Tezepelumab

Participants underwent allergen inhalation challenge on study days 42 and 84 to induce airway bronchoconstriction (measured by a fall in FEV1). FEV1 was measured prior to the challenge and between 3 to 7 hours post allergen challenge to assess late asthmatic response (LAR). The percent change in FEV1 from pre-challenge was calculated to each time point between 3 to 7 hours post challenge. The maximum percent decrease in FEV1 from pre-allergen challenge is the percent change in FEV1 representing the largest percentage decrease (or minimum percentage increase) from pre-allergen challenge FEV1 during late (3-7 hour) asthmatic response time frame.

Participants underwent allergen inhalation challenge on study days 42 and 84 to induce airway bronchoconstriction. FEV1 was measured prior to the challenge and between 3 to 7 hours post challenge to assess late asthmatic response (LAR). The percent change in FEV1 from pre-challenge was calculated to each time point between 3 to 7 hours post challenge. The area under the curve for the percent change at each time point was calculated using the linear trapezoidal rule, then time adjusted by dividing by the length of time over which the AUC was calculated.

Adverse events (AEs) include any untoward medical occurrence in a trial participant administered a study drug and does not necessarily have a causal relationship with this treatment. AEs include worsening of a pre-existing medical condition and laboratory value changes requiring therapy or adjustment in prior therapy. AEs were assessed for severity according to the Common Terminology Criteria for Adverse Events (CTCAE), Version 3, where Grade 1 = Mild AE, Grade 2 = Moderate AE, Grade 3 = severe AE, Grade 4 = life-threatening AE and Grade 5 = death due to AE. Relationship to study treatment was determined by the investigator. A serious adverse event (SAE) is defined as an AE that met 1 or more of below criteria: * was fatal; * was life threatening; * required in-patient hospitalization or prolongation of existing hospitalization; * resulted in persistent or significant disability/incapacity; * was a congenital anomaly/birth defect; * other significant medical hazard.

All study samples (tezepelumab and placebo) were tested using an electrochemiluminescence (ECL) based immunoassay to detect and confirm the presence of antibodies capable of binding to tezepelumab. Samples identified as positive in the immunoassay were tested in a receptor-binding ECL-based assay to detect neutralizing or inhibitory effects toward tezepelumab. The number of participants with positive anti-tezepelumab binding antibodies / neutralizing antibodies at any time post-baseline with a negative or no result at baseline is reported.

Adverse events (AEs) include any untoward medical occurrence in a trial participant administered a study drug and does not necessarily have a causal relationship with this treatment. AEs include worsening of a pre-existing medical condition and laboratory value changes requiring therapy or adjustment in prior therapy. AEs were assessed for severity according to the Common Terminology Criteria for Adverse Events (CTCAE), Version 3, where Grade 1 = Mild AE, Grade 2 = Moderate AE, Grade 3 = severe AE, Grade 4 = life-threatening AE and Grade 5 = death due to AE. Relationship to study treatment was determined by the investigator. A serious adverse event (SAE) is defined as an AE that met 1 or more of below criteria: * was fatal; * was life threatening; * required in-patient hospitalization or prolongation of existing hospitalization; * resulted in persistent or significant disability/incapacity; * was a congenital anomaly/birth defect; * other significant medical hazard.

All study samples (tezepelumab and placebo) were tested using an electrochemiluminescence (ECL) based immunoassay to detect and confirm the presence of antibodies capable of binding to tezepelumab. Samples identified as positive in the immunoassay were tested in a receptor-binding ECL-based assay to detect neutralizing or inhibitory effects toward tezepelumab. The number of participants with positive anti-tezepelumab binding antibodies / neutralizing antibodies at any time post-baseline with a negative or no result at baseline is reported.