RecruitingNCT06089616
Connective Tissue
Fibrodysplasia Ossificans Progressiva
Also known as FOP, myositis ossificans progressiva, stone man syndrome
Fibrodysplasia ossificans progressiva is an ultra-rare and severely disabling disorder caused by a gain-of-function mutation in ACVR1 (encoding ALK2), a BMP type I receptor, leading to progressive and irreversible heterotopic ossification o
ORPHA:337 ↗Gene ACVR1Prevalence 1 in 1,600,000–2,000,000Onset Congenital (malformed great toes); progressive heterotopic ossification from early childhoodGenetic — autosomal dominant (almost always de novo)
4
studies recruiting now
as of 7 Sept 2026
24
studies registered in total
as of 7 Sept 2026
17
countries with a recruiting site
as of 7 Sept 2026
9 Dec 2024
most recent study posted
among recruiting studies
Recruiting trials
RecruitingNCT06724562
IL1 Inhibition in FOP
RecruitingPhase 2NCT05090891
To Assess the Efficacy, Safety, and Tolerability of INCB000928 in Participants With Fibrodysplasia Ossificans Progressiva
RecruitingNCT02745158
The Fibrodysplasia Ossificans Progressiva (FOP) Registry
Showing the 4 most recently updated recruiting studies, as recorded 7 Sept 2026. Live status on each study page.
Search all Fibrodysplasia Ossificans Progressiva studiesWhere recruiting studies are running
Countries with at least one recruiting site among the studies above, 7 Sept 2026. Tap a country to search trials there.
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Registry: FOP Registry (IFOPA) · Join ↗. Registries connect patients to researchers and often hear about trials first.
About Fibrodysplasia Ossificans Progressiva
Fibrodysplasia ossificans progressiva is an ultra-rare and severely disabling disorder caused by a gain-of-function mutation in ACVR1 (encoding ALK2), a BMP type I receptor, leading to progressive and irreversible heterotopic ossification of skeletal muscle, fascia, tendons, and ligaments. The condition is characterised by episodic inflammatory flares that trigger the formation of ectopic bone, ultimately encasing the skeleton and causing profound loss of mobility. A malformed first toe (hallux valgus or monophalangism) present at birth is a pathognomonic clinical sign that permits early diagnosis before ossification begins.
Common clinical features
Bilateral malformed great toes (short, monophasic hallux) present at birthEpisodic painful soft-tissue swellings (flares) triggered by trauma, infection, or injectionProgressive heterotopic bone formation in muscle and connective tissueSevere restriction of joint mobility — neck, shoulders, hips, spineAnkylosis of the jaw limiting mouth openingThoracic insufficiency syndrome from chest wall ossificationConductive hearing loss in some patients
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Treatments being studied
1 approved treatment and 7 in clinical development, from Open Targets (CC BY 4.0). Not medical advice.
Approved: Palovarotene (Sohonos)
Phase 3Garetosmab
Phase 2/3Andecaliximab
Phase 2Fidrisertib
Phase 2Saracatinib
Phase 2Zilurgisertib
Phase 1Midazolam (Midazolam in 0.8% sodium chloride)
Phase 1Prafnosbart
Before you apply
Things trial teams commonly ask about for Fibrodysplasia Ossificans Progressiva. Not eligibility rules; those are set by each study.
- Avoid biopsies, intramuscular injections, or surgical procedures unless absolutely life-threatening — these can trigger catastrophic flare and new bone formation; disclose this history to trial staff immediately.
- Baseline whole-body 18F-NaF PET-CT or nuclear bone scan documenting extent of heterotopic ossification is standard for clinical trial enrolment; ensure imaging is current.
- Active flare at time of enrolment may be an exclusion criterion — document current flare status, recent flare history, and any corticosteroid use prescribed for flare management.
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).