0 records). ClinicalTrials.gov records for earlier REGN1033 studies.

trevogrumab returned 2 narrative reviews (PMIDs 39481534 and 41178728); REGN1033 returned two mouse studies (PMIDs 26457176 and 27214824), a review of cachexia biologics (PMID 24707881) and a cachexia conference summary (PMID 24595460). No peer-reviewed report of a human trevogrumab efficacy trial was found. ClinicalTrials.gov lists four completed phase 1 studies (NCT01507402, n=76; NCT01720576, n=60; NCT01910220, n=125; NCT02741739, n=28), a completed phase 2 sarcopenia study (NCT01963598, n=253, completion February 2015, no results posted) and a withdrawn inclusion body myositis study (NCT03710941, n=0).

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Searches run on 11 October 2026
Study design
Literature search and trial registry review
Funding
not stated in the source

A search result shows what PubMed returned on that date. The sarcopenia study's outcome was not found in any record reviewed.

Read the original source

Does trevogrumab preserve muscle when given with semaglutide?

The claim that it was studied with semaglutide to preserve muscle is accurate and traces to Regeneron's COURAGE trial. The company reports less lean mass and muscle volume loss, but no strength or function benefit, and nothing sold as a research chemical can be matched to the clinical antibody.

Sellers describe trevogrumab as an anti-myostatin antibody from Regeneron that preserves muscle with semaglutide, as studied in COURAGE. In the company's releases, lean mass loss was smaller in every trevogrumab arm, and thigh muscle volume loss on MRI was smaller with 25 mg and 75 mg. The outcomes are DXA lean mass and MRI muscle volume, not strength or physical function, and the size of the effect varied with dose.

The arm that gave the largest lean mass effect added garetosmab, and the same arm carried the higher discontinuation rate and the two deaths. Every COURAGE number on this page comes from company releases and should be compared with the peer-reviewed paper when it appears. An investigational antibody has no approved or off-label source, so a product sold as a research chemical cannot be tied to the antibody tested in COURAGE.

Regeneron release, 17 September 2025: 26-week lean mass, fat and weight

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025.

Semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152) or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass change by DXA: -6.5% (SE 0.5), -3.3% (0.5), -3.8% (0.5) and -2.0% (0.6). Lean mass as a share of total weight loss: 33.0%, 16.8%, 18.1% and 7.4%. Fat mass: -15.7%, -17.3%, -19.1% and -27.1%. Body weight: -10.6%, -9.9%, -11.1% and -13.4%. P-values were not corrected for multiplicity, and the efficacy estimand excludes data after treatment discontinuation. No strength or physical function result is reported.

Participants / model
Adults with obesity (BMI at least 30) in a randomized phase 2 trial
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

About half of lean mass loss prevented is the company's summary of the two trevogrumab-only arms. Here lower dose refers to the 200 mg arm.

Read the original source
Regeneron release, 1 October 2026: 25 mg and 75 mg over 52 weeks

Regulatory record

Regeneron Pharmaceuticals. Phase 2 COURAGE trial results on lean mass with trevogrumab, 52-week and MRI data. Company news release, Regeneron investor relations, 1 October 2026.

Lean mass change by DXA at weeks 26 and 52: -6.7% and -7.3% with semaglutide alone, -4.7% and -5.8% with 25 mg (29.9% and 20.5% preservation), and -3.3% and -4.2% with 75 mg (50.7% and 42.5%). MRI fat-free muscle volume change at weeks 26 and 52: -0.88 and -1.03, -0.32 and -0.29, and -0.24 and -0.32, with no units or evaluable count given. Reported muscle preservation 63.6% and 71.8% (25 mg) and 72.7% and 68.9% (75 mg). Lower-dose trevogrumab did not meaningfully enhance weight loss. 77% of trevogrumab participants had at least one adverse event versus 82% on placebo.

Participants / model
Adults with obesity in the lower-dose portion of a randomized phase 2 trial; MRI substudy subset
Treatment
Semaglutide 2.4 mg with trevogrumab 25 or 75 mg; route not stated in the release
Follow-up
52 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed; stated to be in press at The Lancet
Funding
Sponsor: Regeneron

Here lower dose means 25 and 75 mg, not the 200 mg arm of the September 2025 release. The maintenance phase after semaglutide was stopped is not reported.

