A Study of Zasocitinib in Adults With Hidradenitis Suppurativa

Inclusion Criteria:

Participant Willingness:

1. Participant is willing and able to understand and fully comply with all trialprocedures and requirements (including the use of digital tools and applications),in the opinion of the investigator.

2. Participant has provided written informed consent and any required privacyauthorization before the initiation of any trial procedures. Disease Characteristics:

3. Participants must have signs and symptoms of hidradenitis suppurativa (HS) for atleast 6 months prior to screening, and a diagnosis of HS (confirmed by adermatologist) at the screening visit with stable HS signs and symptoms for 2 monthsbefore screening, as determined by the investigator through interview or medicalhistory.

4. Participants should have HS lesions in at least 2 distinct anatomical areas, one ofwhich must be at least Hurley Stage II or III at both screening and Day 1.

5. Participants must have a total of greater than or equal to (>=) 5 inflammatorylesions (that is, number of abscesses plus number of inflammatory nodules) at bothscreening and Day 1.

6. Participants must have a history of inadequate response to a previous course of oralantibiotic for treatment of HS or exhibited recurrence, intolerance, orcontraindication during that course of oral antibiotic, as assessed by the principalinvestigator. Age and Reproductive Status:

7. Participant is aged >=18 years at the time of consent. In the European Union (EU)/European Economic Area (EEA), for participants aged 65 years or older, theinvestigator must document a favorable benefit-risk assessment to justify theparticipant's inclusion in the trial.

8. Participant meets the following birth control requirement:

9. An individual with potential for pregnancy, who is now surgically sterile; OR

10. An individual of nonchildbearing potential with laboratory confirmation ofpostmenopausal status; OR

11. If sexually active with a nonsterilized individual who produces sperm, anindividual with potential for pregnancy who agrees to use a highly effectivemethod of contraception from the signing of informed consent throughout theduration of the trial. The use of effective contraception will be required for participants assigned malesex at birth. In the EU/EEA, for participants who elect to use hormonal contraception as a form ofhighly effective contraception, the investigator must document a favorablebenefit-risk assessment to justify the participant's inclusion in the trial atscreening and every 3 months during the trial.

12. For participants in the EU/EEA, the investigator must have no reason to believe thatthe participant would be placed at risk by participating in the trial with regard tothe European Commission decision as of 10 March 2023 on measures to minimize risk ofserious side effects with JAK inhibitors (EMA/142279/2023) and the UK Medicines andHealthcare products Regulatory Agency (MHRA) guideline on Janus kinase (JAK)inhibitors: new measures to reduce risks of major cardiovascular events, malignancy,venous thromboembolism, serious infections and increased mortality as of 26 April

Exclusion Criteria:

Target Disease-Related Exclusions:

1. Participant has a draining tunnel count of greater than (>) 20 at screening or Day

3. Participant has any other active skin disease or condition (for example, bacterialcellulitis, Candida intertrigo, extensive condyloma) that may, in the opinion of theinvestigator, interfere with the assessment of HS or participant has developed aconcomitant comorbid skin condition that, in the opinion of the investigator, wouldinterfere with the trial assessments.

4. Participant has a diagnosis of sarcoidosis, systemic lupus erythematosus, or activeinflammatory bowel disease.

5. Participant has a diagnosis of inflammatory conditions other than HS, including butnot limited to, psoriasis, psoriatic arthritis, and rheumatoid arthritis. Recent/Concurrent Infectious Disease Exclusions:

6. Tuberculosis (TB):

7. Participants have a history of active TB infection, regardless of treatmentstatus.

8. Participants have signs or symptoms of active TB (including, but not limitedto, chronic fever, chronic productive cough, night sweats, or weight loss) asjudged by the investigator.

