FDA Approves Ipsen Fibrodysplasia Ossificans Progressiva Treatment

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Ipsen’s Sohonos (palovarotene) capsules are designed to reduce new, abnormal bone formation in soft and connective tissues in individuals with fibrodysplasia ossificans progressiva, a rare bone disease.

Ipsen, a French biopharmaceutical company, announced FDA approval of Sohonos (palovarotene) as a treatment for fibrodysplasia ossificans progressiva (FOP) on Aug. 16, 2023. The capsules are indicated for the reduction in volume of new heterotopic ossification (HO), or abnormal bone growth, in adults and pediatric patients aged 8 and older for females (10 and older for males) with FOP. According to a company press release, palovarotene is the first and only treatment that is approved by FDA for FOP.

FOP is estimated to affect approximately 400 individuals in the United States and 900 people globally, according to the release. As the disease progresses with flare-up episodes, it results in HO that severely restricts mobility and function. Palovarotene is an oral medicine that selects for the gamma subtype of retinoic-acid receptors, which help regulate skeletal development and ectopic bone in the retinoid signaling pathway. Ultimately, the treatment is designed to mediate the interaction between the receptors, growth factors, and proteins within this pathway, ultimately reducing abnormal bone formation in FOP.

FDA approval is based on data from the Phase III MOVE trial, a multicenter, open-label trial in 107 adult and pediatric patients. According to a company press release, the study found that palovarotene reduced annualized HO volume by 54% (via a weighted linear mixed effect model) relative to untreated individuals from Ipsen’s global FOP Natural History Study.

“The FDA approval of Sohonos is a breakthrough for the U.S. FOP community. For the first time doctors have an approved medicine available to them, shown to reduce the formation of new, abnormal bone growth… which causes debilitating mobility challenges and has a devastating impact on the lives of people with FOP,” said Howard Mayer, head of Research and Development, Ipsen, in the release. “Development of medicines for rare diseases takes commitment and belief from everyone involved. We at Ipsen are sincerely grateful to the FOP community of patients and medical experts, as the first-ever treatment in the U.S. for managing FOP would not be possible without their participation in the clinical trials and ongoing support.”


“FOP is life-altering to the individuals diagnosed and their families. There’s not a day that goes by where those impacted don’t worry about the debilitating physical pain of muscle that is replaced by bone, another joint locking, or the relentless emotional toll of losing the ability to do an activity they love, or hold a loved one close,” explained Michelle Davis, executive director, International FOP Association, in the release. “The first treatment for FOP has been proven to reduce the volume of new abnormal bone growth, which may result in better health outcomes for people living with FOP.”

Source: Ipsen