COVID-19Phase 2/3NCT04960202
EPIC-HR: Study of Oral PF-07321332/Ritonavir Compared With Placebo in Nonhospitalized High Risk Adults With COVID-19
A Phase 2/3 study testing PF-07321332 and Ritonavir in people with COVID-19, run by Pfizer at 201 sites in 20 countries.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- COVID-19
- What is being tested?
- PF-07321332 and Ritonavir
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 2,091 participants
- Where
- 201 sitesin 20 countries
- Study dates
- 16 Jul 2021to 25 Apr 2022
- Phase
- Phase 2/3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
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- 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
Trial locations and contacts
201 sites in 20 countries.
201 sites in 20 countries
United States73 sites
PharmaTex Research, LLC
Amarillo, Texas, 79109
ARC Clinical Research at William Cannon
Austin, Texas, 78745
St Hope Foundation
Bellaire, Texas, 77401
Xera Med Research
Boca Raton, Florida, 33487
MOORE Clinical Research, Inc.
Brandon, Florida, 33511
Mercury Street Medical Group, PLLC
Butte, Montana, 59701
Hope Clinical Research
Canoga Park, California, 91303
Research by Design, LLC
Chicago, Illinois, 60643
Premier Medical Group
Clarksville, Tennessee, 37040
Innovative Research of West Florida, Inc.
Clearwater, Florida, 33756
Future Innovative Treatments, LLC
Colorado Springs, Colorado, 80907
Conroe Willis Medical Research
Conroe, Texas, 77304
Herco Medical and Research Center Inc
Coral Gables, Florida, 33134
South Texas Clinical Research
Corpus Christi, Texas, 78413
Advance Clinical Research Group
Cutler Bay, Florida, 33157
Beautiful Minds Clinical Research Center
Cutler Bay, Florida, 33157
Meridian Clinical Research, LLC
Endwell, New York, 13760
Ascada Research
Fullerton, California, 92835
Qway Research
Hialeah, Florida, 33010
Eastern Research Inc
Hialeah, Florida, 33013
Inpatient Research Clinic
Hialeah, Florida, 33013
Doral Medical Research LLC.
Hialeah, Florida, 33016
Doral Medical Research,LLC
Hialeah, Florida, 33016
Unlimited Medical Research Group, LLC
Hialeah Gardens, Florida, 33018
SignatureCare Emergency Center
Houston, Texas, 77008
Trio Clinical Trials, LLC
Houston, Texas, 77008
C & R Research Services USA
Houston, Texas, 77022
Next Level Urgent Care
Houston, Texas, 77057
Atella Clinical Research LLC.
La Palma, California, 90623
Excel Clinical research
Las Vegas, Nevada, 89109
Ark Clinical Research
Long Beach, California, 90806
American Institute of Research
Los Angeles, California, 90017
Advanced Pulmonary Research Institute
Loxahatchee Groves, Florida, 33470
New Orleans Sinus Center (COVID-19 Testing)
Marrero, Louisiana, 70072
Tandem Clinical Research GI, LLC
Marrero, Louisiana, 70072
The Institute for Liver Health dba Arizona Clinical Trials
Mesa, Arizona, 85210
SMS Clinical Research, LLC
Mesquite, Texas, 75149
SMS Clinical Research
Mesquite, Texas, 75149
Angels Clinical Research Institute
Miami, Florida, 33122
LCC Medical Research Institute, LLC
Miami, Florida, 33126
Premium Medical Research Corp
Miami, Florida, 33126
Global Health Clinical Trials Corp
Miami, Florida, 33135
South Florida Research Center, Inc.
Miami, Florida, 33135
Suncoast Research Group, LLC
Miami, Florida, 33135
I.V.A.M. Clinical & Investigational Center, LLC
Miami, Florida, 33144
C'A Research
Miami, Florida, 33174
ProLive Medical Research, Corp.
