Threshold dose for peanut: risk characterization based upon published results from challenges of peanut-allergic individuals.

Population thresholds for peanut are unknown. However, lowest- and no-observed adverse effect levels (LOAELs and NOAELs) are published for an unknown number of peanut-allergic individuals. Publications were screened for LOAELs and NOAELs from blinded, low-dose oral challenges. Data were obtained from 185 peanut-allergic individuals (12 publications). Data were analyzed by interval-censoring survival analysis and three probability distribution models fitted to it (Log-Normal, Log-Logistic, and Weibull) to estimate the ED(10). All three models described the data well and provided ED(10)'s in close agreement: 17.6, 17.0, and 14.6 mg of whole peanut for the Log-Normal, Log-Logistic, and Weibull models, respectively. The 95% lower confidence intervals for the ED(10)'s were 9.2, 8.1, and 6.0mg of whole peanut for the Log-Normal, Log-Logistic, and Weibull models, respectively. The modeling of individual NOAELs and LOAELs identified from three different types of published studies - diagnostic series, threshold studies, and immunotherapy trials - yielded significantly different whole peanut ED(10)'s of 11.9 mg for threshold studies, 18.0mg for diagnostic series and 65.5mg for immunotherapy trials; patient selection and other biases may have influenced the estimates. These data and risk assessment models provide the type of information that is necessary to establish regulatory thresholds for peanut.