This study will evaluate the clinical safety and efficacy of oral brepocitinib in participants with lichen planopilaris

Inclusion Criteria:

1. Age ≥ 18 years
2. Scalp biopsy consistent with LPP
3. Active and symptomatic LPP at screening and baseline-
4. Weight > 40 kg to < 130 kg with BMI ≤ 45 kg/m2

Exclusion Criteria:

1. History of: Lymphoproliferative disorder; Active malignancy; History of cancer within 5 years prior to baseline (exceptions for basal cell carcinoma, squamous cell carcinoma, ductal carcinoma in situ of the breast, carcinoma in situ of the uterine cervix, or thyroid cancer).
2. High risk of thrombosis or cardiovascular disease
3. High risk of herpes zoster
4. Active or recent infection