Miami, Florida, 33175
Entrust Clinical Research
Miami, Florida, 33176
Reed Medical Research
Miami, Florida, 33176
Kendall South Medical Center
Miami, Florida, 33185
Clinical Site Partners, Inc d/b/a CSP Miami
Miami, Florida, 33186
Coral Research Clinic Corp
Miami, Florida, 33186
Savin Medical Group, LLC
Miami Lakes, Florida, 33014
Monroe Biomedical Research
Monroe, North Carolina, 28112
TPMG (Tidewater Physicians Multispecialty Group) Clinical Research
Newport News, Virginia, 23606
Omega Research Orlando, LLC
Orlando, Florida, 32808
LinQ Research, LLC
Pearland, Texas, 77584
Cahaba Research Inc
Pelham, Alabama, 35124
NAPA Research LLC
Pompano Beach, Florida, 33064
CDC Research Institute
Port Saint Lucie, Florida, 34952
Epic Medical Research
Red Oak, Texas, 75154
South Bay Clinical Research Institute
Redondo Beach, California, 90277
Sun Research Institute
San Antonio, Texas, 78215
BFHC Research
San Antonio, Texas, 78249
USPA Advance Concept Medical Research Group LLC
South Miami, Florida, 33143
GCP, Global Clinical Professionals
St. Petersburg, Florida, 33705
Sunrise Research Institute
Sunrise, Florida, 33325
Santos Research Center, CORP
Tampa, Florida, 33615
The Institute for Liver Health dba Arizona Clinical Trials
Tucson, Arizona, 85712
Tranquility Research
Webster, Texas, 77598
Hope Clinical Research (COVID Satellite Site)
West Hills, California, 91304
Accellacare
Wilmington, North Carolina, 28401
Clinical Site Partners, Inc. dba CSP Orlando
Winter Park, Florida, 32789
Bulgaria24 sites
Individual Practice for Primary Medical Care - IPPMC - Dr. P. Panayotov EOOD
Burgas, 8001
"Specialized Hospital for Active Treatment of Pneumo-Phthisiatric Diseases-Haskovo" Ltd
Haskovo, 6300
MHAT "Sv.Ivan. Rilski'' Kozloduy EOOD
Kozloduy, 3320
Diagnostic-Consultative Center I Lom EOOD
Lom, 3600
Multiprofile Hospital for Active Treatment- Sveti Nikolay Chudotvoretz EOOD
Lom, 3600
Medical centre Leo Clinic EOOD
Lovech, 5500
MHAT Heart and Brain EAD
Pleven, 5800
DCC Sveti Georgi EOOD
Plovdiv, 4000
MHAT "St. Panteleimon "- Plovdiv
Plovdiv, 4004
Multiprofile Hospital for Active Treatment Sveti Ivan Rilski - Razgrad AD
Razgrad, 7200
"Specialized Hospital for Active Treatment of Pneumo-Physiatric Diseases Dr. Dimitar Gramatikov -
Rousse, 7002
UMHAT Medica Ruse OOD
Rousse, 7013
Multiprofile Hospital for Active Treatment - Samokov EOOD
Samokov, 2000
Medical Center-1-Sevlievo EOOD
Sevlievo, 5400
Multiprofile Hospital For Active Treatment Shumen AD
Shumen, 9700
Multiprofile hospital for active treatment - Sliven to Military Medical Academy
Sliven, 8800
MHAT "Dr. Ivan Seliminski" AD, Sliven
Sliven, 8801
Diagnostic-Consultative Center XXII- Sofia ЕООD
Sofia, 1113
MHAT "St. Sofia" EOOD
Sofia, 1618
Specialized hospital for active treatment in pulmonology and phthisiology "Stara Zagora" EOOD
Stara Zagora, 6000
Multiprofile Hospital for Active Treatment Targovishte AD
Targovishte, 7700
Outpatient Clinic for Primary Outpatient Medical Care "Puls" - Dr. Mladen Buchvarov EOOD
Tsarevo, 8260
Medical center Leo Clinic EOOD
Varna, 9020
Specialized Hospital for Active Treatment of Pneumo-Phthisiatric Diseases Vratsa EOOD
Vratsa, 3000
Mexico16 sites
Centro de Investigacion Clinica Del Pacifico SA de CV
Acapulco
Hospital Cardiologica Aguascalientes
Aguascalientes, CP 201230
InfectoLab Consultorios de Especialidad en Infectologia
Baja California, Tijuana, 22010
JM Research SC
Cuernavaca, Morelos, 62290
Instituto de Investigaciones Clínicas para la Salud
Durango, 34000
Instituto Jalisciense de Metabolismo, S.C.
