Trial · NCT04517864

PLACEBO-CONTROLLED SAFETY STUDY OF RITLECITINIB (PF-06651600) IN ADULTS WITH ALOPECIA AREATA

NCT04517864, Phase 2, Terminated, Pfizer; results first posted 2022-12-28

3 sourcestrials-2026-11-12-0.5.0

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ConductScience Library. PLACEBO-CONTROLLED SAFETY STUDY OF RITLECITINIB (PF-06651600) IN ADULTS WITH ALOPECIA AREATA. Trials, record NCT04517864. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT04517864

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: PLACEBO-CONTROLLED SAFETY STUDY OF RITLECITINIB (PF-06651600) IN ADULTS WITH ALOPECIA AREATA
NCT number: NCT04517864
Status: Terminated
Phases: Phase 2
Enrollment: 71 participants, actual
Lead sponsor: Pfizer
Conditions: Alopecia Areata
Interventions: PF-06651600, Placebo
First posted: 2020-08-18
Last updated: 2025-07-11
Other registries' IDs: eudract:2020-001509-21
Results first posted: 2022-12-28

Source ClinicalTrials.gov

Registered outcomes36

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Change From Baseline in I-V Interwave Latency on Brainstem Auditory Evoked Potentials (BAEP) at a Stimulus Intensity of 80 Decibels (dB) From the Right Side at Month 9	Baseline, Month 9 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	BAEP interwave I-V latency (in milliseconds) was the primary endpoint for this study. High-intensity stimulation (80dB) was used. Participants had BAEP evaluations performed at the same evaluation center, by the same audiology professional using the same equipment, during the study. Audiology and BAEP evaluations were done on the same day, with audiology assessment first. If they could not be done on the same day, assessments had to be within 7 days of each other. A central reader was used for BAEP to confirm that locally read BAEP waves were labelled appropriately and at their peak so that latency were accurate. Central reading also ensured consistency in BAEP interpretation.
Primary	Change From Baseline in I-V Interwave Latency on BAEP at a Stimulus Intensity of 80 dB From the Left Side at Month 9	Baseline, Month 9 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	BAEP interwave I-V latency was the primary endpoint for this study. High-intensity stimulation (80dB) was used. Participants had BAEP evaluations performed at the same evaluation center, by the same audiology professional using the same equipment, during the study. Audiology and BAEP evaluations were done on the same day, with audiology assessment first. If they could not be done on the same day, assessments had to be within 7 days of each other. A central reader was used for BAEP to confirm that locally read BAEP waves were labelled appropriately and at their peak so that latency were accurate. Central reading also ensured consistency in BAEP interpretation.
Secondary	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 6	Baseline, Month 6 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	High-intensity stimulation (80dB) was used. Participants had BAEP evaluations performed at the same evaluation center, by the same audiology professional using the same equipment, during the study. Audiology and BAEP evaluations were done on the same day, with audiology assessment first. If they could not be done on the same day, assessments had to be within 7 days of each other. A central reader was used for BAEP to confirm that locally read BAEP waves were labelled appropriately and at their peak so that latency were accurate. Central reading also ensured consistency in BAEP interpretation.
Secondary	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 9E and 15E	Baseline, Months 9E and 15E (Month 9/15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the Placebo-controlled Phase.	High-intensity stimulation (80dB) was used. Participants had BAEP evaluations performed at the same evaluation center, by the same audiology professional using the same equipment, during the study. Audiology and BAEP evaluations were done on the same day, with audiology assessment first. If they could not be done on the same day, assessments had to be within 7 days of each other. A central reader was used for BAEP to confirm that locally read BAEP waves were labelled appropriately and at their peak so that latency were accurate. Central reading also ensured consistency in BAEP interpretation.