9. Participants have evidence of latent tuberculosis infection (LTBI) as evidencedby a positive QuantiFERON (QFT) result OR 2 indeterminate QFT results, andparticipant does not have documentation of appropriate LTBI prophylaxis or isnot able or not willing to initiate appropriate LTBI prophylaxis. Participantremains eligible if there are no signs/symptoms of active TB AND documentationof no history of active TB can be provided AND (1) participant can providedocumentation of prior and complete treatment for LTBI (appropriate in durationand type per current local country guidelines) or (2) participant has apositive QFT result or 2 indeterminate QFT results but has initiatedprophylaxis (appropriate in duration and type per current local guidelines) aminimum of 2 weeks prior to Day 1. In the EU/EEA, participants with evidence ofLTBI, regardless of prophylaxis treatment status, must receive approval toparticipate in the trial from an infectious disease or other TB specialist (forexample, pulmonologist).Note: TB prophylaxis regimens should be administered according to localguidelines; however, because of potential interactions with zasocitinib,rifampin should not be used. For isoniazid monotherapy, a minimum of 6 monthsshould be used. TB testing should be conducted using QFT-TB Gold submitted tothe central laboratory unless alternate or additional tests are required perlocal guidelines.

10. Participant has had any imaging trial during or 6 months prior to screening,including x-ray, chest computed tomography, magnetic resonance imaging, orother chest imaging suggesting evidence of current active or a history ofactive TB. X-ray is required for all participants regardless of QFT-TB Goldresults unless the participant has had normal chest imaging in the 6 monthsprior to screening.

11. Herpes infections:

12. Participant has active herpes virus infection, including herpes zoster orherpes simplex 1 and 2 (demonstrated on physical examination and/or medicalhistory) at screening or Day 1.

13. Participant has history of serious herpetic infection that includes any episodeof disseminated disease, multidermatomal herpes zoster, herpes encephalitis,ophthalmic herpes, or recurrent herpes zoster (defined as 2 episodes within 2years).

14. Nonherpetic viral diseases:

15. Participant has presence of hepatitis C virus (HCV) antibody and a positiveconfirmatory test result for HCV RNA (nucleic acid test or polymerase chainreaction [PCR]). In the EU/EEA, if the participant has total anti-HCV antibodypositivity at screening but is confirmed to have no detectable HCV RNA by PCRtesting, HCV RNA PCR testing will be assessed every 3 months until end of trial (EOT).

16. Participant has presence of positive hepatitis B virus surface antigen (HBsAg),or indeterminate HBsAg, presence of HBV DNA (regardless of serology), orpositive anti-hepatitis B core antibody (HBcAb) without concurrent positiveHBsAb (HBcAb+ and HBsAb-). In the EU/EEA, if the participant has total anti-HBcantibody positivity at screening but is confirmed to have no detectable HBV DNAby PCR testing, the participant will repeat HBV DNA PCR testing every 3 monthsuntil the EOT; if a participant has anti-HBsAb positivity at screening but isconfirmed to have no detectable HBV DNA by PCR testing, unless the participanthas documented completion of the HBV vaccination series by medical history, theparticipant will repeat HBV DNA PCR testing every 3 months until the EOT. Note:For other countries in which there are hepatitis B screening guidelines, thesecan be done per local regulations or country standard of care.

17. Participant has positive results for HIV by serology, regardless of viral load.

18. Other infectious diseases:

19. Participant has a history of active infection or febrile illness within 10 daysprior to Day 1, as assessed by the investigator.

20. Participant has a history of symptoms suggestive of systemic or invasiveinfection within 30 days prior to Day 1.

21. Participant has a history of bacterial, viral, or fungal infection thatrequired hospitalization or treatment with intravenous (IV) antimicrobialtherapy within 8 weeks prior to Day 1, or oral antimicrobial therapy within 30days prior to Day 1.

22. Participant has a history of chronic or recurrent bacterial disease, includingbut not limited to chronic pyelonephritis or cystitis, chronicbronchitis/pneumonitis, osteomyelitis, or chronic skin ulcerations (exceptthose part of the HS clinical findings)/infections or fungal infections (exceptungual onychomycosis).

