This is a multicenter, randomized, double-masked, placebo-controlled Phase 3 study to evaluate the efficacy, safety, immunogenicity, and population pharmacokinetic (PopPK) characteristics of KHN939 in Chinese patients with moderate-to-severe active thyroid eye disease (TED). Approximately 60 participants who meet the study eligibility criteria will be randomized in a 2:1 ratio (stratified by smoking status) to receive 8 infusions of KHN939 or placebo q3W.
Aged 18-70 years (inclusive) at the time of signing the informed consent form (ICF), male or female
Weight between 45 kg and 100 kg
Proptosis ≥18 mm, accompanied by at least one of the following: (a) eyelid retraction ≥2 mm; (b) moderate to severe soft tissue involvement; (c) intermittent or continuous diplopia
CAS ≥ 3 points
Known hypersensitivity to any component of the study drug formulation, or prior hypersensitivity to any monoclonal antibodies
Proptosis at Day 1 (pre-dose) that has decreased by ≥2 mm relative to screening
CAS at Day 1 (pre-dose) that has decreased by ≥2 points relative to screening
Prior or investigator-assessed diagnosis of dysthyroid optic neuropathy (DON) at screening