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

July 16, 2025 updated by: Pfizer

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

160

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Bulgaria
      • Gorna Oryahovitsa, Bulgaria, 5100
        • Not yet recruiting
        • МHAT "Sveti Ivan Rilski" Gorna Oryahovitsa
      • Ruse, Bulgaria, 7002
        • Not yet recruiting
        • "Specialized Hospital for Active Treatment of Pneumo-Physiatric Diseases Dr. Dimitar Gramatikov -
      • Sevlievo, Bulgaria, 5400
        • Not yet recruiting
        • Medical Center-1-Sevlievo EOOD
      • Sofia, Bulgaria, 1431
        • Terminated
        • DCC "Alexandrovska"
      • Vratsa, Bulgaria, 3000
        • Not yet recruiting
        • Specialized Hospital for Active Treatment of Pneumo-Phthisiatric Diseases Vratsa EOOD
  • Japan
      • Osaka, Japan, 534-0021
        • Not yet recruiting
        • Osaka City General Hospital
    • Tokyo
      • Fuchu, Tokyo, Japan, 183-8561
        • Not yet recruiting
        • Tokyo Metropolitan Children's Medical Center
  • Mexico
      • Aguascalientes, Mexico, 20259
        • Not yet recruiting
        • Centenario Hospital Miguel Hidalgo
      • Veracruz, Mexico, C.P. 91900
        • Active, not recruiting
        • Sociedad de Metabolismo y Corazón S.C.
      • Veracruz, Mexico, 91900
        • Active, not recruiting
        • Arké SMO S.A de C.V
    • Distrito Federal
      • Mexico City, Distrito Federal, Mexico, 04530
        • Not yet recruiting
        • Instituto Nacional de Pediatría
      • Mexico City, Distrito Federal, Mexico, 06720
        • Active, not recruiting
        • Hospital Infantil de México Federico Gómez
    • Morelos
      • Cuernavaca, Morelos, Mexico, 62290
        • Active, not recruiting
        • JM Research SC
    • Nuevo LEON
      • Monterrey, Nuevo LEON, Mexico, 64718
        • Terminated
        • Eukarya Pharmasite S.C.
    • Nuevo LEÓN
      • Monterrey, Nuevo LEÓN, Mexico, 64710
        • Active, not recruiting
        • Fundación Santos y De la Garza Evia
    • Yucatan
      • Merida, Yucatan, Mexico, 97070
        • Active, not recruiting
        • Kohler & Milstein Research S.A. De C.V.
    • Yucatán
      • Merida, Yucatán, Mexico, 97130
        • Active, not recruiting
        • Centro Multidisciplinario para el Desarrollo Especializado de la Investigacion Clinica en Yucatan S.
      • Mérida, Yucatán, Mexico, 97000
        • Active, not recruiting
        • Unidad de Atención Médica e Investigación en Salud
  • Puerto Rico
      • Trujillo Alto, Puerto Rico, 00976
        • Not yet recruiting
        • San Miguel Medical
  • South Africa
    • Gauteng
      • Benoni, Gauteng, South Africa, 1500
        • Active, not recruiting
        • Worthwhile Clinical Trials
      • Germiston, Gauteng, South Africa, 1401
        • Active, not recruiting
        • CRISMO Research Centre
      • Pretoria, Gauteng, South Africa, 0184
        • Not yet recruiting
        • Botho ke Bontle Health Services
  • United Kingdom
    • England
      • London, England, United Kingdom, SW17 0QT
        • Active, not recruiting
        • St. George's Hospital
  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85016
        • Active, not recruiting
        • Phoenix Children's Hospital
    • California
      • Los Angeles, California, United States, 90095
        • Not yet recruiting
        • UCLA
      • Los Angeles, California, United States, 90027
        • Active, not recruiting
        • Children's Hospital Los Angeles
      • Los Angeles, California, United States, 90027
        • Active, not recruiting
        • Kaiser Permanente
      • Los Angeles, California, United States, 90095
        • Not yet recruiting
        • UCLA David Geffen School of Medicine
    • District of Columbia
      • Washington, District of Columbia, United States, 20010
        • Active, not recruiting
        • Children's National Medical Center
    • Florida
      • Miami, Florida, United States, 33130
        • Recruiting
        • Life Spring Research Foundation
    • Georgia
      • Atlanta, Georgia, United States, 30329
        • Recruiting
        • Children's Healthcare of Atlanta - Arthur M. Blank Hospital
      • Union City, Georgia, United States, 30291
        • Terminated
        • Rophe Adult and Pediatric Medicine/SKYCRNG
    • Illinois
      • Chicago, Illinois, United States, 60637
        • Recruiting
        • University of Chicago Medical Center
      • Chicago, Illinois, United States, 60611
        • Active, not recruiting
        • Ann & Robert H. Lurie Children's Hospital of Chicago
    • Louisiana
      • Shreveport, Louisiana, United States, 71101
        • Recruiting
        • Louisiana State University Health Sciences Shreveport
    • Maryland
      • Baltimore, Maryland, United States, 21287
