Severe equine asthma: does inhaled ciclesonide vs placebo improve lung function and clinical scores? — LIKELY

In horses with severe equine asthma, does inhaled ciclesonide vs placebo improve lung function and clinical scores?

Shelf #814 · gate-verified and displayed under the developer's blinded-trial rule

LIKELY: In Pirie 2021, a prospective multicentre placebo-controlled randomised double-blinded trial in 224 client-owned horses with severe equine asthma, inhaled ciclesonide met the pre-defined success endpoint (30% or greater reduction in weighted clinical score by day 10) in 73.4% (80/109) of horses versus 43.2% (48/111) on placebo (P < 0.0001) - an absolute difference of 30.2 percentage points. Objective lung function agrees under controlled challenge: in Lavoie 2019, a cross-over placebo-controlled blinded randomised experiment, ciclesonide 1687.5 micrograms twice daily for 2 weeks significantly improved pulmonary resistance (2.7 +/- 1.1 to 1.6 +/- 0.8 cm H2O/L/s), pulmonary elastance (5.2 +/- 3.1 to 2.2 +/- 1.3 cm H2O/L) and weighted clinical score (13 +/- 2.9 to 10.8 +/- 4.2), while placebo exerted no significant beneficial effect and ciclesonide at any tested dose did not suppress serum cortisol (systemic dexamethasone did, from day 3). Design class (a): randomisation and blinding are both established by carded records (Pirie 2021: 'placebo-controlled, randomised, double-blinded'; Lavoie 2019: 'Cross-over placebo controlled, blinded, randomised'). The honest limits: the field trial's endpoint is a clinical score with a large placebo response (43.2% met the success definition on placebo, with environmental changes prohibited yet signs varying over time), follow-up is only 10 days, and the lung-function trial used experimentally induced exacerbations in small dose-titration groups (8 horses per study) - that combination is why the stamp is LIKELY and not PROBABLE. Drafted Nov 10, 2026 (VetMed build, topic #814); all figures from abstracts fetched and verified at drafting.

Pirie 2021: inhaled ciclesonide met the success endpoint in 73.4% (80/109) of horses with severe equine asthma vs 43.2% (48/111) on placebo at day 10 (P < 0.0001)

Prospective, multicentre, placebo-controlled, randomised, double-blinded study (record's own wording; publication types include Randomized Controlled Trial, Veterinary)

Who: Horses: 224 client-owned horses with severe equine asthma in a large prospective European clinical trial, randomised 1:1 to ciclesonide inhalation solution (343 micrograms per actuation) or placebo (0 micrograms per actuation), given with a nonpressurised soft-mist inhaler developed for horses at 8 actuations twice daily for the first 5 days and 12 actuations once daily for the following 5 days. The primary outcome was treatment success, defined in advance as a 30% or greater reduction in weighted clinical score (WCS) between day 0 and day 10 (+/-1). Environmental management changes were prohibited during the study.

Result: The treatment success rate in ciclesonide-treated horses was 73.4% (80/109) after 10 (+/-1) days, significantly higher than in the placebo group at 43.2% (48/111; P < 0.0001) - an absolute difference of 30.2 percentage points. Few systemic and local adverse events of ciclesonide were observed, and the authors conclude ciclesonide inhalation effectively reduced the severity of clinical signs in a majority of horses with severe equine asthma and was well tolerated.

Watch out: The endpoint is a weighted clinical score, not a hard outcome, and the placebo success rate was high (43.2%) - the authors note the severity of clinical signs varies over time and a placebo effect was identified despite prohibited environmental changes, which may have contributed in part to improvement in the treated group as well. Follow-up is 10 days only; the record reports success proportions, not mean score changes or lung-function measurements.

Pirie RS, Mueller HW, Engel O, Albrecht B, von Salis-Soglio M. Inhaled ciclesonide is efficacious and well tolerated in the treatment of severe equine asthma in a large prospective European clinical trial. Equine Vet J. 2021;53(6):1094-1104. PMID: 33403727. Registry ID: none in the record. MeSH: Administration, Inhalation · Animals · Asthma*/drug therapy/veterinary · Double-Blind Method · Horse Diseases*/drug therapy · Horses · Pregnenediones* · Prospective Studies · Treatment Outcome

Lavoie 2019: ciclesonide 1687.5 micrograms twice daily significantly improved pulmonary resistance, elastance and clinical score in hay-challenge asthma; placebo did not, and ciclesonide did not suppress cortisol

Cross-over placebo controlled, blinded, randomised experiment (record's own wording)

Who: Horses: 16 horses enrolled in three subsequent dose-titration studies (8 horses per study) with experimentally induced mild to severe airway obstruction by mouldy hay challenge, receiving inhaled ciclesonide for 2 weeks at doses from 450 to 2700 micrograms twice daily or 3712.5 micrograms once daily, with systemic dexamethasone (0.066 mg/kg orally) as positive control and a placebo group also studied. Lung function and clinical scores were performed blindly before and after 7 and 14 days of treatment; serum cortisol was measured before, during and after treatment.

