Daily tablet approved for rare disease that turns soft tissue to bone

The US Food and Drug Administration has approved a once-daily tablet for people aged 12 and older with fibrodysplasia ossificans progressiva (FOP), a rare genetic disease that causes soft tissue to turn into bone. Sold as Atebrioz, it is the third treatment approved in the United States for the condition.

FOP can progressively restrict movement, fuse joints and cause chronic pain. Atebrioz, also called zilurgisertib, blocks an overactive receptor involved in signals that trigger this abnormal bone growth.

The approval was supported by a 24-week trial in which 63 people were randomly assigned to receive the drug or a placebo. Scans showed substantially less new bone growth by volume in the treatment group. One person taking Atebrioz developed a new bone growth, compared with five receiving placebo, although this difference did not reach statistical significance and was therefore not conclusive.

The most common side effects include headache, joint pain, upper respiratory tract infections, nosebleeds and nausea.

The decision gives teenagers and adults another treatment option, following the recent approval of Pasatru for adults. Mirum Pharmaceuticals said it was preparing to launch Atebrioz in October; its price had not yet been announced.