Full Breakdown
FDA Approves Mirum's Oral Drug Atebrioz for Fibrodysplasia Ossificans Progressiva
By Drooid · · How we work
Core Approval and Indication
On September 25 the U.S. Food and Drug Administration approved Atebrioz (zilurgisertib), a once-daily 100 mg pill, for patients >= 12 years old with fibrodysplasia ossificans progressiva (FOP), a rare disorder that causes heterotopic bone formation in muscles, tendons and ligaments.
Clinical Evidence and Comparative Data
Approval was based on the phase-2 PROGRESS study of 63 patients. At week 24, Atebrioz reduced new bone volume by 3.2 cm³ versus an increase of 24.6 cm³ in the placebo group. Only 3.1 % of treated patients developed a new lesion compared with 16.7 % on placebo – an 81 % relative reduction. The trial reported zero treatment discontinuations or dose reductions. By comparison, Regeneron’s monthly infusion Pasatru achieved >= 90 % reduction in lesions at 56 weeks but carries a risk of acute tissue infections; its average annual list price is about $1.4 million.
Market Outlook and Pricing Speculation
Mirum’s chief executive Chris Peetz said the company will launch Atebrioz in October and will announce pricing at that time. Analysts cited by Reuters estimate an annual price near $750,000, which could generate roughly $150 million in peak worldwide sales. Mirum licensed the drug from Incyte in 2026 for an upfront $16 million, with additional milestone payments and royalties.
Official Responses and Regulatory Incentives
The FDA decision also awarded Mirum a rare pediatric disease priority review voucher, an asset that can command $100 million to $200 million if sold. Peetz described the approval as “a game changer for patients” (see Verbatim Quotes). Mirum is pursuing EU review and has expanded the PROGRESS trial to include younger cohorts (ages 6–11 and under-two).
Verbatim Quotes
- “It is a game changer for patients to have a medicine like this that can really stop that progressive, endless accumulation of bone,” — Chris Peetz, chief executive