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Completed

NCT Number: NCT04960202

EPIC-HR: Study of Oral PF-07321332/Ritonavir Compared With Placebo in Nonhospitalized High Risk Adults With COVID-19

The purpose of this study is to determine whether PF-07321332/ritonavir is safe and effective for the treatment of adults who are ill with COVID-19 and do not need to be in the hospital, but are at an increased risk of developing severe illness. Throughout the study period, provision will be made to allow study visits to be conducted at a participant's home or another non-clinic location if available. The total study duration is up to 24 weeks.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2 / Phase 3

Primary location

Instituto de Investigaciones Clinicas Zarate, Zárate, Buenos Aires, Argentina

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Confirmed SARS-CoV-2 infection within 5 days prior to randomization
  • Initial onset of COVID-19 signs/symptoms within 5 days prior to the day of randomization and at least 1 of the specified COVID-19 signs/symptoms present on the day of randomization
  • Fertile participants must agree to use a highly effective method of contraception
  • Has at least 1 characteristic or underlying medical condition associated with an increased risk of developing severe illness from COVID-19

Exclusion criteria

  • History of or need for hospitalization for the medical treatment of COVID-19
  • Prior to current disease episode, any confirmed SARS-CoV-2 infection
  • Known medical history of active liver disease
  • Receiving dialysis or have known moderate to severe renal impairment
  • Known human immunodeficiency virus (HIV) infection with a viral load greater than 400 copies/mL or taking prohibited medications for HIV treatment
  • Suspected or confirmed concurrent active systemic infection other than COVID-19
  • History of hypersensitivity or other contraindication to any of the components of the study intervention
  • Current or expected use of any medications or substances that are highly dependent on CYP3A4 for clearance or are strong inducers of CYP3A4
  • Has received or is expected to receive convalescent COVID-19 plasma
  • Has received or is expected to receive any dose of a SARS-CoV-2 vaccine before the Day 34 visit
  • Participating in another interventional clinical study with an investigational compound or device, including those for COVID-19 through the long-term follow-up visit
  • Known prior participation in this trial or other trial involving PF-07321332
  • Oxygen saturation of <92% on room air, or on their standard home oxygen supplementation for those who regularly receive chronic supplementary oxygen for an underlying lung condition
  • Females who are pregnant or breastfeeding

Treatment and study plan

PF-07321332

Drug

PF-07321332 (tablet)

Ritonavir

Drug

Ritonavir (capsule)

Placebo

Drug

Placebo (tablet or capsule)

Primary outcomes

  1. Percentage of Participants With Covid-19 Related Hospitalization or Death From Any Cause Through Day 28- Modified Intent-To-Treat (mITT) Population

    Time frame: From Day 1 to Day 28

    Percentage of participants with COVID-19 related hospitalization or death from any cause during the first 28 days of the study was estimated using the Kaplan-Meier (KM) method. Using KM method, survival probability for each time interval was calculated as the number of participants surviving divided by the number of participants at risk. Participants who had the event, dropped out, or moved out were not counted as "at risk" i.e., participants who were lost were considered "censored" and were not counted in the denominator.

Secondary outcomes

  1. Number of Participants With Treatment Emergent Adverse Events (TEAEs)

    Time frame: From start of study intervention (Day 1) up to end of safety follow-up (Day 34)

    An adverse event (AE) was any untoward medical occurrence in a participant, temporarily associated with the use of study intervention, whether or not considered related to the study intervention. Serious adverse event (SAE) was any untoward medical occurrence that, at any dose: resulted in death; required inpatient hospitalization or prolongation of existing hospitalization; was life-threatening; resulted in persistent or significant disability/ incapacity; congenital anomaly/birth defect; a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical events. AEs included both SAEs and all non-SAEs. An AE was considered as TEAE if the event started on or after start date of study intervention.

  2. Number of Participants With AEs Leading to Discontinuation and Serious Adverse Events (SAEs)

    Time frame: From start of study intervention (Day 1) up to end of safety follow-up (Day 34)

    An AE was any untoward medical occurrence in a participant, temporarily associated with the use of study treatment, whether or not considered related to the study treatment. An SAE was any untoward medical occurrence that, at any dose: resulted in death; required inpatient hospitalization or prolongation of existing hospitalization; was life-threatening; resulted in persistent or significant disability/ incapacity; congenital anomaly/birth defect; a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical events.

