Inclusion Criteria:

-Male and female participants ≥ 18 years of age.
-Diagnosis of moderate to severe HS ≥ 3 months prior to Screening visit.
 -HS lesions present in ≥ 2 distinct anatomic areas, 1 of which must be at least Hurley Stage II or Hurley Stage III, at both the Screening and Baseline visits.
-Total abscess and inflammatory nodule (AN) count ≥ 5 at both the Screening and Baseline visits.
-History of inadequate response to an appropriate course of at least 1 conventional systemic therapy for HS (or demonstrated intolerance to, or have a contraindication to, a conventional systemic therapy for HS)
-Agree to not use certain topical antiseptics on the areas affected by HS lesions during the placebo-controlled period.
-Willingness to avoid pregnancy or fathering children.
-Other inclusion criteria apply.

Exclusion Criteria:

-Draining tunnel count of > 20 at Screening or Baseline visits.
-Women who are pregnant (or who are considering pregnancy) or breastfeeding.
-Medical history including thrombocytopenia, coagulopathy or platelet dysfunction; venous and arterial thrombosis, deep vein thrombosis, pulmonary embolism, stroke, moderate to severe heart failure, cerebrovascular accident, myocardial infarction, or other significant cardiovascular diseases; Q-wave interval abnormalities; disseminated herpes zoster or dermatomal herpes zoster; disseminated herpes simplex; chronic/recurrent infections; malignancies.
-Evidence of infection with TB, HBV, HCV or HIV. -History of failure to JAK inhibitor treatment of any inflammatory disease.
-Laboratory values outside of the protocol-defined ranges.
-Other exclusion criteria apply.

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

Eligibility last updated 4/16/2024. Questions regarding updates should be directed to the study team contact.