Safety and Efficacy of AT-527 in Subjects With Moderate Coronavirus Disease (COVID-19) in a Hospital Setting

A Phase 2 Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Safety and Efficacy of AT-527 in Subjects With Moderate COVID-19

The objectives of this study are to evaluate the safety, tolerability, antiviral activity and efficacy of AT-527 in adult subjects ≥18 years of age with moderate COVID-19 and risk factors for poor outcomes (such as obesity (BMI>30), hypertension, diabetes or asthma). Eligible subjects will be randomized to blinded AT-527 (nucleotide analog) tablets or matching placebo tablets to be administered orally for 5 days. Part A will evaluate an AT-527 dose of 550 mg BID and Part B will evaluate a second dose of AT-527 (1100 mg BID). Local supportive standard of care (SOC) will be allowed for all subjects. Efficacy, antiviral activity and safety observations will be compared for treatment with active AT-527 tablets vs. placebo tablets.

Key Inclusion Criteria:

• Hospitalized or in a hospital-affiliated confinement facility
• SARS-CoV-2 positive
• Initial COVID-19 symptom onset within 5 days prior to Screening
• SpO2 ≥ 93% on room air or requires ≤ 2L/min oxygen by nasal cannula or mask to maintain SpO2 ≥ 93%
• Must also have a history of at least one of the following known risk factors for poor outcomes: obesity (BMI>30), hypertension, diabetes or asthma.

Key Exclusion Criteria:

• Severe or critical COVID-19 illness: RR ≥30, HR ≥125, SpO2 <93% on room air or requires >2L/min oxygen by nasal cannula or mask to maintain SpO2 ≥93%, systolic blood pressure < 90 mm Hg, diastolic blood pressure < 60 mm Hg or PaO2/FiO2 <300
• Requires mechanical ventilation
• Lobar or segmental consolidation on chest imaging.
• Treatment with other drugs thought to possibly have activity against SARS-CoV-2
• ALT or AST > 5 x upper limit of normal (ULN)
• Female subject is pregnant or breastfeeding
• Has received or is expected to receive any dose of a SARS-CoV-2 vaccine before the Day 14 visit (Part B).