        • Not yet recruiting
        • Johns Hopkins Hospital
    • Massachusetts
      • Boston, Massachusetts, United States, 02118
        • Active, not recruiting
        • Boston Medical Center
      • Worcester, Massachusetts, United States, 01655
        • Terminated
        • University of Massachusetts Chan Medical School
    • Minnesota
      • Minneapolis, Minnesota, United States, 55404
        • Not yet recruiting
        • Childrens Hospitals and Clinics of Minnesota
    • Mississippi
      • Ridgeland, Mississippi, United States, 39157
        • Active, not recruiting
        • SKY Integrative Medical Center/SKYCRNG
    • Missouri
      • Saint Louis, Missouri, United States, 63110
        • Not yet recruiting
        • Washington University School of Medicine
      • Saint Louis, Missouri, United States, 63110
        • Not yet recruiting
        • St. Louis Children's Hospital
    • Nebraska
      • Omaha, Nebraska, United States, 68114
        • Terminated
        • Children's Hospital & Medical Center
    • New Mexico
      • Albuquerque, New Mexico, United States, 87102
        • Terminated
        • University of New Mexico Hospital, COVID-19 Research Clinic
      • Albuquerque, New Mexico, United States, 87106
        • Terminated
        • University of New Mexico Clinical and Translational Science Center
    • New York
      • Buffalo, New York, United States, 14203
        • Not yet recruiting
        • Suny University at Buffalo
      • Commack, New York, United States, 11725
        • Not yet recruiting
        • Advanced Specialty Care
      • East Setauket, New York, United States, 11733
        • Not yet recruiting
        • Stony Brook Medicine Clinical Research Center
      • New Hyde Park, New York, United States, 11040
        • Not yet recruiting
        • Cohen Children's Medical Center
      • New York, New York, United States, 10032
        • Not yet recruiting
        • Columbia University Irving Medical Center
      • Stony Brook, New York, United States, 11794
        • Not yet recruiting
        • Stony Brook University
      • Syracuse, New York, United States, 13210
        • Not yet recruiting
        • SUNY Upstate Medical University
      • Syracuse, New York, United States, 13202
        • Not yet recruiting
        • Upstate Health Care Center
      • Syracuse, New York, United States, 13210
        • Not yet recruiting
        • Crouse Physicians Office Building
      • Syracuse, New York, United States, 13210
        • Not yet recruiting
        • Upstate Golisano Children's Hospital
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27514
        • Terminated
        • Clinical And Translational Research Center
      • Chapel Hill, North Carolina, United States, 27514
        • Terminated
        • investigational Drug Services Pharmacy, UNC Hospitals
      • Chapel Hill, North Carolina, United States, 27514
        • Terminated
        • UNC Children's Hospital
      • Chapel Hill, North Carolina, United States, 27514
        • Terminated
        • UNC Global Clinical Research North
      • Chapel Hill, North Carolina, United States, 27599
        • Terminated
        • University of North Carolina Medical Center
      • Raleigh, North Carolina, United States, 27607
        • Terminated
        • UNC Children's Raleigh
    • Ohio
      • Cleveland, Ohio, United States, 44106
        • Active, not recruiting
        • University Hospitals Cleveland Medical Center
      • Mayfield Heights, Ohio, United States, 44124
        • Active, not recruiting
        • UH Landerbrook Health Center
      • Parma, Ohio, United States, 44129
        • Active, not recruiting
        • UH Parma Medical Center
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15213
        • Not yet recruiting
        • Children's Hospital of Pittsburgh
    • Rhode Island
      • Providence, Rhode Island, United States, 02903
        • Active, not recruiting
        • Rhode Island Hospital
      • Providence, Rhode Island, United States, 02904
        • Active, not recruiting
        • The Miriam Hospital-Clinical Trials
    • South Dakota
      • Sioux Falls, South Dakota, United States, 57105
        • Terminated
        • Avera McKennan Hospital & University Health Center
      • Sioux Falls, South Dakota, United States, 57108
        • Terminated
        • Avera Research Institute - Sioux Falls
    • Texas
      • Houston, Texas, United States, 77030
        • Not yet recruiting
        • Texas Children's Hospital
      • McAllen, Texas, United States, 78503
        • Terminated
        • Biopharma Informatic, LLC
      • Shavano Park, Texas, United States, 78231
        • Recruiting
        • Consano Clinical Research, LLC
    • Utah
      • Salt Lake City, Utah, United States, 84108
        • Not yet recruiting
        • University of Utah

