Bacterial lysate does little to prevent wheezing lower respiratory tract illness in children

Oral administration of the bacterial lysate OM-85 in early life does not appear to reduce the incidence of wheezing lower respiratory tract illness during the preschool years, according to the parallel-arm, double-blind, placebo-controlled ORBEX trial.

ORBEX included 822 children aged 6–18 months (mean age 11.8 months, 59.9 percent male) who were at increased risk for asthma due to atopic dermatitis, parental asthma, or asthma in a blood sibling aged ≥4 years.

The children were randomly assigned to receive OM-85 3.5 mg (n=411) or placebo (n=411). Treatment was administered orally for 10 days each month for 24 months. All children received usual treatment for wheezing illness as per US guidelines and were followed for an additional 36 months to evaluate outcomes while they were off the study drug.

The primary outcome was first wheezing lower respiratory tract illness during the 36-month observation period off the study drug.

A total of 681 children completed the 24-month treatment period, and 596 completed the 36-month observation period. The primary outcome occurred in 21 percent of children in the OM-85 group vs 18 percent of those in the placebo group. There was no significant difference in time to first wheezing lower respiratory tract illness between the two treatment groups (hazard ratio, 1.16, 95 percent confidence interval, 0.82–1.64).

The frequency of adverse events including fever, cough, and colds did not significantly differ between the OM-85 and placebo groups.

The findings demonstrate that bacterial lysates are not efficacious for the primary prevention of asthma-like symptoms during the preschool years.