  3. Percentage of Participants With Covid-19 Related Hospitalization or Death From Any Cause Through Day 28- Modified Intent-To-Treat 1 (mITT1) Population

    Time frame: From Day 1 to Day 28

    Percentage of participants with COVID-19 related hospitalization or death from any cause during the first 28 days of the study was estimated using the Kaplan-Meier method.

  4. Time to Sustained Alleviation of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained alleviation of all targeted COVID-19 signs/symptoms was defined as the event occurring on the first 4 consecutive days when all symptoms scored as moderate or severe at the time of enrollment were scored as mild or absent and those scored mild or absent at the time of enrollment were scored as absent. The first day of the 4 consecutive-day period was considered date of first event. Time to sustained alleviation (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained alleviation (censored), time was calculated as censoring date (last date on which symptom alleviation was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  5. Time to Sustained Alleviation of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT1 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained alleviation of all targeted COVID-19 signs/symptoms was defined as the event occurring on the first 4 consecutive days when all symptoms scored as moderate or severe at the time of enrollment were scored as mild or absent and those scored mild or absent at the time of enrollment were scored as absent. The first day of the 4 consecutive-day period was considered date of first event. Time to sustained alleviation (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained alleviation (censored), time was calculated as censoring date (last date on which symptom alleviation was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  6. Time to Sustained Alleviation of All Targeted COVID-19 Signs and Symptoms Through Day 28- Modified Intent-to-Treat 2 (mITT2) Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained alleviation of all targeted COVID-19 signs/symptoms was defined as the event occurring on the first 4 consecutive days when all symptoms scored as moderate or severe at the time of enrollment were scored as mild or absent and those scored mild or absent at the time of enrollment were scored as absent. The first day of the 4 consecutive-day period was considered date of first event. Time to sustained alleviation (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained alleviation (censored), time was calculated as censoring date (last date on which symptom alleviation was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  7. Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT Population

    Time frame: From Day 1 to Day 28

    Participants were required to record the severity of their Covid-19 symptoms over the past 24 hours daily on a 4-point scale ranging from 0 to 3, higher scores indicated more severity. The scale was reported as 0= no symptoms, 1=mild, 2=moderate and 3=severe. A participant with severe score for any targeted symptoms post-baseline was counted as severe. Percentage of participants with severe Covid-19 signs and symptoms were reported.

  8. Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT1 Population

    Time frame: From Day 1 to Day 28

    Participants were required to record the severity of their Covid-19 symptoms over the past 24 hours daily on a 4-point scale ranging from 0 to 3, higher scores indicated more severity. The scale was reported as 0= no symptoms, 1=mild, 2=moderate and 3=severe. A participant with severe score for any targeted symptoms post-baseline was counted as severe. Percentage of participants with severe Covid-19 signs and symptoms were reported.

  9. Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT2 Population

    Time frame: From Day 1 to Day 28

    Participants were required to record the severity of their Covid-19 symptoms over the past 24 hours daily on a 4-point scale ranging from 0 to 3, higher scores indicated more severity. The scale was reported as 0= no symptoms, 1=mild, 2=moderate and 3=severe. A participant with severe score for any targeted symptoms post-baseline was counted as severe. Percentage of participants with severe Covid-19 signs and symptoms were reported.

