FDA Approves First Drug to Treat Cushing’s Disease in Horses

November 17, 2011

The Food and Drug Administration announced today the approval of Prascend (pergolide mesylate) for the control of clinical signs associated with Pituitary Pars Intermedia Dysfunction (PPID or Equine Cushing’s disease) in horses. Prascend is the first drug approved for use in horses to treat Cushing’s disease, a common disease of older horses that results in significant morbidity and mortality if left untreated.

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.

Equine Cushing’s disease usually affects horses in their mid-to late-years of life. Diagnosis is made by a veterinarian 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 water-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 6 month field study of 122 horses. 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%) of the 113 evaluable cases were treatment successes.

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

Prascend is manufactured for Boehringer Ingelheim Vetmedica Inc. of St. Joseph, Missouri.