HealthyPhase 1NCT05128058

A Target Occupancy Study With Ritlecitinib.

A Phase 1 study testing Ritlecitinib 50 mg and Ritlecitinib 200 mg in people with Healthy, run by Pfizer at 1 site in United States.

Completed

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

Official record

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Trial summary

This is a phase 1, open label, two-arm study to assess target occupancy and functional inhibition of JAK3 and TEC kinases by Ritlecitinib in healthy adult participants Read more about this study

Who is it for?: Ages 18 to 60 yearsHealthy volunteers can take part
Conditions the study is for: Healthy
What is being tested?: Ritlecitinib 50 mg and Ritlecitinib 200 mg
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 16 participants
Where: 1 siteUnited States
Study dates: 22 Oct 2021to 14 Jan 2022
Phase: Phase 1
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 to 60 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Participants are eligible to be included in the study only if all the following criteria apply:
Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures.
Male and female participants who are overtly healthy as determined by medical evaluation including medical history, physical examination including BP and pulse rate measurement, 12-lead ECG, or clinical and laboratory tests.
BMI of 17.5 to 30.5 kg/m2; and a total body weight >50 kg (110 lb).

Who cannot join

Participants are excluded from the study if any of the following criteria apply:
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).
Infection with HIV, hepatitis B or hepatitis C viruses
Have evidence of untreated or inadequately treated active or latent Mycobacterium TB infection
Known active or history of recurrent bacterial, viral, fungal, mycobacterial or other infections.
Have received only one of the 2 required doses of COVID-19 vaccine.
Participants have a known present or a history of malignancy other than a successfully treated or excised non metastatic basal cell or squamous cell cancer of the skin or cervical carcinoma in situ.

Trial locations and contacts

1 site in 1 country.

United States1 site

Pfizer Clinical Research Unit - New Haven
New Haven, Connecticut, 06511

Other trials in United States

About this study

Official title: AN OPEN LABEL, PHASE 1, TWO-ARM STUDY TO ASSESS TARGET OCCUPANCY AND FUNCTIONAL INHIBITION OF JAK3 AND TEC KINASES BY SINGLE DOSES OF RITLECITINIB IN HEALTHY ADULT PARTICIPANTS

This is a phase 1, open label, two-arm study to assess target occupancy and functional inhibition of JAK3 and TEC kinases by Ritlecitinib in healthy adult participants

Conditions: Healthy
Being tested: Ritlecitinib 50 mg, Ritlecitinib 200 mg

What participants receive

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

Ritlecitinib 50 mgDrug
Also called PF-06651600
50 mg single dose
Ritlecitinib 200 mgDrug
Also called PF-06651600
200 mg single dose

Study groups in NCT05128058
Study group	Role	What they receive
Cohort 1	Experimental	Subjects will be dosed with 50 mg Ritlecitinib on Day 1 and followed up till Day 3 Receives: Drug: Ritlecitinib 50 mg
Cohort 2	Experimental	Subjects will be dosed with 200 mg Ritlecitinib on Day 1 and followed up till Day 3 Receives: Drug: Ritlecitinib 200 mg

What is being measured

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

Percent Target Occupancy for JAK3
Target occupancy for janus kinase 3 (JAK3) in peripheral blood mononuclear cells (PBMCs) by ritlecitinib was investigated in human blood by chemical probe-based enrichment and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Measured: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Percent Target Occupancy for BTK
Target occupancy for Bruton's tyrosine kinase (BTK) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Measured: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Percent Target Occupancy for ITK
Target occupancy forIL 2 inducible T-cell kinase (ITK) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Measured: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Percent Target Occupancy for TXK
Target occupancy for tyrosine kinase expressed in T cells (TXK) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Measured: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Percent Target Occupancy for TEC
Target occupancy for tyrosine kinase expressed carcinoma (TEC) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Measured: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Percent Target Occupancy for BMX
Target occupancy for bone marrow tyrosine kinase gene in chromosome X (BMX) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point) *100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Measured: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose