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

1 second to 17 years (Child)

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • 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

Exclusion Criteria:

  • 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
  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Cohort 3 nirmatrelvir/ritonavir

nirmatrelvir/ritonavir

≥2 to <6 years
Drug: nirmatrelvir
PF-07321332
Drug: ritonavir
ritonavir
Experimental: Cohort 1 nirmatrelvir/ritonavir

nirmatrelvir/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
Drug: nirmatrelvir
PF-07321332
Drug: ritonavir
ritonavir
Experimental: Cohort 2 nirmatrelvir/ritonavir
nirmatrelvir/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
Drug: nirmatrelvir
PF-07321332
Drug: ritonavir
ritonavir
Experimental: Cohort 4 nirmatrelvir/ritonavir

nirmatrelvir/ritonavir

≥1 month (≥28 days) to <2 years
Drug: nirmatrelvir
PF-07321332
Drug: ritonavir
ritonavir
Experimental: Cohort 5 nirmatrelvir/ritonavir
nirmatrelvir/ritonavir <1 month (<28 days) old
Drug: nirmatrelvir
PF-07321332
Drug: ritonavir
ritonavir

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of Treatment Emergent Adverse Events (TEAEs) leading to discontinuations.
Time Frame: From Baseline up through Day 34
From Baseline up through Day 34
Incidence of Serious Adverse Events (SAEs) leading to discontinuations.
Time Frame: From Baseline up through Day 34
From Baseline up through Day 34
Incidence of Adverse Events (AEs) leading to discontinuations.
Time Frame: From Baseline up through Day 34
From Baseline up through Day 34
Number of participants with change from Baseline in Vital Signs
Time Frame: From Baseline up through Day 34
From Baseline up through Day 34
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
Day 1: 1 hour-post dose; Day 4: pre-dose; Day 5: pre-dose, and 1, and 2 hours post dose
Cohort 1-2: Area Under the Curve to the End of the Dosing Period (AUC0-tau) 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
Day 1: 1 hour-post dose; Day 4: pre-dose; Day 5: pre-dose, and 1, and 2 hours post dose

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient assessment on acceptability and palatability of nirmatrelvir/ritonavir (film-coated tablets and oral powder)
Time Frame: At baseline only for tablets and after each dose for powder formulation
Frequency of responses to visual questionnaire on taste.
At baseline only for tablets and after each dose for powder formulation
Viral load assessment titers measured via reverse transcription polymerase chain reaction (RT-PCR) in nasopharyngeal or nasal swabs over time
Time Frame: Baseline, Day 5, 6, 10, 14 and 28
Baseline, Day 5, 6, 10, 14 and 28
Proportion of participants with COVID-19 related hospitalization or death from any cause
Time Frame: From Baseline through Day 28
From Baseline through Day 28

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Pfizer

Investigators

  • Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 7, 2022

Primary Completion (Estimated)

July 30, 2026

Study Completion (Estimated)

July 30, 2026

Study Registration Dates

First Submitted

February 25, 2022

First Submitted That Met QC Criteria

February 28, 2022

First Posted (Actual)

March 2, 2022

Study Record Updates

Last Update Posted (Actual)

July 17, 2025

Last Update Submitted That Met QC Criteria

July 16, 2025

Last Verified

July 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • C4671026
  • 2023-509773-23-00 (Registry Identifier: CTIS (EU))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

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.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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