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NCT Number: NCT07228390

A 16-Week Study to Learn About the Study Medicine Called Ritlecitinib in Adults With Long Lasting Painful Red Skin Lumps, Known by the Medical Term, Hidradenitis Suppurativa, or HS.

The purpose of this study is to learn about the safety and effects of the study medicine (called Ritlecitinib) for the possible treatment of hidradenitis suppurativa (HS). HS is a disease causing long lasting painful red skin lumps.

This study is seeking participants who:

* have moderate or severe HS * have previously received antibiotics for HS that did not help, or could not tolerate antibiotics Participants will be randomly (like a flip of coin) assigned to receive either the study medicine or a placebo (a pill that looks like the study medicine but does not contain any medicine). The study medicine or placebo will be taken by mouth once daily at home. For the first part of the study, participants will receive a loading (starting) dose. For the next part of the study, participants will receive a maintenance (ongoing) dose.

Participants will take part in the study for about 24 weeks (about 6 months). There will be about 10 study clinic visits: a screening visit, Day 1, and then every 1, 2, or 4 weeks until week 16. At each visit, participants will report on their health and have tests such as physical exams, blood and urine tests, vital signs, chest X-rays, ECGs, hearing tests, and questionnaires. Participants will record when they take the study medicine and their HS symptoms every day in an eDiary on a mobile phone.

The experiences of participants receiving the study medicine will be compared to those receiving placebo to help see if the study medicine is safe and effective.

Recruiting

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Key information

Conditions

Hidradenitis Suppurativa Bacterial Infections Bacterial Infections and Mycoses Hidradenitis Infections Skin Diseases Skin Diseases, Bacterial Skin Diseases, Infectious Skin and Connective Tissue Diseases Suppuration Sweat Gland Diseases

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Dermatology Research Institute, Calgary, Alberta, Canada

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Eligibility Criteria:

Inclusion criteria

  • Male or female participants ≥18 to ≤75 years of age.
  • Participants with a diagnosis (based on clinical history and physical examination) of moderate to severe HS for at least 6 months prior to Screening Visit and inadequate response to at least 4-week (28 days) treatment with oral antibiotics for the treatment of HS.

Exclusion criteria

  • Presence of ≥20 draining fistulae at Screening or BL visit
  • Evidence of other active skin disease or condition at screening
  • Have a known immunodeficiency disorder
  • Having a history of systemic infection requiring hospitalization or parenteral therapy, including history of infection with Mycobacterium TB
  • Specific Viral Infection History (incl. history of herpes zoster, HBV or HCV Infection
  • Current or recent history of clinically significant severe, progressive, or uncontrolled other medical conditions
  • Any medical or psychiatric condition including any active suicidal ideation in the past year or suicidal behavior in the past 5 years

Treatment and study plan

Ritlecitinib

Drug

Participants will receive one oral dose once daily (QD), starting with a loading dose of ritlecitinib for 8 weeks, followed by maintenance for 8 weeks.

Other names: Investigational Product

Placebo

Drug

Participant will receive matching placebo

Primary outcomes

  1. Difference in proportion of responders based on Hidradenitis Suppurativa Clinical Response achieving at least 50% reduction from baseline (Hidradenitis Suppurativa Clinical Response HiSCR50) in patients with HS treated with ritlecitinib versus placebo.

    Time frame: Week 16

    The difference in proportion of responders based on HiSCR50 response at Week 16 in patients with HS treated with ritlecitinib versus placebo.

Secondary outcomes

  1. Proportion of participants achieving HiSCR50 response

    Time frame: at Weeks 1, 2, 4, 6, 8 and Week 12.

    The difference in proportion of responders based on HiSCR50 response at Weeks 1, 2, 4, 6, 8 and 12 in patients with HS treated with ritlecitinib versus placebo

  2. Proportion of participants achieving HiSCR75 response

    Time frame: at Weeks 1, 2, 4, 6, 8, 12 and Week 16.

    The difference in proportion of responders based on HISCR75 response at Weeks 1, 2, 4, 6, 8, 12 and 16 in patients with HS treated with ritlecitinib versus placebo

  3. Proportion of participants achieving HiSCR90 response

    Time frame: at Weeks 1, 2, 4, 6, 8, 12 and Week 16

    The difference in proportion of responders based on HiSCR90 response at Weeks 1, 2, 4, 6, 8, 12 and 16 in patients with HS treated with ritlecitinib versus placebo

  4. Response based on a on total abscess and inflammatory nodule count (AN Count) of 0 or 1

    Time frame: Week 16

    The difference in proportion of responders based on a total AN count of 0 or 1 at Week 16 in patients with HS treated with ritlecitinib and placebo

  5. Response based on a total AN count of 0, 1, or 2

    Time frame: At week 16

    The difference in proportion of responders based on a total AN count of 0, 1 or 2 at Week 16 in patients with HS treated with ritlecitinib and placebo.

