Australasian COVID-19 Trial (ASCOT) ADAptive Platform Trial

An International Multi-Centre Randomised Adaptive Platform Clinical Trial to Assess the Clinical, Virological and Immunological Outcomes in Patients with SARS-CoV-2 Infection (COVID-19).

ASCOT is an investigator-initiated, multi-centre, open-label, randomised controlled, Bayesian, adaptive platform trial. The objective of ASCOT is to identify the regimen (combination of interventions) associated with the highest chance of improving clinical outcomes in adults hospitalised with COVID-19. Platform trials allow multiple questions to be evaluated simultaneously and sequentially within the platform, and evaluate interaction between different treatment options, to achieve the goal of determining the optimal combination of treatments for the disease as rapidly as possible. Study treatments are categorised into different treatment domains. The adaptive nature of the trial means treatments within a domain or an entire domain can be removed or added based on accruing data analysed at frequent intervals or based on external evidence. \[Domain Closed\] Intervention domain A (antiviral): Participants will be randomised to receive either i) standard of care without nafamostat; or ii) standard of care with nafamostat \[Never Opened\] Intervention domain B (antibody): Participants will be randomised to receive either i) standard of care without hyperimmune globulin; or ii) standard of care with hyperimmune globulin \[Domain Closed\] Intervention domain C (anticoagulation): Participants will be randomised to receive either i) standard dose thromboprophylaxis; or ii) intermediate dose thromboprophylaxis; or iii) therapeutic anticoagulation Intervention domain Q (Antiviral II): Participants will be randomised to receive either i) no antiviral agents; or ii) oral nirmatrelvir-ritonavir; or iii) intravenous remdesivir iiii) oral nirmatrelvir-ritonavir + Intravenous remdesivir

Inclusion Criteria: A.Core Platform (all participants must meet the following): 1\. Adult (as defined by local jurisdiction) patient admitted to hospital with acute illness and suspected or proven SARS-CoV-2 infection. B. Antiviral II Domain (all participants in the Antiviral II domain must meet the following): 1\. SARS-CoV-2 infection has been confirmed by positive rapid antigen test OR polymerase chain reaction test within the last 7 days Exclusion Criteria: A. Core platform exclusions (all participants must not meet the following): 1. Death is deemed to be imminent and inevitable during the next 24 hours AND one or more of the patient, substitute decision maker or attending physician are not committed to full active treatment 2. Patient is expected to be discharged from hospital today or tomorrow 3. More than 14 days have elapsed while admitted to hospital with symptoms of an acute illness due to proven SARS-CoV-2 infection 4. Previous participation in this trial, or another trial that is analysed within the same statistical model as this trial, within the last 90 days B. Antiviral II Domain exclusions (patients at sites participating in the Antiviral II Domain must not meet the following): 1. Severe renal impairment, defined as eGFR\<30ml/min or receipt of renal replacement therapy 2. Severe hepatic impairment, defined as proven or suspected cirrhosis with Child Pugh class of C, OR acute hepatitis, defined as AST or ALT\>5 times the upper limit of normal in the testing laboratory. 3. The patient has received, at the time of eligibility assessment, \>24h of an antiviral agent intended to have activity against SARS-CoV-2, within the past 7 days 4. The patient is known to be pregnant or breastfeeding 5. The treating clinician believes that participation in the domain would not be in the best interests of the patient B.1. Antiviral II Domain Non-Immune Suppressed Stratum-specific Exclusion Criteria (all non-immune suppressed patients at sites participating in the Antiviral II Domain must not meet the following): 1\. Onset of COVID-related symptoms was more than 7 days (i.e., 168 hours) ago B2. Antiviral II domain Intervention-specific Exclusion Criteria (All patients at sites participating in the Antiviral II Domain will be excluded from the below interventions if they meet the following): Will be excluded from receiving Remdesivir if: 1. No venous access is available and none can be created 2. Known hypersensitivity to remdesivir or its excipients Will be excluded from receiving Nirmatrelvir/ritonavir if: 1. The patient is unable to take, tolerate or absorb oral or enteral medications 2. Known hypersensitivity to any of nirmatrelvir, ritonavir or its excipients 3. Receipt of a concomitant drug with a high-risk interaction with nirmatrelvir-ritonavir which cannot be ceased or substituted. Will be excluded from receiving no antiviral agent if: 1. The patient is in the Immune Suppressed Stratum 2. The patient is receiving or has received supplemental oxygen on the calendar day of eligibility assessment. 3. The patient is considered by the treating clinician to be at very high risk for progression to severe COVID-19