EPIC‐PEP 2021.

Study name	A study of a potential oral treatment to prevent COVID‐19 in adults who are exposed to household member(s) with a confirmed symptomatic COVID‐19 infection
Methods	Trial design: double‐blind RCT with 3 parallel arms Type of record: trial register entry Sample size: 2880 Setting: outpatient Country: UK Language: English Number of centres: 358 Study purpose (treatment, prevention): prevention Trial registration number: NCT05047601 Date of registration: 17 September 2021
Participants	Inclusion criteria: participants who have a negative screening SARS‐CoV‐2 rapid antigen test result and who are asymptomatic household contacts with exposure within 96 hours to an individual who is symptomatic and recently tested positive for SARS CoV‐2. fertile participants must agree to use a highly effective method of contraception Exclusion criteria: history of SARS‐CoV‐2 infection in the past 6 months experiencing measured fever (documented temperature >38˚C or 100.4˚F) or other signs or symptoms consistent with COVID‐19 known medical history of active liver disease chronic kidney disease or have known moderate to severe renal impairment. known Human Immunodeficiency Virus (HIV) infection with viral load > 400 copies/mL within the last 6 months or taking prohibited medications for HIV treatment suspected or confirmed concurrent active systemic infection active cancer requiring treatment with prohibited medication. current or expected use of any medications or substances that are highly dependent on Cytochrome P450 3A4 (CYP3A4) for clearance or are strong inducers of CYP3A4 has received approved, authorized, or investigational anti‐SARS‐CoV‐2 mAb, convalescent plasma, other drugs for treatment of COVID‐19, or other anti‐SARS‐CoV‐2 biologic products within 6 months of screening has received any SARS‐CoV‐2 vaccine within 6 months prior to screening or is expected to receive a SARS‐CoV‐2 vaccine or other approved, authorized, or investigational postexposure prophylaxis treatments through Day 38. Participating in another interventional clinical study with an investigational compound or device, including those for COVID‐19 known or prior participation in this trial or another trial involving PF‐07321332. females who are pregnant or breastfeeding.
Interventions	Details of intervention Experimental 1: type and dose: nirmatrelvir/ritonavir 300/100 mg twice daily for 5 days followed by placebo twice daily for days 6‐10 route of administration: oral :Experimental 2: type and dose: nirmatrelvir/ritonavir 300 mg/100 mg twice daily for 10 days route of administration: oral Details of control group Placebo twice daily for 10 days
Outcomes	Primary study outcome: proportion of participants who have a negative reverse transcription polymerase chain reaction (RT‐PCR) result at baseline who develop a symptomatic, RT‐PCR or rapid antigen test confirmed SARS‐CoV‐2 infection through day 14  Relevant review outcomes planned: proportion of participants who have a negative reverse transcription polymerase chain reaction (RT‐PCR) result at baseline who develop a symptomatic, RT‐PCR or rapid antigen test confirmed SARS‐CoV‐2 infection on day 1 to day 14 percentage of participants who experience adverse events through day 38  proportion of participants with symptomatic, RT‐PCR or Rapid Antigen Test confirmed SARS‐CoV‐2 infection through day 14 proportion of participants with COVID‐19 related hospitalization or death from any cause proportion of participants with symptomatic or asymptomatic, RT‐PCR or Rapid Antigen Test confirmed SARS‐CoV‐2 infection. all‐cause mortality in participants who have a negative RT‐PCR result at baseline through day 38 Additional study outcomes: time to SARS‐CoV‐2 infection. compare the duration of COVID‐19 related signs and symptoms in participants who have a negative RT‐PCR result at baseline through day 28 compare the severity of COVID‐19 related signs and symptoms in participants who have a negative RT‐PCR result at baseline through day 28 minimal Concentration (Ctrough) of PF‐07321332 on day 1 post dose and day 5 pre‐dose  viral titers measured via RT‐PCR in nasal swabs in participants who have a negative or positive RT‐PCR result at baseline through day 14 number of days of hospital and intensive care unit stay in participants with COVID‐19‐related hospitalization who have a negative RT‐PCR result at baseline through day 28 number of COVID‐19‐related medical visits in participants who have a negative RT‐PCR result at baseline through day 28
Starting date	17 September 2021
Contact information	Pfizer CT.gov Call Center 1‐800‐718‐1021 ClinicalTrials.gov_Inquiries@pfizer.com
Notes	Recruitment status: recruiting Prospective completion date: 18 April 2022 Date last update posted: 18 April 2022 Sponsor/funding: Pfizer