  10. Time to Sustained Resolution of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained resolution was defined as when all targeted symptoms were scored as absent for 4 consecutive days. Time to sustained resolution (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained resolution (censored), time was calculated as censoring date (last date on which symptom resolution was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  11. Time to Sustained Resolution of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT1 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained resolution was defined as when all targeted symptoms were scored as absent for 4 consecutive days. Time to sustained resolution (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained resolution (censored), time was calculated as censoring date (last date on which symptom resolution was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  12. Time to Sustained Resolution of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT2 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained resolution was defined as when all targeted symptoms were scored as absent for 4 consecutive days. Time to sustained resolution (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained resolution (censored), time was calculated as censoring date (last date on which symptom resolution was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  13. Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained alleviation of each targeted COVID-19 signs/symptoms was defined as the event occurring on the first 4 consecutive days when each symptom scored as moderate or severe at the time of enrollment were scored as mild or absent and those scored mild or absent at the time of enrollment were scored as absent. The first day of the 4 consecutive-day period was considered date of first event. Time to sustained alleviation (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained alleviation (censored), time was calculated as censoring date (last date on which symptom alleviation was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  14. Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT1 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained alleviation of each targeted COVID-19 signs/symptoms was defined as the event occurring on the first 4 consecutive days when each symptom scored as moderate or severe at the time of enrollment were scored as mild or absent and those scored mild or absent at the time of enrollment were scored as absent. The first day of the 4 consecutive-day period was considered date of first event. Time to sustained alleviation (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained alleviation (censored), time was calculated as censoring date (last date on which symptom alleviation was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  15. Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT2 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained alleviation of each targeted COVID-19 signs/symptoms was defined as the event occurring on the first 4 consecutive days when each symptom scored as moderate or severe at the time of enrollment were scored as mild or absent and those scored mild or absent at the time of enrollment were scored as absent. The first day of the 4 consecutive-day period was considered date of first event. Time to sustained alleviation (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained alleviation (censored), time was calculated as censoring date (last date on which symptom alleviation was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  16. Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained resolution was defined as when each targeted symptom was scored as absent for 4 consecutive days. Time to sustained resolution (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained resolution (censored), time was calculated as censoring date (last date on which symptom resolution was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  17. Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT1 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained resolution was defined as when each targeted symptom was scored as absent for 4 consecutive days. Time to sustained resolution (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained resolution (censored), time was calculated as censoring date (last date on which symptom resolution was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  18. Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT2 Population

    Time frame: From Day 1 (baseline) to Day 28

    Sustained resolution was defined as when each targeted symptom was scored as absent for 4 consecutive days. Time to sustained resolution (event) was calculated as first event date minus first dose date plus 1, for participants with event. For participants who completed Day 28 or discontinued the study before Day 28 without sustained resolution (censored), time was calculated as censoring date (last date on which symptom resolution was assessed) minus first dose date plus 1 or Day 25 whichever occurred first.

  19. Number of Participants With Progression to a Worsening Status in 1 or More Self-reported COVID-19 Associated Symptoms Through Day 28-mITT Population

    Time frame: From Day 1 (baseline) to Day 28

    Participants were required to record the severity of their Covid-19 symptoms over the past 24 hours daily on a 4-point scale where 0 = no symptoms; 1= mild; 2= moderate; and 3= severe. Vomiting and diarrhea were each rated on a 4-point frequency scale where 0= no occurrence, 1= mild for 1 to 2 times, 2= moderate for 3 to 4 times, and 3= severe for 5 or greater. Progression to a worsening status for any targeted symptom was based up on increasing severity (i.e. the first time any targeted symptoms worsened after treatment relative to baseline).

  20. Number of Participants With Progression to a Worsening Status in 1 or More Self-reported COVID-19 Associated Symptoms Through Day 28-mITT1 Population

    Time frame: From Day 1 (baseline) to Day 28

    Participants were required to record the severity of their Covid-19 symptoms over the past 24 hours daily on a 4-point scale where 0 = no symptoms; 1= mild; 2= moderate; and 3= severe. Vomiting and diarrhea were each rated on a 4-point frequency scale where 0= no occurrence, 1= mild for 1 to 2 times, 2= moderate for 3 to 4 times, and 3= severe for 5 or greater. Progression to a worsening status for any targeted symptom was based up on increasing severity (i.e. the first time any targeted symptoms worsened after treatment relative to baseline).

  21. Number of Participants With Progression to a Worsening Status in 1 or More Self-reported COVID-19 Associated Symptoms Through Day 28-mITT2 Population

    Time frame: From Day 1 (baseline) to Day 28

    Participants were required to record the severity of their Covid-19 symptoms over the past 24 hours daily on a 4-point scale where 0 = no symptoms; 1= mild; 2= moderate; and 3= severe. Vomiting and diarrhea were each rated on a 4-point frequency scale where 0= no occurrence, 1= mild for 1 to 2 times, 2= moderate for 3 to 4 times, and 3= severe for 5 or greater. Progression to a worsening status for any targeted symptom was based up on increasing severity (i.e. the first time any targeted symptoms worsened after treatment relative to baseline).

