FDA Approves Mirum's Once-Daily Atebrioz for Rare Bone Disorder FOP
核心洞察
The US FDA approved Mirum Pharmaceuticals' once-daily pill zilurgisertib, branded Atebrioz (搜索), for patients aged 12 and older with fibrodysplasia ossificans progressiva (搜索).
Atebrioz (搜索) blocks ALK2 (搜索), a protein abnormally active in most FOP patients that drives bone formation outside the skeleton, at a recommended 100 milligram dose.
Approval was based on a 63-patient study in which Atebrioz (搜索) significantly reduced new bone formation versus placebo at week 24.
The US Food and Drug Administration (搜索) on Sept 25 approved Mirum Pharmaceuticals' pill for fibrodysplasia ossificans progressiva (搜索) (FOP), giving patients a new treatment option that can help slow progression of the rare bone disorder.
The once-daily drug, zilurgisertib, will be marketed as Atebrioz (搜索) and is approved for patients aged 12 years and older. FOP causes muscles, tendons and ligaments to gradually transform into bone, restricting movement and leading to severe disability.
Mechanism and Dosing
Atebrioz (搜索) blocks ALK2 (搜索), a protein that is abnormally active in most patients with FOP and drives bone formation outside the skeleton. The recommended dose is 100 milligrams.
FOP is typically diagnosed in early childhood. According to Mirum, about 300 people in the United States and 900 worldwide have the condition.
Trial Basis for Approval
The FDA approval was based on a 63-patient study in which Atebrioz (搜索) significantly cut new bone formation compared with placebo at week 24.
Launch and Licensing
Mirum expects to launch the drug in October and plans to announce its price at launch, chief executive officer Chris Peetz told Reuters.
"It is a game changer for patients to have a medicine like this that can really stop that progressive, endless accumulation of bone," Peetz said.
Mirum licensed the drug from Incyte earlier in 2026 for US$16 million upfront, along with potential milestone payments and sales royalties.
Existing FOP Therapies
Current treatment options for FOP include Ipsen's oral drug Sohonos and Regeneron's Pasatru (搜索), a monthly infusion. Sohonos is approved for certain children and adults, while Pasatru is approved for adults.
Citizens analyst Jonathan Wolleben said Atebrioz (搜索) could become a preferred treatment because it combines oral dosing with strong efficacy and a favorable safety profile, offering greater convenience than Regeneron's monthly infusion and potentially fewer safety concerns than Ipsen's Sohonos. Wolleben estimates Atebrioz could cost about US$750,000 annually and generate roughly US$150 million in peak worldwide sales.