FDA Approves Mirum’s Atebrioz for Rare Bone Disorder FOP

The U.S. Food and Drug Administration has approved Mirum Pharmaceuticals’ Atebrioz, a new oral treatment for fibrodysplasia ossificans progressiva (FOP), a rare genetic disorder that causes abnormal bone formation in soft tissues.

Mirum Pharmaceuticals (NASDAQ: MIRM) said the FDA approval covers Atebrioz, also known by its generic name zilurgisertib, for patients aged 12 years and older with FOP. The medication is taken orally once a day, with a recommended dose of 100 milligrams.

FOP is an extremely rare genetic condition in which bone gradually forms in areas where it normally should not develop, including muscles, tendons and ligaments. This abnormal bone growth can progressively restrict movement and eventually result in severe disability for affected patients.

Atebrioz is designed to address a key biological mechanism associated with the disease. The drug works by blocking ALK2, a protein that is abnormally active in most people with FOP. Excessive ALK2 activity contributes to the formation of bone outside the normal skeleton, a process that is central to the progression of the disorder.

By inhibiting ALK2, zilurgisertib is intended to target the underlying pathway responsible for abnormal bone formation in FOP patients.

The FDA decision expands Mirum Pharmaceuticals’ portfolio of treatments for rare diseases and provides another therapeutic option for eligible adolescents and adults living with FOP. The once-daily oral dosing could also offer a relatively straightforward treatment regimen for patients aged 12 and above.

The approval puts additional attention on Mirum Pharmaceuticals and its rare-disease drug pipeline as the biotechnology company moves forward with the commercial rollout of Atebrioz in the United States. The FDA authorization also marks an important regulatory milestone for zilurgisertib and its use in treating a debilitating genetic bone disorder with limited treatment options.