Procedures
Meplazumab or placebo was administered intravenously in 100 mL 0.9% saline solution within 1 h after randomization. A single dose of 0.12 mg/kg was administered on day 1; and a double dose of 0.2 mg/kg, a double dose of 0.3 mg/kg, and a placebo was administered on days 1 and 8. The dose range of meplazumab was determined based on data of phase 1 clinical trial data from healthy patients (NCT04369586) and exploratory clinical trial from patients with COVID-19 (NCT04275245) to optimize the efficacy and safety.