Clinical Trials

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 Visit 1 (screening). Diagnosis must be verifiable through medical notes or other documentation.

  • Must have HS lesions present in at least 2 distinct anatomic areas (eg, left and right axilla), 1 of which must be at least Hurley Stage II or Hurley Stage III at both the Screening and BL visits.

  • Study participants must have moderate to severe HS defined as a total of ≥5 inflammatory lesions (ie, number of abscesses plus number of inflammatory nodules) at both the Screening and BL visits.

  • Inadequate response to at least 4-week (28 days) treatment with oral antibiotics for the treatment of HS at the Screening Visit as assessed by the investigator through study participant interview and review of medical history; inadequate response must be verifiable through medical notes or other documentation. Study participants who meet any of the following are NOT automatically excluded from the study:

    • Demonstrated intolerance to (or during therapy became intolerant to) systemic antibiotics.

    • Had a contraindication to systemic antibiotics (eg, because of important side effects or safety risks).

    • Responded to course(s) of systemic antibiotic(s) and subsequently exhibited recurrence after discontinuation of the antibiotic.

  • Participants may enter the study on a background of concomitant oral antibiotic therapy for treatment of HS; the dosing regimen (dose and frequency) must have been stable for at least 8 weeks (56 days) prior to the BL visit and must remain stable throughout study participation.

  • Anti-TNF- α, IL-17 inhibitor, or IL-23 inhibitor naïve; or

    • Have been exposed to a single anti-TNF- α, a single IL-17, or a single IL23 inhibitor treatment. No double or triple class exposures will be allowed (ie, prior exposure to more than one of these classes: anti-TNF or IL-17 inhibitors or IL-23 inhibitors). The anti-TNF- α, IL-17 inhibitors or IL-23 inhibitors should have been discontinued for a minimum washout period. Enrollment of participants with exposure to an anti-TNF- α, a IL-17 inhibitor or a IL-23 inhibitor will be limited to approximately ≤40% of total participant population.

Exclusion Criteria:

• Presence of ≥20 draining fistulae at Screening or BL visit

• Evidence of other active skin disease or condition (eg, bacterial, fungal, or viral infection) (eg, bacterial cellulitis, candida intertrigo, extensive condyloma) at the time of screening or BL visit that would interfere with the evaluation of HS.

• Have a known immunodeficiency disorder (including positive serology for HIV at screening) or a first-degree relative with a hereditary immunodeficiency (unless known negative carrier status) or have had a splenectomy.

• General Infection History:

  • Having 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 BL visit.

  • Have active acute or chronic infection requiring treatment with oral antibiotics (with the exception of HS), antivirals, antiparasitics, antiprotozoals, or antifungals within 3 months prior to BL visit. 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 TB as evidenced by the following:

  • A positive QFT-G and/or QFT-G+ test or positive or borderline T-SPOT®TB performed within 12 weeks prior to Screening is exclusionary and is not permitted to be repeated during the Screening period for this study.

  • Participants without a prior exclusionary test result within 12 weeks prior to Screening must have an IGRA test performed during Screening period for this study:

    • A positive QFT-G and/or QFT-G+ (completed by central laboratory) or a positive or borderline T-SPOT®TB during Screening.

    • If the QFT-G and/or QFT-G+ test result is indeterminate/borderline or the T-SPOT®TB test result is indeterminate, the test should be repeated. If the repeat QFT-G and/or QFT-G+ test result is indeterminate/borderline or the TSPOT®TB test result is indeterminate, a PPD test may be substituted for the IGRA test only with the approval from the Pfizer medical monitor on a case-by-case basis.

    • Participants with a history BCG vaccination must have a negative IGRA test.

  • Assessment of the Screening chest imaging for latent or active tuberculosis is required if QFT-G and/or QFT-G+ is positive or T-SPOT is positive or borderline or if the participant has been previously treated for latent or active TB, and is to be performed according to local standards of care or country-specific guidelines. Chest imaging performed within 12 weeks prior to Screening showing no active TB will be accepted with a copy of the report available in the source document.

• 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.

    • Hepatitis B: At Screening, HBsAg and HBcAb will be tested

      • If both tests are negative, the participant is eligible for study inclusion.

      • If HBsAg is positive, the participant must be excluded from participation in the study.

      • If HBsAg is negative and HBcAb is positive, HBsAb reflex testing is required:

        • If HBsAb is negative, the participant must be excluded from participation in the study;

        • If HBsAb is positive, the participant is eligible for study inclusion

    • Hepatitis C: At screening, HCVAb will be tested:

      • Participants who are HCVAb negative are eligible.