Secondary	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Left Side at Month 6	Baseline, Month 6 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	High-intensity stimulation (80dB) was used. Participants had BAEP evaluations performed at the same evaluation center, by the same audiology professional using the same equipment, during the study. Audiology and BAEP evaluations were done on the same day, with audiology assessment first. If they could not be done on the same day, assessments had to be within 7 days of each other. A central reader was used for BAEP to confirm that locally read BAEP waves were labelled appropriately and at their peak so that latency were accurate. Central reading also ensured consistency in BAEP interpretation.
Secondary	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Left Side at Month 9E and 15E	Baseline, Month 9E and 15E (Month 9/15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the Placebo-controlled Phase.	High-intensity stimulation (80dB) was used. Participants had BAEP evaluations performed at the same evaluation center, by the same audiology professional using the same equipment, during the study. Audiology and BAEP evaluations were done on the same day, with audiology assessment first. If they could not be done on the same day, assessments had to be within 7 days of each other. A central reader was used for BAEP to confirm that locally read BAEP waves were labelled appropriately and at their peak so that latency were accurate. Central reading also ensured consistency in BAEP interpretation.
Secondary	Change From Baseline in Percentage of Intraepidermal Nerve Fiber (IENF) With Axonal Swelling in Skin Punch Biopsies at Month 9	Baseline, Month 9 (Month 6 for the 2 participants who entered the Active Therapy Extension Phase at Month 6). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	The endpoint "axonal dystrophy" referred to the percentage of IENF with axonal swellings. Axonal swellings were evaluated in peripheral skin punch biopsies from the distal part of lower extremities. Axonal swellings were counted by axon. Any IENF with single or multiple swellings was counted as a single event, ie, a single axon with axonal swellings. For each participant, data were reported as the percentage of IENF with any number of swellings. IENF was assessed at Day 1 and Month 9. Participants who had entered the Active Therapy Extension Phase at Month 6 had a skin punch biopsy taken at Month 6 for IENF assessments instead of at Month 9. The skin biopsy was collected before the start of Active Therapy Extension Phase.
Secondary	Change From Baseline in Percentage of IENFs With Axonal Swelling in Skin Punch Biopsies at Month 15E	Baseline, Month 15E (Month 15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	The endpoint "axonal dystrophy" referred to the percentage of IENF with axonal swellings. Axonal swellings were evaluated in peripheral skin punch biopsies from the distal part of lower extremities. Axonal swellings were counted by axon. Any IENF with single or multiple swellings was counted as a single event, ie, a single axon with axonal swellings. For each participant, data were reported as the percentage of IENF with any number of swellings.
Secondary	Change From Baseline in Intraepidermal Nerve Fiber Density (IENFD) in Skin Punch Biopsies at Month 9	Baseline, Month 9 (Month 6 for the 2 participants who entered the Active Therapy Extension Phase at Month 6). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	IENFD was evaluated in peripheral skin punch biopsies from the distal part of lower extremities. IENFD was measured by counting the number of fibers and fiber branches that independently crossed the dermal-epidermal barrier (basement membrane). Secondary branching was excluded from quantification and fragments were not counted. The length of the histology section was measured (mm) and the linear epidermal nerve fiber density was reported as number of intraepidermal nerve fibers/mm.
Secondary	Change From Baseline in IENFD in Skin Punch Biopsies at Month 15E	Baseline, Month 15E (Month 15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	IENFD was evaluated in peripheral skin punch biopsies from the distal part of lower extremities. IENFD was measured by counting the number of fibers and fiber branches that independently crossed the dermal-epidermal barrier (basement membrane). Secondary branching was excluded from quantification and fragments were not counted. The length of the histology section was measured (mm) and the linear epidermal nerve fiber density was reported as number of intraepidermal nerve fibers/mm.

