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COVID-19Phase 3NCT05261139

EPIC-Peds: A Study to Learn About the Study Medicine Called PF-07321332 (Nirmatrelvir)/Ritonavir in Patients Under 18 Years of Age With COVID-19 That Are Not Hospitalized But Are at Risk for Severe Disease

A Phase 3 study testing nirmatrelvir and ritonavir in people with COVID-19, run by Pfizer at 73 sites in 7 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

The purpose of this clinical trial is to learn about the safety, pharmacokinetics (pharmacokinetics helps us understand how the drug is changed and eliminated from your body after you take it), and efficacy (how well a study treatment works in the study) of the study medicine (called nirmatrelvir/ritonavir) for… Read more about this study

Who is it for?
Ages 0 to 17 years
Conditions the study is for
COVID-19
What is being tested?
nirmatrelvir and ritonavir
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
160 participants
Where
73 sitesin 7 countries
Study dates
7 Mar 2022to 30 Jul 2026
Phase
Phase 3
Are there results?
Not yet: the study is under way

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 0 to 17 years
  • All sexes
  • No healthy volunteers
  • Child

Who may be able to join

  • Male and female, age 0 to < 18 years, able to swallow for some participants
  • Confirmed SARS-CoV-2 infection within 72 hours prior to enrollment
  • Initial onset of COVID-19 signs/symptoms within 5 days prior to the day of enrollment and at least 1 of the specified COVID-19 signs/symptoms present at enrollment
  • 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
  • Total bilirubin >=2X upper limit of normal (ULN) (except for Gilbert's syndrome)
  • Receiving dialysis or have known moderate to severe renal impairment
  • 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 strong inducers of cytochrome P450 (CYP)3A4
Show all 9Show fewer
  • Has received or is expected to receive antibody treatment, antiviral treatment or convalescent COVID-19 plasma
  • Participating in another interventional clinical study with an investigational compound or device, including those for COVID-19 through the study follow up
  • Females who are pregnant or breastfeeding

Trial locations and contacts

73 sites in 7 countries. Contact the study team or a site near you to ask about taking part.

73 sites in 7 countries

United States50 sites, 24 recruiting
  • University of New Mexico Hospital, COVID-19 Research Clinic

    Albuquerque, New Mexico, 87102

    Terminated
  • University of New Mexico Clinical and Translational Science Center

