The US FDA on Friday approved ​Mirum Pharmaceuticals’ pill for a rare bone disorder, offering patients a ‌new treatment option that can help slow the disease’s progression.

The once-daily drug zilurgisertib, branded as Atebrioz, is approved for patients aged 12 years and older with fibrodysplasia ossificans progressiva (FOP), which ​causes muscles, tendons and ligaments to gradually transform into bone, restricting movement ​and leading to severe disability.

Atebrioz blocks ALK2, 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. ​About 300 people in the US and 900 worldwide, according to Mirum, have the condition.

Mirum expects to launch the drug in October and plans to announce its price at the launch, ​CEO 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.

Citizens ‌analyst ⁠Jonathan Wolleben estimates Atebrioz could cost about $750,000 annually and generate roughly $150 million in peak worldwide sales.

Mirum had licensed the drug from Incyte earlier this year for $16 million upfront, along with potential milestone payments and sales royalties.

The approval by the US Food ​and Drug Administration ​was based on ⁠a 63-patient study, in which Atebrioz significantly cut new bone formation compared to placebo at week 24.

Current treatment options for ​FOP include Ipsen’s oral drug Sohonos and Regeneron’s Pasatru, a ​monthly infusion. ⁠Sohonos is approved for certain children and adults, while Pasatru is approved for adults.

Wolleben said Atebrioz 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.