FDA Approves First EPM Treatment

The Food and Drug Administration (FDA) has approved the first drug to treat equine protozoal myeloencephalitis (EPM) in horses. Bayer Animal Health of Shawnee Mission, Kan., is the sponsor of the drug ponazuril, which will have the trade name Marquis.

EPM is a neurological disease caused by the single-celled protozoan parasite Sarcocystis neurona, which is widespread in North America, South America, and Canada. EPM is the leading cause of neurological disease in horses in the United States, according to industry experts. FDA expedited the approval process for ponazuril, stating that it "may help reduce the suffering and death associated with EPM, and because there is no other approved therapeutic for treating this devastating disease."

In clinical efficacy trials conducted at equine referral clinics across the country, Marquis proved effective at the recommended dose level, offering clinical improvement of at least one grade (on a 0-5 scale) within three months post-treatment. According to Bayer, Marquis should effectively clear the horse of S. neurona, but might have no effect on the pre-existing damage caused by the parasite.

"EPM is a debilitating and often fatal disease," said Kenton Morgan, DVM, Senior Technical Services Veterinarian with Bayer. "Accurate diagnosis can be challenging even for the most experienced clinicians. Until now, current therapies were not approved for the treatment of EPM, and some of these treatments have legitimate safety issues. Marquis will offer the veterinarian and horse owner a product that is safe, efficacious, and convenient."

The EPM treatment is supplied as an oral paste given once a day at the dose of 5 mg/kg for 28 days in adult horses. It will be available by prescription only from a licensed veterinarian, and it should be available in late August.

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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