RecruitingPhase 1Drug trialClinical Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of HT31-1 for Treating ARDSThis Phase 1/2A, randomized, double-blind study will evaluate the safety, tolerability, and pharmacokinetics (PK) of HT31-1 (hCitH3-mAb) in healthy adult volunteers and in patients with mild-to-moderate acute respiratory distress syndrome (ARDS) due to an infectious source. The current trial (Part A) focuses on single ascending doses (SAD) in healthy volunteers to characterize the safety profile, PK parameters, and immunogenicity of HT31-1. Emerging data from this phase will inform dose selection for the subsequent Part B study in ARDS patients and help establish the recommended Phase 2 dose (RP2D). Additionally, exploratory pharmacodynamic and biomarker assessments will be performed to evaluate target engagement and potential early biological activity.