23. Participant has a history of an infected joint prosthesis unless thatprosthesis has been removed or replaced at least 60 days prior to Day 1.

24. Participant has a history of opportunistic infections (for example,Pneumocystis jirovecii pneumonia, histoplasmosis, or coccidiomycosis).

25. Participant had a bacterial infection within 60 days prior to Day 1 for whichhe or she did not receive treatment. Noninfectious Disorders Exclusions:

26. Participant has any clinically significant medical condition, evidence of anunstable clinical condition (for example, cardiovascular, renal, hepatic,hematologic, gastrointestinal, endocrine, pulmonary, neurologic, nutritional,ophthalmologic, or immunologic), or vitalsigns/physical/laboratory/electrocardiogram (ECG) abnormality that would, in theopinion of the investigator, put the participant at undue risk or interfere withinterpretation of trial results. These include but are not limited to:

27. Participant has a history of known or suspected condition/illness that isconsistent with compromised immunity, including but not limited to anyidentified congenital or acquired immunodeficiency, splenectomy.

28. Participant has a history of new or unstable autoimmune disease (including butnot limited to autoimmune thyroid disease, alopecia areata, lupus, Sjogren's,myasthenia gravis, or rheumatoid arthritis).

29. Participant had a major surgery within 60 days prior to Day 1 or has a majorsurgery planned during the trial.

30. Participant has unstable, poorly controlled, or severe hypertension atscreening, confirmed by 2 repeat assessments.

31. Participant has a history of Class III or IV congestive heart failure asdefined by New York Heart Association criteria.

32. Participant has a history of lymphoproliferative disease.

33. For participants with asthma, chronic obstructive pulmonary disease, or otherpulmonary illnesses, participant has been hospitalized in the past 3 months,has ever required intubation for treatment, currently requires oralcorticosteroids, or has required more than 1 course of oral corticosteroidswithin 6 months prior to Day 1.

34. Participant has any of the following cardiovascular disease history:

• A new diagnosis of atrial fibrillation or an episode of atrialfibrillation with rapid ventricular response or other dysrhythmia,nonacute cardiac hospitalization (for example, pacemaker implantation),pulmonary embolism, or deep venous thrombosis within the past 6 monthsprior to screening.
• Any history of cerebrovascular event, myocardial infarction, coronarystenting, or aortocoronary bypass surgery. If, however, the investigatordocuments there are no suitable treatment alternatives available for theparticipant and it has been at least 6 months since the occurrence of anysuch event, the participant may enroll; in the EU/EEA, investigators mustdocument a favorable benefit-risk assessment.

9. Participant has significant/uncontrolled psychiatric illness, in the opinion ofthe investigator.

10. Participant has any lifetime history of suicide attempts, or active suicidalideation or suicidal behavior in the past 5 years, or any diagnosis of severedepression or other unstable psychiatric condition in the last 6 months, basedon: (1) medical history; or (2) Columbia-Suicide Severity Rating Scale (C-SSRS)documentation by answering "yes" to Question 4 or 5 for suicidal ideationconcerning the previous 5 years before participation on the C-SSRS at screeningor Day 1; or (3) is clinically deemed to have a suicide risk by theinvestigator, or in the opinion of the investigator, would pose an unacceptablerisk to the participant's safety or impact their ability to comply with trialprocedures.

11. Participant has a score of 15 or above at screening or Day 1 on the 8-itemPatient Health Questionnaire-8 (PHQ-8).

12. Participant has a history of active substance abuse or a history of substanceabuse within 12 months prior to screening. Laboratory/Physical Exclusions:

13. Participant has ECG abnormalities that are considered clinically significant andwould pose an unacceptable risk to the participant if they participated in thetrial, in the opinion of the investigator.