Read the original source
Regeneron release, 17 September 2025: adverse events, triplet deaths

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025. Safety statements.

The trevogrumab combination with semaglutide was described as generally well tolerated. Adverse events in at least 5% of any group: muscle spasms, nausea, constipation, fatigue, diarrhea, headache, vomiting, gastroesophageal reflux disease, upper respiratory tract infection, nasopharyngitis, urinary tract infection, influenza and COVID-19, most mild to moderate. The triplet with garetosmab had a substantially higher rate of discontinuations, and two deaths occurred in that arm. Regeneron stated it has not identified a causal association. No discontinuation counts are given.

Participants / model
Adults with obesity in the semaglutide, trevogrumab and triplet arms
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

One death was of undetermined cause in a person with multiple cardiovascular risk factors; the other was cardiac arrest in a person with a history of cardiovascular disease.

Read the original source
openFDA, 11 October 2026: no application for trevogrumab or REGN1033

Regulatory record

U.S. Food and Drug Administration, openFDA Drugs@FDA API. Queries for trevogrumab and for REGN1033 run on 11 October 2026, each returning no application. Regeneron press releases of 17 September 2025 and 1 October 2026 state that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

No application was returned for trevogrumab or REGN1033. Regeneron states that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Queries run on 11 October 2026
Study design
Dated US approval-record search, with a company regulatory statement
Funding
not stated in the source

The database search covers the United States; the company statement covers other regulators.

Read the original source

How does trevogrumab work?

Trevogrumab blocks myostatin (GDF8). In mice, REGN1033 increased muscle fiber size, mass and force and prevented muscle loss in several atrophy models, but the mouse strength and treadmill gains have not been shown in people.

In a preclinical study by Regeneron authors, chronic REGN1033 treatment in mice increased muscle fiber size, muscle mass and force. It prevented muscle loss from immobilization, glucocorticoid treatment or hindlimb unweighting, and in aged mice it raised muscle mass and strength and improved treadmill performance. The abstract does not state the route or dose.

In people, the reported effects are on lean mass and muscle volume. No COURAGE release reports a strength or function result.

Mouse study: REGN1033 raised muscle size, mass and force

Animal study

Latres E et al. Skelet Muscle. 2015;5:34. PMID 26457176.

Chronic REGN1033 treatment increased muscle fiber size, muscle mass and force, prevented muscle loss from immobilization, glucocorticoid treatment or hindlimb unweighting, and in aged mice raised muscle mass and strength and improved treadmill performance. REGN1033 is a fully human monoclonal antibody that blocks myostatin (GDF8); PubChem name lookups for trevogrumab and REGN1033 returned no compound on 11 October 2026.

Participants / model
Mice, including aged mice
Treatment
Chronic REGN1033 treatment; route and dose not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study with in vitro binding and cell assays
Funding
Sponsor authors (Regeneron)

Mouse data. The strength and treadmill gains have not been shown in people.

Read the original source
Regeneron release, 17 September 2025: 26-week lean mass, fat and weight

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025.

Semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152) or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass change by DXA: -6.5% (SE 0.5), -3.3% (0.5), -3.8% (0.5) and -2.0% (0.6). Lean mass as a share of total weight loss: 33.0%, 16.8%, 18.1% and 7.4%. Fat mass: -15.7%, -17.3%, -19.1% and -27.1%. Body weight: -10.6%, -9.9%, -11.1% and -13.4%. P-values were not corrected for multiplicity, and the efficacy estimand excludes data after treatment discontinuation. No strength or physical function result is reported.

Participants / model
Adults with obesity (BMI at least 30) in a randomized phase 2 trial
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

About half of lean mass loss prevented is the company's summary of the two trevogrumab-only arms. Here lower dose refers to the 200 mg arm.

Read the original source

What safety findings have been reported for trevogrumab?

Per the sponsor, trevogrumab with semaglutide was generally well tolerated, with adverse events such as muscle spasms, nausea and constipation, mostly mild to moderate. The arm that also added garetosmab had more discontinuations and two deaths, for which Regeneron stated it has not identified a causal association. None of this has been peer reviewed.