  6. Percent change from Baseline(CFB) in total AN count

    Time frame: Weeks 1, 2, 4, 6, 8, 12 and 16.

    The difference in mean percent CFB in total AN count at Weeks 1, 2, 4, 6, 8, 12 and 16 in patients with HS treated with ritlecitinib and placebo

  7. Absolute score in Hidradenitis Suppurativa Investigator Global Assessment (HS-IGA)

    Time frame: at Weeks 1, 2, 4, 6, 8, 12 and 16

    The difference in mean absolute score in HS-IGA at Weeks 1, 2, 4, 6, 8, 12 and 16 in patients with HS treated with ritlecitinib and placebo

  8. CFB in Hidradenitis Suppurativa Investigator Global Assessment (HS-IGA)

    Time frame: at Weeks 1, 2, 4, 6, 8, 12 and 16

    Mean CFB in HS-IGA at Weeks 1, 2, 4, 6, 8, 12 and 16 in patients with HS treated with ritlecitinib and placebo

  9. Proportion of participants achieving a HS-IGA=0 or 1

    Time frame: Weeks 1, 2, 4, 6, 8, 12 and 16

    The difference in proportion of responders based on HS-IGA=0 or 1 at Weeks 1, 2, 4, 6, 8, 12 and 16 in patients with HS treated with ritlecitinib and placebo

  10. Participants who experience an HS flare, defined as at least a 25% increase in total AN count with a minimum increase of 2 relative to Baseline

    Time frame: Weeks 4, 8, 12 and 16.

    The difference in proportion of HS flare at Weeks 4, 8, 12 and 16 in patients with HS treated with ritlecitinib and placebo

  11. CFB in Hidradenitis Suppurativa Symptom Daily Diary (HSSDD)

    Time frame: Weeks 1, 2, 4, 6, 8, 12 and 16

  12. Skin pain NRS30 (numeric rating scale) response, at worst and on average, respectively among participants with baseline skin pain NRS ≥3

    Time frame: Weeks 1, 2, 4, 6, 8, 12, and 16

  13. Percent CFB in skin pain NRS, at worst and on average, respectively, in participants with baseline skin pain NRS ≥3

    Time frame: Weeks 1, 2, 4, 6, 8, 12, and 16

  14. CFB in skin pain NRS, at worst and on average, respectively

    Time frame: at Weeks 1, 2, 4, 6, 8, 12, and 16

  15. Skin pain NRS50 response, at worst and on average, respectively among participants with baseline skin pain NRS ≥3.

    Time frame: at Weeks 1, 2, 4, 6, 8, 12, and 16

  16. Skin pain NRS70 response, at worst and on average, respectively among participants with baseline skin pain NRS ≥3

    Time frame: at Weeks 1, 2, 4, 6, 8, 12, and 16,

  17. Incidence of treatment emergent adverse events (TEAE), adverse events (AE) and serious adverse events (SAE) leading to discontinuation

    Time frame: up to 24 Weeks

  18. Incidence of clinically significant laboratory abnormalities over time

    Time frame: up to 24 Weeks

  19. Absolute score and CFB in Hidradenitis Suppurativa Quality of Life (HiSQOL)

    Time frame: at Weeks 1, 2, 4, 6, 8, 12 and 16.

  20. Absolute score and % CFB in International Hidradenitis Suppurativa Severity Score System (IHS4)

    Time frame: Weeks 1, 2, 4, 6, 8, 12 and 16.

Study contacts

Contact information is provided by the study sponsor or research team.

Pfizer CT.gov Call Center

CONTACT

[email protected]

1-800-718-1021

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

A PHASE 2, MULTICENTER, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED, 16-WEEK STUDY EVALUATING THE SAFETY AND EFFICACY OF RITLECITINIB (PF-06651600) IN ADULTS WITH MODERATE TO SEVERE HIDRADENITIS SUPPURATIVA

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Nov 14, 2025
Registry last updated
Jul 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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