  22. Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT Population

    Time frame: Day 1, 5

    In this outcome measure, the percentage of participants with a resting peripheral oxygen saturation >=95% were reported.

  23. Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT1 Population

    Time frame: Day 1, 5

    In this outcome measure, the percentage of participants with a resting peripheral oxygen saturation >=95% were reported.

  24. Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT2 Population

    Time frame: Day 1, 5

    In this outcome measure, the percentage of participants with a resting peripheral oxygen saturation >=95% were reported.

  25. Percentage of Participants Who Died Through Week 24- mITT Population

    Time frame: From Day 1 up to Week 24

    In this outcome measure, percentage of participants with death due to any cause was presented.

  26. Percentage of Participants Who Died Through Week 24- mITT1 Population

    Time frame: From Day 1 up to Week 24

    In this outcome measure, percentage of participants with death due to any cause was presented.

  27. Percentage of Participants Who Died Through Week 24- mITT2 Population

    Time frame: From Day 1 up to Week 24

    In this outcome measure, percentage of participants with death due to any cause was presented.

  28. Plasma Concentration Versus Time Summary of PF-07321332

    Time frame: 1 Hour post-dose on Day 1 and pre-dose on Day 5

  29. Change From Baseline in Logarithm to Base10 (Log10) Transformed Viral Load at Day 3, 5, 10 and 14- mITT Population

    Time frame: Baseline, Day 3, 5, 10 and 14

    The viral load was measured in nasal or nasopharyngeal samples using reverse transcription polymerase chain reaction (RT-PCR).

  30. Change From Baseline in Log10 Transformed Viral Load at Day 3, 5, 10 and 14- mITT1 Population

    Time frame: Baseline, Day 3, 5, 10 and 14

    The viral load was measured in nasal or nasopharyngeal samples using RT-PCR.

  31. Change From Baseline in Log10 Transformed Viral Load at Day 3, 5, 10 and 14- mITT2 Population

    Time frame: Baseline, Day 3, 5, 10 and 14

    The viral load was measured in nasal or nasopharyngeal samples using RT-PCR.

  32. Number of COVID-19 Related Medical Visits- mITT Population

    Time frame: From Day 1 up to Day 34

    Medical visits included emergency room, practitioner's office, home healthcare services, urgent care, telephone consultation, outpatient infusion center, other, COVID-19-related-hospitalization (intensive care unit [ICU] and non-ICU stays). In this outcome measure, COVID-19-related medical visits of participants were reported.

  33. Number of COVID-19 Related Medical Visits- mITT1 Population

    Time frame: From Day 1 up to Day 34

    Medical visits included emergency room, practitioner's office, home healthcare services, urgent care, telephone consultation, outpatient infusion center, other, COVID-19-related-hospitalization (ICU and non-ICU stays). In this outcome measure, COVID-19-related medical visits of participants were reported.

  34. Number of COVID-19 Related Medical Visits- mITT2 Population

    Time frame: From Day 1 up to Day 34

    Medical visits included emergency room, practitioner's office, home healthcare services, urgent care, telephone consultation, outpatient infusion center, other, COVID-19-related-hospitalization (ICU and non-ICU stays). In this outcome measure, COVID-19-related medical visits of participants were reported.

  35. Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT Population

    Time frame: From Day 1 up to Day 34

  36. Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT1 Population

    Time frame: From Day 1 up to Day 34

  37. Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT2 Population

    Time frame: From Day 1 up to Day 34

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

AN INTERVENTIONAL EFFICACY AND SAFETY, PHASE 2/3, DOUBLE-BLIND, 2-ARM STUDY TO INVESTIGATE ORALLY ADMINISTERED PF-07321332/RITONAVIR COMPARED WITH PLACEBO IN NONHOSPITALIZED SYMPTOMATIC ADULT PARTICIPANTS WITH COVID-19 WHO ARE AT INCREASED RISK OF PROGRESSING TO SEVERE ILLNESS

Important dates

Study start
2021
Primary completion
2021
Study completion
2022
First posted
Jul 13, 2021
Registry last updated
Jul 10, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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