Study of F-652 (IL-22:IgG2 Fusion Protein) in Patients With Moderate to Severe COVID-19

The study is planned to include 4 cohorts, with enrolled patients being randomized 1:1 in a blinded manner on Day 1, following screening, to F-652 or placebo as follows:

* Cohort 1 (sentinel cohort): Four patients will receive either dose level 1 F-652 or placebo. Upon completion of sentinel, the Data Monitoring Committee will evaluate the safety and tolerability data of the sentinel patients and determine if it is acceptable to dose the remaining patients in this dosing group in Cohort 2. * Cohort 2: Fourteen patients will receive either dose level 1 F-652 or placebo. Upon completion of Cohort 2, the DMC will convene and review all available safety data to determine if the study can proceed to the next dose level. * Cohort 3 (sentinel cohort): Four patients will receive either dose level 2 F-652 or placebo. Upon completion of sentinel dosing, the DMC will evaluate the safety and tolerability data of the sentinel patients and determine if it is acceptable to dose the remaining patients in this dosing group in Cohort 4. * Cohort 4: Sixteen patients will receive either dose level 2 F-652 or placebo. Treatment will begin on Day 1 following randomization. Patients assigned to active drug will receive a total of 2 doses of F-652 (1 IV infusion on Day 1 and 1 IV infusion on Day 8). Patients assigned to placebo will receive identical IV infusions of placebo vehicle on Days 1 and 8. All patients will receive available supportive and antiviral therapies as standard of care. Efficacy will be assessed on Days 15 and 29. Patients will be followed for safety until Day 60.

The primary efficacy endpoint is the proportion of patients with a ≥2-point increase in the National Institute of Allergy and Infectious Diseases (NIAID) 8-point ordinal scale from baseline to Day 29.

The secondary efficacy endpoints include the proportion of patients with a ≥2-point increase in the NIAID 8-point ordinal scale from baseline to Day 15, mortality rate by Days 15 and 29, percentage of patients who have recovered and discharged from the hospital by Days 15 and 29, and percentage of patients progressed to severe/critical disease by Day 15.

The safety endpoints include all cause treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs); change from screening (baseline) in clinical symptoms and abnormal vital signs, abnormal laboratory tests; and relationship of any AEs with F-652 treatment.

The exploratory endpoints include time to negative SARS-CoV-2 PCR test from randomization; and changes in pharmacodynamic parameters.