Living dossier · Competitive landscape

Myostatin/activin (ActRII) in Obesity (lean-mass preservation)

Primary identifiers: 5
Sponsors tracked: 5
Evidence types: 2 of 3
Last refreshed: 2026-07-28 · monthly

MightyRayn panel synthesis

OmniRayn’s reading of this landscape — our interpretation, not a registry fact

This is the axis on which the obesity field is now differentiating, and it is contested rather than open. The record couples an established incretin backbone with agents aimed at preserving lean mass, spanning preclinical work in non-human primates through active clinical study. Anyone treating muscle-sparing as whitespace should read the preclinical citation here first: the mechanism has already been demonstrated in primates by a large developer. The open question in the record is not whether the mechanism works, but which modality and which population will carry it.

Programs and primary evidence

Sponsor	Asset	Phase	Mechanism	Primary source
Regeneron Pharmaceuticals	GDF8 + activin A blockade	—	dual GDF8 (myostatin) and activin A blockade	10.1038/s41467-025-59485-9 — Dual blockade prevents GLP-1-associated muscle loss and enhances fat loss in obese mice and non-human primates
Actimed Therapeutics	(S)-pindolol benzoate (ACM-001.1)	2	beta-blocker investigated for lean-mass preservation	NCT07101939 — PROACT Phase 2a on lean body mass during and after semaglutide therapy
University of Texas Health Science Center at San Antonio	Tirzepatide (investigator study)	2	incretin effect on muscle and vascular function	NCT06811324 — Effects on muscle and vascular function among obese older adults
University Hospital 12 de Octubre	review	—	activin type II receptor blockade	10.1097/MCO.0000000000001130 — Up to 40% of GLP-1-associated weight loss can be fat-free mass; ActRII blockade shows promise for preserving muscle
AMRA Medical / Linkoping University	imaging analysis	—	MRI-based muscle volume assessment	10.1161/CIRCULATIONAHA.124.067676 — Muscle changes under GLP-1 therapy assessed by muscle volume z-score

Method and limits

Programs are enumerated from primary registries (ClinicalTrials.gov, PubMed). A program appears here only if a primary record links this target to this indication as a therapeutic hypothesis — associations and risk markers are excluded by design.
Every claim above carries the identifier it rests on. We report what the record states; we do not assert efficacy, and computational findings are pending wet-lab confirmation.
Absence is not evidence of absence: unregistered, non-US and stealth-stage programs are not visible to these sources.
This page refreshes monthly (no net-new primary entity in 118 days). Mechanism classifications are our reading of the public record and may be revised.

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