AzTrials
AzTrials

Coronavirus Disease 2019Phase 1NCT07552779

A Study of How Ibuzatrelvir is Taken up Into the Blood of Healthy Adults After Taking Different Tablets of Ibuzatrelvir

A Phase 1 study testing Ibuzatrelvir co-process API film coated tablet and Ibuzatrelvir filmcoated tablet in people with Coronavirus Disease 2019 and Coronavirus Disease 2019 (COVID-19), run by Pfizer at 1 site in Belgium.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

Healthy adults will be enrolled into this open-label, Phase 1 research study. Participants will spend about 9 nights and 10 days in the clinical research unit (CRU) and the total time in the study will be about 11 weeks. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
What is being tested?
Ibuzatrelvir co-process API film coated tablet and Ibuzatrelvir filmcoated tablet
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
17 participants
Where
1 siteBelgium
Study dates
13 Apr 2026to 29 Jun 2026
Phase
Phase 1
Are there results?
None posted in the registry

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
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • 18 years of age or older (or the minimum age of consent in accordance with local regulations) at screening who are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and ECGs.
  • BMI of 16-32 kg/m2; and a total body weight >45 kg.
  • Participants who are capable of giving signed informed consent and willing and able to comply with all scheduled visits, treatment plans, laboratory tests, lifestyle considerations, and other study procedures.

Who cannot join

  • 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).
  • Any condition possibly affecting drug absorption (eg, gastrectomy, cholecystectomy).
  • History of HIV infection, hepatitis B, or hepatitis C; positive testing for HIV, HBsAg, or HCVAb. Hepatitis B vaccination is allowed.
  • Any medical or psychiatric condition including any active suicidal ideation in the past year or suicidal behavior in the past 5 years or laboratory abnormality or other conditions that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
  • Use of prescription or nonprescription drugs and dietary and herbal supplements within 14 days or 5 half-lives (whichever is longer) prior to the first dose of study intervention with the exception of moderate or strong CYP3A inducers which are prohibited within 14 days plus 5 half-lives prior to the first dose of study intervention.
  • Previous administration of an investigational product (drug or vaccine) within 30 days or 5 half-lives preceding the first dose of study intervention used in this study (whichever is longer).
Show all 17Show fewer
  • Participation in studies of other investigational products (drug or vaccine) at any time during participation in this study.
  • A positive urine drug test. A single repeat for positive drug screen may be allowed.
  • Screening supine BP ≥140 mm Hg (systolic) or ≥90 mm Hg (diastolic) for participants <60 years; and ≥150/90 mm/Hg for participants ≥60 years old, following at least 5 minutes of supine rest. If systolic BP is ≥140 or 150 mm Hg (based on age) or diastolic ≥90 mm Hg, the BP should be repeated 2 more times and the average of the 3 BP values should be used to determine the participant's eligibility.
  • An eGFR <60 mL/min/1.73 m² as determined by the CKD-EPI equation using Screat.
  • Standard 12 lead ECG that demonstrates clinically relevant abnormalities that may affect participant safety or interpretation of study results (including, but not limited to, QTcF >450 ms, complete LBBB, signs of an acute or indeterminate age myocardial infarction, ST segment and/or T wave changes suggestive of myocardial ischemia, second or third degree AV block, or serious bradyarrhythmias or tachyarrhythmias). If QTcF exceeds 450 ms, or QRS exceeds 120 ms, the ECG should be repeated twice and the average of the 3 QTcF or QRS values used to determine the participant's eligibility. Computer interpreted ECGs with abnormal findings should be overread by an investigator experienced in reading ECGs before excluding a participant.
  • Participants with ANY of the following abnormalities in clinical laboratory tests at screening, as assessed by the study specific laboratory and confirmed by a single repeat test, if deemed necessary:
  • ALT, AST, T Bili >1.5× ULN.
  • History of alcohol abuse or repeated binge drinking and/or any other illicit drug use or dependence within 6 months of screening. Binge drinking is defined as a pattern of 5 (male) and 4 (female) or more alcoholic drinks in about 2 hours. As a general rule, alcohol intake should not exceed 14 units per week (1 unit = 8 ounces (240 mL) beer, 1 ounce (30 mL) of 40% spirit, or 3 ounces (90 mL) of wine).
  • Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.
  • Use of tobacco/nicotine containing products in excess of the equivalent of 5 cigarettes/day or 2 chews of tobacco/day.
  • History of sensitivity reactions to ibuzatrelvir or any of the formulation components of ibuzatrelvir.

