New Study Challenges the Role of Oral Bacterial Extract in Preventing Asthma in Children
Recent findings from a national clinical trial led by the University of Arizona College of Medicine – Tucson raise questions about the efficacy of using an oral bacterial extract to prevent severe wheezing and respiratory illnesses in young children, which are precursors to asthma.
Published in The Lancet, the ORBEX trial evaluated the preventive potential of OM-85, also known as Broncho-Vaxom®. Dr. Fernando Martinez and Dr. Wayne Morgan led the study, which examined the treatment’s ability to mimic microbial exposure thought to shield against asthma, a concept rooted in the hygiene hypothesis.
The hygiene hypothesis suggests that reduced exposure to microbes in highly sanitized environments may contribute to rising allergic and asthmatic conditions. The researchers at the Asthma and Airway Disease Research Center have studied various early-life exposures, such as daycare and pets, to understand their potential protective effects against asthma.
However, the ORBEX trial’s results showed no significant difference in outcomes between children treated with OM-85 and those given a placebo. “We need to rethink what we have thought until now,” Martinez stated. “There’s no easy solution for these complex diseases that are part of our time.”
Examining the Data
The double-blind study included 822 children aged 6 to 18 months who were at high risk for asthma due to family history or conditions like eczema. The study spanned 11 U.S. locations, with participants receiving either OM-85 or a placebo for two years. Originally planned for one year, the follow-up period extended to three years due to the COVID-19 pandemic temporarily reducing common respiratory virus circulation.
The primary aim was to see if OM-85 could permanently train the immune system to prevent severe wheezing illnesses. Yet, the time to the first severe wheezing episode showed no meaningful difference between OM-85 and placebo groups. Moreover, 21% of children in both groups were diagnosed with clinical asthma by age 6.
New Directions in Asthma Research
According to Morgan, the difference in ORBEX results compared to previous studies might be due to the fact that earlier successful trials involved children with frequent wheezing, not just those at risk. This suggests that OM-85 might be effective only after asthma pathways are active. Future research will explore this hypothesis and alternative delivery methods, such as nasal sprays.
Beyond the hygiene hypothesis, Martinez emphasizes the need to explore other factors influencing asthma susceptibility. These include prenatal factors and epigenetic changes, which can affect gene expression without altering DNA. Such insights could lead to a deeper understanding of immune development and its role in asthma.
“We are left with a big challenge – even greater than before,” Martinez remarked. “This is what science is all about. I still think we will find a way to prevent asthma, but it will take much more understanding.”
The ORBEX trial was funded by the National Heart, Lung, and Blood Institute, with additional support from OM Pharma, which provided the study drug and placebo.
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