FDA Grants Fast Track Designation to BioCryst’s ALK-2 Inhibitor for Rare Bone Disease

Rare Daily Staff

The U.S. Food and Drug Administration granted Fast Track designation to BioCryst’s BCX9250 for the prevention of heterotopic ossification in patients with fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare, severely disabling genetic disorder characterized by heterotopic ossification (HO), or the irregular formation of bone outside the normal skeleton. HO can occur in muscles, tendons, ligaments, and other connective tissues. Patients with FOP become bound by this irregular ossification over time, with restricted movement and fused joints, resulting in deformities, restricted mobility, and premature mortality.

BCX9250 is designed to inhibit the ALK-2 enzyme, which is a part of the normal signaling pathway for bone formation and responds to binding its specific ligands (bone morphogenic proteins, BMPs) by stimulating normal bone growth and renewal in healthy children and adults. Specific activating mutations of the ALK-2 gene are seen in all cases of FOP. An activating mutation in ALK-2 is necessary for the disease to occur, making the ALK-2 enzyme an ideal drug target for treatment of FOP.

In a phase 1 clinical trial in healthy subjects, BCX9250 was safe and well tolerated at all doses studied, with linear and dose-proportional exposure supporting the potential for once-daily dosing.

“We are pleased with the FDA’s decision to grant Fast Track designation to BCX9250, as there is a significant unmet need among patients living with FOP. With this designation following the EMA’s recent decision to grant PRIME eligibility for BCX9250 in Europe, we believe the non-clinical data and the first-in-human phase 1 safety, tolerability and pharmacokinetics study in healthy subjects support the potential of our ALK-2 inhibitor program to be a meaningful therapeutic advance for the FOP community,” said Helen Thackray, chief research and development officer of BioCryst.

The purpose of the FDA Fast Track designation is to get important new drugs to patients earlier by facilitating the development, and expediting the review, of drugs to treat serious conditions and fill an unmet medical need. Companies that receive this designation are eligible for benefits including more frequent meetings with and written communication from the FDA, eligibility for accelerated approval and priority review, if relevant criteria are met, and rolling review of the new drug application (NDA).

Photo: Helen Thackray, chief research and development officer of BioCryst