Pilot Study to Evaluate the Effect of Ketotifen on the Adverse Events Associated With Peanut Desensitization

The development of a safe oral peanut challenge procedure permits patients that do not have severe life threatening allergic reactions, to be safely desensitized with the ability to maintain peanut tolerance . The peanut desensitization procedure is however associated with unpleasant allergic side effects mainly gastrointestinal and cutaneous manifestations. The use of premedication drugs may lessen these side effects and facilitate the peanut desensitization procedure. Ketotifen is a fast acting, noncompetitive, H1-receptor blocker (antihistamine/inverse agonist) that also inhibits the release of mediators from mast cells involved in hypersensitivity reactions. The study will enroll 6 (4 in the peanut treatment group, 2 in the control group) children with a known history of peanut allergies. The treated subjects will be randomized in a 2:1 ratio into either a pre-treatment group (final dose of 2 mg bid ketotifen) or a control group. All subjects will undergo a one-day peanut desensitization protocol designed to enable the subject to tolerate 50 mg of peanut flour (initial escalation phase). After the initial escalation day achieving up to 50 mg of peanut flour, the dosing build-up will occur every two weeks through 44 weeks. Subjects will ingest the 50mg and increased doses of peanut flour at home (every day for 2 weeks) between each dose escalation. The target dose is 8000 mg of peanut flour. A maintenance dose will be given for 4 weeks following the last (highest dose) visit.