This is a Phase Id, randomised, double-blind, placebo-controlled, multiple-dose, bridging study conducted at a single Phase I clinical research unit in Australia. The study is designed to evaluate the pharmacokinetics, safety, tolerability, and immunogenicity of XKH001 following repeated subcutaneous administration in healthy adult Caucasian participants, and to provide an ethnic-bridging pharmacokinetic comparison with the prior Phase I dataset in Chinese participants, required for XKH001's global development programme.