ORAL DESENSITIZATION TO PEANUT USING AR101 PEANUT ORAL IMMUNOTHERAPY IN A ROLL-OVER SAFETY STUDY ARC002

Introduction This phase 2, open-label trial was designed to study the safety and tolerability of long-term AR101 exposure in peanut-allergic subjects. Methods Treatment consisted of continued AR101 maintenance for previously treated PA subjects (group 1) or dose escalation over ∼6 months to 300 mg/day maintenance for placebo crossovers (group 2). After 3 months’ maintenance, all subjects underwent a double-blind, placebo-controlled food challenge (DBPCFC); those who tolerated ≥300 mg peanut protein could elect to continue with AR101 300 mg/day or up-dose to a maximum of 2000 mg/day. Results Forty-seven subjects were enrolled. The median overall exposure to AR101 was 3.0 and 2.3 years in groups 1 (21 subjects) and 2 (26 subjects), respectively. In the DBPCFC, group 1 subjects who continued maintenance treatment (300 mg/day), 95.2% (95% CI: 77.3, 99.2) tolerated 300 mg; 85.7% (95% CI: 65.4, 95.0) tolerated 600 mg; and 66.7% (95% CI: 45.4, 82.8) tolerated 1000 mg as the single highest dose of peanut protein with no more than mild symptoms. Similar efficacy was observed in group 2. Overall, adverse events (AEs) were primarily mild and moderate allergy symptoms, mainly reported in the up-dosing period (group 2 and 2000mg group) and consistent with the expected safety profile of initiating AR101 treatment. AR101 treatment continued to be generally well tolerated for up to 3 years in subjects receiving 300mg dose with higher numbers of AEs reported in subjects receiving 2000 mg/day. Conclusions Long-term treatment with 300mg/day AR101 appears to maintain desensitization and is well tolerated. Higher doses are associated with more AEs.