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

• Povorcitinib (Drug), also known as INCB054707: Oral; Tablet

Primary outcomes

• Proportion of participants with Treatment-Emergent Adverse Events (TEAEs) [Baseline through Week 54]: TEAE is defined as any AE either reported for the first time or worsening of a pre-existing event after the first dose of study drug up to 30 days after the last dose of study drug.
• Apparent clearance [Up to Week 24]
• Apparent volume of distribution [Up to Week 24]
• Apparent oral absorption rate constant [Up to Week 24]
• Absorption lag time [Up to Week 24]
• Maximum plasma drug concentration at steady state [Up to Week 24]
• Average plasma drug concentration at steady state [Up to Week 24]
• Plasma concentration at steady state for the dosing interval [Up to Week 24]
• Time to maximum plasma concentration at steady state [Up to Week 24]
• Terminal half-life [Up to Week 24]

Secondary outcomes

• Proportion of participants who achieve Hidradenitis Suppurativa Clinical Response 50 (HiSCR50) [54 weeks]: HiSCR50 is defined as at least a 50% reduction from baseline in the total abscess and inflammatory nodule count, with no increase from baseline in abscess or draining tunnel count.
• Proportion of participants who achieve Hidradenitis Suppurativa Clinical Response 75 (HiSCR75) [54 weeks]: HiSCR75 is defined as at least a 75% reduction from baseline in the total abscess and inflammatory nodule count, with no increase from baseline in abscess or draining tunnel count.
• Mean change from baseline in abscess count at each visit [54 weeks]: Defined as mean change of abscess count relative to baseline.
• Mean percentage change from baseline in abscess count at each visit [54 weeks]: Defined as mean percentage change from baseline in abscess count.
• Mean change from baseline in inflammatory nodule count at each visit [54 weeks]: Defined as mean change of inflammatory nodule count relative to baseline.
• Mean percentage change from baseline in inflammatory nodule count at each visit [54 weeks]: Defined as mean percentage change from baseline in inflammatory nodule count.
• Mean change from baseline in draining tunnel count at each visit [54 weeks]: Defined as mean change of draining tunnel count relative to baseline.
• Mean percentage change from baseline in draining tunnel count at each visit [54 weeks]: Defined as mean percentage change from baseline in draining tunnel count.
• Proportion of participants who achieve Skin Pain Numeric Rating Scale (NRS)30 among participants with baseline Skin Pain NRS score ≥ 3 [54 weeks]: Defined as participants with a Skin Pain NRS score of at least 3 at baseline and who achieve Skin Pain NRS30, defined as at least a 30% reduction and at least 1-unit reduction from baseline in the Skin Pain NRS.
• Proportion of participants with a ≥ 3-point decrease in Skin Pain NRS score among participants with baseline Skin Pain NRS score ≥ 3 [54 weeks]: Participants with a Skin Pain score of at least 3 at baseline and who experience at least a 3-point decrease in Skin Pain score.
• Change from baseline in Children's Dermatology Life Quality Index (CDLQI) score at each visit [54 weeks]: The CDLQI is a simple, 10-question validated questionnaire to measure how much the skin problem has affected the participant over the previous 7 days, across symptoms and feelings, leisure, school or holidays, personal relationships, sleep, and treatment.

Sex: All, ages: 12 Years to 17 Years

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.

• Incyte Medical Monitor, Study director, Incyte Corporation