In a landmark decision for rare disease treatment, Health Canada has approved Sohonos (palovarotene) as the first therapeutic option for patients with fibrodysplasia ossificans progressiva (FOP), an ultra-rare genetic disorder. The approval represents a significant breakthrough in treating this devastating condition that causes soft tissues to progressively transform into bone-like structures.
The oral selective retinoic-acid receptor gamma (RARγ) agonist has been authorized for both chronic use and flare-up treatment in adults and children, with age restrictions of 8 years and above for females and 10 years and above for males. The drug's primary function is to reduce the formation of new heterotopic ossification, the abnormal bone formation characteristic of FOP.
Regulatory Journey and Clinical Development
The Canadian approval comes after a series of regulatory challenges for Ipsen, particularly in the United States. The company was forced to withdraw its marketing application with the FDA in summer 2022 following requests for additional phase 3 trial data. Earlier setbacks included a failed futility test in a pivotal trial and a partial clinical hold by the FDA due to safety concerns.
Dr. Howard Mayer, Head of R&D at Ipsen, emphasized the significance of this approval: "FOP is a progressive and debilitating condition which has such a profound impact on patients, and their families. Until today, there was no approved medicine, and we are proud to bring this important new medicine to the FOP community."
Market Impact and Competition
The approval validates Ipsen's $1.3 billion acquisition of Clementia Pharma in 2019, which brought palovarotene into their portfolio. This regulatory success gives Ipsen a competitive advantage in the FOP treatment landscape, particularly over Regeneron, their main rival in this space.
Regeneron's competing drug candidate, garetosmab, has faced its own challenges. Despite promising phase 2 results in 2020, the antibody-based therapy was placed on clinical hold by the FDA following patient fatalities in their trial program. Regeneron has since terminated their phase 2 study and announced plans to initiate a new phase 3 study.
Strategic Portfolio Development
Ipsen's commitment to FOP treatment extends beyond Sohonos. The company has strengthened its position in this therapeutic area through a $535 million agreement with Blueprint in 2019 for BLU-782, an ALK2 inhibitor. This strategic investment is particularly relevant given that FOP is caused by mutations in the ALK2 gene, also known as ACVR1.
The company has indicated plans to refile for approval in the United States during the first half of this year, potentially expanding access to this groundbreaking treatment for FOP patients in other markets.
