Trevogrumab

ID: trevogrumab

Aliases: REGN1033, anti-GDF8 antibody, anti-myostatin antibody

Type: compound

Route/form: subcutaneous injection in COURAGE Parts B/C; IV or SC in Part A registry context

Status: investigational

Evidence level: human RCT

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

Support scope: human, non-human/mechanistic, context

Source types: clinical_trial_registry, company, human_rct, preclinical

Linked sources: 6

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

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

Targets / mechanism

• GDF8/myostatin neutralization
• ActRII-SMAD2/3 muscle-minimization pathway modulation
• GLP-1-associated lean-mass preservation signal

Optimization domains

• metabolic
• obesity
• body composition
• muscle
• sarcopenia
• myostatin
• activin signaling
• fat loss
• GLP-1 adjunct

Research basis

• Peer-reviewed randomized phase 1 human data show that GDF8 blockade, especially with activin A blockade, can move MRI/DXA muscle and fat-mass endpoints in humans.
• COURAGE sponsor/conference results in obesity report that adding trevogrumab to semaglutide cut the lean-mass share of semaglutide-associated weight loss from about 33% to about 17-18% and shifted more loss toward fat mass.
• Mouse and non-human-primate GLP-1 add-on data provide a mechanism-adjacent bridge for why myostatin/activin blockade could preserve lean mass during appetite-driven weight loss.

Limits, risks, and missing evidence

• The obesity-specific COURAGE data are sponsor-reported and conference-presented at this curation point, not a peer-reviewed obesity paper.
• Lean-mass preservation or gain is not automatically useful performance: strength, tendon/connective-tissue adaptation, cardiometabolic outcomes, and durability need direct evidence.
• This is an investigational monoclonal antibody program with immunogenicity, tolerability, regulatory, cost, and medical-supervision constraints; it is not comparable to a supplement or casual SARM add-on.

Risk flags

• investigational
• monoclonal antibody
• myostatin blockade
• muscle spasms
• sponsor reported obesity data
• lean mass not function
• medical supervision
• doping

Linked papers, labels, and reviews

1. GDF8 and activin A are the key negative regulators of muscle mass in postmenopausal females: a randomized phase I trial
   human_rct / nature_trevogrumab_garetosmab_phase1_2025
   Peer-reviewed randomized phase 1 human pharmacodynamic study of trevogrumab and garetosmab, alone and together, with MRI/DXA body-composition endpoints and safety signals including muscle spasms.
2. Results from Phase 2 COURAGE Trial Demonstrating Potential to Improve Quality of GLP-1 receptor agonist-induced Weight Loss by Preserving Lean Mass, Presented at EASD
   company / regeneron_courage_easd_2025
   Sponsor-reported 26-week COURAGE phase 2 obesity results: semaglutide 2.4 mg plus trevogrumab with or without garetosmab shifted weight-loss composition toward fat mass; not a peer-reviewed paper at this curation point.
3. COURAGE: Trevogrumab or Trevogrumab With Garetosmab in Addition to Semaglutide in Patients With Obesity
   clinical_trial_registry / clinicaltrials_courage_trevogrumab_garetosmab_semaglutide
   ClinicalTrials.gov registry for COURAGE; useful for design, enrollment, active-not-recruiting status, endpoints, and route details: trevogrumab SC in Parts B/C, garetosmab IV in Part B, semaglutide SC.
4. GDF8 and activin A blockade protects against GLP-1-induced muscle loss while enhancing fat loss in obese male mice and non-human primates
   preclinical / nature_gdf8_activin_glp1_animals_2025
   Mechanism-adjacent mouse and non-human-primate study supporting the COURAGE logic: GDF8 plus activin A blockade during semaglutide exposure preserved or increased lean mass while increasing fat loss.
5. Myostatin blockade with a fully human monoclonal antibody induces muscle hypertrophy and reverses muscle atrophy in young and aged mice
   preclinical / skeletalmuscle_regn1033_mice_2015
   Preclinical characterization of REGN1033/trevogrumab as a selective myostatin antibody with muscle-hypertrophy, atrophy-prevention, and functional endpoints in mice.
6. Anti-myostatin antibody increases muscle mass and strength and improves insulin sensitivity in old mice
   preclinical / pubmed_antimyostatin_old_mice_insulin_2016
   Old-mouse anti-myostatin antibody study showing increased muscle mass/strength and improved insulin-stimulated glucose metabolism; mechanism-adjacent support for myostatin blockade.