A Study of 2 Doses of Ritlecitinib in People 12 Years of Age and Older With Alopecia Areata

• Ritlecitinib 100 mg (Drug), also known as PF-06651600, Litfulo: 100 mg Capsule
• Ritlecitinib 50 mg (Drug), also known as PF-06651600, Litfulo: 50 mg Capsule
• Placebo - 100 mg (Drug): Capsule (to match Ritlecitinib 100 mg)
• Placebo - 50 mg (Drug): Capsule (to match Ritlecitinib 50 mg)

Primary outcomes

• Part 1: Percentage of participants with absolute Severity of Alopecia Tool (SALT) score less than or equal to 20 [Week 24]: Difference in the percentage of participants with SALT score less than or equal to 20 between ritlecitinib 100 mg once-daily (QD) versus placebo
• Part 2: Percentage of participants with TEAEs, SAEs, and AEs leading to discontinuation [Baseline to Follow-up visit (Week 52)]: Percentage of participants with events, based on those reported in the study including the safety follow-up period for ritlecitinib 100 mg QD
• Part 2: Percentage of participants with clinically significant laboratory abnormalities [Baseline to Follow-up visit (Week 52)]: Percentage of participants with clinically significant laboratory abnormalities, based on those reported in the study including the safety follow-up period for ritlecitinib 100 mg QD

