FDA Issues Complete Response Letter for Palovarotene

The FDA has issued a complete response letter (CRL) for Ipsen’s new drug application for palovarotene. It is being studied to reduce new abnormal bone formation in people living with fibrodysplasia ossificans progressiva (FOP), an ultra rare genetic disease that transforms the body’s soft issue into bone.

In October 2022, the FDA had requested additional information on palovarotene clinical trial data, which Ipsen said in a press release is not related to additional efficacy or safety data beyond existing studies. The company plans to respond to the request in the first quarter of 2023 with an expected six-month FDA review cycle. The FDA has not announced a rescheduled date for the Endocrinologic and Metabolic Drugs Advisory Committee meeting for palovarotene. The original advisory committee meeting was scheduled for October 31, 2022.

Howard Mayer, M.D.

“Although this extends the review timeline for palovarotene, we continue to work with the FDA to provide the requested information and believe that investigational palovarotene has the potential to be an innovative treatment to reduce new abnormal bone formation to slow the progression of FOP,” Howard Mayer, M.D., executive vice president and head of research and development for Ipsen, said in the release. “Currently, people living with FOP in the United States have no approved treatment option to slow the progression of the disease and this remains our reason for being steadfast in our pursuit of bringing this potential treatment option for FOP.”

FOP impacts the lives of fewer than an estimated 400 people in the U.S. and 900 people globally. Due to abnormal bone formation, in childhood and early adulthood people living with FOP may lose the permanent ability to move their neck, back, shoulders, chest, legs and arm joints.

Palovarotene is an oral, selective retinoic-acid receptor gamma (RARγ) agonist for the prevention of heterotopic ossification.It is authorized for use in patients in Canada and United Arab Emirates, where it is marketed as Sohonos.