Background: Sustained unresponsiveness (SU) remains a major challenge for peanut OIT. The short chain fatty acid (SCFA) butyrate has the potential to upregulate regulatory T cells (Tregs) to improve long term tolerance. We conducted a superiority randomised controlled trial to assess the efficacy and safety of the addition of daily oral butyrate to peanut OIT.
Methods: Peanut allergic children (aged 10-16 years) were recruited in a single-centre randomised double-blind placebo-controlled trial and randomised 2:2:1 to receive 12 months daily peanut OIT with HAMSB (OIT + butyrate), peanut OIT with LAMS (OIT + placebo) or no OIT (control) following an entry DBPCFC. Allocation of HAMSB and LAMS was blinded. Peanut OIT was open. Exit DBPCFC was performed after at least 6 weeks of treatment cessation. The primary outcome was the proportion of participants who tolerated ≥ 1000 mg of peanut protein (cumulative dose 1449 mg) at exit DBPCFC. Adverse events and compliance were recorded. Blood Treg responses and stool SCFA analysis were performed.
Results: A total of 65 participants were enrolled (male 57%, median age 12 years). Of these 26 participants received OIT + butyrate, 26 received OIT + placebo, and 13 received standard care with no OIT (control). After 6 weeks of treatment cessation, 73% (19/26) of OIT + butyrate, 69% (18/26) of OIT + placebo (OR 95% CI = 1.21 (0.36-4.0) for OIT + butyrate relative to OIT + placebo, p = 0.76) and 0% (0/13) of the control group tolerated at least 1000 mg (cumulative dose 1449 mg) of peanut protein. The most common adverse events observed in OIT + butyrate and OIT + placebo were gastrointestinal related (73%). Treatment-related anaphylaxis occurred in eight participants; four in each OIT group (15%). There was no statistically significant difference in AE rate between OIT + butyrate and OIT + placebo.
Interpretation: In a first in food allergy clinical trial setting, the addition of oral butyrate to peanut OIT was well tolerated but did not enhance SU rate in our cohort.
Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR) - ACTRN12617000914369; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12617000914369; Trial was registered on 22 June 2017.
Keywords: butyrate; oral tolerance; peanut oral immunotherapy; short chain fatty acid; sustained unresponsiveness.
© 2025 John Wiley & Sons Ltd.