The Risk Reduction of Accidental Exposure-Related Systemic Allergic Reactions Extrapolated Based on Food Challenge Data After 1 Year of Peanut Oral Immunotherapy
Advances in Therapy, 2021
Introduction
The phase 3 trial PALISADE, comparing peanut (Arachis hypogaea) allergen powder-dnfp (PTAH) oral immunotherapy versus placebo in peanut-allergic children, reported that a significantly higher percentage of PTAH-treated participants tolerated higher doses of peanut protein after 1 year of treatment. This study used PALISADE data to estimate the reduction in the risk of systemic allergic reaction (SAR) after accidental exposure following 1 year of PTAH treatment.
Methods
Participants (aged 4-17 years) enrolled in PALISADE were included. Parametric interval-censoring survival analysis with the maximum likelihood estimation was used to construct a real-world distribution of peanut protein exposure using lifetime SAR history and highest tolerated dose (HTD) from a double-blind, placebo-controlled food challenge conducted at baseline. The SAR risk reduction was extrapolated using the exposure distribution and the HTD were collected at baseline and trial exit for PTAH- and placebo-treated participants.
Results
Assuming a maximum peanut protein intake of 1500 mg, participants were estimated to have < 1% probability of ingesting > 0.01 mg during daily life. The mean annual SAR risk at trial entry was 9.25-9.98%. At trial exit, the relative SAR risk reduction following accidental exposure was 94.9% for PTAH versus 6.4% for placebo. For PTAH-treated participants with exit HTD of 600 or 1000 mg without dose-limiting symptoms, the SAR risk reduction increased to 97.2%. The result was consistent in the sensitivity analysis across different parametric distributions.
Conclusion
Oral immunotherapy with PTAH is expected to result in a substantially greater reduction in risk of SAR following accidental exposure compared to placebo among children with peanut allergy.
Authors
Yu S, Smith A, Hass S, Wu E, Chai X, Zhou J, Ayyagari R, Liu JS, Robison D, Donelson SM, Tilles S