These Patients Struggle With Runaway Bones. Finally There’s Hope.

It was Jordyn Bugarin’s grandmother who first suspected what was wrong. In a television documentary that aired in the summer of 2006, she watched as a child showed off a shortened, misshapen big toe just like Jordyn’s.

According to the narrator, this was one of the early signs of fibrodysplasia ossificans progressiva, or F.O.P., a rare genetic disorder that slowly turns muscle, tendons and connective tissue into bone. To the woman watching, it was a revelation: “That’s what Jordyn has,” she told her family.

The mutated gene that causes F.O.P. was discovered only 20 years ago, and until recently there was no approved treatment. Now, there are three, and for patients like Ms. Bugarin, 22, they offer the first real hope that this terrible disease can be slowed.

“Honestly, it feels like a dream,” she said in an interview. “It wasn’t something I thought I’d see in my lifetime.”

In August, the Food and Drug Administration approved garetosmab (brand name: Pasatru), a monoclonal antibody made by Regeneron for adults with F.O.P. A month later, the F.D.A. approved zilurgisertib (brand name: Atebrioz), a pill by Mirum for use in patients 12 and older.

Both drugs greatly reduce new abnormal bone formation. Another medication, palovarotene (brand name: Sohonos) was approved by the F.D.A. in August 2023, although European regulators have refused marketing authorization because of concerns about safety and efficacy.