Guadalajara, Jalisco, 44670
EME RED Hospitalaria
Mérida, Yucatán, 97000
Kohler & Milstein Research S.A. de C.V.
Mérida, Yucatán, 97070
Christus - Latam Hub Center of Excellence and Innovation Center S.C.
Monterrey, Nuevo León, 64060
Eukarya Pharmasite S.C.
Monterrey, Nuevo León, 64718
Oaxaca Site Management Organization
Oaxaca City, Oaxaca, 68000
Asociacion Mexicana para la Investigacion Clinica A.C. (AMIC)
Pachuca, Hidalgo, 42070
Clinical Research Institute Saltillo S.A. de C.V.
Saltillo, Coahuila, 25020
FAICIC S. de R.L. de C.V.
Veracruz, 91900
Sociedad de Metabolismo y Corazon S.C.
Veracruz, 91900
Arké SMO S.A de C.V
Veracruz, 91910
Turkey (Türkiye)15 sites
Ankara University Medical Faculty, Ibni-Sina Hospital
Ankara, 06230
Hacettepe University Medical Faculty Hospital
Ankara, 06230
Akdeniz Universitesi Hastanesi
Antalya, 07059
Istanbul Medipol University Clinical Research Ethics Committee
Beykoz / Istanbul, 34810
Gaziantep University Medical Faculty
Gaziantep, 27300
Istanbul Yedikule Gogus Hastaliklari ve Gogus Cerrahisi Egitim Arastirma Hastanesi
Istanbul, 34020
Istanbul University Cerrahpasa-Cerrahpasa Medical Faculty
Istanbul, 34098
Acibadem Saglik Hizmetleri ve Tic.A.S, Acibadem Atakent Hastanesi
Istanbul, 34303
Istanbul Universitesi Klinik Arastirmalar Mukemmeliyet Uygulama ve Arastirma Merkezi
Istanbul, 34452
Basaksehir Cam ve Sakura Sehir Hastanesi
Istanbul, 34480
Kocaeli University Medical Faculty
Kocaeli, 41380
Sbü Dr. Suat Seren Göğüs Hastaliklari Ve Cerrahisi Eğitim Ve Araştirma Hastanesi
Konak/Izmir, 35170
Mersin University Health Research and Application Hospital
Mersin, 33110
Sakarya University Training and Research Hospital
Sakarya, 54100
Karadeniz Teknik Universitesi Farabi Hastanesi
Trabzon, 61080
Ukraine15 sites
Communal non-profit enterprise "City Clinical Hospital #16" of Dnipro City Council
Dnipro, 49069
Municipal Nonprofit Enterprise "Ivano-Frankivsk Regional Clinical Infectious Diseases Hospital of
Ivano-Frankivsk, 76007
Communal nonprofit enterprise "Central City Clinical Hospital of Ivano-Frankivsk City Council"
Ivano-Frankivsk, 76018
Municipal Nonprofit Enterprise "City Student Hospital" of Kharkiv City Council
Kharkiv, 61002
Municipal Nonprofit Enterprise of Kharkiv Regional Council "Regional Clinical Infectious Diseases
Kharkiv, 61096
"Municipal Non-Profit Enterprise "Alexander Clinical Hospital of Kyiv" of the Kyiv City Council
Kyiv, 01601
Municipal non-commercial enterprise "Kyiv City Clinical Hospital #1" Of Executive Body Of the Kyiv
Kyiv, 02091
