Pharmacokinetics, Safety, and Efficacy of Povorcitinib in Adolescent Participants With Moderate to Severe Hidradenitis Suppurativa

Inclusion Criteria: * Aged ≥ 12 to \< 18 years at the time of informed consent/assent signing. * Body weight ≥ 30 kg at both screening and baseline visits. * Diagnosis of moderate to severe HS for at least 3 months prior to the screening visit. * Total abscess and inflammatory nodule count of at least 5 at both the screening and baseline visits. * HS lesions corresponding to refined Hurley Stage IB, IC, IIB, IIC, or III at both the screening and baseline visits. * Documented history of inadequate response to at least a 3-month course of at least 1 conventional systemic therapy (oral antibiotic or biologic drug) for HS (or demonstrated intolerance to, or have a contraindication to, a conventional systemic therapy for treatment of their HS). * Agreement to use contraception. * Willing and able to comply with the study protocol and procedures. * Further inclusion criteria apply. Exclusion Criteria: * Presence of \> 20 draining tunnels (fistulas) at either the screening or baseline visit. * Women who are pregnant (or who are considering pregnancy) or breastfeeding. * Medical history including thrombocytopenia, coagulopathy or platelet dysfunction, Q-wave interval abnormalities, current or history of certain infections, cancer, lymphoproliferative disorders and other medical conditions at the discretion of the investigator. * Laboratory values outside of the protocol-defined ranges. * Further exclusion criteria apply.