Result: After 7 days, dexamethasone significantly reduced pulmonary resistance (2.5 +/- 0.6 to 1.1 +/- 0.7 cm H2O/L/s), pulmonary elastance (5.0 +/- 2.6 to 1.2 +/- 1.0 cm H2O/L) and weighted clinical score (14.8 +/- 4.7 to 8.0 +/- 4.4). Ciclesonide 1687.5 micrograms twice daily likewise significantly improved pulmonary resistance (2.7 +/- 1.1 to 1.6 +/- 0.8 cm H2O/L/s), pulmonary elastance (5.2 +/- 3.1 to 2.2 +/- 1.3 cm H2O/L) and weighted clinical score (13 +/- 2.9 to 10.8 +/- 4.2). Placebo exerted no significant beneficial effect. Serum cortisol suppression (below 50 nmol/L) occurred systematically with dexamethasone from day 3 to 3 days post treatment, but not with ciclesonide at any tested dose.

Watch out: Experimentally induced exacerbations in small groups (8 horses per dose study) may respond differently from naturally occurring exacerbations, as the authors caution; several doses were tested and only the 1687.5 micrograms twice-daily result is reported with figures in the abstract, so this card supports efficacy at that dose rather than a full dose-response. Lung-function gains were smaller than with systemic dexamethasone on the score measure.

Lavoie JP, Bullone M, Rodrigues N, Germim P, Albrecht B, von Salis-Soglio M. Effect of different doses of inhaled ciclesonide on lung function, clinical signs related to airflow limitation and serum cortisol levels in horses with experimentally induced mild to severe airway obstruction. Equine Vet J. 2019;51(6):779-786. PMID: 30854685. Registry ID: none in the record. MeSH: Administration, Inhalation · Animals · Cross-Over Studies · Dose-Response Relationship, Drug · Glucocorticoids/administration & dosage/therapeutic use* · Horse Diseases/drug therapy* · Horses · Hydrocortisone/blood* · Lung Diseases, Obstructive/chemically induced/drug therapy/veterinary* · Pregnenediones/administration & dosage/therapeutic use*

Synthesis: inhaled ciclesonide improves clinical scores in severe equine asthma in a large double-blinded field trial and improves measured lung function under controlled challenge, without cortisol suppression - LIKELY

Synthesis

Who: Synthesis of the cards above: Pirie 2021 (224 client-owned horses with severe equine asthma, randomised double-blinded placebo-controlled field trial, 10 days) and Lavoie 2019 (16 horses in three dose-titration studies, cross-over placebo-controlled blinded randomised hay-challenge experiment, 2 weeks).

Result: (1) Clinical scores (field, severe asthma): success (30% or greater weighted clinical score reduction) in 73.4% (80/109) on ciclesonide vs 43.2% (48/111) on placebo, an absolute difference of 30.2 percentage points (P < 0.0001). (2) Lung function (challenge model): at 1687.5 micrograms twice daily, pulmonary resistance fell from 2.7 +/- 1.1 to 1.6 +/- 0.8 cm H2O/L/s and elastance from 5.2 +/- 3.1 to 2.2 +/- 1.3 cm H2O/L, with placebo showing no significant benefit. (3) Safety signal in these records: no serum cortisol suppression at any ciclesonide dose, unlike systemic dexamethasone, and few adverse events in the field trial.

Watch out: Both carded programmes come from the product's development setting and the field endpoint is a symptom score with a substantial placebo response; durability beyond 10-14 days, exacerbation prevention, and comparison against other inhaled or systemic corticosteroids are not answered by these records. A separate randomised double-blinded trial in moderate asthma in Thoroughbred racehorses (Sanz 2025) is a different severity population and is not carded on this severe-asthma shelf.

Synthesis of Pirie RS et al. PMID: 33403727; Lavoie JP et al. PMID: 30854685. Registry IDs as on the individual cards.

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