Trial of Delgocitinib 20 mg/g Cream in Subjects With Frontal Fibrosing Alopecia (FFA)

Inclusion Criteria: * Subject is willing to participate and is capable of giving informed consent. Note: Consent must be obtained prior to any trial-related procedures. * Subjects must be willing to comply with all trial procedures and must be available for the duration of the trial. * Male or female subject aged 18 years of age or older at the time of consent. * Female subject of childbearing potential has had a negative serum pregnancy test at screening and negative urine pregnancy test at Day 1. * Subject has clinically confirmed diagnosis of FFA based on investigator judgment. * Subject has a target area with moderate to severe perifollicular erythema and/or scale at Screening and Day 1. * For subject who uses make-up, moisturizers, creams, lotions, cleansers, and/or sunscreens on the face, subject has used the same product brands/types for a minimum period of 4 weeks prior to Day 1, agrees not to change brand/type or frequency of use throughout the trial, agrees not to apply those products on the treated area during the trial, and agrees not to use make-up, moisturizers, creams, lotions, cleansers, and/or sunscreens on the face on the clinic visit days before the visit. * Subject is willing to maintain a consistent hair style and hair style regimen, including shampoo and hair products (including hair dye, process, and timing to hair appointments), and to refrain from weaves or extensions throughout the course of the trial and for 4 weeks prior to Day 1. Note: Hair dying and shaving of scalp is allowed during the trial but not within 48 hours prior to a trial visit. Exclusion Criteria: * Subject is a female who is breastfeeding, pregnant, or who is planning to become pregnant during the trial. * Subject has received any marketed or investigational biological agent within 12 weeks or 5 half-lives (whichever is longer) prior to Day 1. * Subject is currently receiving a nonbiological investigational product or device or has received one within 4 weeks prior to Day 1. * Subject has had excessive sun exposure or has used tanning booths within 4 weeks prior to Day 1 or is not willing to minimize natural and artificial sunlight exposure during the trial. Use of sunscreen products (except on treated areas for subjects in Cohort 1) and protective apparel are recommended when sun exposure cannot be avoided. * History of other scalp/hair disease including discoid lupus erythematosus and central centrifugal cicatricial alopecia. Note: Subjects with lichen planopilaris/FFA overlap are not to be excluded. * Presence of active dermatologic condition that might interfere with FFA diagnosis and/or interfere with the trial assessments such as seborrheic dermatitis, psoriasis, or telogen effluvium. * Subject who has undergone scalp reduction surgery or hair transplantation. * Use of adhesive wigs during the trial. * Subject is known to have immune deficiency or is immunocompromised. * Subject has a history of cancer or lymphoproliferative disease within 5 years prior to Day 1. Subjects with successfully treated nonmetastatic cutaneous squamous cell or basal cell carcinoma and/or localized carcinoma in situ of the cervix are not to be excluded. * Subject had a major surgery within 8 weeks prior to Day 1 or has a major surgery planned during the trial. * Subject has any clinically significant medical condition or physical/laboratory/vital signs abnormality that would, in the opinion of the investigator, put the subject at undue risk or interfere with interpretation of trial results. * Subject has positive results for hepatitis B surface antigens (HBsAg), antibodies to hepatitis B core antigens (anti-HBc), hepatitis C virus (HCV), or human immunodeficiency virus (HIV). * Subject has used treatment with agents (including natural products or nutritional supplement such as Viviscal, Nutrafol, and/or biotin) that may affect hair regrowth in the last 4 weeks prior to Day 1. Patients who have been on oral minoxidil or oral spironolactone for 6 or more months may continue these medications at the same doses. * Subject has used intralesional scalp corticosteroids or platelet rich plasma injection in the last 4 weeks prior to Day 1. * Subject has used systemic treatment with immunosuppressive/modulating medication or medication that could affect FFA (eg, corticosteroids, methotrexate, hydroxychloroquine, retinoids, calcineurin inhibitor, tetracyclines, pioglitazone, oral JAK inhibitor, or 5-α-reductase-inhibitors) within 4 weeks prior to Day 1. Note: Intranasal corticosteroids and inhaled corticosteroids are allowed. Eye and ear drops containing corticosteroids are also allowed. Note: Standard doses of systemic antihistamines are allowed. * Subject has used any topical medicated treatment that could affect FFA within 2 weeks prior to Day 1, including, but not limited to, topical corticosteroids, calcineurin inhibitors, phosphodiesterase-4 (PDE-4) inhibitors, topical JAK inhibitors. * Subject has received any ultraviolet (UV)-B phototherapy (including tanning beds), excimer laser, or any other phototherapy within 4 weeks prior to Day 1. * Subject has had psoralen-UV-A (PUVA) treatment within 4 weeks prior to Day 1. * Subject has a known or suspected allergy to delgocitinib or any component of the IMP. * Subject has a history of an allergic reaction or significant sensitivity to hypoallergenic ink. * Subject has a known history of clinically significant drug or alcohol abuse in the last year prior to Day 1. * Subject has prior use of delgocitinib cream as treatment for frontal fibrosing alopecia. * Subject has prior failure of adequate response of frontal fibrosing alopecia to a topical JAK inhibitor or oral JAK inhibitor.