The Food and Drug Administration (FDA) has granted Fast Track designation to BCX9250 for the prevention of heterotopic ossification in patients with fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic connective tissue disorder characterized by an abnormal development of bone in areas outside the normal skeleton. The disorder causes restricted movement and fused joints, leading to deformities, restricted mobility and premature mortality. In all cases of FOP, activating mutations of the ALK-2 gene have been observed and necessary for the disease to occur.

BCX9250 is an investigational activin receptor-like kinase-2 (ALK-2) inhibitor designed to stimulate normal bone growth and renewal. In an experimental model of ALK-2-driven heterotopic ossification in laboratory rats, BCX9250 has been shown to reduce excess bone formation. The investigational treatment was also found to be safe and well tolerated at all doses studied in a phase 1 clinical trial involving healthy participants. 

“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,” said Dr Helen Thackray, chief research and development officer of BioCryst. “With this designation following the EMA’s recent decision to grant PRIME eligibility for BCX9250 in Europe, we believe the nonclinical 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.”


  1. FDA grants Fast Track designation for BioCryst’s ALK-2 inhibitor, BCX9250. News release. BioCryst Pharmaceuticals, Inc. Accessed June 8, 2022.
  2. Our Programs: FOP Program. BioCryst Pharmaceuticals, Inc. Accessed June 8, 2022.