Rare Daily Staff

The U.S. Food and Drug Administration granted Rare Pediatric Disease designation to Clementia Pharmaceuticals’ palovarotene for the treatment of fibrodysplasia ossificans, a progressive, rare, and severely disabling disorder.

Fibrodysplasia ossificans progressive (FOP) is characterized by heterotopic ossification—bone that forms outside the normal skeleton, in muscles, tendons, or soft tissue. In FOP, this bone growth progressively restricts movement by locking joints, leading to a cumulative loss of function, progressive disability, and increased risk of early death. FOP is caused by a mutation in the ACVR1 gene, resulting in excess signaling in the bone morphogenetic pathway, a key pathway controlling bone growth and development, by way of both ligand-dependent and independent mechanisms. There are currently no approved treatments for the condition.

Palovarotene is being developed as a potential treatment for FOP and multiple osteochondromas (MO), as well as other diseases.

Palovarotene has received Orphan Drug status for FOP and MO from the FDA and the European Medicines Agency. In addition, palovarotene has been granted Fast Track and Breakthrough Therapy designations for FOP from the FDA.

“The receipt of this designation highlights the urgent need for a treatment for people with FOP,” said Clarissa Desjardins, founder and CEO of Clementia. “The entire Clementia team is working towards an NDA submission in the second half of 2019 in hopes of achieving our first regulatory approval, an important step toward achieving our mission of bringing innovative and effective treatments to individuals who currently have none.”

In October 2018, based on a meeting with the FDA, Clementia announced that the agency was supportive of the company’s plan to submit a New Drug application for palovarotene for the prevention of heterotopic ossification associated with flare up symptoms in patients with FOP. The FDA based its assessment on the efficacy and safety data generated in the completed phase 2 clinical program. The company expects to submit an application to the FDA for approval of the drug in the second half of 2019. If approved, Clementia expects a first commercial launch for palovarotene in 2020.

The FDA grants Rare Pediatric Disease designation for serious or life-threatening diseases with manifestations in individuals aged from birth to 18 years, including access to the FDA’s expedited review and approval process. The designation makes palovarotene eligible for a Rare Pediatric Disease Priority Review voucher upon approval of the therapy by the FDA. 

The vouchers can be used to reduce the time of an FDA new drug approval review to six months from ten months. The vouchers are potentially lucrative because they are transferable. Most recently, Ultragenyx and Kyowa Hakko Kirin sold their Priority Review voucher for $80.6 million.

Photo: Clarissa Desjardins, founder and CEO of Clementia