Recent Updates
Recently added Catalysts

PF-07321332/ritonavir

Phase 1

Bioavailability | Small molecule | Other |Pfizer, Inc.|Last Updated: Jun 11, 2025

Target and mechanism

ModalitySmall molecule

Also known as nirmatrelvir

Success Probability

Subscribe to view

Market & Valuation

Subscribe to view

Trial Design

RandomizedACTIVE_CONTROLLED
Total Trials2
Total Enrollment24

FDA Designations

No designations recorded

Clinical trial landscape

PF-07321332/ritonavir · 5 trials · 3 indications

Phase 1 5
NCT05263921Relative Bioavailability Study of PF-07321332/Ritonavir Oral Powder Relative to the Commercial Tablets in Healthy ParticipantsBioavailability
COMPLETED12 Analytics
NCT05263895Relative Bioavailability Study of 4 Different Formulations of PF-07321332 Relative to the Commercial Tablet FormulationBioavailability
COMPLETED12 Analytics
NCT04962022Drug-Drug Interaction Study Assessing Effect of Itraconazole on PF-07321332/Ritonavir in Healthy ParticipantsHealthy Participant
COMPLETED12 Analytics
NCT04962230Drug-Drug Interaction Study Assessing Effect of Carbamazepine on PF-07321332 Boosted With RitonavirHealthy Participant
COMPLETED12 Analytics
NCT04909853Renal Impairment Study of PF-07321332 Boosted With Ritonavir in Adult Participants With Renal Impairment and in Healthy Participants With Normal Renal Function.Renal Impairment
COMPLETED35 Analytics
PHASE1COMPLETED
Relative Bioavailability Study of PF-07321332/Ritonavir Oral Powder Relative to the Commercial Tablets in Healthy Participants
BioavailabilityUnlock trial analytics
PHASE1COMPLETED
Relative Bioavailability Study of 4 Different Formulations of PF-07321332 Relative to the Commercial Tablet Formulation
BioavailabilityUnlock trial analytics
PHASE1COMPLETED
Drug-Drug Interaction Study Assessing Effect of Itraconazole on PF-07321332/Ritonavir in Healthy Participants
Healthy ParticipantUnlock trial analytics
PHASE1COMPLETED
Drug-Drug Interaction Study Assessing Effect of Carbamazepine on PF-07321332 Boosted With Ritonavir
Healthy ParticipantUnlock trial analytics
PHASE1COMPLETED
Renal Impairment Study of PF-07321332 Boosted With Ritonavir in Adult Participants With Renal Impairment and in Healthy Participants With Normal Renal Function.
Renal ImpairmentUnlock trial analytics

Study Endpoints

Primary Endpoints

AUCinf of Nirmatrelvir Following the Administration of Nirmatrelvir/Ritonavir in Different Delivery Vehicles Under Fasted Conditions
0 (pre-dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours post-dose on Day 1 of each period

Area under the plasma concentration time profile from time 0 extrapolated to infinity (AUCinf) was measured. AUCinf was determined by AUClast + (Clast/kel), where Clast is the predicted plasma concentration at the last quantifiable time point estimated from the log-linear regression analysis.

AUClast of Nirmatrelvir Following the Administration of Nirmatrelvir/Ritonavir in Different Delivery Vehicles Under Fasted Conditions
0 (pre-dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours post-dose on Day 1 of each period

Area under the plasma concentration time profile from time 0 to the time of the last quantifiable concentration (Clast) was measured. AUClast was determined by Linear/Log trapezoidal method.

Cmax of Nirmatrelvir Following the Administration of Nirmatrelvir/Ritonavir in Different Delivery Vehicles Under Fasted Conditions
0 (pre-dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours post-dose on Day 1 of each period

Maximum plasma concentration (Cmax) was measured. Cmax was observed directly from data.