1 to 10 of 36Source ClinicalTrials.gov

See all 36 registered outcomes

Outcomes36

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Change From Baseline in I-V Interwave Latency on Brainstem Auditory Evoked Potentials (BAEP) at a Stimulus Intensity of 80 Decibels (dB) From the Right Side at Month 9	Baseline, Month 9 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	Analysis population included all participants who received at least 1 dose of study intervention.	Millisecond (ms)	LEAST_SQUARES_MEAN
PRIMARY	Change From Baseline in I-V Interwave Latency on BAEP at a Stimulus Intensity of 80 dB From the Left Side at Month 9	Baseline, Month 9 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	Analysis population included all participants who received at least 1 dose of study intervention.	ms	LEAST_SQUARES_MEAN
SECONDARY	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 6	Baseline, Month 6 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	Analysis population included all participants who received at least 1 dose of study intervention.	millisecond (ms)	LEAST_SQUARES_MEAN
SECONDARY	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 9E and 15E	Baseline, Months 9E and 15E (Month 9/15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the Placebo-controlled Phase.	Overall number of participants analyzed included all participants who received at least 1 dose of study intervention. Number analyzed refers to number of participants evaluable for specified rows of categories.	millisecond (ms)	MEAN
SECONDARY	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Left Side at Month 6	Baseline, Month 6 (Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase)	Analysis population included all participants who received at least 1 dose of study intervention.	millisecond (ms)	LEAST_SQUARES_MEAN
SECONDARY	Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Left Side at Month 9E and 15E	Baseline, Month 9E and 15E (Month 9/15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the Placebo-controlled Phase.	Overall number of participants analyzed included all participants who received at least 1 dose of study intervention. Number analyzed refers to number of participants evaluable for specified rows of categories.	millisecond (ms)	MEAN
SECONDARY	Change From Baseline in Percentage of Intraepidermal Nerve Fiber (IENF) With Axonal Swelling in Skin Punch Biopsies at Month 9	Baseline, Month 9 (Month 6 for the 2 participants who entered the Active Therapy Extension Phase at Month 6). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	Analysis population included all participants who received at least 1 dose of study intervention.	Percentage of Nerve Fibers	MEDIAN
SECONDARY	Change From Baseline in Percentage of IENFs With Axonal Swelling in Skin Punch Biopsies at Month 15E	Baseline, Month 15E (Month 15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	Overall number of participants analyzed included all participants who received at least 1 dose of study intervention. Number analyzed refers to number of participants evaluable for specified rows of categories.	Percentage of Nerve Fibers	MEDIAN
SECONDARY	Change From Baseline in Intraepidermal Nerve Fiber Density (IENFD) in Skin Punch Biopsies at Month 9	Baseline, Month 9 (Month 6 for the 2 participants who entered the Active Therapy Extension Phase at Month 6). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	Analysis population included all participants who received at least 1 dose of study intervention.	fibers/mm	MEAN
SECONDARY	Change From Baseline in IENFD in Skin Punch Biopsies at Month 15E	Baseline, Month 15E (Month 15 in the Active Therapy Extension Phase). Baseline was defined as the last non-missing measurement obtained before the first dose in the placebo-controlled phase.	Overall number of participants analyzed included all participants who received at least 1 dose of study intervention. Number analyzed refers to number of participants evaluable for specified rows of categories.	fibers/mm	MEAN

1 to 10 of 36Source ClinicalTrials.gov

See all 36 outcomes

Results by group309

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Category	Value	Spread	Units
Change From Baseline in I-V Interwave Latency on Brainstem Auditory Evoked Potentials (BAEP) at a Stimulus Intensity of 80 Decibels (dB) From the Right Side at Month 9	Ritlecitinib 200/50 mg QD		0.011	95% Confidence Interval -0.043 to 0.065	Millisecond (ms)
Change From Baseline in I-V Interwave Latency on Brainstem Auditory Evoked Potentials (BAEP) at a Stimulus Intensity of 80 Decibels (dB) From the Right Side at Month 9	Placebo		-0.010	95% Confidence Interval -0.063 to 0.043	Millisecond (ms)
Change From Baseline in I-V Interwave Latency on BAEP at a Stimulus Intensity of 80 dB From the Left Side at Month 9	Ritlecitinib 200/50 mg QD		0.031	95% Confidence Interval -0.012 to 0.075	ms
Change From Baseline in I-V Interwave Latency on BAEP at a Stimulus Intensity of 80 dB From the Left Side at Month 9	Placebo		0.022	95% Confidence Interval -0.020 to 0.065	ms
Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 6	Ritlecitinib 200/50 mg QD		-0.030	95% Confidence Interval -0.072 to 0.011	millisecond (ms)
Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 6	Placebo		-0.024	95% Confidence Interval -0.065 to 0.017	millisecond (ms)
Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 9E and 15E	Ritlecitinib 200/50/50 mg QD	Month 9E (Month 9 in the Active Therapy Extension Phase)	0.010	Standard Deviation 0.1233	millisecond (ms)
Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 9E and 15E	Placebo -> Ritlecitinib 200/50 mg QD	Month 9E (Month 9 in the Active Therapy Extension Phase)	-0.033	Standard Deviation 0.2448	millisecond (ms)
Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 9E and 15E	Ritlecitinib 200/50/50 mg QD	Month 15E (Month 15 in the Active Therapy Extension Phase)	0.051	Standard Deviation 0.1188	millisecond (ms)
Change From Baseline in I-V Interwave Latency on BAEP at 80 dB From the Right Side at Month 9E and 15E	Placebo -> Ritlecitinib 200/50 mg QD	Month 15E (Month 15 in the Active Therapy Extension Phase)	0.034	Standard Deviation 0.2224	millisecond (ms)

