Investigational Therapy STMC-103H May Protect At-Risk Infants Against Development of Atopic Disease

STMC-103H (Siolta Therapeutics), an investigational live biotherapeutic, may help protect at-risk infants from developing atopic disease when treatment is completed, according to data presented at the 2026 American Academy of Allergy, Asthma & Immunology Annual Meeting in Philadelphia, Pennsylvania. The abstract, published simultaneously in the Journal of Allergy and Clinical Immunology, suggests that STMC-103H may be a potential early-life intervention for infants who are more likely to develop atopic dermatitis (AD) or food allergy.¹

Atopic diseases affect more than 20% of US infants and children, with higher observed rates in at-risk individuals who have a familial incidence of atopic disease. Development of atopic disease can result in chronic and long-standing symptoms, impaired quality of life, and potentially severe comorbidities and complications, including hospitalization and death. Currently, there are no approved therapies that can reduce the development of these chronic conditions; only treatments that manage symptoms after the disease has developed are available.²

STMC-103H supports the infant microbiome in a manner that promotes a healthy immune system early in life. The agent contains a defined set of beneficial bacterial strains that are naturally found in healthy infants and that are intended to work synergistically over the first year of life to prevent the development of atopic diseases, such as food allergies and AD. In infants and children, the development of atopic disease typically follows a progression—the “atopic march”—which often begins with AD and food allergy, followed by asthma and allergic rhinitis. STMC-103H aims to reduce immune dysregulation before symptoms appear.²

The safety, tolerability, and preliminary clinical efficacy of STMC-103H were evaluated in ADORED (NCT05003804), a randomized, double-blind, placebo-controlled, proof-of-concept phase 1b/2 trial. Parts A1 and A2 of the trial enrolled at-risk children (aged 1 year to < 6 years) and infants (aged 28 days to < 12 months) to evaluate safety and tolerability following 28 days of treatment with STMC-103H or placebo and 28 days of follow-up, and part B—the current analysis—enrolled newborns aged 0 to 14 days who were at risk for the development of AD based on a positive family history of atopic disease in a biological parent and/or full sibling.³

The infants were randomly assigned and stratified by delivery mode and feeding method to receive STMC-103H or placebo orally once daily for 336 days. Following the treatment period, they were monitored for an additional 336 days. The primary efficacy end point was physician-diagnosed AD at the end of treatment. Frequency of adverse events (AEs) was also assessed.^1,3

The findings indicated that infants who completed the full duration of STMC-103H treatment demonstrated an approximate 64% reduction in the risk of developing AD compared with placebo (23.3% vs 43.1%; OR, 0.36; 90% CI, 0.20-0.66; unadjusted P = .005) at the end of treatment. Additionally, STMC-103H reduced the risk of development of physician-diagnosed food allergy by 77% (4.7 vs 16.7%; OR, 0.23; 90% CI, 0.09-0.63; unadjusted P = .02) and time to AD diagnosis (unadjusted P = .01) in subjects who completed treatment as planned and total serum IgE (unadjusted P = .03).¹

The authors wrote that, when all infants randomly assigned treatment were included in the analysis, the results did not reach significance. Of note, STMC-103H was well tolerated with no differences in serious AEs or AEs of special interest.¹ The findings support the need for further investigation in larger, confirmatory trials, the authors concluded.¹

REFERENCES

1. O’Sullivan M, Vickery B, Varshney P, et al. STMC-103H reduces risk of atopic dermatitis and food allergy in at-risk infants: results of the phase 1b/2 randomized, double-blind, placebo-controlled ADORED trial. J Allergy Clin Immunol. 2026;157(suppl 2):AB423. doi:10.1016/j.jaci.2025.12.938

2. Siolta Therapeutics reports positive phase 2 results from the ADORED study. News release. Siolta Therapeutics. November 17, 2025. Accessed February 27, 2026. https://www.prnewswire.com/news-releases/siolta-therapeutics-reports-positive-phase-2-results-from-the-adored-study-302616190.html

3. Allergic Disease Onset Prevention Study (adored). ClinicalTrials.gov. Updated November 20, 2025. Accessed February 27, 2026. https://clinicaltrials.gov/study/NCT05003804