Kyiv Railway Clinical Hospital No.2 of Branch "Health Center of the Public Joint Stock Company
Kyiv, 03049
Polyclinic of Center for Medical Services and Rehabilitation of State Joint-Stock Holding Company
Kyiv, 04050
Municipal NonProfit Enterprise of the Lviv Regional Council Lviv Regional Information and Analitical
Lviv, 79008
Municipal Nonprofit Enterprise "Lviv City Clinic Hospital #4"
Lviv, 79011
Municipal Enterprise "Poltava Regional Clinical Infectious Diseases Hospital" of Poltava Regional
Poltava, 36011
Municipal Enterprise "Volyn Regional Clinical Hospital" of Volyn Regional Council
Tarasove Village, 45625
Municipal Non-commercial Enterprise "Vinnytsia City Clinical Hospital №1"
Vinnytsia, 21029
Communal Enterprise "Hospital #1" of Zhytomyr City Council
Zhytomyr, 10002
India12 sites
Jawahar Lal Nehru Medical College
Ajmer, Rajasthan, 305001
BGS Global Institute of Medical Sciences and Hospital
Bangalore, Karnataka, 560060
Apex Hospitals Pvt Ltd
Jaipur, Rajasthan, 302017
Maharaja Agrasen Superspeciality Hospital
Jaipur, Rajasthan, 302039
Lisie Hospital
Kochi, Kerala, 682018
Nil Ratan Sircar Medical College and Hospital
Kolkata, West Bengal, 700014
Aakash Healthcare Private Limited
New Delhi, 110075
Sardar Patel Medical College
Pavan PURI Bikaner, Rajasthan, 334003
Jehangir Clinical Development Centre Pvt. Ltd
Pune, Maharashtra, 411001
Lifepoint Research LLP
Pune, Maharashtra, 411057
AIIMS Raipur
Raipur, Chhattisgarh, 492099
Jupiter Hospital
Vadodara, Gujarat, 390012
South Africa6 sites
East Rand Research Centre T/A Worthwhile Clinical Trials
Benoni, Gauteng, 1500
Synapta Clinical Research Center
Durban, KwaZulu-Natal, 4001
MERC Middelburg
Middelburg, Mpumalanga, 1055
Botho Ke Bontle Health Services
Pretoria, Gauteng, 0122
Limpopo Clinical Research Initiative
Thabazimbi, Limpopo, 0380
MERC Welkom
Welkom, Free State, 9460
Thailand6 sites
Bangkok Centre Hotel
Bang Rak, Bangkok, 10500
Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University,
Hat Yai, Changwat Songkhla, 90110
Faculty of Medicine - Khon Kaen University
Muang, Changwat Khon Kaen, 40002
Chula Field Hospital, Chulalongkorn University Sport center (Chantanayingyong Gymnasium)
Pathum Wan District,, Bangkok, 10330
The HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT),
Pathumwan, Bangkok, 10330
Thai Red Cross Emerging Infectious Diseases (EDI) Clinic
Pathumwan,, Bangkok, 10330
Hungary5 sites
Trial Pharma Kft.
Békéscsaba, 5600
Debreceni Egyetem Klinikai Kozpont Infektologiai Klinika
Debrecen, 4031
Agria-Study Kft.
Eger, 3300
Trial Pharma Kft.
Gyula, 5700
Medifarma-98 Kft.
