Tezepelumab (AMG 157) is a monoclonal antibody that targets thymic stromal lymphopoietin and has shown benefits in treating asthma. We assessed the safety, tolerability, and pharmacokinetics of single‐ascending and multiple‐ascending doses in two randomized, double‐blind, placebo‐controlled phase I studies. Healthy and atopic dermatitis subjects were enrolled in the single‐dose study, and healthy subjects in the multiple‐dose study. Tezepelumab showed linear pharmacokinetics in both healthy and atopic dermatitis subjects. The half‐life after a subcutaneous or intravenous administration ranged from 19.9 to 25.7 days. After multiple doses, the mean area under the curve accumulation ratio was 1.82, 1.64, and 1.59 for the 35 mg, 105 mg, and 210 mg monthly subcutaneous doses, respectively. The mean maximum serum concentration (Cmax) accumulation ratio was 1.59, 2.84, and 6.74 for the 210 mg dose given every 28, 14, and 7 days, respectively. Tezepelumab was well tolerated in both studies with no evidence of immunogenicity.