    Albuquerque, New Mexico, 87106

    Terminated
  • Children's Healthcare of Atlanta - Arthur M. Blank Hospital

    Atlanta, Georgia, 30329

    Recruiting
  • Johns Hopkins Hospital

    Baltimore, Maryland, 21287

    Not yet recruiting
  • Boston Medical Center

    Boston, Massachusetts, 02118

    Active, not recruiting
  • Suny University at Buffalo

    Buffalo, New York, 14203

    Not yet recruiting
  • Clinical and Translational Research Center

    Chapel Hill, North Carolina, 27514

    Terminated
  • investigational Drug Services Pharmacy, UNC Hospitals

    Chapel Hill, North Carolina, 27514

    Terminated
  • UNC Children's Hospital

    Chapel Hill, North Carolina, 27514

    Terminated
  • UNC Global Clinical Research North

    Chapel Hill, North Carolina, 27514

    Terminated
  • University of North Carolina Medical Center

    Chapel Hill, North Carolina, 27599

    Terminated
  • Ann & Robert H. Lurie Children's Hospital of Chicago

    Chicago, Illinois, 60611

    Active, not recruiting
  • University of Chicago Medical Center

    Chicago, Illinois, 60637

    Recruiting
  • University Hospitals Cleveland Medical Center

    Cleveland, Ohio, 44106

    Active, not recruiting
  • Advanced Specialty Care

    Commack, New York, 11725

    Not yet recruiting
  • Stony Brook Medicine Clinical Research Center

    East Setauket, New York, 11733

    Not yet recruiting
  • Texas Children's Hospital

    Houston, Texas, 77030

    Not yet recruiting
  • Children's Hospital Los Angeles

    Los Angeles, California, 90027

    Active, not recruiting
  • Kaiser Permanente

    Los Angeles, California, 90027

    Active, not recruiting
  • UCLA David Geffen School of Medicine

    Los Angeles, California, 90095

    Not yet recruiting
  • UCLA

    Los Angeles, California, 90095

    Not yet recruiting
  • UH Landerbrook Health Center

    Mayfield Heights, Ohio, 44124

    Active, not recruiting
  • Biopharma Informatic, LLC

    McAllen, Texas, 78503

    Terminated
  • Life Spring Research Foundation

    Miami, Florida, 33130

    Recruiting
  • Childrens Hospitals and Clinics of Minnesota

    Minneapolis, Minnesota, 55404

    Not yet recruiting
  • Cohen Children's Medical Center

    New Hyde Park, New York, 11040

    Not yet recruiting
  • Columbia University Irving Medical Center

    New York, New York, 10032

    Not yet recruiting
  • Children's Hospital & Medical Center

    Omaha, Nebraska, 68114

    Terminated
  • UH Parma Medical Center

    Parma, Ohio, 44129

    Active, not recruiting
  • Phoenix Children's Hospital

    Phoenix, Arizona, 85016

    Active, not recruiting
  • Children's Hospital of Pittsburgh

    Pittsburgh, Pennsylvania, 15213

    Not yet recruiting
  • Rhode Island Hospital

    Providence, Rhode Island, 02903

    Active, not recruiting
  • The Miriam Hospital-Clinical Trials

    Providence, Rhode Island, 02904

    Active, not recruiting
  • UNC Children's Raleigh

    Raleigh, North Carolina, 27607

    Terminated
  • SKY Integrative Medical Center/SKYCRNG

    Ridgeland, Mississippi, 39157

    Active, not recruiting
  • University of Utah

    Salt Lake City, Utah, 84108

    Not yet recruiting
  • Consano Clinical Research, LLC

    Shavano Park, Texas, 78231

    Recruiting
  • Louisiana State University Health Sciences Shreveport

    Shreveport, Louisiana, 71101

    Recruiting
  • Avera McKennan Hospital & University Health Center

    Sioux Falls, South Dakota, 57105

    Terminated
  • Avera Research Institute - Sioux Falls

    Sioux Falls, South Dakota, 57108

    Terminated
  • St. Louis Children's Hospital

    St Louis, Missouri, 63110

    Not yet recruiting
  • Washington University School of Medicine

    St Louis, Missouri, 63110

    Not yet recruiting
  • Stony Brook University

    Stony Brook, New York, 11794

    Not yet recruiting
  • Upstate Health Care Center

    Syracuse, New York, 13202

    Not yet recruiting
  • Crouse Physicians Office Building

    Syracuse, New York, 13210

    Not yet recruiting
  • SUNY Upstate Medical University

    Syracuse, New York, 13210

    Not yet recruiting
  • Upstate Golisano Children's Hospital

    Syracuse, New York, 13210

    Not yet recruiting
  • Rophe Adult and Pediatric Medicine/SKYCRNG

    Union City, Georgia, 30291

    Terminated
  • Children's National Medical Center

    Washington D.C., District of Columbia, 20010

    Active, not recruiting
  • University of Massachusetts Chan Medical School

    Worcester, Massachusetts, 01655

    Terminated

Other trials in United States

Mexico11 sites, 2 recruiting
  • Centenario Hospital Miguel Hidalgo

    Aguascalientes, 20259

    Not yet recruiting
  • JM Research SC

    Cuernavaca, Morelos, 62290

    Active, not recruiting
  • Unidad de Atención Médica e Investigación en Salud

    Mérida, Yucatán, 97000

    Active, not recruiting
  • Kohler & Milstein Research S.A. De C.V.

    Mérida, Yucatán, 97070

    Active, not recruiting
  • Centro Multidisciplinario para el Desarrollo Especializado de la Investigacion Clinica en Yucatán S.