Nyíregyháza, 4400
Japan5 sites
Tokyo Medical University Hachioji Medical Center
Hachiōji, Tokyo, 1930998
Rinku General Medical Center
Izumisano, Osaka, 598-8577
International University of Health and Welfare Narita Hospital
Narita, Chiba, 286-8520
National Hokkaido Medical Center
Sapporo, Hokkaido, 063-0005
National Center for Global Health and Medicine
Shinjuku, Tokyo, 162-8655
Russia4 sites
Barnaul City Hospital Number 5
Barnaul, 656045
KDC "Evromedservis", OJSC
Moscow, 115419
LLC Trekhgorka Medicine
Odintsovo, Moscow Oblast, 143005
Smolensk State Medical University
Smolensk, 214019
South Korea4 sites
Kyungpook National University Chilgok Hospital
Daegu, 41404
Incheon Medical Center
Incheon, 22532
Chonnam National University Bitgoeul Hospital
Nam-gu, 61748
SMG-SNU Boramae Medical Center
Seoul, 07061
Brazil3 sites
Chronos Pesquisa Clinica
Brasília, Federal District, 72145-450
CECIP JAÚ - Centro de Estudos Clínicos do Interior Paulista - LTDA
Jaú, São Paulo, 17201-130
Hospital Agamenon Magalhaes
Recife, Pernambuco, 52051-380
Argentina2 sites
Hospital De Clínicas Presidente Dr.Nicolas Avellaneda
San Miguel de Tucumán, Tucumán Province, 4000
Instituto de Investigaciones Clinicas Zarate
Zárate, Buenos Aires, B2800DGH
Czechia2 sites
Zdraví-Fit, s.r.o.
Protivín, 398 11
Nemocnice Slany
Slaný, 274 01
Malaysia2 sites
Hospital Umum Sarawak
Kuching, Sarawak, 93586
Hospital Miri
Miri, Sarawak, 98000
Poland2 sites
KLIMED Marek Klimkiewicz
Bialystok, 15-704
Centrum Badań Klinicznych Piotr Napora Lekarze Spółka Partnerska
Wroclaw, 51-162
Puerto Rico2 sites
Clinical Research Management Group Inc
Ponce, 00780
Advance Medical Research Center
San Juan, 00926
Spain2 sites
Complexo Hospitalario Universitario da Coruna
A Coruña, 15006
Eba Centelles
Centelles, Barcelona [barcelona], 08540
Colombia1 site
Fundacion Cardiomet Cequin
Armenia, Quindío Department, 630004
About this study
Official 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
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.
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PF-07321332Drug
PF-07321332 (tablet)
RitonavirDrug
Ritonavir (capsule)
PlaceboDrug
Placebo (tablet or capsule)
| Study group | Role | What they receive |
|---|---|---|
| PF-07321332/ritonavir | Experimental | Orally administered PF-07321332+ritonavir Receives: Drug: PF-07321332; Drug: Ritonavir |
| Placebo | Placebo comparator | Orally administered placebo Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of Participants With Covid-19 Related Hospitalization or Death From Any Cause Through Day 28- Modified Intent-To-Treat (mITT) Population
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.
Measured: From Day 1 to Day 28
Secondary outcomes (37)
Number of Participants With Treatment Emergent Adverse Events (TEAEs)
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.
Measured: From start of study intervention (Day 1) up to end of safety follow-up (Day 34)
Number of Participants With AEs Leading to Discontinuation and Serious Adverse Events (SAEs)
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.
Measured: From start of study intervention (Day 1) up to end of safety follow-up (Day 34)
Percentage of Participants With Covid-19 Related Hospitalization or Death From Any Cause Through Day 28- Modified Intent-To-Treat 1 (mITT1) Population
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.
Measured: From Day 1 to Day 28
Time to Sustained Alleviation of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT1 Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of All Targeted COVID-19 Signs and Symptoms Through Day 28- Modified Intent-to-Treat 2 (mITT2) Population
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.
Measured: From Day 1 (baseline) to Day 28
Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT Population
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.
Measured: From Day 1 to Day 28
Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT1 Population
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.
Measured: From Day 1 to Day 28
Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT2 Population
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.
Measured: From Day 1 to Day 28
Time to Sustained Resolution of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT1 Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of All Targeted COVID-19 Signs and Symptoms Through Day 28- mITT2 Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT1 Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT2 Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT1 Population
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.
