French biopharmaceutical company Ipsen has received the US Food and Drug Administration (FDA) approval for Sohonos (palovarotene) capsules to treat fibrodysplasia ossificans progressiva (FOP), a rare genetic disorder in children and adults.

Sohonos is an oral medicine particularly selective for the gamma subtype of retinoic-acid receptors, which regulate skeletal development and ectopic bone in the retinoid signalling pathway.

It is designed to mediate the interactions between the receptors, growth factors and proteins within the retinoid signalling pathway to reduce new abnormal bone formation in FOP.

The drug is indicated for the reduction in volume of new heterotopic ossification in adults and children, aged eight years and above for females and 10 years and above for males with FOP.

Sohonos is recommended for administration at a chronic daily dosage of 5mg, which can be modified or increased for flare-up symptoms.

The US FDA also issued a Rare Pediatric Disease Priority Review Voucher (PRV), which can be used for future drug applications that would not qualify for a priority review.

Ipsen research and development head Howard Mayer said: “The FDA approval of Sohonos is a breakthrough for the US FOP community.

“For the first time, doctors have an approved medicine available to them, shown to reduce the formation of new, abnormal bone growth, known as heterotopic ossification (HO), which causes debilitating mobility challenges and has a devastating impact on the lives of people with FOP.

“We at Ipsen are sincerely grateful to the FOP community of patients and medical experts, as the first-ever treatment in the US for managing FOP would not be possible without their participation in the clinical trials and ongoing support.”

The FDA approval is based on the efficacy and safety data from the MOVE, a multi-centre, open-label Phase 3 clinical trial in 107 adult and paediatric patients with FOP.

The study compared the patients who received Sohonos capsules with untreated individuals from Ipsen’s global FOP Natural History Study.

According to the study results, the drug effectively reduces annualised heterotopic ossification volume compared with no treatment beyond the standard of care.

Also, the drug showed a well-characterised safety profile, with adverse events consistent with the systemic retinoid class.

The most common adverse reactions include dry skin, lip dryness, alopecia, drug eruption, rash, pruritus, arthralgia, and premature growth plate closure in growing children.

Furthermore, the French biopharmaceutical company is offering a patient support programme to provide eligible individuals in the US with access to Sohonos.