  • Participants who are HCVAb positive will be reflex-tested for HCV RNA. Participants who are positive for HCVAb and HCV RNA will not be eligible for this study. For countries required by local SOC, HBV-DNA testing will be performed at screening and approximately at least every 3 months for those participants who are HBsAg negative, HBsAb positive and HBcAb positive. If HBV-DNA is detectable at screening or at any time thereafter, the participant must be excluded/discontinued from study intervention.

• Medical Conditions, Other:

  • Current or recent history of clinically significant severe, progressive, or uncontrolled renal (including but not limited to active renal disease or recent kidney stones), hepatic, hematological, gastrointestinal, metabolic, endocrine (eg, untreated hypovitaminosis D, hyperthyroidism, or hypothyroidism), pulmonary, cardiovascular, immunologic/rheumatologic or neurologic disease; or have any other severe acute or chronic infection, medical or psychiatric condition or laboratory abnormality not otherwise listed, that may increase the risk associated with study participation or investigational product administration, or interfere with the interpretation of study results; or in the opinion of the investigator or Pfizer (or designee), the participant is inappropriate for entry into this study.

  • 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.

  • Study participant has had a myocardial infarction or stroke within the 6 months prior to the Screening Visit

  • Chronic alcohol or drug abuse within 6 months of the Screening visit, as determined by the investigator or by the urine drug screening if required per local regulations. Use of cannabinoids products for medicinal purposes will be allowed.

  • 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. Documentation of the official reading must be located and available in the source documentation.

  • 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, or has planned major surgery after entering the study.

• Any medical or psychiatric condition including any active suicidal ideation in the past year or suicidal behavior in the past 5 years that may increase the risk of study participation or, in the investigator’s judgment, make the participant inappropriate for the study.

  • Any psychiatric condition including recent or active suicidal ideation or behavior that meets any of the following criteria:

    • Suicidal ideation associated with actual intent and a method or plan in the past 12 months (for the Screening visit assessment) or since the last visit (for the BL visit assessment): “Yes” answers on items 4 or 5 of the C-SSRS

    • Previous history of suicidal behaviors in the past 5 years (for the Screening visit assessment) or since the last visit (for the BL visit assessment): “Yes” answer (for events that occurred in the past 5 years for the Screening visit or since the last visit for the BL visit) to any of the suicidal behavior items of the C-SSRS.

    • Any lifetime history of serious suicidal behavior or recurrent suicidal behavior.

• Prior exposure to any JAK inhibitor or BTK inhibitor for any condition, including HS.

• Current or prior use of any prohibited concomitant medication(s), vaccine(s), or therapies(s) within the timeframes.

• Previous administration of an investigational product (drug or vaccine) or participation in an investigational device study within 8 weeks or, for investigational products, 5 half-lives preceding the first dose of study intervention used in this study (whichever is longer). Participation in studies of other investigational products (drug or vaccine) at any time during participation in this study.

• Any of the following abnormalities in laboratory values at Screening, as assessed by the study-specific laboratory and, if deemed necessary, confirmed by a single repeat:

  • Hepatic dysfunction defined as having any one of the following:

    • Total bilirubin 2.0 × ULN; participants with Gilbert’s syndrome would be eligible for this study, provided the direct bilirubin ≤1 x ULN

    • AST ≥2.5 × ULN

    • ALT ≥2.5 × ULN

  • Other laboratory abnormalities defined as:

    • Absolute WBC count ≤3.0 x 109 /L (≤3000/mm3 )

    • Absolute lymphocyte count <0.8 x 109 /L (<800/mm3 )

    • Absolute neutrophils (abs) ≤1.2 x 109 /L (<1200/mm3 )

    • Hemoglobin <10.0g/dL or hematocrit <30%

    • Platelet count <150 x 109 /L

    • HbA1c >8% or 64 mmol/mol

    • CK >3 x ULN

  • NOTE: If an exclusionary laboratory value is obtained at the Screening visit and results are not in alignment with the participant’s previous results, one additional sample may be drawn at the discretion of the investigator to confirm eligibility for the study.

• Screening standard 12-lead ECG that demonstrates clinically relevant abnormalities that may affect participant safety or interpretation of study results (eg, QTcF interval >450 msec, complete LBBB, signs of an acute or indeterminate age myocardial infarction, STT interval changes suggestive of myocardial ischemia, second or third degree AV block, or serious bradyarrhythmias or tachyarrhythmias). If QTcF exceeds 450 ms, or QRS exceeds 120 ms, the ECG should be repeated twice and the average of the 3 QTcF or QRS values used to determine the participant’s eligibility. Computer-interpreted ECGs with abnormal findings should be overread by an investigator experienced in reading ECGs before excluding a participant.

• 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.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 09/11/2025. Questions regarding updates should be directed to the study team contact.