AUCinf of Ritonavir Following the Administration of Nirmatrelvir/Ritonavir in Different Delivery Vehicles Under Fasted Conditions
0 (pre-dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours post-dose on Day 1 of each period

Area under the plasma concentration time profile from time 0 extrapolated to infinity (AUCinf) was measured. AUCinf was determined by AUClast + (Clast/kel), where Clast is the predicted plasma concentration at the last quantifiable time point estimated from the log-linear regression analysis.

AUClast of Ritonavir Following the Administration of Nirmatrelvir/Ritonavir in Different Delivery Vehicles Under Fasted Conditions
0 (pre-dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours post-dose on Day 1 of each period

Area under the plasma concentration time profile from time 0 to the time of the last quantifiable concentration (Clast) was measured. AUClast was determined by Linear/Log trapezoidal method.

Cmax of Ritonavir Following the Administration of Nirmatrelvir/Ritonavir in Different Delivery Vehicles Under Fasted Conditions
0 (pre-dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, 24, 48 and 72 hours post-dose on Day 1 of each period

Maximum plasma concentration (Cmax) was measured. Cmax was observed directly from data.

Area Under the Plasma Concentration-Time Profile From Time 0 to the Time of the Last Quantifiable Concentration (Clast) (AUClast) of Nirmatrelvir
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.

Area Under the Plasma Concentration-Time Profile From Time 0 Extrapolated to Infinite Time (AUCinf) of Nirmatrelvir
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.

Maximum Plasma Concentration (Cmax) of Nirmatrelvir
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.

Maximum Observed Concentration (Cmax) of PF-07321332
Days 1, 2, 3 (pre-dose, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, and 48 hours postdose on Day 3) in Period 1; Days 1, 4, 5, 6 (pre-dose, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, 48, and 72 hours postdose on Day 6) of Period 2.

The Cmax of PF-07321332 in the study was observed directly from data.

Area Under the Plasma Concentration-time Profile From Time Zero to Time Tau (τ), Where Tau=12-hour Dosing Interval(AUCtau) for PF-07321332
Days 1, 2, 3 (pre-dose, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, and 48 hours postdose on Day 3) in Period 1; Days 1, 4, 5, 6 (pre-dose, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, 48, and 72 hours postdose on Day 6) of Period 2.

The AUCtau of PF-07321332 was determined by Linear/Log trapezoidal method.

Maximum Observed Plasma Concentration (Cmax) of PF-07321332
Day 1 pre-dose, and at 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, and 48 hours post dose in Period 1; Day 14 pre-dose, and at 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, and 48 hours post-dose or early termination/discontinuation in Period 2

Cmax was defined as maximum observed plasma concentration and can be observed directly from data.

Area Under the Curve From Time Zero to Extrapolated Infinite Time (AUCinf) of PF-07321332
Day 1 pre-dose, and at 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, and 48 hours post dose in Period 1; Day 14 pre-dose, and at 0.5, 1, 1.5, 2, 4, 6, 8, 12, 16, 24, and 48 hours post-dose or early termination/discontinuation in Period 2

AUCinf was defined as area under the concentration-time curve from time 0 to infinity and was calculated as AUClast + (Clast\*/kel), where Clast\* is the predicted plasma concentration at the last quantifiable time point estimated from the log-linear regression analysis.

Area Under the Plasma Concentration-time Profile From Time Zero (0) to Extrapolated Infinite Time (AUCinf) of PF-07321332
Part 1 and Part 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 24, 36 and 48 hours post-dose on Day 1

AUCinf was calculated by AUClast + (Clast/kel). AUClast was the area under the plasma concentration-time profile from time 0 to the time of Clast. Clast was the predicted plasma concentration at the last quantifiable time point estimated from the log-linear regression analysis and kel was the terminal phase rate constant calculated by a linear regression of the log-linear concentration-time curve.

Amount of PF-07321332 Excreted Unchanged in Urine Over 48 Hours (Ae48)
Part 1 and Part 2: 0 to 48 hours post dose on Day 1

Total amount of unchanged drug excreted in the urine over 48 hours.

