Study to Assess the Effect of Meplazumab on COVID-19

1. Rationale:

Meplazumab is a humanized anti-CD147 immunoglobulin 2 (IgG2) monoclonal antibody which is expected to block the binding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein to the human host-cell-expressed CD147, thereby blocking entry of SARS-CoV-2 into human tissue. This expectation is based on in vitro functional studies using Vero E6 cells infected with SARS-CoV-2 that demonstrated effective meplazumab mediated virus gene copy number inhibition upwards of 90% as evaluated by quantitative polymerase chain reaction. Meplazumab may also inhibit COVID-19 associated cytokine storm syndrome based on inhibition of the pro inflammatory factor Cyclophilin A host-cell CD147 interaction. 2. Overall Design:

This is a multicenter, seamless, randomized, third-party-blind, study to evaluate the safety and efficacy of meplazumab for the treatment of COVID 19 in hospitalized adults (≥18 years). Neither the subject nor the investigator shall be aware of the study drug identity, as the study drug is dispensed by a third party (eg, a pharmacist or nurse).

Enrollment of subjects will be stopped once the total number of planned subjects have completed the Stage 1 Day 29 visit procedures. Once the interim analysis of Stage 1 study data is complete and the Independent Data Monitoring Committee (IDMC) has recommended the meplazumab dose that is safe and effective to carry forward into Stage 2, the study will resume subject enrollment. A summary of the key Stage 1 interim analysis results will be sent to the relevant Health Authorities involved, if requested. 3. Number of Investigators and Study Centers:

There will be 15 to 20 Investigators, at 12 to 20 study centers globally, participating in this study. 4. Number of Subjects:

Subjects will be screened 1 day before randomization. Stage 1: Approximately 168 subjects will be randomized and allocated 1:1:1:1 (42:42:42:42) to receive meplazumab low dose, meplazumab medium dose, meplazumab high dose, or control. An interim analysis will be conducted to select the optimal dose of meplazumab compared with the control group based on response rates of clinical improvement at Day 29.

Stage 2: 276 more subjects will be randomized and allocated 1:1 (138:138) to receive 0.2mg/kg meplazumab or control. At interim analysis, primary endpoint, sample size calculation for Stage 2 will be re evaluated based on the observed outcomes at Stage 1 and will be capped at 300 subjects total. 5. Treatment Groups and Duration: