Relative Bioavailability Study of 4 Different Formulations of PF-07321332 Relative to the Commercial Tablet Formulation

May 23, 2025 updated by: Pfizer

A PHASE 1, OPEN-LABEL, RANDOMIZED, SINGLE-DOSE, CROSSOVER STUDY TO ESTIMATE THE RELATIVE BIOAVAILABILITY OF PF-07321332 FOLLOWING ORAL ADMINISTRATION OF 4 DIFFERENT FORMULATIONS RELATIVE TO THE COMMERCIAL TABLET FORMULATION IN HEALTHY ADULT PARTICIPANTS UNDER FASTED CONDITIONS

The purpose of this study is to estimate the relative bioavailability of PF-07321332 in different formulations in healthy adult participants.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

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

Study Locations

  • United States
    • Connecticut
      • New Haven, Connecticut, United States, 06511
        • Pfizer Clinical Research Unit - New Haven

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Participants who are overtly healthy as determined by medical evaluation including medical history, physical examination (PE), laboratory tests, vital signs and standard 12 lead ECGs.
  • Body mass index (BMI) of 17.5 to 30.5 kg/m2; and a total body weight >50 kg (110 lb).
  • Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures

Exclusion Criteria:

  • Positive test result for SARS-CoV-2 infection at the time of Screening or Day -1.
  • Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at the time of dosing).
  • Clinically relevant abnormalities requiring treatment (eg, acute myocardial infarction, unstable ischemic conditions, evidence of ventricular dysfunction, serious tachy or brady arrhythmias) or indicating serious underlying heart disease (eg, prolonged PR interval, cardiomyopathy, heart failure greater than New York Heart Association (NYHA) 1, underlying structural heart disease, Wolff Parkinson-White syndrome).
  • Any condition possibly affecting drug absorption (eg, gastrectomy, cholecystectomy).
  • History of human immunodeficiency virus (HIV) infection, hepatitis B, or hepatitis C; positive testing for HIV, hepatitis B surface antigen (HBsAg), or hepatitis B surface antibody (HCVAb). Hepatitis B vaccination is allowed.
  • Use of prescription or nonprescription drugs and dietary and herbal supplements within 7 days or 5 half lives (whichever is longer) prior to the first dose of study intervention.
  • Participant who have received a COVID-19 vaccine within 7 days before screening or admission, or who are to be vaccinated with a COVID-19 vaccine at any time during the study confinement period.
  • A positive urine drug test.

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Treatment A: PF-0732133/ritonavir
PF-07321332 ritonavir
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single dose orally
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single oral dose orally.
Experimental: Treatment B: PF-07321332/ritonavir
PF-07321332 ritonavir
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single dose orally
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single oral dose orally.
Experimental: Treatment C: PF-07321332/ritonavir
PF-07321332 ritonavir
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single dose orally
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single oral dose orally.
Experimental: Treatment D: PF-07321332/ritonavir
PF-07321332 ritonavir
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single dose orally
Drug: PF-07321332/ritonavir
PF-07321332 ritonavir will be administered as single oral dose orally.
Experimental: Treatment E: PF-07321332
PF-07321332
Drug: PF-07321332
PF-07321332 will be administered as single oral dose orally.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Area Under the Plasma Concentration-Time Profile From Time 0 to the Time of the Last Quantifiable Concentration (Clast) (AUClast) of Nirmatrelvir
Time Frame: 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours postdose
AUClast for nirmatrelvir was calculated by Linear/Log trapezoidal method. Natural log-transformed AUClast for nirmatrelvir (slower dissolution tablets and large particle size tablets) was analyzed using a mixed effect model with sequence, period and treatment as fixed effects and participant within sequence as a random effect. Natural log-transformed AUClast for Nirmatrelvir (SDD suspension) was analyzed using a mixed effect model with sequence and treatment as fixed effects and participant within sequence as a random effect.
0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours postdose
Area Under the Plasma Concentration-Time Profile From Time 0 Extrapolated to Infinite Time (AUCinf) of Nirmatrelvir
Time Frame: 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours postdose
AUCinf for nirmatrelvir was calculated by AUClast + (Clast/kel), where Clast was the predicted plasma concentration at the last quantifiable time point from the log-linear regression analysis and kel is the terminal phase rate constant calculated by a linear regression of the log-linear concentration time curve. Natural log-transformed AUCinf for nirmatrelvir (slower dissolution tablets and large particle size tablets) was analyzed using a mixed effect model with sequence, period and treatment as fixed effects and participant within sequence as a random effect. Natural log-transformed AUCinf for Nirmatrelvir (SDD suspension) was analyzed using a mixed effect model with sequence and treatment as fixed effects and participant within sequence as a random effect.
0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours postdose
Maximum Plasma Concentration (Cmax) of Nirmatrelvir
Time Frame: 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours postdose
Cmax for nirmatrelvir was observed directly from data. Natural log-transformed Cmax for nirmatrelvir (slower dissolution tablets and large particle size tablets) was analyzed using a mixed effect model with sequence, period and treatment as fixed effects and participant within sequence as a random effect. Natural log-transformed Cmax for Nirmatrelvir (SDD suspension) was analyzed using a mixed effect model with sequence and treatment as fixed effects and participant within sequence as a random effect.
0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours postdose