Secondary outcomes (10)

Maximum Observed Plasma Concentration (Cmax) of Ritlecitinib
Cmax is maximum observed plasma concentration. Cmax for ritlecitinib was observed directly from data.
Measured: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Time to Reach Maximum Observed Plasma Concentration (Tmax) of Ritlecitinib
Tmax is time for Cmax. Tmax for ritlecitinib was observed directly from data as time of first occurrence.
Measured: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Last Quantifiable Plasma Concentration (Clast) of Ritlecitinib
Clast is last quantifiable plasma concentration. Clast for ritlecitinib was observed directly from data.
Measured: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Average Plasma Concentration From Time 0 to 24 Hours (Cav) of Ritlecitinib
Cav is average plasma concentration from time 0 to 24 hours over the 24 hours period. Cav for ritlecitinib was calculated as area under the plasma concentration-time curve from 0 to 24 hours (AUC24) divided by 24.
Measured: 0 (pre-dose), 1, 2, 4, 8, 24 hours post-dose
Area Under the Curve From Time Zero to Last Quantifiable Concentration (AUClast) of Ritlecitinib
AUClast is area under the plasma concentration-time profile from time 0 to the time of the Clast. AUClast for ritlecitinib was determined using linear/log trapezoidal method.
Measured: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Area Under the Curve From Time 0 to 24 Hours (AUC24) of Ritlecitinib
AUC24 is area under the plasma concentration-time curve from time 0 to 24 hours. AUC24 for ritlecitinib was determined using linear/log trapezoidal method.
Measured: 0 (pre-dose), 1, 2, 4, 8, 24 hours post-dose
Number of Participants With All-Causality and Treatment-Related Treatment-Emergent Adverse Events (TEAEs)
An AE was any untoward medical occurrence in a participant who received study treatment without regard to possibility of causal relationship. Treatment-related AE was any untoward medical occurrence attributed to study treatment in a participant who received study treatment. Relatedness to study treatment was assessed by the investigator. A serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent were events between first dose of study treatment and up to 35 days after last dose that were absent before treatment or that worsened relative to pretreatment state.
Measured: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)
Number of Participants With Treatment-Emergent Adverse Events by Severity
An AE was any untoward medical occurrence in a participant who received study treatment without regard to possibility of causal relationship. Treatment-related AE was any untoward medical occurrence attributed to study treatment in a participant who received study treatment. Relatedness to study treatment was assessed by the investigator. Treatment-emergent are events between first dose of study treatment and up to 35 days after last dose that were absent before treatment or that worsened relative to pretreatment state. AEs are classified according to the severity in 3 categories a) mild - AEs does not interfere with participant's usual function b) moderate - AEs interferes to some extent with participant's usual function c) severe - AEs interferes significantly with participant's usual function.
Measured: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)
Number of Participants With Laboratory Abnormalities Without Regard to Baseline Abnormality
Laboratory parameters included: hematology (hemoglobin, hematocrit, erythrocyte, platelet, neutrophils, eosinophils, monocytes, basophils, lymphocytes, etc), chemistry (glucose, calcium, sodium, potassium, chloride, total bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, protein, albumin, etc), and urinalysis (glucose, protein, hemoglobin, ketones, nitrite, leukocytes, urine bacteria, etc). Baseline = the pre-dose measurement on Day -1. Laboratory abnormalities meeting pre-defined criteria are reported for this outcome measure. Only those categories in which at least 1 participant had data were reported. ULN=upper limit of normal. LPF=low power field.
Measured: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)
Number of Participants With Pre-defined Criteria for Vital Signs
Pre-defined criteria included: 1) Diastolic blood pressure (DBP), a) supine DBP: less than (<) 50 mmHg, b) supine DBP: change of >= 20mmHg increase, c) supine DBP: change of >= 20mmHg decrease; 2) Systolic blood pressure (SBP), a) supine SBP: <90 mmHg, b) supine SBP: change of >=30mmHg increase, c) supine SBP: change of >=30mmHg decrease; 3) Supine pulse rate, a) <40 bpm, b) >120 bpm. mmHg=millimeters of mercury, bpm=beats per minute.
Measured: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)