Measured: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT2 Population
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.
Measured: From Day 1 (baseline) to Day 28
Number of Participants With Progression to a Worsening Status in 1 or More Self-reported COVID-19 Associated Symptoms Through Day 28-mITT Population
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).
Measured: From Day 1 (baseline) to Day 28
Number of Participants With Progression to a Worsening Status in 1 or More Self-reported COVID-19 Associated Symptoms Through Day 28-mITT1 Population
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).
Measured: From Day 1 (baseline) to Day 28
Number of Participants With Progression to a Worsening Status in 1 or More Self-reported COVID-19 Associated Symptoms Through Day 28-mITT2 Population
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).
Measured: From Day 1 (baseline) to Day 28
Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT Population
In this outcome measure, the percentage of participants with a resting peripheral oxygen saturation >=95% were reported.
Measured: Day 1, 5
Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT1 Population
In this outcome measure, the percentage of participants with a resting peripheral oxygen saturation >=95% were reported.
Measured: Day 1, 5
Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT2 Population
In this outcome measure, the percentage of participants with a resting peripheral oxygen saturation >=95% were reported.
Measured: Day 1, 5
Percentage of Participants Who Died Through Week 24- mITT Population
In this outcome measure, percentage of participants with death due to any cause was presented.
Measured: From Day 1 up to Week 24
Percentage of Participants Who Died Through Week 24- mITT1 Population
In this outcome measure, percentage of participants with death due to any cause was presented.
Measured: From Day 1 up to Week 24
Percentage of Participants Who Died Through Week 24- mITT2 Population
In this outcome measure, percentage of participants with death due to any cause was presented.
Measured: From Day 1 up to Week 24
Plasma Concentration Versus Time Summary of PF-07321332
Measured: 1 Hour post-dose on Day 1 and pre-dose on Day 5
Change From Baseline in Logarithm to Base10 (Log10) Transformed Viral Load at Day 3, 5, 10 and 14- mITT Population
The viral load was measured in nasal or nasopharyngeal samples using reverse transcription polymerase chain reaction (RT-PCR).
Measured: Baseline, Day 3, 5, 10 and 14
Change From Baseline in Log10 Transformed Viral Load at Day 3, 5, 10 and 14- mITT1 Population
The viral load was measured in nasal or nasopharyngeal samples using RT-PCR.
Measured: Baseline, Day 3, 5, 10 and 14
Change From Baseline in Log10 Transformed Viral Load at Day 3, 5, 10 and 14- mITT2 Population
The viral load was measured in nasal or nasopharyngeal samples using RT-PCR.
Measured: Baseline, Day 3, 5, 10 and 14
Number of COVID-19 Related Medical Visits- mITT Population
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.
Measured: From Day 1 up to Day 34
Number of COVID-19 Related Medical Visits- mITT1 Population
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.
Measured: From Day 1 up to Day 34
Number of COVID-19 Related Medical Visits- mITT2 Population
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.
Measured: From Day 1 up to Day 34
Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT Population
Measured: From Day 1 up to Day 34
Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT1 Population
Measured: From Day 1 up to Day 34
Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT2 Population
Measured: From Day 1 up to Day 34
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Jul 2021
- Study start16 Jul 2021
- Primary completion9 Dec 2021
- Study completion25 Apr 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for COVID-19Studies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2/3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Eligible participants with a confirmed diagnosis of SARS-CoV-2 infection will be randomized (1:1) to receive PF-07321332/ritonavir or placebo orally every 12 hours for 5 days (10 doses total).
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 2,091 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04960202
- Sponsor's protocol ID
- C4671005
- Other IDs
- 2021-002895-38, EPIC-HR
- Status last verified
- Jul 2025
- First submitted
- 10 Jul 2021
- Last updated
- 10 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.
