FDA okays first veterinary drug to treat Cushing's disease in horses

FDA okays first veterinary drug to treat Cushing's disease in horses

Nov 17, 2011
By dvm360.com staff
Rockville, Md. -- The Food and Drug Administration (FDA) just approved the veterinary drug Prascend (pergolide mesylate for the control of clinical signs associated with Pituitary Pars Intermedia Dysfunction (PPID or Equine Cushing's disease) in horses.

Prascend, from St. Joseph, Mo.-based Boehringer Ingelheim Vetmedica, is the first drug approved for use in horses to treat Cushing's disease, which is considered a common disease of older horses that results in significant morbidity and mortality if left untreated, according to FDA.

"Pergolide mesylate is a dopamine agonist that is believed to work by stimulating dopamine receptors in horses with PPID. It has been shown to decrease the plasma levels of adrenocorticotropic hormone (ACTH), melanocyte stimulating hormone (MSH) and other pro-opiomelanocortin peptides," FDA says.

Equine Cushing's disease usually affects horses in their mid-to late-years of life. Veterinarians typically diagnose the disease using a combination of clinical findings and diagnostic testing. Signs of the equine disease include a coat of long curly hair that does not shed properly, excessive drinking and urination, abnormal fat distribution, muscle loss, excessive sweating, general malaise, chronic laminitis and a compromised immune system (which can lead to respiratory ailments, skin infections, hoof abscesses and tooth infections).

Safety and effectiveness of Prascend was supported by a six-month field study of 122 horses, FDA reports. Success was measured by improvements in both endocrinology testing (ACTH test) and clinical signs related to PPID (abnormal hair growth and shedding, excessive sweating, urination and water-drinking, abnormal fat distribution and/or muscle wasting). Based on endocrine testing and investigators' clinical assessment scores, 86 (76.1 percent) of the 113 evaluable cases were considered treatment successes, FDA says.

The most common adverse effects seen were loss of appetite, lameness, diarrhea, colic and lethargy.