In the September 2025 release, adverse events in at least 5% of participants in any group were muscle spasms, nausea, constipation, fatigue, diarrhea, headache, vomiting, gastroesophageal reflux disease, upper respiratory tract infection, nasopharyngitis, urinary tract infection, influenza and COVID-19, most mild to moderate. In the October 2026 release, 77% of trevogrumab participants in the lower-dose portion had at least one adverse event versus 82% on placebo.

The triplet arm with garetosmab had a substantially higher rate of discontinuations due to tolerability issues and other adverse events; the release gives no counts. Two deaths occurred in that arm: one of undetermined cause in a person with multiple cardiovascular risk factors, and one from cardiac arrest in a person with a history of cardiovascular disease. Regeneron stated it has not identified a causal association.

Garetosmab data come from a rare bone disease and do not transfer to trevogrumab alone. The PASATRU label warns of embryo-fetal toxicity (contraindicated in pregnancy), skin and soft tissue infections and epistaxis, with abscess, acne, increased hair growth, madarosis, oral ulcers and epistaxis in at least 10%. In the LUMINA-1 trial in fibrodysplasia ossificans progressiva, all patients had at least one adverse event in the first period, and 5 of 44 (11.4%) died in the open-label period; the authors considered the deaths unlikely to be related but could not rule out causality.

Regeneron release, 17 September 2025: adverse events, triplet deaths

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025. Safety statements.

The trevogrumab combination with semaglutide was described as generally well tolerated. Adverse events in at least 5% of any group: muscle spasms, nausea, constipation, fatigue, diarrhea, headache, vomiting, gastroesophageal reflux disease, upper respiratory tract infection, nasopharyngitis, urinary tract infection, influenza and COVID-19, most mild to moderate. The triplet with garetosmab had a substantially higher rate of discontinuations, and two deaths occurred in that arm. Regeneron stated it has not identified a causal association. No discontinuation counts are given.

Participants / model
Adults with obesity in the semaglutide, trevogrumab and triplet arms
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

One death was of undetermined cause in a person with multiple cardiovascular risk factors; the other was cardiac arrest in a person with a history of cardiovascular disease.

Read the original source
Regeneron release, 1 October 2026: 25 mg and 75 mg over 52 weeks

Regulatory record

Regeneron Pharmaceuticals. Phase 2 COURAGE trial results on lean mass with trevogrumab, 52-week and MRI data. Company news release, Regeneron investor relations, 1 October 2026.

Lean mass change by DXA at weeks 26 and 52: -6.7% and -7.3% with semaglutide alone, -4.7% and -5.8% with 25 mg (29.9% and 20.5% preservation), and -3.3% and -4.2% with 75 mg (50.7% and 42.5%). MRI fat-free muscle volume change at weeks 26 and 52: -0.88 and -1.03, -0.32 and -0.29, and -0.24 and -0.32, with no units or evaluable count given. Reported muscle preservation 63.6% and 71.8% (25 mg) and 72.7% and 68.9% (75 mg). Lower-dose trevogrumab did not meaningfully enhance weight loss. 77% of trevogrumab participants had at least one adverse event versus 82% on placebo.

Participants / model
Adults with obesity in the lower-dose portion of a randomized phase 2 trial; MRI substudy subset
Treatment
Semaglutide 2.4 mg with trevogrumab 25 or 75 mg; route not stated in the release
Follow-up
52 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed; stated to be in press at The Lancet
Funding
Sponsor: Regeneron

Here lower dose means 25 and 75 mg, not the 200 mg arm of the September 2025 release. The maintenance phase after semaglutide was stopped is not reported.

Read the original source
PASATRU label, version effective 14 August 2026: garetosmab for FOP

FDA prescribing information

DailyMed, U.S. National Library of Medicine. PASATRU (garetosmab-grts) injection for intravenous infusion, 300 mg/5 mL single-dose vial, prescribing information, label version effective 14 August 2026. Set ID 0d5cec96-b02b-4f1d-bc66-51e62ce04e3c. openFDA lists BLA 761508 with an original approval status date of 19 August 2026.