Timeline

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

22 Oct 202114 Jan 2022

First posted19 Nov 2021
Study start22 Oct 2021
Primary completion14 Jan 2022
Study completion14 Jan 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for HealthyStudies of the same condition, open and under way.
More trials run by PfizerThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

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: Non-randomised
Intervention model: Parallel groups
Masking: None (open label)
Enrolment: 16 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05128058
Sponsor's protocol ID: B7981045
Status last verified: Nov 2023
First submitted: 15 Oct 2021
Last updated: 13 Nov 2023
Results posted: Yes, on ClinicalTrials.gov
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.

Publications

Saadeddin A, Purohit V, Huh Y, Wong M, Maulny A, Dowty ME, Sagawa K. Virtual Bioequivalence Assessment of Ritlecitinib Capsules with Incorporation of Observed Clinical Variability Using a Physiologically Based Pharmacokinetic Model. AAPS J. 2024 Jan 24;26(1):17. doi: 10.1208/s12248-024-00888-9.
PubMed 38267790

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 13 Nov 2023. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: AN OPEN LABEL, PHASE 1, TWO-ARM STUDY TO ASSESS TARGET OCCUPANCY AND FUNCTIONAL INHIBITION OF JAK3 AND TEC KINASES BY SINGLE DOSES OF RITLECITINIB IN HEALTHY ADULT PARTICIPANTS
ClinicalTrials.gov ID: NCT05128058
Acronym / sponsor ID: B7981045
Conditions: Healthy
Phase: Phase 1
Study type: Interventional
Recruitment status: Completed
Enrolment: 16 participants (actual)
Lead sponsor: PfizerIndustry (pharma, biotech, devices)
Study start: 22 Oct 2021 (actual)
Primary completion: 14 Jan 2022 (actual)
Study completion: 14 Jan 2022 (actual)
First posted: 19 Nov 2021 (actual)
Results: Posted 13 Nov 2023

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

This is a phase 1, open label, two-arm study to assess target occupancy and functional inhibition of JAK3 and TEC kinases by Ritlecitinib in healthy adult participants

Study design

Primary purpose: Basic science
Allocation: Non-randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 2

Arm	Type	Receives
Cohort 1	Experimental	Drug: Ritlecitinib 50 mgSubjects will be dosed with 50 mg Ritlecitinib on Day 1 and followed up till Day 3
Cohort 2	Experimental	Drug: Ritlecitinib 200 mgSubjects will be dosed with 200 mg Ritlecitinib on Day 1 and followed up till Day 3

Who may qualify

Ages: 18 to 60 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (4 listed)

Participants are eligible to be included in the study only if all the following criteria apply:
Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures.
Male and female participants who are overtly healthy as determined by medical evaluation including medical history, physical examination including BP and pulse rate measurement, 12-lead ECG, or clinical and laboratory tests.
BMI of 17.5 to 30.5 kg/m2; and a total body weight >50 kg (110 lb).

Key exclusion criteria (7 listed)

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).
Infection with HIV, hepatitis B or hepatitis C viruses
Have evidence of untreated or inadequately treated active or latent Mycobacterium TB infection
Known active or history of recurrent bacterial, viral, fungal, mycobacterial or other infections.
Have received only one of the 2 required doses of COVID-19 vaccine.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Ritlecitinib 50 mgAlso: PF-0665160050 mg single dose	Drug	Cohort 1
Ritlecitinib 200 mgAlso: PF-06651600200 mg single dose	Drug	Cohort 2