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of Participants With Treatment-Emergent Adverse Events (TEAEs)
Time Frame: Baseline up to 35 days after last dose of study intervention (up to 12 weeks)
An adverse event (AE) was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. AEs might arise from symptoms or other complaints reported to the investigator by the participant (or, when appropriate, by a caregiver, surrogate, or the participant's legally authorized representative), or they might arise from clinical findings of the investigator or other healthcare providers (clinical signs, test results, etc.). TEAEs were those with initial onset or increasing in severity after the first dose of study treatment.
Baseline up to 35 days after last dose of study intervention (up to 12 weeks)
Number of Participants With Laboratory Abnormalities (Without Regard to Baseline Abnormality)
Time Frame: Screening (from Day-28 to Day-2), Day-1 of Period 1 (before 1st dose) and Day4 of Period 5 (4 days after the last dose on study discharge day). Each treatment period was 4 days long (Day1 to Day4) with a minimum of 4 days washout between each period
The laboratory abnormality parameters included Chemistry: bicarbonate (milliequivalents per liter [mEq/L]) <0.9 x lower limit of normal (LLN), urobilinogen (ehrlich units per deciliter [EU/dL]) >=1, and fibrinogen (milligram/deciliter [mg/dL]) >1.25 x baseline; Urinalysis: URINE hemoglobin (Scalar) >=1, only those categories in which at least 1 participant had data were reported. All the safety laboratory samples were collected following at least a 4 hour fast. Clinical laboratory evaluations only included treatments of nirmatrelvir SDD suspension/ritonavir 300/100 mg and nirmatrelvir SDD suspension 300 mg. No participant was evaluable for clinical laboratory evaluations for the other treatments.
Screening (from Day-28 to Day-2), Day-1 of Period 1 (before 1st dose) and Day4 of Period 5 (4 days after the last dose on study discharge day). Each treatment period was 4 days long (Day1 to Day4) with a minimum of 4 days washout between each period
Number of Participants With Vital Signs Abnormalities
Time Frame: Screening (D28-D2), D1 of Period 1 (before 1st dose), D1 hr 0,2,and 6 of each period, and D4 of Period 5 (4 days after the last dose on study discharge day). Each treatment Period was 4 days long (D1-D4) with a minimum 4 days washout between each period
Single supine blood pressure (BP) and pulse rate (PR) were measured with the participant's arm supported at the level of the heart and recorded to the nearest mm Hg after approximately 5 minutes of rest. The same arm (preferably the dominant arm) was used throughout the study. Participants were instructed not to speak during measurements.
Screening (D28-D2), D1 of Period 1 (before 1st dose), D1 hr 0,2,and 6 of each period, and D4 of Period 5 (4 days after the last dose on study discharge day). Each treatment Period was 4 days long (D1-D4) with a minimum 4 days washout between each period
Number of Participants With ECG Abnormalities
Time Frame: Screening (from D-28 to D-2), D1, hr0 of Period 1 (before 1st dose) and D4 of Period 5 (4 days after last dose on study discharge day). Each treatment period was 4 days long (D1 to D4) with a minimum of 4 days washout between each period
Standard 12-lead ECGs utilizing limb leads (with a 10 second rhythm strip) were collected. All scheduled ECGs were performed after the participant had rested quietly for at least 5 minutes in a supine position.
Screening (from D-28 to D-2), D1, hr0 of Period 1 (before 1st dose) and D4 of Period 5 (4 days after last dose on study discharge day). Each treatment period was 4 days long (D1 to D4) with a minimum of 4 days washout between each period
Number of Participants With Physical Examination Abnormalities
Time Frame: Screening (from Day-28 to Day-2), Day-1 of Period 1 (before 1st dose. Each treatment period was 4 days long (Day1 to Day4) with a minimum of 4 days washout between each period
A complete PE included, at a minimum, head, ears, eyes, nose, mouth, skin, heart and lung examinations, lymph nodes, and gastrointestinal, musculoskeletal, and neurological systems. A brief physical examination included, at a minimum, assessments of general appearance, the respiratory and cardiovascular systems, and participant reported symptoms.
Screening (from Day-28 to Day-2), Day-1 of Period 1 (before 1st dose. Each treatment period was 4 days long (Day1 to Day4) with a minimum of 4 days washout between each period

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Pfizer

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 3, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 16, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 16, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 25, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 25, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 3, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 11, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 23, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • C4671008
  • NCT05263895 (Registry Identifier: ClinicalTrials.gov)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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

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