    Mérida, Yucatán, 97130

    Active, not recruiting
  • Instituto Nacional de Pediatria

    Mexico City, Mexico City, 04530

    Not yet recruiting
  • Hospital Infantil de Mexico Federico Gomez

    Mexico City, Mexico City, 06720

    Active, not recruiting
  • Fundación Santos y De la Garza Evia

    Monterrey, Nuevo León, 64710

    Active, not recruiting
  • Eukarya Pharmasite S.C.

    Monterrey, Nuevo León, 64718

    Terminated
  • Arké SMO S.A de C.V

    Veracruz, 91900

    Active, not recruiting
  • Sociedad de Metabolismo y Corazon S.C.

    Veracruz, C.P. 91900

    Active, not recruiting

Other trials in Mexico

Bulgaria5 sites, 4 recruiting
  • МHAT "Sveti Ivan Rilski" Gorna Oryahovitsa

    Gorna Oryahovitsa, 5100

    Not yet recruiting
  • "Specialized Hospital for Active Treatment of Pneumo-Physiatric Diseases Dr. Dimitar Gramatikov -

    Rousse, 7002

    Not yet recruiting
  • Medical Center-1-Sevlievo EOOD

    Sevlievo, 5400

    Not yet recruiting
  • DCC "Alexandrovska"

    Sofia, 1431

    Terminated
  • Specialized Hospital for Active Treatment of Pneumo-Phthisiatric Diseases Vratsa EOOD

    Vratsa, 3000

    Not yet recruiting

Other trials in Bulgaria

South Africa3 sites, 1 recruiting
  • Worthwhile Clinical Trials

    Benoni, Gauteng, 1500

    Active, not recruiting
  • CRISMO Research Centre

    Germiston, Gauteng, 1401

    Active, not recruiting
  • Botho Ke Bontle Health Services

    Pretoria, Gauteng, 0184

    Not yet recruiting

Other trials in South Africa

Japan2 sites, 2 recruiting
  • Tokyo Metropolitan Children's Medical Center

    Fuchū, Tokyo, 183-8561

    Not yet recruiting
  • Osaka City General Hospital

    Osaka, 534-0021

    Not yet recruiting

Other trials in Japan

Puerto Rico1 site, 1 recruiting
  • San Miguel Medical

    Trujillo Alto, 00976

    Not yet recruiting

Other trials in Puerto Rico

United Kingdom1 site
  • St. George's Hospital

    London, England, SW17 0QT

    Active, not recruiting

Other trials in United Kingdom

About this study

Official title: A PHASE 2/3, INTERVENTIONAL SAFETY, PHARMACOKINETICS, AND EFFICACY, OPEN-LABEL, MULTI-CENTER, SINGLE-ARM STUDY TO INVESTIGATE ORALLY ADMINISTERED PF-07321332 (NIRMATRELVIR)/RITONAVIR IN NONHOSPITALIZED SYMPTOMATIC PEDIATRIC PARTICIPANTS WITH COVID-19 WHO ARE AT RISK OF PROGRESSION TO SEVERE DISEASE

The purpose of this clinical trial is to learn about the safety, pharmacokinetics (pharmacokinetics helps us understand how the drug is changed and eliminated from your body after you take it), and efficacy (how well a study treatment works in the study) of the study medicine (called nirmatrelvir/ritonavir) for potential treatment of coronavirus disease 2019 (COVID-19).

The study medicine will be given to patients under 18 years of age with COVID-19 that are not hospitalized but are at risk for severe disease.