Secondary outcomes

• Part 1: Percentage of participants with absolute SALT score less than or equal to 20 [Week 24]: Difference in the percentage of participants with SALT score less than or equal to 20 between ritlecitinib 50 mg QD versus placebo
• Part 1: EU Only: Percentage of participants with Patient Global Impression of Change (PGI-C) response, defined as a score of "moderately improved" or "greatly improved" [Week 24]: Difference in percentage of participants with PGI-C response between ritlecitinib 100 mg QD versus placebo and ritlecitinib 50 mg QD versus placebo
• Part 1: US Only: Percentage of participants with absolute SALT score less than or equal to 20 [Week 36]: Difference in the percentage of participants with SALT score less than or equal to 20 between ritlecitinib 100 mg QD versus placebo
• Part 1: Change from baseline in SALT score [Week 24]: Difference in the mean absolute change from baseline in SALT score between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with absolute SALT score equal to 0 [Week 24]: Difference in the percentage of participants with SALT score equal to 0 between ritlecitinib 100 mg QD versus placebo and ritlecitinib 50 mg QD versus placebo
• Part 1: Percentage of participants with absolute SALT score less than or equal to 10 [Baseline through Week 24]: Difference in the percentage of participants with SALT score less than or equal to 10 between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with absolute SALT score less than or equal to 20 [Baseline through Week 24]: Difference in the percentage of participants with SALT score less than or equal to 20 between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with absolute SALT score equal to 0 [Baseline through Week 24]: Difference in the percentage of participants with SALT score equal to 0 between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Change from baseline in SALT score [Baseline through Week 24]: Difference in the mean absolute change from baseline in SALT score between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with EBA (Eyebrow Assessment) response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal EBA score at baseline) [Baseline through Week 24]: Difference in the percentage of participants with EBA response (among participants without a normal EBA score at baseline) between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with ELA (Eyelash Assessment) response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal ELA score at baseline) [Baseline through Week 24]: Difference in the percentage of participants with ELA response (among participants without a normal ELA score at baseline) between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with PGI-C response, defined as a score of "moderately improved" or "greatly improved" [Baseline through Week 24]: Difference in the percentage of participants with PGI-C response between ritlecitinib 100 mg QD versus ritlecitinib 50 mg QD
• Part 1: Percentage of participants with absolute SALT score less than or equal to 10 [Week 24]: Difference in the percentage of participants with SALT score less than or equal to 10 between ritlecitinib 100 mg QD versus placebo and ritlecitinib 50 mg QD versus placebo
• Part 1: Percentage of participants with EBA response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal EBA score at baseline) [Week 24]: Difference in the percentage of participants with EBA response (among participants without a normal EBA score at baseline) between ritlecitinib 100 mg QD versus placebo and ritlecitinib 50 mg QD versus placebo
• Part 1: Percentage of participants with ELA response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal ELA score at baseline) [Week 24]: Difference in the percentage of participants with ELA response (among participants without a normal ELA score at baseline) between ritlecitinib 100 mg QD versus placebo and ritlecitinib 50 mg QD versus placebo
• Part 1: Percentage of participants with absolute SALT score less than or equal to 20 [Week 48]: Difference in the percentage of participants with SALT score less than or equal to 20 between ritlecitinib 50 mg non-responder (NR)-->ritlecitinib 100 mg QD versus ritlecitinib 50 mg NR-->ritlecitinib 50 mg QD
• Part 1: Percentage of participants with absolute SALT score less than or equal to 10 [Week 48]: Difference in the percentage of participants with SALT score less than or equal to 10 between ritlecitinib 50 mg NR-->ritlecitinib 100 mg QD versus ritlecitinib 50 mg NR-->ritlecitinib 50 mg QD
• Part 1: Change from Week 24 in SALT score [Week 48]: Difference in the mean absolute change from Week 24 in SALT score between ritlecitinib 50 mg NR-->ritlecitinib 100 mg QD versus ritlecitinib 50 mg NR-->ritlecitinib 50 mg QD
• Part 1: Percentage of participants with PGI-C response, defined as a score of "moderately improved" or "greatly improved" [Week 48]: Percentage of participants with PGI-C response between ritlecitinib 50 mg NR-->ritlecitinib 100 mg QD versus ritlecitinib 50 mg NR-->ritlecitinib 50 mg QD
• Part 1: Percentage of participants with absolute SALT score less than or equal to 20 [Week 24 through Week 48]: Percentage of participants with SALT score less than or equal to 20 for ritlecitinib 100 mg QD, ritlecitinib 50 mg responder (R)-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 1: Percentage of participants with absolute SALT score less than or equal to 10 [Week 24 through Week 48]: Percentage of participants with SALT score less than or equal to 10 for ritlecitinib 100 mg QD, ritlecitinib 50 mg R-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 1: Percentage of participants with absolute SALT score equal to 0 [Week 24 through Week 48]: Percentage of participants with SALT score equal to 0 for ritlecitinib 100 mg QD, ritlecitinib 50 mg R-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 1: Change from Week 24 in SALT score [Week 24 through Week 48]: Mean absolute change from Week 24 in SALT score for ritlecitinib 100 mg QD, ritlecitinib 50 mg R-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 1: Percentage of participants with EBA response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal EBA score at baseline) [Week 24 through Week 48]: Percentage of participants with EBA response for ritlecitinib 100 mg QD, ritlecitinib 50 mg R-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 1: Percentage of participants with ELA response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal ELA score at baseline) [Week 24 through Week 48]: Percentage of participants with ELA response for ritlecitinib 100 mg QD, ritlecitinib 50 mg R-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 1: Percentage of participants with PGI-C response, defined as a score of "moderately improved" or "greatly improved" [Week 24 through Week 48]: Percentage of participants with PGI-C response for ritlecitinib 100 mg QD, ritlecitinib 50 mg R-->50 mg QD, ritlecitinib 50 mg NR-->50 mg QD, and ritlecitinib 50 mg NR-->100 mg QD
• Part 2: Percentage of participants with absolute SALT score less than or equal to 20 [Baseline through Week 48]: Percentage of participants with absolute SALT score less than or equal to 20 for ritlecitinib 100 mg QD
• Part 2: Percentage of participants with absolute SALT score less than or equal to 10 [Baseline through Week 48]: Percentage of participants with absolute SALT score less than or equal to 10 for ritlecitinib 100 mg QD
• Part 2: Percentage of participants with absolute SALT score equal to 0 [Baseline through Week 48]: Percentage of participants with absolute SALT score equal to 0 for ritlecitinib 100 mg QD
• Part 2: Change from baseline in SALT score [Baseline through Week 48]: Mean change from baseline in SALT score for ritlecitinib 100 mg QD
• Part 2: Percentage of participants with EBA (Eyebrow Assessment) response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal EBA score at baseline) [Baseline through Week 48]: Percentage of participants with EBA response for ritlecitinib 100 mg QD
• Part 2: Percentage of participants with ELA (Eyelash Assessment) response, defined as at least a 2-grade improvement from baseline or a score of 3 (among participants without a normal ELA score at baseline) [Baseline through Week 48]: Percentage of participants with ELA response for ritlecitinib 100 mg QD
• Part 2: Percentage of participants with PGI-C response, defined as a score of "moderately improved" or "greatly improved" [Baseline through Week 48]: Percentage of participants with PGI-C response for ritlecitinib 100 mg QD
• Part 1: Percentage of participants with TEAEs, SAEs, and AEs leading to discontinuation [Baseline to Follow-up visit (Week 52)]: Percentage of participants with events, based on those reported in the study including the safety follow-up period for ritlecitinib 100 mg QD and ritlecitinib 50 mg
• Part 1: Percentage of participants with clinically significant laboratory abnormalities [Baseline to Follow-up visit (Week 52)]: Percentage of participants with clinically significant laboratory abnormalities, based on those reported in the study including the safety follow-up period for ritlecitinib 100 mg QD and ritlecitinib 50 mg

Sex: All, ages: 12 Years to any

Inclusion Criteria:

Age:

1. 18 years of age or older at screening. Adolescents (12 to <18 years of age at screening) are also eligible for this study, but only if permitted by the local IRB/EC and local regulatory health authority (if applicable). Where these approvals have not been granted, only participants 18 years of age and older at screening will be enrolled. In Part 2 of the study, only adolescents (12 to <18 years of age at both Screening and Day 1) who did not participate in Part 1 will be enrolled.

