Abstract:TAVO101 is a humanized anti‐human thymic stromal lymphopoietin (TSLP) monoclonal antibody under clinical development for the treatment of atopic dermatitis (AD) and other allergic inflammatory conditions. The crystallizable fragment region of the antibody was engineered for half‐life extension and attenuated effector functions. This Phase 1, double‐blinded, randomized, placebo‐controlled study assessed the safety, tolerability, pharmacokinetics, and immunogenicity of TAVO101 in healthy adult subjects in seven ascending dose cohorts. Subjects received a single intravenous administration of TAVO101 or placebo with a 195‐day follow‐up. TAVO101 was safe and well tolerated. The incidences and severities of treatment‐emergent adverse events were mostly mild and comparable between the active and placebo groups, with no trends of dose relationship. There were no severe adverse events, deaths, or treatment‐related withdrawals. TAVO101 exhibited a linear pharmacokinetic profile, low clearance, and a median elimination half‐life of 67 days in healthy subjects. All TAVO101‐treated subjects tested negative for anti‐drug antibodies. To support development in AD, TAVO101 was studied in an oxazolone‐induced AD model in hTSLP transgenic mice and demonstrated efficacy. This long‐acting anti‐TSLP antibody has the potential for stronger and sustained allergic inflammatory disease control. The results from this study warranted further clinical development of TAVO101 in patients.