PASATRU is indicated to reduce formation of new heterotopic ossification lesions and clinician-assessed flare-ups in adults with fibrodysplasia ossificans progressiva. Warnings cover embryo-fetal toxicity (contraindicated in pregnancy), skin and soft tissue infections and epistaxis. Adverse reactions in at least 10% were abscess, acne, increased hair growth, madarosis, oral ulcers and epistaxis.

Participants / model
Adults with fibrodysplasia ossificans progressiva
Treatment
PASATRU intravenous infusion, 300 mg/5 mL single-dose vial
Follow-up
Label version effective 14 August 2026
Study design
FDA prescribing information and FDA application record
Funding
not stated in the source

This label is for garetosmab only. It does not cover trevogrumab or any use in obesity.

Read the original source
LUMINA-1: garetosmab, 44 adults with FOP, 5 deaths in open label

Randomized controlled trial

Di Rocco M et al. Nat Med. 2023;29(10):2615-2624. PMID 37770652.

All patients had at least one treatment-emergent adverse event in period 1, notably epistaxis, madarosis and skin abscesses. Five of 44 patients (11.4%) died in the open-label period; the authors considered the deaths unlikely to be related but could not rule out causality. The primary efficacy endpoint in period 1 was not met (P = 0.0741).

Participants / model
Adults with fibrodysplasia ossificans progressiva; garetosmab n=20, placebo n=24
Treatment
Garetosmab; route not stated in the abstract
Follow-up
28 weeks, then open label
Study design
Randomized phase 2 trial (NCT03188666)
Funding
Sponsor authors

Garetosmab data in a rare disease; it does not transfer to trevogrumab alone.

Read the original source

Why does trevogrumab sit in B tier?

A credible mechanism and a randomized phase 2 trial of 1,005 people with less lean mass loss in every trevogrumab arm support B. The results are company-reported and not yet peer reviewed, measure lean mass rather than strength or function, vary with dose, and no regulator has reviewed the drug.

Lean mass preservation at 26 weeks was 29.9% with 25 mg and 50.7% with 75 mg in the company's 52-week release, so the benefit depends on dose. The grade reflects the data, not availability: trevogrumab is an investigational antibody with no approved or off-label route.

COURAGE registry: 1,005 enrolled, no posted results

Trial registry record

ClinicalTrials.gov record NCT06299098, COURAGE (sponsor study R1033-OB-2288). Randomized, quadruple-masked phase 2 study of trevogrumab, garetosmab and semaglutide.

Enrolled 1,005 people (actual). Part A in healthy adults aged 18 to 55; Parts B and C in adults aged 18 to 80 with obesity and no history of diabetes. Trevogrumab is given subcutaneously in Parts B and C, garetosmab intravenously and semaglutide subcutaneously. Primary outcomes are percent change in total lean mass, total fat mass and body weight at week 26 (Part B) and week 52 (Part C). Start 13 March 2024, primary completion 16 June 2026, estimated completion 21 October 2026, active not recruiting; no posted results.

Participants / model
Healthy adults aged 18 to 55 (BMI 18 to 32) and adults aged 18 to 80 with obesity (BMI at least 30) and no history of diabetes
Treatment
Subcutaneous trevogrumab, intravenous garetosmab and subcutaneous semaglutide
Follow-up
Primary outcomes at week 26 (Part B) and week 52 (Part C)
Study design
Randomized, quadruple-masked phase 2 trial registry record
Funding
Sponsor: Regeneron (sponsor study R1033-OB-2288)

The registry lists REGN1033 as another name for trevogrumab and REGN2477 as garetosmab.

Read the original source
Regeneron release, 17 September 2025: 26-week lean mass, fat and weight

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025.

Semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152) or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass change by DXA: -6.5% (SE 0.5), -3.3% (0.5), -3.8% (0.5) and -2.0% (0.6). Lean mass as a share of total weight loss: 33.0%, 16.8%, 18.1% and 7.4%. Fat mass: -15.7%, -17.3%, -19.1% and -27.1%. Body weight: -10.6%, -9.9%, -11.1% and -13.4%. P-values were not corrected for multiplicity, and the efficacy estimand excludes data after treatment discontinuation. No strength or physical function result is reported.