   Disease Characteristics:
2. Must meet the following alopecia areata criteria at both Screening and Baseline:

   1. Have a clinical diagnosis of alopecia areata with no other etiology of hair loss.
   2. ≥50% hair loss of the scalp, as measured by SALT, without evidence of terminal hair regrowth within the previous 6 months.
   3. Current episode of hair loss ≤10 years.

Exclusion Criteria:

Medical Conditions:

1. Diseases or conditions other than alopecia areata which affect hair loss, including other types of alopecia, other scalp disease that may impact the alopecia areata assessment, or active systemic diseases that may cause hair loss.
2. History of severe allergic or anaphylactoid reaction to any kinase inhibitor or a known allergy/hypersensitivity to any component (including excipients) of the study intervention.
3. Any psychiatric condition including recent or active suicidal ideation or behavior that meets protocol-defined criteria.
4. General Infection History:

   * Have a history of systemic infection requiring hospitalization or parenteral therapy (antimicrobial, antiviral, antiparasitic, antiprotozoal, or antifungal), or as otherwise judged clinically significant by the investigator, within 3 months prior to Day 1.
   * Have active acute or chronic infection requiring treatment with oral antibiotics, antivirals, antiparasitics, antiprotozoals, or antifungals within 4 weeks prior to Day 1. NOTE: participants may be rescreened after the infection resolves.
   * Evidence or history of untreated, currently treated or inadequately treated active or latent infection with Mycobacterium tuberculosis.
5. Specific Viral Infection History:

   * History (single episode) of disseminated herpes zoster or disseminated herpes simplex, or a recurrent (more than one episode of) localized, dermatomal herpes zoster.
   * Infected with hepatitis B or hepatitis C viruses: all participants will undergo screening for hepatitis B and C for eligibility.
6. Other Medical Conditions:

   * Have hearing loss with progression over the previous 5 years, sudden hearing loss, or middle or inner ear disease such as otitis media, cholesteatoma, Meniere's disease, labyrinthitis, or other auditory condition that is considered acute, fluctuating or progressive.
   * Abnormal findings on the screening chest imaging (eg, chest x-ray) including, but not limited to, presence of active TB or other infections, cardiomyopathy, or malignancy. Chest imaging may be performed up to 12 weeks prior to Screening.
   * Have any malignancies or have a history of malignancies with the exception of adequately treated or excised nonmetastatic basal cell or squamous cell cancer of the skin or cervical carcinoma in situ.
   * Have a history of any lymphoproliferative disorder such as EBV-related lymphoproliferative disorder, history of lymphoma, history of leukemia, or signs and symptoms suggestive of current lymphatic or lymphoid disease.
   * Significant trauma or major surgery within 1 month of the first dose of study drug or considered in imminent need for surgery.
7. Adolescent participants 12 to <18 years of age without one of the following:

   * Documented evidence from a health professional of having received varicella vaccination (2 doses); or
   * Evidence of prior exposure to varicella zoster virus (VZV) based on serological testing (ie, a positive VZV IgG Ab result) at Screening.
8. Any medical or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.

   Prior/Concomitant Therapy:
9. Current or prior use of any prohibited medication(s), vaccine(s), or treatment(s) within the protocol-defined timelines.

   Prior/Concurrent Clinical Study Experience:
10. Previous administration with an investigational drug or vaccine within 8 weeks (or longer as determined by the local requirement) or 5 half-lives (whichever is longer) before the first dose of study intervention in this study. Participation in studies of other investigational products (drug or vaccine) at any time during their participation in this study. Receipt of study intervention in Study B7981094 or other studies of ritlecitinib.

    Diagnostic Assessments:
11. Any exclusionary abnormalities in laboratory values at Screening, as assessed by the study-specific laboratory and, if deemed necessary, confirmed by a single repeat.
12. Screening standard 12-lead ECG that demonstrates clinically relevant abnormalities.

    Other Exclusion Criteria:
13. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.

48 more sites not listed.

• Results publication: King B, McMichael A, Sinclair R, Vano-Galvan S, Wolk R, Woodworth D, Soma K, Robbana F, Lejeune A, Napatalung L, Law E, Wajsbrot D, Wang C, Roychoudhury S. Rationale and Design of a Novel, Phase 3, External and Synthetic Placebo-Controlled Clinical Trial of Ritlecitinib 50 mg and 100 mg for Alopecia Areata. Dermatol Ther (Heidelb). 2025 Dec;15(12):3793-3803. doi: 10.1007/s13555-025-01543-7. Epub 2025 Oct 14. PMID 41083802

• Pfizer CT.gov Call Center, Study director, Pfizer