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Fibrodysplasia Ossificans Progressiva →Connective Tissue & Musculoskeletal

Pasatru (garetosmab) for Fibrodysplasia ossificans progressiva (FOP)

Regeneron · BLA
FDA decision
Aug 192026
Approved
August has 7 FDA decisions on our calendar, this one included. Before it, Genglycos on Aug 19th. After it, Imaavy on Aug 24th.
Approved
The FDA approved this application. Approval is the starting line, not the finish: our guide to what happens in the 90 days after a rare disease approval walks through specialty pharmacies, insurance review, and how families shorten the wait.

What the FDA decided on Pasatru for FOP

The FDA approved Pasatru (garetosmab) for fibrodysplasia ossificans progressiva (FOP).

Approved for adults with FOP. Sohonos, approved in 2023, also covers adults, so Pasatru gave adults a second option.

Who the Pasatru decision matters to

Fibrodysplasia Ossificans Progressiva (FOP) is an extremely rare genetic disorder characterized by progressive heterotopic ossification, where soft tissues (muscles, tendons, ligaments) gradually transform into bone. This leads to progressive immobility and severe physical disability.

FOP is caused by mutations in the ACVR1 gene, and nearly all cases involve a single mutation (c.617G>A).

Prevalence: Extremely rare, about 1 in 1 million to 1 in 2 million people worldwide. See our full Fibrodysplasia Ossificans Progressiva page for current treatments, recruiting trials, and community resources.

How Pasatru works

Pasatru: fully human monoclonal antibody that binds and blocks activin A, the signal that switches on the mutant ACVR1 (ALK2) receptor and drives new bone formation in FOP. Our full Pasatru profile covers how it works, side effects in plain language, and its trial history.

Where Fibrodysplasia Ossificans Progressiva treatment stands today

FDA approved for Fibrodysplasia Ossificans Progressiva (3)
Sohonos (palovarotene)Retinoic acid receptor gamma agonistsince 2023Atebrioz (zilurgisertib)ALK2 (ACVR1) kinase inhibitorsince 2026Pasatru (garetosmab-grts)Activin A-blocking monoclonal antibody (activin signaling inhibitor)since 2026
Read our full Fibrodysplasia Ossificans Progressiva treatment summary

Research in Fibrodysplasia Ossificans Progressiva is advancing through ALK2 inhibitors targeting the specific ACVR1 mutation that causes the disease, along with approaches to block BMP signaling pathways that drive abnormal bone formation.

Clinical trials measure treatment success through imaging tracking ossification progression, assessments of functional mobility, and importantly, reductions in flare frequency and severity that cause pain and rapid progression. Quality of life improvements matter significantly.

Your genetic confirmation of the ACVR1 mutation guides therapy selection. Baseline imaging documents disease extent and helps track progression.

The trials behind the newest approvals counted new bone on low-dose whole-body CT scans. Pain management and reducing inflammation during flares are equally important as slowing bone formation.

A specialist experienced in FOP can help identify appropriate trials and explain how the approved ALK2 inhibitor Atebrioz differs from the other options.

The FDA has approved 3 medicines for FOP: Sohonos (palovarotene) capsules on August 16, 2023 for adults and for girls 8 and older and boys 10 and older, Pasatru (garetosmab) infusions on August 19, 2026 for adults, and Atebrioz (zilurgisertib) on September 25, 2026 for people 12 and older. No trial has compared them with each other, so ask your FOP specialist whether an approved medicine or a clinical trial is the better fit for you.

The Fibrodysplasia Ossificans Progressiva page has every treatment and trial →

Meanwhile, 5 Fibrodysplasia Ossificans Progressiva studies are open or about to open

The FDA's decision does not end research on Fibrodysplasia Ossificans Progressiva. Of these, 2 test a treatment; the others follow patients over time. The most recently updated:

A Study to Document and to Further Describe Long-term Safety and Effectiveness of Palovarotene in Participants With Fibrodysplasia Ossifican
Observational study, no treatment given · NCT06089616 · has US sites
To Assess the Efficacy, Safety, and Tolerability of INCB000928 in Participants With Fibrodysplasia Ossificans Progressiva
Treatment trial · NCT05090891 · has US sites
IL1 Inhibition in FOP
Observational study, no treatment given · NCT06724562 · has US sites
See all 5 open studies →
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Frequently asked questions

Has the FDA decided on Pasatru?

The FDA has already decided. It approved the application.

Details: the outcome and what it means are at the top of this page.

Source: Regeneron press release

What was Pasatru approved for?

The FDA approved Regeneron's BLA for Pasatru in Fibrodysplasia ossificans progressiva (FOP).

What to know: Approved for adults with FOP. Sohonos, approved in 2023, also covers adults, so Pasatru gave adults a second option.

How it works: Fully human monoclonal antibody that binds and blocks activin A, the signal that switches on the mutant ACVR1 (ALK2) receptor and drives new bone formation in FOP.

More: the Pasatru drug page explains it in plain language.

Is there already an FDA-approved treatment for Fibrodysplasia Ossificans Progressiva?

Yes. Trial Friend's drug list includes 3 FDA-approved drugs for Fibrodysplasia Ossificans Progressiva.

Approved: Sohonos (palovarotene), Atebrioz (zilurgisertib), Pasatru (garetosmab-grts).

Check: the Fibrodysplasia Ossificans Progressiva page also searches FDA drug labels for approved treatments.

What did the Pasatru trials show?

Approval rested on OPTIMA (NCT05394116), a Phase 3 trial in 63 adults with FOP (median age 25, range 18 to 42) randomly assigned to Pasatru 10mg/kg, Pasatru 3mg/kg or placebo every 4 weeks for 56 weeks. On low-dose whole-body CT scans, 5 of 21 placebo patients developed a total of 19 new bone lesions, against 2 lesions in 2 of 23 patients on 10mg/kg and 1 lesion in 1 of 19 on 3mg/kg, reductions of 90% and 94%.

More: the Pasatru drug page has the full trial history and sources.

What are the side effects of Pasatru?

Pasatru has no boxed warning, but it must not be used during pregnancy because it can harm an unborn baby. A pregnancy test is needed before starting, and women who could become pregnant should use effective birth control during treatment and for 6 months after the last dose.

Most common: Abscess (35% on 10mg/kg against 10% on placebo), Acne (30% against 10%), Increased hair growth (26% against 0%; 42% on 3mg/kg), Loss of eyebrow or eyelash hair, madarosis (26% against 19%), Mouth sores (26% against 5%), Nosebleeds (17% against 24%; 53% on 3mg/kg).

More: the Pasatru drug page has the label's warnings in full.

How much will Pasatru cost?

Trial Friend does not list a price for Pasatru. What you pay depends on your insurance and on help from the drugmaker or a charity fund.

Drugmaker help: myRARE (Regeneron).

Find help: the patient assistance finder lists programs by insurance type.

What happens after the Pasatru decision?

The FDA approved Pasatru for Fibrodysplasia ossificans progressiva (FOP) on August 19, 2026.

Next steps: getting the drug still takes time. Specialty pharmacy setup, insurance review and patient assistance often take weeks. Our guide covers what families can do on day 1.

Where this outcome comes from

The outcome on this page comes from Regeneron press release. This page rechecks against our calendar, which is re-verified daily.