14. Participant has inadequate renal, hepatic, or pancreatic function before enrollmentbased on the following parameters:

15. Total bilirubin (unconjugated and/or conjugated) >1.5 × upper limit of thenormal range (ULN) unless the participant has known Gilbert's syndrome that canexplain the elevation of bilirubin, or

16. Serum alanine aminotransferase (ALT) or AST >3 × ULN, or

17. Creatinine >1.5 × ULN. Note: The participant may be retested (1 time) to meeteligibility criteria at the discretion of the investigator.

18. Estimated creatinine clearance lesser than (<)45 milliliter per minute (mL/min)based on the Cockcroft-Gault calculation.

19. A history of chronic pancreatitis or recent acute pancreatitis (<60 days/notfully resolved).

20. Participant has any of the following laboratory values at the screening visit:

21. Hemoglobin <9.0 gram per deciliter (g/dL) (<90.0 gram per liter [g/L]).

22. Absolute white blood cell count <3.0 × 10^9/L (<3000/ cubic millimeters [mm^3]).

23. Absolute neutrophil count (ANC) of <1.0 × 10^9/L (<1000/mm^3).

24. Absolute lymphocyte count of <0.5 × 10^9/L (<500/mm^3).

25. Platelet count <100 × 10^9/L (<100,000/mm^3).

26. Thyroid-stimulating hormone (TSH) (>10 milli-international units per liter [mIU/L]) or free T4 or T3 outside the normal reference range. Note:Participants would be allowed to rescreen after treatment.

27. Triglyceride level >=750 milligram per deciliter [mg/dL] (>=8.5 millimole perliter [mmol/L]).

28. Creatine phosphokinase (CPK) > ULN. CPK may be repeated once; if repeat valueis Common Terminology Criteria for Adverse Events (National Cancer Institute) (CTCAE) Grade 1 or lower (or lesser than or equal to [<=]2.5 × ULN) and nohigher than the initial value, participant remains eligible. Investigatorsshould assess the participant for modulating factors including concomitantmedications or vigorous exercise that may affect CPK levels.

29. Participant has any other significant laboratory abnormalities that, in theopinion of the investigator, might place the participant at unacceptable riskfor participation in this trial.

30. Participant does not tolerate venipuncture or inability to be venipunctured. Allergies and Adverse Drug Reactions Exclusions:

31. Participant has a history of significant drug allergy (such as anaphylaxis).

32. Participant has a known or suspected allergy to zasocitinib or any of itscomponents. Other Exclusions:

33. Participant has a positive pregnancy test result or plans to become pregnant duringthe trial period, including plans to donate ova (eggs) or sperm, or participant ispregnant or lactating/nursing.

34. Participant has a history of substance abuse within 12 months prior to Day 1.

35. Participants who have given greater than 500 mL of blood or plasma within 30 daysprior to screening (during a clinical trial or at a blood bank donation) or plan todonate blood during the course of the trial.

36. Participant is compulsorily detained for treatment of either a psychiatric orphysical (for example, infectious disease) illness, or is committed to aninstitution (for example, prison) by virtue of an order issued either by judicial oradministrative authorities.

37. Participant is a trial site employee, an immediate family member (for example,spouse, parent, child, sibling), or is in a dependent relationship with trial siteemployee who is involved in the conduct of this trial or may consent under duress.

38. In Germany, participant is incapable of giving consent or otherwise meets criteriain Sections 136 or 137 of the Verordnung zum Schutz vor der schädlichen Wirkungionisierender Strahlung Strahlenschutzverordnung.

39. Participants with a history of malignancy within the past 5 years prior to thescreening visit are excluded, EXCEPT if the malignancy was a cutaneous squamous orbasal cell carcinoma, or in situ cervical cancer that has been successfully treatedand is considered cured; in the EU/EEA, investigators must document a favorablebenefit-risk assessment.

40. History or current status of substance use disorder and or tobacco use disorder. Forparticipants with excessive alcohol intake or currently smoking or using chewingtobacco or with a history of long-term smoking (>=20 pack years) or chewing tobaccouse, the investigator must document a favorable benefit-risk assessment to justifythe participant's inclusion in the trial.

Further exclusion criteria apply.