Participants / model
Adults with obesity (BMI at least 30) in a randomized phase 2 trial
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

About half of lean mass loss prevented is the company's summary of the two trevogrumab-only arms. Here lower dose refers to the 200 mg arm.

Read the original source
Regeneron release, 1 October 2026: 25 mg and 75 mg over 52 weeks

Regulatory record

Regeneron Pharmaceuticals. Phase 2 COURAGE trial results on lean mass with trevogrumab, 52-week and MRI data. Company news release, Regeneron investor relations, 1 October 2026.

Lean mass change by DXA at weeks 26 and 52: -6.7% and -7.3% with semaglutide alone, -4.7% and -5.8% with 25 mg (29.9% and 20.5% preservation), and -3.3% and -4.2% with 75 mg (50.7% and 42.5%). MRI fat-free muscle volume change at weeks 26 and 52: -0.88 and -1.03, -0.32 and -0.29, and -0.24 and -0.32, with no units or evaluable count given. Reported muscle preservation 63.6% and 71.8% (25 mg) and 72.7% and 68.9% (75 mg). Lower-dose trevogrumab did not meaningfully enhance weight loss. 77% of trevogrumab participants had at least one adverse event versus 82% on placebo.

Participants / model
Adults with obesity in the lower-dose portion of a randomized phase 2 trial; MRI substudy subset
Treatment
Semaglutide 2.4 mg with trevogrumab 25 or 75 mg; route not stated in the release
Follow-up
52 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed; stated to be in press at The Lancet
Funding
Sponsor: Regeneron

Here lower dose means 25 and 75 mg, not the 200 mg arm of the September 2025 release. The maintenance phase after semaglutide was stopped is not reported.

Read the original source
openFDA, 11 October 2026: no application for trevogrumab or REGN1033

Regulatory record

U.S. Food and Drug Administration, openFDA Drugs@FDA API. Queries for trevogrumab and for REGN1033 run on 11 October 2026, each returning no application. Regeneron press releases of 17 September 2025 and 1 October 2026 state that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

No application was returned for trevogrumab or REGN1033. Regeneron states that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Queries run on 11 October 2026
Study design
Dated US approval-record search, with a company regulatory statement
Funding
not stated in the source

The database search covers the United States; the company statement covers other regulators.

Read the original source

Studies and sources

Mouse study: REGN1033 raised muscle size, mass and force

Animal study

Latres E et al. Skelet Muscle. 2015;5:34. PMID 26457176.

Chronic REGN1033 treatment increased muscle fiber size, muscle mass and force, prevented muscle loss from immobilization, glucocorticoid treatment or hindlimb unweighting, and in aged mice raised muscle mass and strength and improved treadmill performance. REGN1033 is a fully human monoclonal antibody that blocks myostatin (GDF8); PubChem name lookups for trevogrumab and REGN1033 returned no compound on 11 October 2026.

Participants / model
Mice, including aged mice
Treatment
Chronic REGN1033 treatment; route and dose not stated in the abstract
Follow-up
not stated in the source
Study design
Original preclinical study with in vitro binding and cell assays
Funding
Sponsor authors (Regeneron)

Mouse data. The strength and treadmill gains have not been shown in people.

Read the original source
openFDA, 11 October 2026: no application for trevogrumab or REGN1033

Regulatory record

U.S. Food and Drug Administration, openFDA Drugs@FDA API. Queries for trevogrumab and for REGN1033 run on 11 October 2026, each returning no application. Regeneron press releases of 17 September 2025 and 1 October 2026 state that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

No application was returned for trevogrumab or REGN1033. Regeneron states that the safety and efficacy of trevogrumab have not been evaluated by any regulatory authority.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Queries run on 11 October 2026
Study design
Dated US approval-record search, with a company regulatory statement
Funding
not stated in the source

The database search covers the United States; the company statement covers other regulators.

Read the original source
Phase 1: 82 healthy people, combination gave more muscle growth

Randomized controlled trial

Gonzalez Trotter D et al. Nat Commun. 2025;16(1):4376. PMID 40360471.

Combining an anti-GDF8 antibody with an anti-activin A antibody gave greater muscle growth than either alone, with increases in muscle accompanied by reductions in fat. The combination was generally well tolerated and no participant tested positive for anti-drug antibodies. The abstract gives no doses, effect sizes or per-arm numbers.