1 to 10 of 309Source ClinicalTrials.gov

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Participant flow27

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Placebo-Controlled Phase	STARTED	Ritlecitinib 200/50/50 mg QD	36
Placebo-Controlled Phase	STARTED	Placebo -> Ritlecitinib 200/50 mg QD	35
Placebo-Controlled Phase	STARTED	Ritlecitinib 50 mg QD	0
Placebo-Controlled Phase	COMPLETED	Ritlecitinib 200/50/50 mg QD	32
Placebo-Controlled Phase	COMPLETED	Placebo -> Ritlecitinib 200/50 mg QD	33
Placebo-Controlled Phase	COMPLETED	Ritlecitinib 50 mg QD	0
Placebo-Controlled Phase	NOT COMPLETED	Ritlecitinib 200/50/50 mg QD	4
Placebo-Controlled Phase	NOT COMPLETED	Placebo -> Ritlecitinib 200/50 mg QD	2
Placebo-Controlled Phase	NOT COMPLETED	Ritlecitinib 50 mg QD	0
Active Therapy Extension Phase	STARTED	Ritlecitinib 200/50/50 mg QD	32

1 to 10 of 27Source ClinicalTrials.gov

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Adverse events160

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Lymphadenopathy	Blood and lymphatic system disorders	Ritlecitinib 200/50 mg QD - Placebo-Controlled Phase	0	36
other	Lymphadenopathy	Blood and lymphatic system disorders	Placebo - Placebo-Controlled Phase	2	35
other	Lymphadenopathy	Blood and lymphatic system disorders	Ritlecitinib 50 mg QD - Active Therapy Extension Phase	0	32
other	Lymphadenopathy	Blood and lymphatic system disorders	Ritlecitinib 200/50 mg QD - Active Therapy Extension Phase	0	33
other	Lymphadenopathy	Blood and lymphatic system disorders	Ritlecitinib 50 mg QD: Extension Phase	0	45
other	Tinnitus	Ear and labyrinth disorders	Ritlecitinib 200/50 mg QD - Placebo-Controlled Phase	2	36
other	Tinnitus	Ear and labyrinth disorders	Placebo - Placebo-Controlled Phase	0	35
other	Tinnitus	Ear and labyrinth disorders	Ritlecitinib 50 mg QD - Active Therapy Extension Phase	0	32
other	Tinnitus	Ear and labyrinth disorders	Ritlecitinib 200/50 mg QD - Active Therapy Extension Phase	0	33
other	Tinnitus	Ear and labyrinth disorders	Ritlecitinib 50 mg QD: Extension Phase	0	45

1 to 10 of 160Source ClinicalTrials.gov

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Adverse event totals15

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Ritlecitinib 200/50 mg QD - Placebo-Controlled Phase	0	36
Total, all-cause mortality	Placebo - Placebo-Controlled Phase	0	35
Total, all-cause mortality	Ritlecitinib 50 mg QD - Active Therapy Extension Phase	0	32
Total, all-cause mortality	Ritlecitinib 200/50 mg QD - Active Therapy Extension Phase	0	33
Total, all-cause mortality	Ritlecitinib 50 mg QD: Extension Phase	0	45
Total, other adverse events	Ritlecitinib 200/50 mg QD - Placebo-Controlled Phase	23	36
Total, other adverse events	Placebo - Placebo-Controlled Phase	17	35
Total, other adverse events	Ritlecitinib 50 mg QD - Active Therapy Extension Phase	16	32
Total, other adverse events	Ritlecitinib 200/50 mg QD - Active Therapy Extension Phase	12	33
Total, other adverse events	Ritlecitinib 50 mg QD: Extension Phase	10	45

1 to 10 of 15Source ClinicalTrials.gov

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Papers3

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
38263353	DERIVED	PubMed
41917311	DERIVED	PubMed
42481842	DERIVED	PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons0

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

None in this release.

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

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