A Study to Learn About PAXLOVID (a Commercial Medicine) In People With COVID-19

NCT05263908 | Completed Results

• 2 other identifiers: C4671018NCT05263908
• Study Type: observational
• Target: 3,346
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this post marketing observational study is to learn about the safety and effects of the commercial medicine (called PAXLOVID) for the treatment of COVID-19. This study is intended to be registered with the participants who:

• Have taken PAXLOVID PACK and have no history of using this medicine.
• Are 12 years and older All participants will receive PAXLOVID, a standard treatment for COVID-19. Participants will take PAXLOVID 2 times a day by mouth or as prescribed. We will examine the experiences of people taking PAXLOVID. This will help us determine if PAXLOVID is safe and effective. Participants will be followed up for 28 days after taking PAXLOVID. During this time, participants will be closely watched for the safety and effects of PAXLOVID.

Conditions

SARS-CoV-2 Infection

Keywords

severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); coronavirus disease 2019 (COVID-19); Paxlovid; Nirmatrelvir

Outcome Measures

Primary Outcomes (1)

• Incidence of Adverse Drug Reactions

  Adverse drug reaction (ADR) was a treatment-related adverse event and any untoward medical occurrence attributed to Paxlovid PACK in a participant who received Paxlovid PACK. Serious adverse drug reaction (SADR) was a treatment-related adverse event resulting in any of the following outcomes or deemed significant for any other reason: death; life-threatening; initial or prolonged inpatient hospitalization; persistent or significant disability/incapacity; congenital anomaly/birth defect. Relatedness to Paxlovid PACK was assessed by the physician.

  From the start date of treatment with Paxlovid PACK to 28 days after the end of treatment, up to approximately 45 days.

Secondary Outcomes (5)

• Percentage of Participants With Worsening Severity (Efficacy Analysis Set #1)

  From the start date of treatment with Paxlovid PACK to 28 days after the end of treatment, up to approximately 45 days.

• Percentage of Participants With Worsening Severity (Efficacy Analysis Set #2)

  From the start date of treatment with Paxlovid PACK to 28 days after the end of treatment, up to approximately 35 days.

• Percentage of Participants With Worsening Severity (Efficacy Analysis Set #3)

  From the start date of treatment with Paxlovid PACK to 28 days after the end of treatment, up to approximately 35 days.

• Cumulative Incidence Rate of COVID-19 Related Hospitalization or Death From Any Cause Through Day 28 (Efficacy Analysis Set #3)

  3, 5, 7, 14, 21 and 28 days after the start of administration with Paxlovid PACK.

• Cumulative Incidence Rate of COVID-19 Related Hospitalization or Death From Any Cause Through Day 28 (Sensitivity Analysis) (Efficacy Analysis Set #3)

  3, 5, 7, 14, 21 and 28 days after the start of administration with Paxlovid PACK.

Study Arms (1)

PAXLOVID PACK

Subjects administered PAXLOVID PACK

Drug: nirmatrelvir / ritonavir

Interventions

nirmatrelvir / ritonavir DRUG

The usual dosage in adults and pediatric patients (≥12 years of age weighing ≥40 kg) is 300 mg of Nirmatrelvir and 100 mg of ritonavir all taken together orally twice daily for 5 days.

Also known as: PAXLOVID PACK

PAXLOVID PACK

Eligibility Criteria

• Age: 12 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

The subjects who have been treated with PAXLOVID PACK for the first time.

You may qualify if:

• Subjects who are administered PAXLOVID PACK and have no history of using this drug.

Sponsors & Collaborators

• Pfizer: lead

Study Sites (1)

Pfizer Local County

Tokyo, 1518589, Japan

Location

Related Publications (1)

• Murata K, Hyokai S, Fujii Y, Morimasa M. Real-world safety of nirmatrelvir plus ritonavir in patients with COVID-19 in Japan: A post-marketing surveillance study. Jpn J Infect Dis. 2026 Jan 30. doi: 10.7883/yoken.JJID.2024.380. Online ahead of print.

  PMID: 41621946 DERIVED

Related Links

• To obtain contact information for a study center near you, click here.

MeSH Terms

Conditions

COVID-19

Interventions

nirmatrelvir and ritonavir drug combination

Condition Hierarchy (Ancestors)

Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases

Results Point of Contact

• Title: Pfizer ClinicalTrials.gov Call Center
• Organization: Pfizer, Inc.

ClinicalTrials.gov_Inquiries@pfizer.com

1-800-718-1021

Study Officials

• Pfizer CT.gov Call Center

  Pfizer

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: observational
• Observational Model: CASE ONLY
• Time Perspective: PROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 25, 2022
• First Posted: March 3, 2022
• Study Start: March 31, 2022
• Primary Completion: July 10, 2023
• Study Completion: July 10, 2023
• Last Updated: September 3, 2025
• Results First Posted: September 3, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

JP (1)