Mass General - Division of Clinical Research

Subjects are eligible to be included in the trial only if all the following criteria apply: - Part 1: Male or female aged 12 through 65 years (inclusive) on the day of enrollment Part 2: Male or female aged 4 through 65 years (inclusive) on the day of enrollment Part 3: Male or female aged 4 through 65 years (inclusive) on the day of randomization - Documented clinical history of an IgE-mediated allergic reaction towards peanut- containing food - Peanut-specific serum IgE ≥ 0.7 kU/L at screening measured at central laboratory - Skin prick test to peanut ≥ 5 mm at screening - Cohorts 1-8: Experience dose-limiting symptoms at the 10 mg, 30 mg or 100 mg challenge dose of peanut protein on screening DBPCFC Cohorts 9-10: Experience dose-limiting symptoms at the 1 mg or 3 mg challenge dose of peanut protein on the screening DBPCFC Part 3: Experience dose-limiting symptoms at the 3 mg, 10 mg, 30 mg or 100 mg challenge dose of peanut protein on screening DBPCFC

Subjects are excluded from the trial if any of the following criteria apply: - Diagnosis or history of eosinophilic esophagitis - Uncontrolled asthma as defined by the Asthma Control Test questionnaire with a score of 19 or below at enrollment (subjects with a diagnosis of asthma only) - All subjects ≥ 5 years old with FEV1 or PEFR < 70% of predicted value at enrollment Subjects 4 years old with a history of recurrent wheeze requiring inhaled corticosteroids for 2 consecutive weeks or more within 3 months prior to enrollment - Up-dosing with any allergy immunotherapy product. Maintenance dose of any subcutaneous immunotherapy product other than peanut is allowed - History of peanut oral immunotherapy within the last 12 months prior to visit 1 - Chronic or acute oral inflammation at enrollment - History of cardiovascular disease, including uncontrolled or inadequately controlled hypertension - Currently using any prohibited medication on the list of prohibited medication - Part 1 and 2: Allergic symptoms in reaction to the placebo part of the screening DBPCFC Part 3: Dose-limiting allergic symptoms in reaction to the placebo part of the screening DBPCFC - History of severe or life-threatening episode of anaphylaxis or anaphylactic shock within 60 days of the screening DBPCFC - Part 1 and 2: Asthma according to below criteria: - Severe asthma as per the current GINA guidelines - Uncontrolled or poorly controlled asthma as per the current GINA guidelines - Asthma that requires more than a daily dose above 800 µg of inhaled budesonide (or clinically comparable inhaled corticosteroids) - History of 2 or more systemic corticosteroid courses within 6 months of screening - Prior intubation/mechanical ventilation for asthma - Emergency room visit or hospitalization for asthma in the 12 months prior to screening - Any history of a life-threatening asthma attack - Part 3: Asthma fulfilling the below criteria: - History of 2 or more systemic corticosteroid courses within 6 months of screening - Prior intubation/mechanical ventilation for asthma - Emergency room visit or hospitalization for asthma in the 12 months prior to screening - Any history of a life-threatening asthma attack - (US only) Severe asthma as per the current GINA guidelines - (US only) Uncontrolled or poorly controlled asthma as per the current GINA guidelines - (US only) Asthma that requires more than a daily maintenance dose above 800 μg of inhaled budesonide (or clinically comparable inhaled corticosteroids)