FDA approves Ipsen rare bone disease drug

Aug. 17, 2023

Earlier this week, the FDA signed off on Ipsen's palovarotene capsules for the treatment of fibrodysplasia ossificans progressiva (FOP), a rare bone disease.

The drug, to be sold as Sohonos, is approved as a retinoid designed to decrease the size of newly formed abnormal bone in adults and pediatric patients, aged 8 and older for females and 10 and older for males.

Sohonos is an oral medicine that targets a specific receptor involved in bone development. It reduces abnormal bone growth in FOP, a progressive musculoskeletal condition. FOP affects around 400 individuals in the U.S. and 900 worldwide and is usually managed palliatively, shortening life expectancy to about 56 years. Premature death often results from bone growth around the ribcage, leading to breathing issues, or from falls causing fractures or head injuries.

The drug was initially developed by Canadian biopharma Clementia and was perhaps the most important incentive to Ipsen when it decided to buy all outstanding shares of the company in 2019, looking to bolster its rare disease portfolio. In May 2021, Ipsen confirmed that the FDA had accepted its NDA for the drug, only to announce a few months later that the application had been withdrawn. 

After conversations with the FDA and going through the review process, it was concluded that the agency needed more analysis and data evaluation from Ipsen's phase 3 MOVE and FOP program before moving ahead. Then in December 2022, the drugmaker received a Complete Response letter to its NDA for Sohonos.  

The agency has finally signed off, after reviewing updated safety and efficacy data from the phase 3 MOVE trial which demonstrated that Sohonos effectively lessened abnormal bone growth in FOP patients. In the 18-month trial with 107 participants, the drug led to a 54% reduction in abnormal bone growth volume compared to those not receiving treatment.

Sohonos will be listed for $624,000.