A Study on 2 Different Combination Tablets of Nirmatrelvir Plus Ritonavir to Compare Them With Marketed Paxlovid in Healthy Participants

Summary

Medicines that may have different names or be made in different ways but have the same effect on the body are called bioequivalent.

The purpose of this study is to learn about the bioequivalence of nirmatrelvir plus ritonavir after taking 2 different combination tablet forms by mouth. These combination tablets are compared to the tablet formulation that is already in the market. This study will be done under fasted conditions in healthy adult participants.

This study is seeking participants who are:

* Male and non-pregnant female participants aged 18 years and above.
* with a body weight of more than 50 kilograms and Body Mass Index (BMI) between 16 to 32 kilograms per meter squared.
* are healthy as confirmed by medical history, physical examination, laboratory tests.

The study will also look at the safety and tolerability of nirmatrelvir plus ritonavir combination tablet and marketed tablet formulations in healthy adult participants.

The study will consist of 4 treatments:

Treatment A: Single oral dose of nirmatrelvir plus ritonavir 150 (1 × 150)/100 milligrams marketed tablets under fasted conditions (Reference 1) Treatment B (low dose strength): Single oral dose of nirmatrelvir plus ritonavir 150/100 milligrams (2 × \[75/50 milligrams\]) combination tablets under fasted conditions (Test 1) Treatment C: Single oral dose of nirmatrelvir/ritonavir 300 (2 × 150)/100 milligrams marketed tablets under fasted conditions (Reference 2) Treatment D (high dose strength): Single oral dose of nirmatrelvir/ritonavir 300/100 milligrams (2 × \[150/50 milligrams\]) combination tablets under fasted conditions (Test 2)

All treatments will be given under fasted conditions. Fasted condition means the participants would not have had anything to eat before taking the medicines.

Around 28 participants will be enrolled in the study. Healthy participants will be tested to see if they can be in the study within 28 days before receiving the study medicine. Selected participants will be admitted to the clinical research unit (CRU) one day before receiving the study medicine and will remain in the CRU until discharge after completing all the treatment periods.

On Day 1 of each period, participants will be given a single dose of study medicine nirmatrelvir/ritonavir 300/100 mg or 150/100 mg by mouth by chance. Study medicine will be given with approximately 240 milliliters of room temperature water under fasted conditions (overnight fast of at least 10 hours and no food until 4 hours after receiving the study medicine). Blood samples will be collected at different times of the day up to 48 hours after taking the study medicine. Participants will be discharged from the CRU on Day 3 of Period 4, after all the study related procedures have been completed.

A follow-up call will be made to participants around 28 to 35 days from receiving the final dose of the study medicine. The study will look at the experiences of participants receiving the study medicine. This will help to understand if the study medicine is safe and effective.

Conditions

• Biological Availability
• Healthy Participants

Interventions

DRUG

Paxlovid

Reference 1

DRUG

Paxlovid

Reference 2

DRUG

Nirmatrelvir/ritonavir

Test 1

DRUG

Nirmatrelvir/ritonavir

Test 2

Sponsors & Collaborators

• Pfizer

  lead INDUSTRY

Principal Investigators

• Pfizer CT.gov Call Center · Pfizer

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-08-15

Primary Completion

2025-12-09

Completion

2025-12-09

FDA Drug

Yes