- For Regulatory Affairs: the approval closes an important U.S. regulatory milestone after an earlier development setback.
- For Clinical Research: the 56-week efficacy data now sit at the center of the approval story.
- For Pharmacovigilance and safety teams: the earlier trial history remains an important part of understanding the drug’s development pathway.
Pasatru Reaches FDA Approval After a Troubled 2020 Trial Halt
Regeneron’s route to approval was not straightforward. In 2020, the company paused dosing in a mid-stage garetosmab study after five patient deaths. It ultimately discontinued that study and worked with global regulators to design the later-stage trial, according to Reuters. Importantly, the Reuters report does not state that the drug caused those deaths.
The later study produced a very different outcome. Over 56 weeks, 63 participants received Pasatru or placebo. The 3 mg/kg dose reduced the development of new bone abnormalities by 94%, while the 10 mg/kg dose produced a 90% reduction compared with placebo.
From Trial Halt to FDA Approval
| Development stage | Reported outcome |
|---|---|
|
2020 |
Dosing paused after five patient deaths; the mid-stage study was later discontinued |
|
Later-stage development |
Regeneron worked with global regulators on the new trial design |
|
56-week study |
94% reduction at 3 mg/kg and 90% at 10 mg/kg versus placebo |
|
August 19, 2026 |
FDA approved Pasatru for adults with FOP |
A 63-Patient Trial Changed Garetosmab’s Path Back to FDA
Pasatru blocks Activin A, a protein involved in abnormal bone formation in patients with fibrodysplasia ossificans progressiva, or FOP. The ultra-rare genetic disorder causes muscle, tendon and ligament tissue to gradually turn into bone, progressively restricting mobility and reducing life expectancy. Reuters reported that FOP affects roughly one person in two million worldwide, with only about 800 to 900 active diagnosed cases globally.
The approval also changes the competitive landscape. Pasatru will compete with Ipsen’s oral therapy Sohonos, which gained FDA approval in 2023. Incyte and partner Mirum Pharma, along with privately held Ashibio, are also developing treatments for FOP. Meanwhile, Regeneron shares rose 4% following the FDA decision.
If your team reviewed a rare-disease program after an earlier trial halt, which evidence would you examine first the redesigned efficacy dataset or the updated safety profile?
What Pasatru’s Approval Means for Regulatory and Clinical Teams
For teams tracking this development, the immediate actions are to document the new U.S. approval in regulatory-intelligence systems, review the dose-specific 56-week evidence, retain the earlier safety history in benefit-risk discussions, and monitor the next planned clinical study. These actions follow the reported development path without suggesting that the FDA has changed broader approval standards.
Pasatru Wins Adult Approval; Pediatric Development Is Next to Watch
The clearest next development is Regeneron’s planned trial in children later in 2026. Susan Rhee of Regeneron’s clinical team told Reuters that the company intends to begin the study later this year. Therefore, future pediatric evidence will become the next important clinical milestone to watch.
From FDA Approval to Quality Action: What Pharma Teams Should Control
Among Zamann Pharma’s current services, Quality Management System support is the closest fit for teams translating regulatory developments into controlled risk-management, change-control, CAPA, and quality-governance activities. Explore the service when a regulatory milestone requires structured implementation across the pharmaceutical quality system.
Source: Reuters.Com