A Phase 2 interventional study of PF-06651600 in Cicatricial Alopecia, sponsored by Emma Guttman. Completed at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-15.
Sponsored by Emma Guttman · Phase 2, Interventional, and Treatment
Alopecia could be subdivided into two main groups of diseases: non-scarring alopecia, such as male pattern baldness, or alopecia areata (AA), in which hair follicles are preserved, yet quiescent, and scarring alopecia, also known as cicatricial alopecia (CA), in which hair follicles are irreversibly destroyed. CA leads to scarred areas, most commonly on the scalp, that cannot re-grow hair. Despite being a long-term condition, that often has significant impact on patients' well-being, available effective treatments for these diseases are lacking. In addition, the molecular abnormalities causing CA are largely unknown. The research team will be administering a new investigational drug (a JAK3/TEC inhibitor), ritlecitinib, which has shown statistically significant improvement in scalp hair loss for AA patients in a proof of concept and phase 2b/3 studies (B7981015 AA study). This is an open-label clinical trial. CA patients will be asked to provide small samples of skin and blood throughout the treatment period, to find out how they respond to the drug, and to attempt to better understand these diseases.
511 studies on the registry are indexed under Alopecia; 128 are open to participants now.
This study's enrollment of 50 is close to the median of 50 across 430 interventional studies indexed under Alopecia.
Browse Alopecia studies →Emma Guttman is the lead sponsor of 4 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies:
EXCLUSION CRITERIA
ANY of the following abnormalities in the clinical laboratory tests at screening, as assessed by the study-specific laboratory and confirmed by a single repeat, if deemed necessary:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
200 mg once-daily for 8 weeks and then 100 mg once daily for the remaining 40 weeks
Drug: PF-06651600
tablets containing active drug (a combined JAK3/TEC inhibitor)
Also known as: Ritlecitinib
Change in Ct Values of mRNA Levels of CCL5 Gene
Log-fold Changes in mRNA Levels of CCL5 gene expression in skin biopsies quantified by normalized Ct values obtained by quantitative real-time PCR assay, measured at baseline and week 24. The unit of the outcome is called Ct value and it represents the number of amplification cycles to reach a level of fluorescence in the experiment. The Ct value is directly associated to the level of expression of a gene
Time frame: Baseline to Week 24
Number of Treatment-Emergent Adverse Events
The adverse event will be described and categorized as Treatment-emergent, Serious, abnormal in vital signals, and abnormalities in laboratory parameters.
Time frame: Week 48
Percent Change in the Frontal Fibrosis Alopecia Severity Index (FFASI)
The Frontal Fibrosis Alopecia Severity Index utilizes clinical images of the entire hairline from a total score of 0-84, with higher score indicating more severity. Percent change in FFASI at Week 24 and Week 48 as compared to baseline.
Time frame: Baseline, Week 24, and Week 48
Percent Change in the Lichen Planopilaris Activity Index (LPPAI)
The Lichen Planopilaris Activity Index is a numeric composite index that aggregates symptoms and signs of pruritus, pain, burning, scalp erythema , perifollicular erythema, perifollicular scale , pull test and spreading. Symptoms and signs are measured in a 4-point scale (0-absent, 1-mild, 2-moderate and 3-severe). Full range from 0-10, higher score indicates more severity. Percent change in the LPPAI at Week 24 and Week 48 as compared to baseline.
Time frame: Baseline, Week 24 and Week 48
Percentage Change From Baseline in Change in Central Hair Loss Grade (CHLG)
Percent change in Central Hair Loss Grade (CHLG) is an ordinal photographic outcome derived from a validated central scalp alopecia photographic scale to capture the pattern and severity of central hair loss. The scale uses standardized photographs and grades severity from 0 to 5, with 0 representing no hair loss, grades 1 and 2 representing early hair loss, and grades 3 to 5 representing probable CCCA with increasing severity.
