#Ipsen #Fibrodysplasia #SoHonos

Groundbreaking Launch of SOHONOS™ in Japan

On July 7, 2026, IPSEN Corporation announced the launch of SOHONOS™ (palovarotene), marking a significant milestone as the very first treatment made available for patients suffering from Fibrodysplasia Ossificans Progressiva (FOP) in Japan. FOP is an exceptionally rare disorder characterized by an abnormal and progressive formation of bone in muscles, tendons, and ligaments. This condition often leads to severe impairments in mobility and a reduced lifespan, posing a significant challenge for those affected.

Understanding Fibrodysplasia Ossificans Progressiva (FOP)

FOP is known for its debilitating effects as it causes soft tissues to convert into bone permanently, which severely restricts everyday activities for patients. Estimates suggest that approximately 60 to 84 individuals are diagnosed with FOP in Japan. As the disease progresses, many patients experience considerable declines in their daily functioning. Particularly concerning is when heterotopic ossification (HO) extends to the thoracic area, leading to respiratory difficulties and impacting survival rates.

The Role of SOHONOS™ in FOP Treatment

SOHONOS™ is a selective agonist of the retinoic acid receptor gamma (RARγ) and works by inhibiting the phosphorylation of Smad1/5/8 through the RARγ pathway. This mechanism disrupts the bone morphogenetic protein (BMP) signaling pathway, thereby reducing cartilage formation and the progression of HO. The drug was first approved for use in Canada under the name