Renal Clearance (CLr) of PF-07321332
Part 1 and Part 2: 0 to 48 hours post dose on Day 1

Renal clearance was calculated as total amount of unchanged drug excreted in the urine over 48 hours (Ae48) divided by area under the plasma concentration-time profile from time 0 to 48 hours post dose.

Secondary Endpoints

Number of Participants With Treatment-Emergent Adverse Event
Baseline up to Follow-up (35 days after last dose administration), an average of 10 weeks.
Number of Participants With Laboratory Abnormalities
Screening, Period 1 Day -1, Period 4 Day 4 and early termination/discontinuation.
Number of Participants With Clinically Significant Vital Sign Values
Screening, Day 1 of each period and early termination/discontinuation.
Unlock Study Endpoints

Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelCROSSOVER
PurposeBASIC_SCIENCE

Treatment Arms

ArmTypeDescription
Treatment A: PF-07321332/ritonavirACTIVE_COMPARATORPF-07321332 ritonavir
Treatment B: PF-07321332/ritonavirEXPERIMENTALPF-07321332/ritonavir mixed with water
Treatment C: PF-07321332/ritonavirEXPERIMENTALPF-07321332/ritonavir mixed with applesauce
Treatment D: PF-07321332/ritonavirEXPERIMENTALPF-07321332/ritonavir mixed with vanilla pudding
Treatment A: PF-0732133/ritonavirACTIVE_COMPARATORPF-07321332 ritonavir
Treatment E: PF-07321332EXPERIMENTALPF-07321332
Period 1EXPERIMENTALPF-07321332/ritonavir orally
Period 2EXPERIMENTALItraconazole + PF-07321332/ritonavir orally.
PF-07321332EXPERIMENTALPF 07321332/ritonavir

Interventions

NameTypeDescription
PF-07321332/ritonavirDRUGSingle oral dose of PF-07321332/ritonavir under fasted conditions
PF-07321332DRUGPF-07321332 will be administered as single oral dose orally.
ItraconazoleDRUGAdministered orally once daily for 8 days from Days 1 through 8
CarbamazepineDRUGIn Period 2, Days 1-3, participants will receive low-dose of carbamazepine twice daily (BID), then a titrated mid-dose of carbamazepine BID on Days 4-7, and finally maintaining carbamazepine at the high-dose on Days 8-15.
PF 07321332/ritonavirDRUGIn Period 2, Day 14, participants will receive a single dose of PF-07321332/ritonavir orally.
Unlock Study Design Details

Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersYes
Study Sites1

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). * Pa...

Countries:United StatesBelgium
Unlock Eligibility Criteria

Frequently asked questions about PF-07321332/ritonavir

What is Nirmatrelvir/ritonavir used for?

Nirmatrelvir/ritonavir is an investigational small molecule being studied for COVID-19, hepatic impairment, and bioavailability in healthy participants. It is developed by Pfizer, Inc. (PFE) and is currently in Phase 1 clinical development.

Who makes Nirmatrelvir/ritonavir?

Nirmatrelvir/ritonavir is developed by Pfizer, Inc., which trades under the ticker PFE. The drug is in Phase 1 clinical development for conditions including COVID-19 and hepatic impairment.

What phase is Nirmatrelvir/ritonavir in?

Nirmatrelvir/ritonavir is in Phase 1 clinical development. It is an investigational drug and has not been approved by the FDA. Clinical trials are ongoing or completed to evaluate its safety and effects.

What clinical trials is Nirmatrelvir/ritonavir in?

Nirmatrelvir/ritonavir has been studied in several Phase 1 trials, including NCT04962022, NCT04962230, NCT05064800, and NCT05441215. These trials assess drug-drug interactions and effects in healthy participants, including lactating women.

Is Nirmatrelvir/ritonavir the same as nirmatrelvir?

Yes, nirmatrelvir/ritonavir is also known as nirmatrelvir. The drug is a combination product that includes nirmatrelvir and ritonavir, and it is being developed by Pfizer, Inc. for COVID-19 and other conditions.