Trial locations and contacts

1 site in 1 country.

Belgium1 site

  • Pfizer Clinical Research Unit - Brussels

    Brussels, Bruxelles-capitale, Région de, B-1070

Other trials in Belgium

About this study

Official title: A PHASE 1, OPEN-LABEL, RANDOMIZED, SINGLE-DOSE, 4-PERIOD, CROSSOVER STUDY TO ESTIMATE THE RELATIVE BIOAVAILABILITY AND EFFECT OF FOOD FOLLOWING ORAL ADMINISTRATION OF A NEW TABLET FORMULATION RELATIVE TO THE ORIGINAL FORMULATION OF IBUZATRELVIR IN HEALTHY ADULT PARTICIPANTS

Healthy adults will be enrolled into this open-label, Phase 1 research study. Participants will spend about 9 nights and 10 days in the clinical research unit (CRU) and the total time in the study will be about 11 weeks.

The goal of this clinical trial is to compare how much of the study drug ibuzatrelvir is in participants' blood after taking one of the two different types of tablets containing the same amount of ibuzatrelvir without food. The study will also measure how much ibuzatrelvir is in participants' blood after taking one type of the tablets dispersed in water and when one type of the tablets is taken with food. This study drug is taken by mouth.

Read the detailed description

This is a Phase 1, open-label, randomized, 4-period, 6-sequence crossover study in healthy adult participants. The goal of this clinical study is to compare how much of the oral (taken by mouth) study drug ibuzatrelvir is in participants' blood after taking one of the two different types of tablets containing the same amount of ibuzatrelvir without food (fasted). The study will also measure how much ibuzatrelvir is in participants' blood after taking one type of the tablets dispersed in water and when one type of the tablets is taken with food. Safety and tolerability after taking the study medication will also be assessed.

Healthy adult participants will be screened within 28 days prior to the first day of study treatment. Participants will take one dose of study drug on the first day of each of 4 dosing periods that are 2-3 days each. Participants will remain in the clinical research unit (CRU) from Day -1 of Period 1 until completion of procedures on Day 3 of Period 4. This means that participants will stay in the CRU for a total of 9 nights and 10 days. The follow-up phone call will take place approximately 28-35 days after the last dose of study drug. The total time in the study is about 10-11 weeks.

The study treatments are:

Treatment A: ibuzatrelvir (original) fasted Treatment B: ibuzatrelvir (new) fasted Treatment C: ibuzatrelvir (new as dispersion in water) fasted Treatment D: ibuzatrelvir (new) fed

This is a crossover study which means that the treatment groups will receive the same treatments (A, B, C, and D) in a different order during the 4 dosing periods.

Group Period 1 Period 2 Period 3 Period 4

  1. A (fasted) B (fasted) C (fasted) D (Fed)
  2. A (fasted) C (fasted) B (fasted) D (Fed)
  3. B (fasted) A (fasted) C (fasted) D (Fed)
  4. B (fasted) C (fasted) A (fasted) D (Fed)
  5. C (fasted) A (fasted) B (fasted) D (Fed)
  6. C (fasted) B (fasted) A (fasted) D (Fed)

During the screening and time in the CRU participants will have:

  • Blood and urine samples collected for safety lab tests
  • Pharmacokinetics (PK) blood samples collected to detect concentrations of ibuzatrelvir (up to 40 samples)
  • Up to 8 electrocardiograms (ECGs - records the electrical signals controlling your heart)
  • To fast (not eat) for at least 10 hours overnight before 3 of the 4 doses

Approximately 18 participants will be enrolled in the study.