Conditions
COVID-19
Being tested
nirmatrelvir, ritonavir
Keywords
Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), Pediatrics
Medical subject headings
COVID-19

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • nirmatrelvirDrug

    PF-07321332

  • ritonavirDrug

    ritonavir

Study groups in NCT05261139
Study groupRoleWhat they receive
Cohort 1 nirmatrelvir/ritonavirExperimentalnirmatrelvir/ritonavir will be given by tablets or powder by mouth twice a day for 5 days (10 doses total). Weight ≥40 kg 1. ≥12 to <18 years 2. ≥6 to <12 years
Receives: Drug: nirmatrelvir; Drug: ritonavir
Cohort 2 nirmatrelvir/ritonavirExperimentalnirmatrelvir/ritonavir will be given as powder by mouth twice a day for 5 days (10 doses total) Weight ≥20 to <40 kg, ≥6 to <18 years
Receives: Drug: nirmatrelvir; Drug: ritonavir
Cohort 3 nirmatrelvir/ritonavirExperimentalnirmatrelvir/ritonavir ≥2 to <6 years
Receives: Drug: nirmatrelvir; Drug: ritonavir
Cohort 4 nirmatrelvir/ritonavirExperimentalnirmatrelvir/ritonavir ≥1 month (≥28 days) to <2 years
Receives: Drug: nirmatrelvir; Drug: ritonavir
Cohort 5 nirmatrelvir/ritonavirExperimentalnirmatrelvir/ritonavir <1 month (<28 days) old
Receives: Drug: nirmatrelvir; Drug: ritonavir

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Cohort 1-2: Maximum Observed Plasma Concentration (Cmax) of nirmatrelvir and ritonavir

    Measured: Day 1: 1 hour-post dose; Day 4: pre-dose; Day 5: pre-dose, and 1, and 2 hours post dose

  2. Cohort 1-2: Area Under the Curve to the End of the Dosing Period (AUC0-tau) of nirmatrelvir and ritonavir

    Measured: Day 1: 1 hour-post dose; Day 4: pre-dose; Day 5: pre-dose, and 1, and 2 hours post dose

  3. Incidence of Treatment Emergent Adverse Events (TEAEs) leading to discontinuations.

    Measured: From Baseline up through Day 34

  4. Incidence of Serious Adverse Events (SAEs) leading to discontinuations.

    Measured: From Baseline up through Day 34

  5. Incidence of Adverse Events (AEs) leading to discontinuations.

    Measured: From Baseline up through Day 34

  6. Number of participants with change from Baseline in Vital Signs

    Measured: From Baseline up through Day 34

Secondary outcomes (3)
  1. Viral load assessment titers measured via reverse transcription polymerase chain reaction (RT-PCR) in nasopharyngeal or nasal swabs over time

    Measured: Baseline, Day 5, 6, 10, 14 and 28

  2. Proportion of participants with COVID-19 related hospitalization or death from any cause

    Measured: From Baseline through Day 28

  3. Patient assessment on acceptability and palatability of nirmatrelvir/ritonavir (film-coated tablets and oral powder)

    Frequency of responses to visual questionnaire on taste.

    Measured: At baseline only for tablets and after each dose for powder formulation

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Mar 2022
  2. Study start7 Mar 2022
  3. Primary completion30 Jul 2026 (estimated)
  4. Study completion30 Jul 2026 (estimated)

Resources

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 3
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Single group
Masking
None (open label)
Enrolment
160 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05261139
Sponsor's protocol ID
C4671026
Other IDs
2023-509773-23-00, 2023
Status last verified
Jul 2025
First submitted
25 Feb 2022
Last updated
17 Jul 2025
Results posted
No
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.

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing nirmatrelvir and ritonavir in people with COVID-19, run by Pfizer at 73 sites in 7 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 9 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: looking for participants now, as of the sponsor's last update on 17 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 73 sites in United States, Mexico, Bulgaria, South Africa, Japan and 2 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

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?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Pfizer CT.gov Call Center (1-800-718-1021, ClinicalTrials.gov_Inquiries@pfizer.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Cohort 1-2: Maximum Observed Plasma Concentration (Cmax) of nirmatrelvir and ritonavir (time frame: Day 1: 1 hour-post dose; Day 4: pre-dose; Day 5: pre-dose, and 1, and 2 hours post dose). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?
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 17 Jul 2025.

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Clinical Trial NCT05261139 | AzTrials