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Garetosmab

Phase 3

Fibrodysplasia Ossificans Progressiva | Small molecule | Rare Disease |Regeneron Pharmaceuticals, Inc.|Last Updated: Aug 24, 2026

Target and mechanism

Molecular targetINHBA
Target classInhibitor
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLEDDMC
Total Trials1
Total Enrollment63

FDA Designations

PRIORITY_REVIEW

Clinical trial landscape

Garetosmab · 2 trials · 2 indications

Phase 3 2
NCT07559513A Study to Investigate the Safety, Pharmacokinetics (PK), and Efficacy of Garetosmab in Children and Adolescents With Fibrodysplasia Ossificans Progressiva (FOP)Fibrodysplasia Ossificans Progressiva (FOP)
NOT YET_RECRUITING18 Analytics
NCT05394116A Study to Assess Safety, Tolerability and Efficacy of Garetosmab Versus Placebo Administered Intravenously (IV) in Adult Participants With Fibrodysplasia Ossificans Progressiva (FOP)Fibrodysplasia Ossificans Progressiva
ACTIVE NOT_RECRUITING63 Analytics
PHASE3NOT YET_RECRUITING
A Study to Investigate the Safety, Pharmacokinetics (PK), and Efficacy of Garetosmab in Children and Adolescents With Fibrodysplasia Ossificans Progressiva (FOP)
Fibrodysplasia Ossificans Progressiva (FOP)Unlock trial analytics
PHASE3ACTIVE NOT_RECRUITING
A Study to Assess Safety, Tolerability and Efficacy of Garetosmab Versus Placebo Administered Intravenously (IV) in Adult Participants With Fibrodysplasia Ossificans Progressiva (FOP)
Fibrodysplasia Ossificans ProgressivaUnlock trial analytics

Study Endpoints

Primary Endpoints

Occurrence of Treatment-Emergent Adverse Event (TEAEs)
Baseline to week 28
Occurrence of TEAEs
Baseline to week 56
Severity of TEAEs
Baseline to week 28
Concentrations of functional garetosmab in serum
Through week 56
Number of new HO lesions
At Week 56
Incidence and severity of treatment-emergent adverse events of special interest (AESIs)
Baseline to Week 56

Secondary Endpoints

Total volume of new Heterotopic Ossification (HO) lesion
At week 28 and week 56
Number of new HO lesions
At week 28 and week 56
Occurrence of new HO lesions
At week 28 and week 56
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSINGLE_GROUP
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Cohort 1: AdolescentsEXPERIMENTAL -
Cohort 2: ChildrenEXPERIMENTAL -
Cohort 3: Children and AdolescentsEXPERIMENTAL -
High dose GaretosmabEXPERIMENTALGaretosmab is administered by intravenous (IV) administration every 4 weeks (Q4W)
Low dose GaretosmabEXPERIMENTALGaretosmab is administered by IV administration Q4W
PlaceboEXPERIMENTALPlacebo to match garetosmab, is supplied as a liquid solution without the monoclonal antibody (or the protein) and is administered IV Q4W.

Interventions

NameTypeDescription
garetosmabDRUGAdministered per the protocol
PlaceboDRUGPlacebo to match garetosmab, is supplied as a liquid solution without the monoclonal antibody (or the protein) and is administered IV.
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Eligibility Criteria

Age Range2 Years to 18 Years
SexALL
Healthy VolunteersNo

Key Inclusion Criteria: 1. For USA participants, age criteria are 4 to \< 18 years old, at the time of the administration of the first dose of study intervention. Non-USA participants age criteria are 2 to \< 18 years old 2. Must have a confirmation of FOP diagnosis, as described in the protocol 3....

Countries:United StatesAustraliaBrazilChileChinaColombiaFinlandFranceHong KongItalyJapanMalaysiaNetherlandsPolandSouth AfricaSouth KoreaSpainUnited Kingdom
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Recent Changes (Last 90 Days)

LOWAug 24, 2026NCT07559513startDate: changed
LOWAug 24, 2026NCT07559513startDate: changed
LOWJul 17, 2026NCT05394116lastUpdatePostDate: changed
LOWJul 17, 2026NCT05394116lastUpdatePostDate: changed

Frequently asked questions about Garetosmab

What is Garetosmab used for?

Garetosmab is an investigational drug being developed for the treatment of Fibrodysplasia Ossificans Progressiva (FOP), a rare genetic disorder characterized by progressive heterotopic bone formation. It is currently in Phase 3 clinical trials for this condition.

What does Garetosmab target?

Garetosmab is a monoclonal antibody (mab) that targets a specific molecular pathway involved in FOP. As an antibody, it is designed to bind to and modulate its target to potentially slow or prevent abnormal bone growth in patients with FOP.

Who makes Garetosmab?

Garetosmab is being developed by Regeneron Pharmaceuticals, Inc., a biopharmaceutical company. Regeneron is conducting clinical trials to evaluate the safety and efficacy of Garetosmab in patients with Fibrodysplasia Ossificans Progressiva.

What phase is Garetosmab in?

Garetosmab is currently in Phase 3 clinical development. It is being studied in adult patients with Fibrodysplasia Ossificans Progressiva in a randomized, double-blind, placebo-controlled trial. It is also being investigated in a pediatric trial for the same condition.

What clinical trials is Garetosmab in?

Garetosmab is being evaluated in two Phase 3 trials. The first, NCT05394116, is an active, not recruiting study in adults with FOP, enrolling 63 participants across multiple countries. The second, NCT07559513, is a not yet recruiting study in children and adolescents with FOP, with a planned enrollment of 18 participants.

Is Garetosmab FDA approved?

Garetosmab has received Priority Review designation from the FDA, but it is not yet approved. It is still in clinical development, with ongoing Phase 3 trials assessing its safety and efficacy in patients with Fibrodysplasia Ossificans Progressiva.