A Double-blind, Placebo-controlled, Parallel-group Study to Evaluate the Safety and Efficacy of Briquilimab in Participants with Allergic Asthma

Inclusion Criteria:

• Men and women 18 to 65 years of age; stable, allergic asthma; history of episodicwheeze and shortness of breath; forced expiratory volume in 1 second (FEV1) atbaseline at least 70% of the predicted value; able to comprehend and follow allrequired study procedures; willing and able to sign an informed consent form;positive methacholine challenge at baseline (concentration of methacholine causing 20% decrease in FEV1 [PC20] PC20 ≤ 16 mg/mL or PD20 equivalent to ≤400µg); andpositive skin-prick test and positive allergen-induced early and late airwaybronchoconstriction to common aeroallergens.

Exclusion Criteria:

• Worsening of asthma or respiratory infection in the preceding 6 weeks; lung diseaseother than allergic asthma; prior treatment with a c-Kit inhibiting therapy;anaphylaxis to any parenterally administered biologics; use of asthma medications (note: intermittent doses of short-acting β2-agonist are allowed once weekly forrelief of symptoms but prophylactic use for exercise is allowed as-needed); pregnantor lactating women; and women actively seeking pregnancy or who are not usingadequate contraception.