Publications
Ansari W, Coetzer H, Gebo KA, Ren J, Scott A, Cappelleri JC, Cha-Silva AS, Leister-Tebbe H. Patient-Reported Outcomes of Nirmatrelvir Treatment for High-Risk, Nonhospitalized Adults With Symptomatic COVID-19. Open Forum Infect Dis. 2025 Aug 1;12(8):ofaf449. doi: 10.1093/ofid/ofaf449. eCollection 2025 Aug.
PubMed 40809391Baniecki ML, Guan S, Rai DK, Yang Q, Lee JT, Hao L, Weinstein E, Hyde C, Cardin RD, Soares H, Hammond J. Integrated virologic analysis of resistance to nirmatrelvir/ritonavir in individuals across four phase 2/3 clinical studies for the treatment of COVID-19. EBioMedicine. 2025 Aug;118:105819. doi: 10.1016/j.ebiom.2025.105819. Epub 2025 Jun 30.
PubMed 40592258Hammond J, Leister-Tebbe H, Gardner A, Abreu P, Bao W, Wisemandle W, Ansari W, Harrington MA, Simon-Campos A, Chew KW, Pypstra R, Rusnak JM. Alleviation of COVID-19 Symptoms and Reduction in Healthcare Utilization Among High-risk Patients Treated With Nirmatrelvir/Ritonavir (NMV/R): A Phase 3 Randomized Trial. Clin Infect Dis. 2025 Feb 24;80(2):323-330. doi: 10.1093/cid/ciae551.
PubMed 39523543Hammond J, Leister-Tebbe H, Gardner A, Abreu P, Bao W, Wisemandle W, Baniecki M, Hendrick VM, Damle B, Simon-Campos A, Pypstra R, Rusnak JM; EPIC-HR Investigators. Oral Nirmatrelvir for High-Risk, Nonhospitalized Adults with Covid-19. N Engl J Med. 2022 Apr 14;386(15):1397-1408. doi: 10.1056/NEJMoa2118542. Epub 2022 Feb 16.
PubMed 35172054
Study at a glance
From the registry record, last updated by the sponsor on 10 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official 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
- ClinicalTrials.gov ID
- NCT04960202
- Acronym / sponsor ID
- C4671005
- Conditions
- COVID-19
- Keywords
- severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 2,091 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 16 Jul 2021 (actual)
- Primary completion
- 9 Dec 2021 (actual)
- Study completion
- 25 Apr 2022 (actual)
- First posted
- 13 Jul 2021 (actual)
- Results
- Posted 9 Feb 2023
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Eligible participants with a confirmed diagnosis of SARS-CoV-2 infection will be randomized (1:1) to receive PF-07321332/ritonavir or placebo orally every 12 hours for 5 days (10 doses total).
| Arm | Type | Receives |
|---|---|---|
| PF-07321332/ritonavir | Experimental | Drug: PF-07321332, Drug: RitonavirOrally administered PF-07321332+ritonavir |
| Placebo | Placebo comparator | Drug: PlaceboOrally administered placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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
Key exclusion criteria (14 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PF-07321332PF-07321332 (tablet) | Drug | PF-07321332/ritonavir |
| RitonavirRitonavir (capsule) | Drug | PF-07321332/ritonavir |
| PlaceboPlacebo (tablet or capsule) | Drug | Placebo |
Primary outcome
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.
