EquineReview

Ciclesonide is a glucocorticoid prodrug that is registered for treatment of allergic rhinitis and asthma in humans. It is de-esterified in the lungs to desisobutyryl-ciclesonide, which has a 12 times higher binding affinity for glucocorticoid receptors than dexamethasone. Inhaled corticosteroids are desirable in treating equine asthma as they lower the potential for systemic side effects.

Pirie et al's (2021) study hypothesis was that inhaled ciclesonide, with a novel inhalation technology (Aservo, Equihaler), would improve clinical signs of asthma compared with a placebo, and would have a good safety profile. A multicentre prospective randomised double-blinded clinical trial was performed at 24 separate sites, using client owned horses that had moderate to severe equine asthma. Horses received inhaled ciclesonide or an inhaled placebo solution.

Asthma was assessed using a previously described scoring system with 224 horses enrolled. Primary analysis revealed a treatment response rate of 73.4%, compared with 43.2% for the placebo group. The reduction in score was greater in horses with severe clinical signs at the time of enrolment, compared with horses with moderate clinical signs. There was no such difference in the placebo group. The Equihaler® was well tolerated. The number of adverse effects was low and equally distributed between groups. The authors concluded that the treatment was efficacious and safe.