Primary outcome

Percent Target Occupancy for JAK3
Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Target occupancy for janus kinase 3 (JAK3) in peripheral blood mononuclear cells (PBMCs) by ritlecitinib was investigated in human blood by chemical probe-based enrichment and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Percent Target Occupancy for BTK
Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Target occupancy for Bruton's tyrosine kinase (BTK) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Percent Target Occupancy for ITK
Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Target occupancy forIL 2 inducible T-cell kinase (ITK) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Percent Target Occupancy for TXK
Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Target occupancy for tyrosine kinase expressed in T cells (TXK) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Percent Target Occupancy for TEC
Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Target occupancy for tyrosine kinase expressed carcinoma (TEC) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point)*100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.
Percent Target Occupancy for BMX
Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Target occupancy for bone marrow tyrosine kinase gene in chromosome X (BMX) in PBMCs by ritlecitinib was investigated in human blood by chemical probe-based enrichment and LC-MS/MS analysis. % TO is calculated as [(baseline value - value at specified time point) *100/baseline value], where baseline value in this formula is defined as the mean of the two pre-dose measurements at Hour -1 and Hour 0 on Day 1. Since (baseline value - value at specified time point)=0 at baseline, % TO at baseline is 0.

10 secondary outcomes

Maximum Observed Plasma Concentration (Cmax) of Ritlecitinib
Time frame: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Time to Reach Maximum Observed Plasma Concentration (Tmax) of Ritlecitinib
Time frame: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Last Quantifiable Plasma Concentration (Clast) of Ritlecitinib
Time frame: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Average Plasma Concentration From Time 0 to 24 Hours (Cav) of Ritlecitinib
Time frame: 0 (pre-dose), 1, 2, 4, 8, 24 hours post-dose
Area Under the Curve From Time Zero to Last Quantifiable Concentration (AUClast) of Ritlecitinib
Time frame: 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose
Area Under the Curve From Time 0 to 24 Hours (AUC24) of Ritlecitinib
Time frame: 0 (pre-dose), 1, 2, 4, 8, 24 hours post-dose
Number of Participants With All-Causality and Treatment-Related Treatment-Emergent Adverse Events (TEAEs)
Time frame: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)
Number of Participants With Treatment-Emergent Adverse Events by Severity
Time frame: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)
Number of Participants With Laboratory Abnormalities Without Regard to Baseline Abnormality
Time frame: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)
Number of Participants With Pre-defined Criteria for Vital Signs
Time frame: From the first dose of study treatment up to 35 days after the last dose of study treatment (up to 35 days)

Results and safety

Results posted to the registry on 13 Nov 2023, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
RITLECITINIB 50 MG CAPSULE	8	8
RITLECITINIB 200 MG CAPSULE	8	8

Primary outcome: Percent Target Occupancy for JAK3

Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose. Median (Full Range). Unit: percentage of occupancy

Measure	RITLECITINIB 50 MG CAPSULE n = 8	RITLECITINIB 200 MG CAPSULE n = 8
Baseline	0.00 (0.0 to 0.0)	0.00 (0.0 to 0.0)
1H	72.41 (49.2 to 98.0)	28.74 (-5.8 to 51.1)
2H	12.28 (-30.1 to 39.5)	64.14 (54.1 to 75.0)
4H	-1.39 (-19.6 to 5.2)	62.06 (45.3 to 73.9)
8H	-23.34 (-49.1 to 17.7)	58.76 (38.9 to 65.2)
24H	-24.72 (-58.2 to -10.2)	37.08 (30.2 to 53.1)
48H	-25.34 (-51.8 to 3.7)	33.44 (9.4 to 52.9)

Population analysed: The analysis population included all participants who enrolled and treated with non-misssing value at the specified time point.

Primary outcome: Percent Target Occupancy for BTK

Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose. Median (Full Range). Unit: percentage of occupancy

Measure	RITLECITINIB 50 MG CAPSULE n = 8	RITLECITINIB 200 MG CAPSULE n = 8
Baseline	0.00 (0.0 to 0.0)	0.00 (0.0 to 0.0)
1H	98.45 (95.4 to 99.8)	99.57 (98.2 to 99.8)
2H	96.83 (92.1 to 99.2)	99.37 (98.6 to 99.8)
4H	96.43 (90.4 to 99.1)	99.35 (99.2 to 99.8)
8H	93.52 (85.3 to 97.8)	99.21 (97.1 to 99.5)
24H	83.21 (76.5 to 86.3)	92.13 (87.0 to 95.5)
48H	69.86 (63.3 to 76.4)	82.66 (75.8 to 88.1)

Population analysed: The analysis population included all participants who enrolled and treated with non-misssing value at the specified time point.

