Clinical Data

• 457 patients (78%) were reactors, who experienced dose-limiting symptoms in the DBPCFC at or before the 100 mg dose (median = 44 mg cumulative amount of peanut protein); 116 subjects (20%) were “non-reactors” who consumed all 144 mg in the DBPCFC with only mild symptoms or no symptoms at all; 10 subjects (2%) reacted to placebo
• Reactors demonstrated higher baseline peanut-specific IgE (psIgE) and Ara h2-specific IgE levels and larger peanut skin prick test (SPT) wheal diameters than non-reactors, and psIgE appeared to provide the greatest utility to discriminate between reactors and non-reactors
• The median psIgE in reactors was 70.2 kUA/L, compared with 5.3 kUA/L in non-reactors (a threshold psIgE of 19.25 kUA/L showed the greatest sensitivity and specificity for predicting reactors)
• Sensitivity to peanut and severity of symptoms during screening DBPCFCs were not closely linked, and neither was associated with baseline immune parameters or age

“In general, our findings build on the published literature and highlight the clinical and immunologic heterogeneity among patients with peanut allergy,” said Dr. Adelman. “More specifically, insights on our PALISADE screening population are helping to guide our clinical development strategy and design of future AR101 clinical trials. In our PALISADE screening analysis, we saw that psIgE was a valuable predictor of whether or not patients would react at or before the 100 mg dose of peanut protein. For our upcoming RAMSES trial, entry will not require a food challenge but will be based on stringent enrollment criteria to ensure that patients are peanut allergic, including a clinical history, positive skin prick test and elevated peanut-specific IgE.”Also at the AAAAI meeting, Blake Rust, Ph.D., and Erik Wambre, Ph.D., of the Benaroya Research Institute at Virginia Mason (BRI) presented data on peanut-specific effector and regulatory T cells in a blinded subset of samples from patients screened for PALISADE. Key findings from this work include:

• Percent of activated CD4+ effector T cells were significantly higher after individuals underwent the DBPCFC as compared to their pre-challenge levels
• At baseline, peanut-allergic individuals exhibit higher frequency of peanut-specific effector T cells relative to DBPCFC non-reactors. Peanut-allergic individuals exhibit low frequencies of peanut-specific regulatory T cells at baseline, but higher than those seen in DBPCFC non-reactors
• Within the group of patients who reacted to the DBPCFC, two distinct immunophenotypes were observed as defined by mutually exclusive CRTH2 and CCR6 expression