Preclinical test showed reduced efficacy

The study is a multicenter, adaptive, randomized, double-blinded and placebo-controlled Phase II/III trial, and will be conducted globally. The study is comprised of two parts: dose selection (Phase II) and pivotal treatment effect (Phase III).

In this study, Phase II part will evaluate the efficacy, safety and PK of SCTA01 low dose+BSC, high dose+BSC and placebo+BSC in patients with severe COVID-19.

In Phase II part, subjects will be randomized at 1:1:1 ratio. At the end of Phase II part, a dose for the Phase III will be determined.

The Phase III part will evaluate the efficacy, safety, and immunogenicity of SCTA01 at the recommended dose recommended. Subjects in Phase III part will be randomized at 1:1 ratio to SCTA01+BSC and placebo+BSC groups.

Inclusion Criteria:

• Hospitalized patients with severe COVID-19 (5 point on NIH 8-point ordinal scale).
• Male or female adult ≥18 years of age at time of enrollment;
• Biological samples (not limited to any specific type) collected within 72 hours before randomization is laboratory-confirmed as SARS-CoV-2 infection (PCR or antigen-based diagnostic tests);
• ≤ 10 days since symptoms of COVID-19 onset.

Exclusion Criteria:

• Patients who need non-invasive ventilation or high flow oxygen (i.e., 6 point on the 8-point ordinal scale);
• Patients with critical COVID-19;
• Patients with Severe COVID-19 who received convalescent plasma or COVID-19 vaccine, or anti-SARS-CoV-2 spike (S) protein targeted therapy;
• Alanine-amino transferase (ALT) or aspartate transaminase (AST) is 5 times higher than the upper limit of the normal value;
• Estimated glomerular filtration rate (eGFR) <30 mL/min or on dialysis {eGFR calculated by Cockcroft-Gault formula (Cockcroft DW, 1976), Male: CrCL (mL/min) = [(140 - age) × weight (kg)] × 1/ [SCr (mg/dL) × 72]; Female: CrCL (mL/min) = [(140 - age) × weight (kg)] × 0.85/ [SCr (mg/dL) × 72]}.

The advese events were collected over 120 days

An adverse event (AE) is any unfavorable or unintended sign, symptom, disease, or abnormal lab result related to a medicinal product, regardless of causality. It includes new/worsening conditions, procedure complications, lack of efficacy, overdose, misuse, or occupational exposure. A serious AE (SAE) results in death, life-threatening risk, hospitalization, disability, birth defect, or other important events.