Primary outcome: Percent Target Occupancy for ITK

Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose. Median (Full Range). Unit: percentage of occupancy

Measure	RITLECITINIB 50 MG CAPSULE n = 8	RITLECITINIB 200 MG CAPSULE n = 8
Baseline	0.00 (0.0 to 0.0)	0.00 (0.0 to 0.0)
1H	94.40 (86.2 to 100.0)	97.03 (73.8 to 98.0)
2H	67.77 (42.2 to 88.4)	97.06 (94.5 to 98.1)
4H	57.54 (23.0 to 73.9)	92.27 (86.0 to 97.4)
8H	28.76 (-5.5 to 58.0)	76.59 (60.0 to 88.9)
24H	-16.77 (-42.1 to 30.5)	32.33 (12.4 to 43.8)
48H	-9.87 (-61.0 to 21.6)	20.62 (-16.0 to 44.7)

Population analysed: The analysis population included all participants who enrolled and treated with non-misssing value at the specified time point.

Primary outcome: Percent Target Occupancy for TXK

Time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose. Median (Full Range). Unit: percentage of occupancy

Measure	RITLECITINIB 50 MG CAPSULE n = 8	RITLECITINIB 200 MG CAPSULE n = 8
Baseline	0.00 (0.0 to 0.0)	0.00 (0.0 to 0.0)
1H	100.00 (88.6 to 100.0)	100.00 (37.7 to 100.0)
2H	44.97 (27.1 to 66.7)	100.00 (100.0 to 100.0)
4H	34.01 (-15.8 to 52.1)	100.00 (87.9 to 100.0)
8H	23.17 (-41.0 to 60.7)	82.46 (63.1 to 100.0)
24H	-4.09 (-43.4 to 31.4)	49.70 (33.2 to 59.7)
48H	-38.98 (-83.7 to 17.7)	20.34 (1.9 to 58.8)

Population analysed: The analysis population included all participants who enrolled and treated with non-misssing value at the specified time point.

10 secondary outcomes are reported in the full results.

Adverse events

Time frame: Baseline up to 35 days after the last dose of study treatment on Day 1 (up to 35 days). Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
RITLECITINIB 50 MG CAPSULE	0 of 8 (0%)	3 of 8 (37.5%)	0 of 8
RITLECITINIB 200 MG CAPSULE	0 of 8 (0%)	2 of 8 (25%)	0 of 8

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 13 Nov 2023.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 38267790Saadeddin A, Purohit V, Huh Y, Wong M, Maulny A, Dowty ME, Sagawa K. Virtual Bioequivalence Assessment of Ritlecitinib Capsules with Incorporation of Observed Clinical Variability Using a Physiologically Based Pharmacokinetic Model. AAPS J. 2024 Jan 24;26(1):17. doi: 10.1208/s12248-024-00888-9.
To obtain contact information for a study center near you, click here.Link provided by the sponsor.
Individual participant dataSharing planned: 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.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Pfizer CT.gov Call Center study director

Pfizer

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Ritlecitinib 50 mg and Ritlecitinib 200 mg in people with Healthy, run by Pfizer at 1 site in United States.

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 4 inclusion and 7 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 13 Nov 2023. 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 United States. 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?

Yes. Results are posted in the registry (first posted 13 Nov 2023). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Percent Target Occupancy for JAK3 (time frame: -1 (pre-dose), 0 (pre-dose), 1, 2, 4, 8, 24, 48 hours post-dose). The study lists 6 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 NCT05128058, which also lists 1 linked publication.

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 13 Nov 2023.