Time frame: Baseline, Week 24 and Week 48
| Milestone | PF-06651600 (Ritlecitinib) |
|---|---|
| Started | 50 |
| Completed | 30 |
| Not completed | 20 |
| Withdrew: Adverse event | 3 |
| Withdrew: Lack of efficacy | 3 |
| Withdrew: Lost to follow-up | 2 |
| Withdrew: Pregnancy | 1 |
| Withdrew: Protocol violation | 6 |
| Withdrew: Withdrawal by subject | 3 |
| Withdrew: Lack of satisfaction | 1 |
| Withdrew: Not reported | 1 |
Log-fold Changes in mRNA Levels of CCL5 gene expression in skin biopsies quantified by normalized Ct values obtained by quantitative real-time PCR assay, measured at baseline and week 24. The unit of the outcome is called Ct value and it represents the number of amplification cycles to reach a level of fluorescence in the experiment. The Ct value is directly associated to the level of expression of a gene
| amplification cycles | PF-06651600 (Ritlecitinib) |
|---|---|
| Change in Ct Values of mRNA Levels of CCL5 Gene | -1.11 ± 0.225 |
The adverse event will be described and categorized as Treatment-emergent, Serious, abnormal in vital signals, and abnormalities in laboratory parameters.
| events | PF-06651600 (Ritlecitinib) |
|---|---|
| Number of Treatment-Emergent Adverse Events | 60 |
The Frontal Fibrosis Alopecia Severity Index utilizes clinical images of the entire hairline from a total score of 0-84, with higher score indicating more severity. Percent change in FFASI at Week 24 and Week 48 as compared to baseline.
| Percent change in score on a scale | PF-06651600 (Ritlecitinib) |
|---|---|
| Week 24 | -27.6 ± 4.6 |
| Week 48 | -51.3 ± 6.7 |
The Lichen Planopilaris Activity Index is a numeric composite index that aggregates symptoms and signs of pruritus, pain, burning, scalp erythema , perifollicular erythema, perifollicular scale , pull test and spreading. Symptoms and signs are measured in a 4-point scale (0-absent, 1-mild, 2-moderate and 3-severe). Full range from 0-10, higher score indicates more severity. Percent change in the LPPAI at Week 24 and Week 48 as compared to baseline.
| Percent change in score on a scale | PF-06651600 (Ritlecitinib) |
|---|---|
| Week 24 | -57.9 ± 5.9 |
| Week 48 | -69.9 ± 3.8 |
Percent change in Central Hair Loss Grade (CHLG) is an ordinal photographic outcome derived from a validated central scalp alopecia photographic scale to capture the pattern and severity of central hair loss. The scale uses standardized photographs and grades severity from 0 to 5, with 0 representing no hair loss, grades 1 and 2 representing early hair loss, and grades 3 to 5 representing probable CCCA with increasing severity.
| Percent change in score on a scale | PF-06651600 (Ritlecitinib) |
|---|---|
| Week 24 | -24.4 ± 7.8 |
| Week 48 | -46.9 ± 12.4 |
Collected over 48 Weeks. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| PF-06651600 (Ritlecitinib) | 0/50 (0%) | 0/50 (0%) | 43/50 (86%) |
| Event | PF-06651600 (Ritlecitinib) |
|---|---|
| Elevated CPKBlood and Lymphatic System Disorders | 19/50 |
| LymphopeniaBlood and Lymphatic System Disorders | 14/50 |
| LymphocytopeniaBlood and Lymphatic System Disorders | 8/50 |
| NeutropeniaBlood and Lymphatic System Disorders | 7/50 |
| LeukopeniaBlood and Lymphatic System Disorders | 6/50 |
| FatigueGeneral Disorders | 5/50 |
| Lymphocytopenia <500Blood and Lymphatic System Disorders | 2/50 |
| ThrombocytopeniaBlood and Lymphatic System Disorders | 2/50 |
| DiarrrheaGastrointestinal Disorders | 2/50 |
| HeadachesGeneral Disorders | 2/50 |
| Age, Continuous(years) | PF-06651600 (Ritlecitinib) |
|---|---|
| Mean | 48.72 ± 13.41 |
| Sex: Female, Male(Participants) | PF-06651600 (Ritlecitinib) |
|---|---|
| Female | 42 |
| Male | 8 |
| Race (NIH/OMB)(Participants) | PF-06651600 (Ritlecitinib) |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 1 |
| Native Hawaiian or Other Pacific Islander | 1 |
| Black or African American | 21 |
| White | 27 |
| More than one race | 0 |
| Unknown or Not Reported | 0 |
| Ethnicity (NIH/OMB)(Participants) | PF-06651600 (Ritlecitinib) |
|---|---|
| Hispanic or Latino | 5 |
| Not Hispanic or Latino | 45 |
| Unknown or Not Reported | 0 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No — Not shared
This study is completed, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: PF-06651600