Peptides

Garetosmab

FDA-approved as Pasatru for adults with FOP to reduce new abnormal bone formation and flare-ups; it is not a general muscle or injury-recovery peptide.

Phase 2 primary report and 2026 FDA approval evidence; rare-disease limits

Also known as: Pasatru · garetosmab-grts · REGN2477

Practical use

Evidence interpretation and clinical context

Keep new and existing lesions separate: A prevention result should not be described as reversal of established disease.
Read counts with group sizes: A number of lesions and a percentage of patients are different denominators.
Use the current safety source: The 2026 prescribing information should accompany discussion of this recent approval.

Garetosmab in fibrodysplasia ossificans progressiva: a randomized, double-blind, placebo-controlled phase 2 trial.

What supported the later approval — primary or official source

The current label is specific — primary or official source

Overview

Garetosmab is an antibody that binds activin A. In fibrodysplasia ossificans progressiva (FOP), abnormal signaling causes bone to form in soft tissues. The August 2026 US approval addresses new heterotopic ossification lesions and clinician-assessed flare-ups in adults with this rare disease.

Risks and limitations

Pasatru is contraindicated during pregnancy because of fetal harm. The label also warns about skin and soft-tissue infections and nosebleeds that can require medical intervention. Abscesses, acne and hair changes occur.

How to read this

Preventing new lesions is a different outcome from dissolving existing bone, restoring all lost movement or improving ordinary sports injuries.

Research explained

Garetosmab in fibrodysplasia ossificans progressiva: a randomized, double-blind, placebo-controlled phase 2 trial.

Who was studied

LUMINA-1 randomized 44 adults with FOP to garetosmab or placebo for 28 weeks, followed by an open-label period.

What was found

The original lesion-activity primary endpoint was not met. New-lesion suppression prompted a prospectively changed endpoint for the later period. Five deaths occurred during the open-label period; investigators considered a treatment relationship unlikely but could not exclude it.

What it cannot establish

The later crossover result was not the original parallel placebo comparison. Both the endpoint change and deaths belong in an accurate account of the study.

Read the original study

What supported the later approval

FDA describes a separate randomized 63-adult trial. At week 56, the two active groups had one and two new lesions, versus 19 with placebo. Those are lesion counts in groups of different sizes, not percentages of patients cured.

Supporting source

The current label is specific

Pasatru is indicated for reducing new lesions and clinician-assessed flare-ups in adults with FOP. Existing ectopic bone is not claimed to dissolve, and an activin mechanism does not create a general regenerative indication.

Supporting source