Navicular syndrome, a disease of the horse’s foot disease that causes lameness and loss of performance, has been thrown into the spotlight recently with the U.S. Food and Drug Administration’s (FDA) approval of a new treatment for the disease: tiludronate disodium (trade name Tildren). And with any new drug comes a slew of efficacy studies.

Kent Allen, DVM, of Virginia Equine Imaging, in The Plains, described several of these studies during the 2014 American Association of Equine Practitioners (AAEP) Convention, held Dec. 6-10 in Salt Lake City, Utah. As a part of the FDA approval process, Tildren manufacturer CEVA Animal Health conducted the research on horses treated with tiludronate disodium to manage navicular syndrome.

The progressive degenerative disease commonly causes bilateral lameness in the front feet, and in many cases there’s evidence of abnormal bone remodeling of the distal sesamoid (navicular bone). The treatment is designed to interrupt this process and ameliorate clinical signs.

Veterinarians at 12 equine hospitals within the United States conducted the study. On clinical exam the horses were Grade 2 or 3 lame (on a scale of 5), and clinicians ruled out all other lameness issues. Allen said they diagnosed the horses with navicular syndrome based on lameness exam, radiographs, and MRI evaluation showing primary bone lesions.

The study included 181 horses–119 treated with tiludronate and 62 with a placebo. The horses received no other drugs at the time of tiludronate treatment. Farriers performed corrective shoeing on all the horses (treated and placebo to standardize breakover, hoof-pastern angle, pa