PAEDIATRIC JOURNAL CLUB · TRIAL PROTOCOL
OM-85 to prevent readmission in preschool wheeze (ARROW)
Costa-Pinto JC, van Arragon M, Lee KJ, et al; CIRCAN Investigator Group. J Paediatr Child Health. 2026;62:1244-1254. doi:10.1111/jpc.70434. A published protocol for a phase 3 randomised, double-blind, placebo-controlled trial.
FOR PRESCHOOL
WHEEZE
The question that counts
Whether OM-85 can cut admissions is an outcome prioritised by clinicians, policymakers and families. ARROW is the first adequately sized trial to test it.
Why OM-85
OM-85 is an oral bacterial lysate thought to stimulate antiviral immunity and dampen the airway inflammation that drives viral wheeze.
A real-world endpoint
The primary outcome is a hospital admission for wheeze - robust, clinically meaningful, and verified against hospital records rather than caregiver report.
Powered to change practice
Powered to detect a 25% relative reduction in readmission (the minimum the investigators felt would shift practice); the observed placebo-group rate ran around 33%.
No answer yet
This is a protocol. Read it as a heads-up on evidence to come, not a reason to change what you do now.
WHY THIS MATTERS
- Acute wheeze is one of the commonest reasons preschoolers are admitted
- Readmission rates are high - around a third within 12 months in this group
- There is no well-proven preventive that reduces admissions in this age group
- Families and clinicians prioritise fewer admissions as the outcome that counts
- A large, pragmatic Australia and New Zealand trial could directly change practice
STRENGTHS
- The first trial large enough to answer the admission question
- A robust, clinically important primary outcome, verified against hospital records
- A pragmatic, decentralised design that reaches regional and remote families
- Extensive consumer and end-user engagement from the outset
- Over 40 sites across Australia and New Zealand, aiding generalisability
LIMITATIONS
- A protocol only - no efficacy or safety results yet
- Relies on caregivers to give the medication and record data (though admissions are record-verified)
- No biological sampling, so mechanism is not explored in this trial
- The sample size was revised down after a higher-than-expected event rate
- Generalisability beyond Australasia will need confirmation
How to read this
Preschool wheeze is bread-and-butter paediatrics, and the children who keep coming back are a real burden on families and the system. ARROW is testing whether a monthly course of the oral bacterial lysate OM-85 can reduce those readmissions. For now this is a protocol, so nothing changes in clinic: OM-85 is not a standard preventive for preschool wheeze, and management still rests on getting the acute episode right, reviewing inhaler technique and the action plan, considering a preventive trial where the pattern fits, and addressing smoke exposure and other triggers. The value of reading the protocol now is to understand the question and the design, so that when the results land you can judge them quickly. One to watch.
What do you currently offer the preschooler who keeps being readmitted with wheeze?
How convincing is a bacterial lysate mechanism for preventing viral wheeze?
Is a 25% relative reduction in admissions enough to change your practice?
What would you want to see on safety before using OM-85 routinely?
J Paediatr Child Health 2026PAEDIATRICS
Outpatient approaches & toolsRCH GUIDELINES
Acute asthma / wheezeANZCTR
Trial record ACTRN12620001370998
Take-home message: ARROW is a large Australia and New Zealand trial testing whether the oral bacterial lysate OM-85, given 10 days a month for a year, reduces hospital admissions in young children with recurrent preschool wheeze. This is the published protocol, so there are no results yet and nothing changes in practice today - OM-85 is not a standard preventive. It is worth knowing the question and the design now, so the results are easy to judge when they come. One to watch.
For educational purposes only. Journal club appraisal - figures paraphrased from the published trial; read the full article for complete data. Always align practice to your local guidelines.