37 secondary outcomes
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)
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)
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
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
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
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
Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT Population
Time frame: From Day 1 to Day 28
Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT1 Population
Time frame: From Day 1 to Day 28
Percentage of Participants With Severe Covid-19 Signs and Symptoms Through Day 28- mITT2 Population
Time frame: From Day 1 to Day 28
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
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
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
Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT Population
Time frame: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT1 Population
Time frame: From Day 1 (baseline) to Day 28
Time to Sustained Alleviation of Each Targeted COVID-19 Signs and Symptoms- mITT2 Population
Time frame: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT Population
Time frame: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT1 Population
Time frame: From Day 1 (baseline) to Day 28
Time to Sustained Resolution of Each Targeted COVID-19 Signs and Symptoms- mITT2 Population
Time frame: From Day 1 (baseline) to Day 28
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
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
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
Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT Population
Time frame: Day 1, 5
Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT1 Population
Time frame: Day 1, 5
Percentage of Participants With a Resting Peripheral Oxygen Saturation >=95% at Days 1 and 5- mITT2 Population
Time frame: Day 1, 5
Percentage of Participants Who Died Through Week 24- mITT Population
Time frame: From Day 1 up to Week 24
Percentage of Participants Who Died Through Week 24- mITT1 Population
Time frame: From Day 1 up to Week 24
Percentage of Participants Who Died Through Week 24- mITT2 Population
Time frame: From Day 1 up to Week 24
Plasma Concentration Versus Time Summary of PF-07321332
Time frame: 1 Hour post-dose on Day 1 and pre-dose on Day 5
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
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
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
Number of COVID-19 Related Medical Visits- mITT Population
Time frame: From Day 1 up to Day 34
Number of COVID-19 Related Medical Visits- mITT1 Population
Time frame: From Day 1 up to Day 34
Number of COVID-19 Related Medical Visits- mITT2 Population
Time frame: From Day 1 up to Day 34
Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT Population
Time frame: From Day 1 up to Day 34
Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT1 Population
Time frame: From Day 1 up to Day 34
Number of Days in Hospital and ICU for the Treatment of COVID-19- mITT2 Population
Time frame: From Day 1 up to Day 34
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 40809391Ansari W, Coetzer H, Gebo KA, Ren J, Scott A, Cappelleri JC, Cha-Silva AS, Leister-Tebbe H. Patient-Reported Outcomes of Nirmatrelvir Treatment for High-Risk, Nonhospitalized Adults With Symptomatic COVID-19. Open Forum Infect Dis. 2025 Aug 1;12(8):ofaf449. doi: 10.1093/ofid/ofaf449. eCollection 2025 Aug.
- Derived from this study: PubMed 40592258Baniecki ML, Guan S, Rai DK, Yang Q, Lee JT, Hao L, Weinstein E, Hyde C, Cardin RD, Soares H, Hammond J. Integrated virologic analysis of resistance to nirmatrelvir/ritonavir in individuals across four phase 2/3 clinical studies for the treatment of COVID-19. EBioMedicine. 2025 Aug;118:105819. doi: 10.1016/j.ebiom.2025.105819. Epub 2025 Jun 30.
- Derived from this study: PubMed 39523543Hammond J, Leister-Tebbe H, Gardner A, Abreu P, Bao W, Wisemandle W, Ansari W, Harrington MA, Simon-Campos A, Chew KW, Pypstra R, Rusnak JM. Alleviation of COVID-19 Symptoms and Reduction in Healthcare Utilization Among High-risk Patients Treated With Nirmatrelvir/Ritonavir (NMV/R): A Phase 3 Randomized Trial. Clin Infect Dis. 2025 Feb 24;80(2):323-330. doi: 10.1093/cid/ciae551.
- Derived from this study: PubMed 35172054Hammond J, Leister-Tebbe H, Gardner A, Abreu P, Bao W, Wisemandle W, Baniecki M, Hendrick VM, Damle B, Simon-Campos A, Pypstra R, Rusnak JM; EPIC-HR Investigators. Oral Nirmatrelvir for High-Risk, Nonhospitalized Adults with Covid-19. N Engl J Med. 2022 Apr 14;386(15):1397-1408. doi: 10.1056/NEJMoa2118542. Epub 2022 Feb 16.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
201 sites in 20 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing PF-07321332 and Ritonavir in people with COVID-19, run by Pfizer at 201 sites in 20 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 10 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 201 sites in United States, Bulgaria, Mexico, Turkey (Türkiye), Ukraine and 15 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 9 Feb 2023). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04960202, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jul 2025.