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Product Development

FIRST-in Class Therapy with PAX-001


The initial target for humans is PAX-001 to optimize repair of hand flexor tendon injuries, with 100,000 Flexor tendon injuries per year in the US alone. Having already had a pre-IND meeting with the FDA, PAX is completing a GLP toxicology and dose-range finding study, in preparation for filing an IND application anticipated for 1H 2025.

Future conditions for which PAX-001 will be applicable include other tendon injuries (e.g. Achilles tendon and extensor tendon injuries) as well as ligament tears (e.g., Anterior Cruciate Ligament- ACL, and medial collateral ligament- MCL). Just the top 4 tendon and ligament injuries (flexor tendon, extensor tendon, ACL, and Achilles tendon) account for 420,000 injuries a year in the US. Future applications will include administration via injection through the skin when the rupture is incomplete, thus avoiding surgery.


Veterinary applications:

Horses: 30% of thoroughbreds have career-threatening Achilles tendinosis, and up to 20% of horses with Superficial Digital Flexor Tendon injuries need euthanasia on the racetrack.

Dogs: Dogs commonly tear the Cranial Curciate Ligament (the equivalent of the human ACL).  


Goal of PAX-001


We believe that gene therapy is a well-suited strategy for the treatment of tendon injuries due to the anatomic locations and physiologic aspect of the disease with scare vascularity. By delivering the gene for the growth factor to the tendon cells, we will facilitate healing by increasing vessel production and blood supply, which is essential for the healing process. 

One of the most valuable aspects of our therapy is that it is a one-time local injection and not a systemic drug. The doses required are orders of magnitude less than what are used for other indications. In addition, in our animal studies, the transgene expression dissipated after healing was complete.

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