Participants / model
82 healthy people: postmenopausal women aged 45 to 70 and men aged 35 to 60, BMI 18 to 32; 48 in the single-dose part and 34 in the multiple-dose part
Treatment
Single and multiple doses of REGN2477 (garetosmab) alone and with REGN1033; route not stated in the abstract
Follow-up
not stated in the source
Study design
Two-part randomized, placebo-controlled phase 1 trial (NCT02943239)
Funding
Authors are Regeneron employees or former employees, except one at a New Zealand clinical research site

The size of the anti-GDF8 effect alone cannot be read from the abstract.

Read the original source
COURAGE registry: 1,005 enrolled, no posted results

Trial registry record

ClinicalTrials.gov record NCT06299098, COURAGE (sponsor study R1033-OB-2288). Randomized, quadruple-masked phase 2 study of trevogrumab, garetosmab and semaglutide.

Enrolled 1,005 people (actual). Part A in healthy adults aged 18 to 55; Parts B and C in adults aged 18 to 80 with obesity and no history of diabetes. Trevogrumab is given subcutaneously in Parts B and C, garetosmab intravenously and semaglutide subcutaneously. Primary outcomes are percent change in total lean mass, total fat mass and body weight at week 26 (Part B) and week 52 (Part C). Start 13 March 2024, primary completion 16 June 2026, estimated completion 21 October 2026, active not recruiting; no posted results.

Participants / model
Healthy adults aged 18 to 55 (BMI 18 to 32) and adults aged 18 to 80 with obesity (BMI at least 30) and no history of diabetes
Treatment
Subcutaneous trevogrumab, intravenous garetosmab and subcutaneous semaglutide
Follow-up
Primary outcomes at week 26 (Part B) and week 52 (Part C)
Study design
Randomized, quadruple-masked phase 2 trial registry record
Funding
Sponsor: Regeneron (sponsor study R1033-OB-2288)

The registry lists REGN1033 as another name for trevogrumab and REGN2477 as garetosmab.

Read the original source
Regeneron release, 17 September 2025: 26-week lean mass, fat and weight

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025.

Semaglutide 2.4 mg alone (n=151) or with trevogrumab 200 mg (n=149), trevogrumab 400 mg (n=152) or trevogrumab 400 mg plus garetosmab 10 mg/kg (n=147). Lean mass change by DXA: -6.5% (SE 0.5), -3.3% (0.5), -3.8% (0.5) and -2.0% (0.6). Lean mass as a share of total weight loss: 33.0%, 16.8%, 18.1% and 7.4%. Fat mass: -15.7%, -17.3%, -19.1% and -27.1%. Body weight: -10.6%, -9.9%, -11.1% and -13.4%. P-values were not corrected for multiplicity, and the efficacy estimand excludes data after treatment discontinuation. No strength or physical function result is reported.

Participants / model
Adults with obesity (BMI at least 30) in a randomized phase 2 trial
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

About half of lean mass loss prevented is the company's summary of the two trevogrumab-only arms. Here lower dose refers to the 200 mg arm.

Read the original source
Regeneron release, 1 October 2026: 25 mg and 75 mg over 52 weeks

Regulatory record

Regeneron Pharmaceuticals. Phase 2 COURAGE trial results on lean mass with trevogrumab, 52-week and MRI data. Company news release, Regeneron investor relations, 1 October 2026.

Lean mass change by DXA at weeks 26 and 52: -6.7% and -7.3% with semaglutide alone, -4.7% and -5.8% with 25 mg (29.9% and 20.5% preservation), and -3.3% and -4.2% with 75 mg (50.7% and 42.5%). MRI fat-free muscle volume change at weeks 26 and 52: -0.88 and -1.03, -0.32 and -0.29, and -0.24 and -0.32, with no units or evaluable count given. Reported muscle preservation 63.6% and 71.8% (25 mg) and 72.7% and 68.9% (75 mg). Lower-dose trevogrumab did not meaningfully enhance weight loss. 77% of trevogrumab participants had at least one adverse event versus 82% on placebo.