Being tested
Ibuzatrelvir co-process API film coated tablet, Ibuzatrelvir filmcoated tablet
Keywords
COVID-19 infection, Pneumonia, Respiratory tract infections, Coronavirus infection, RNA virus infection, Lung disease, Pneumonia, viral, Infections, Viral protease inhibitor, Protease inhibitor, Enzyme inhibitor, Anti-viral agents, Anti-infectives, Ibuzatrelvir, COVID-19
Medical subject headings
COVID-19, Respiratory Tract Infections, Respiratory Tract Diseases, Pneumonia, Lung Diseases, Coronavirus Infections, RNA Virus Infections, Pneumonia, Viral

What participants receive

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

  • Ibuzatrelvir co-process API film coated tabletDrug

    original

  • Ibuzatrelvir filmcoated tabletDrug

    new

Study groups in NCT07552779
Study groupRoleWhat they receive
Treatment AExperimentalsingle dose of ibuzatrelvir original tablet formulation in the fasted state on Day 1 of the treatment period
Receives: Drug: Ibuzatrelvir co-process API film coated tablet
Treatment BExperimentalsingle dose of ibuzatrelvir new tablet formulation in the fasted state on Day 1 of the treatment period
Receives: Drug: Ibuzatrelvir filmcoated tablet
Treatment CExperimentalsingle dose of ibuzatrelvir of the new tablet formulation dispersed in water and given in the fasted state on Day 1 of the treatment period
Receives: Drug: Ibuzatrelvir filmcoated tablet
Treatment DExperimentalsingle dose of ibuzatrelvir new tablet formulation in the fed state on Day 1 of the treatment period
Receives: Drug: Ibuzatrelvir filmcoated tablet

What is being measured

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

  1. Plasma ibuzatrelvir AUCinf (as data permit, otherwise AUClast) in the fasted state

    Relative bioavailability of a new oral formulation of ibuzatrelvir compared to the original tablet formulation in the fasted state

    Measured: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period

  2. Plasma ibuzatrelvir AUCinf (as data permit, otherwise AUClast) in the fasted state

    Relative bioavailability of a dispersion of a new oral formulation of ibuzatrelvir compared to the original tablet formulation in the fasted state

    Measured: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period

  3. Plasma ibuzatrelvir Cmax in the fasted state

    Relative bioavailability of a new oral formulation of ibuzatrelvir compared to the original tablet formulation in the fasted state

    Measured: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period

  4. Plasma ibuzatrelvir Cmax in the fasted state

    Relative bioavailability of a dispersion of a new oral formulation of ibuzatrelvir compared to the original tablet formulation in the fasted state

    Measured: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period

Secondary outcomes (3)

  1. Incidence of AEs, clinical laboratory measurements, vital signs, and standard 12-lead ECGs

    Evaluate the safety and tolerability of different single-dose oral treatments of ibuzatrelvir

    Measured: Day 1-35

  2. Plasma ibuzatrelvir AUCinf (as data permit, otherwise AUClast)

    Relative bioavailability of a new oral formulation of ibuzatrelvir administered in the fed state compared to the fasted state

    Measured: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period

  3. Plasma ibuzatrelvir Cmax

    Relative bioavailability of a new oral formulation of ibuzatrelvir administered in the fed state compared to the fasted state

    Measured: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period

Timeline

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

  1. First posted27 Apr 2026
  2. Study start13 Apr 2026
  3. Primary completion3 Jun 2026
  4. Study completion29 Jun 2026

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 1
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Model description
Randomized, single-dose, 4-period, 6-sequence crossover study
Masking
None (open label)
Enrolment
17 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07552779
Sponsor's protocol ID
C5091029
Other IDs
2025-525041-43-00, 2025
Status last verified
Jul 2026
First submitted
7 Apr 2026
Last updated
28 Jul 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: 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 1 study testing Ibuzatrelvir co-process API film coated tablet and Ibuzatrelvir filmcoated tablet in people with Coronavirus Disease 2019 and Coronavirus Disease 2019 (COVID-19), run by Pfizer at 1 site in Belgium.

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 3 inclusion and 17 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 28 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Belgium. 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Plasma ibuzatrelvir AUCinf (as data permit, otherwise AUClast) in the fasted state (time frame: Hour 0 pre-dose in each period and 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 post-dose in each period). The study lists 4 primary outcomes in all. 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 NCT07552779.

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 28 Jul 2026; AzTrials last refreshed its copy on 26 Oct 2026.

AzTrials uses cookies for analytics and advertising. You can accept or reject them; the site works either way. Privacy Policy.

Free account

Keep searching with a free account

You’ve used your 3 free searches for this session. Log in or create a free AzTrials account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in