Participants / model
Adults with obesity in the lower-dose portion of a randomized phase 2 trial; MRI substudy subset
Treatment
Semaglutide 2.4 mg with trevogrumab 25 or 75 mg; route not stated in the release
Follow-up
52 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed; stated to be in press at The Lancet
Funding
Sponsor: Regeneron

Here lower dose means 25 and 75 mg, not the 200 mg arm of the September 2025 release. The maintenance phase after semaglutide was stopped is not reported.

Read the original source
Regeneron release, 17 September 2025: adverse events, triplet deaths

Regulatory record

Regeneron Pharmaceuticals. Results from Phase 2 COURAGE trial on lean mass preservation during GLP-1 receptor agonist weight loss, presented at EASD. Company press release distributed by GlobeNewswire, 17 September 2025. Safety statements.

The trevogrumab combination with semaglutide was described as generally well tolerated. Adverse events in at least 5% of any group: muscle spasms, nausea, constipation, fatigue, diarrhea, headache, vomiting, gastroesophageal reflux disease, upper respiratory tract infection, nasopharyngitis, urinary tract infection, influenza and COVID-19, most mild to moderate. The triplet with garetosmab had a substantially higher rate of discontinuations, and two deaths occurred in that arm. Regeneron stated it has not identified a causal association. No discontinuation counts are given.

Participants / model
Adults with obesity in the semaglutide, trevogrumab and triplet arms
Treatment
Semaglutide 2.4 mg with trevogrumab 200 or 400 mg, with or without intravenous garetosmab 10 mg/kg
Follow-up
26 weeks
Study design
Company press release on a randomized phase 2 trial; not peer reviewed
Funding
Sponsor: Regeneron

One death was of undetermined cause in a person with multiple cardiovascular risk factors; the other was cardiac arrest in a person with a history of cardiovascular disease.

Read the original source
PASATRU label, version effective 14 August 2026: garetosmab for FOP

FDA prescribing information

DailyMed, U.S. National Library of Medicine. PASATRU (garetosmab-grts) injection for intravenous infusion, 300 mg/5 mL single-dose vial, prescribing information, label version effective 14 August 2026. Set ID 0d5cec96-b02b-4f1d-bc66-51e62ce04e3c. openFDA lists BLA 761508 with an original approval status date of 19 August 2026.

PASATRU is indicated to reduce formation of new heterotopic ossification lesions and clinician-assessed flare-ups in adults with fibrodysplasia ossificans progressiva. Warnings cover embryo-fetal toxicity (contraindicated in pregnancy), skin and soft tissue infections and epistaxis. Adverse reactions in at least 10% were abscess, acne, increased hair growth, madarosis, oral ulcers and epistaxis.

Participants / model
Adults with fibrodysplasia ossificans progressiva
Treatment
PASATRU intravenous infusion, 300 mg/5 mL single-dose vial
Follow-up
Label version effective 14 August 2026
Study design
FDA prescribing information and FDA application record
Funding
not stated in the source

This label is for garetosmab only. It does not cover trevogrumab or any use in obesity.

Read the original source
LUMINA-1: garetosmab, 44 adults with FOP, 5 deaths in open label

Randomized controlled trial

Di Rocco M et al. Nat Med. 2023;29(10):2615-2624. PMID 37770652.

All patients had at least one treatment-emergent adverse event in period 1, notably epistaxis, madarosis and skin abscesses. Five of 44 patients (11.4%) died in the open-label period; the authors considered the deaths unlikely to be related but could not rule out causality. The primary efficacy endpoint in period 1 was not met (P = 0.0741).

Participants / model
Adults with fibrodysplasia ossificans progressiva; garetosmab n=20, placebo n=24
Treatment
Garetosmab; route not stated in the abstract
Follow-up
28 weeks, then open label
Study design
Randomized phase 2 trial (NCT03188666)
Funding
Sponsor authors

Garetosmab data in a rare disease; it does not transfer to trevogrumab alone.

Read the original source

Why is Trevogrumab in B tier?

B fits an investigational antibody with a credible mechanism whose largest dataset is a randomized phase 2 trial of 1,005 people, in which lean mass loss was smaller in every trevogrumab arm. The results are company-reported and not yet peer reviewed, the measures are lean mass and muscle volume rather than strength or function, the effect varies with dose, and no regulator has reviewed the drug.