Severe Alopecia Areata

Alopecia areata (AA) is a disease that happens when the immune system attacks hair follicles and causes hair loss. AA usually affects the scalp and face, but hair loss can happen on any hair-bearing part of the body. Some treatment options are available for adults and adolescents with AA, however there is still high unmet need for systemic treatments (treatment that moves throughout the bloodstream) approved for young patients with AA. Treatments may not work for all patients or may stop working over time. Because of this, researchers are developing new AA treatments, like upadacitinib. Upadacitinib is a type of medicine called a Janus- Kinase (JAK) inhibitor and works with the body to fight the inflammation that can cause AA. In this study, different doses (amounts) of upadacitinib are being compared to treatment with placebo (looks like the study treatment but contains no medicine). Upadacitinib is an investigational JAK inhibitor being developed for the treatment of severe alopecia areata in pediatric patients. This is a randomized, double-blind, placebo-controlled study. Participants are placed in 3 groups, called treatment arms. Each group receives a different treatment. There is a 1 in 5 chance that participants will be assigned to placebo. Pediatric participants with a diagnosis of severe alopecia areata with SALT score ≥ 50 scalp hair loss will be enrolled. Participants will be at least 6 years old at Screening and less than 18 years old at Baseline. Approximately 300 participants will be enrolled in the study at approximately 120 sites worldwide. Participants will receive oral doses of upadacitinib or matching placebo daily, or twice daily, for approximately 160 weeks. The study comprises a 35-day Screening Period, a 24-week placebo-controlled double-blinded treatment period (Period A), a 28-week blinded extension treatment period (Period B), a 108-week blinded long-term extension period (Period C), and a 30-day follow-up period. There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects and completing questionnaires.

The purpose of this observation study is to learn about the safety and effects of the study medicine (called Litfulo) for the potential treatment of Severe Alopecia Areata.

A multicenter clinical study to evaluate the safety, PK characteristics, immunogenicity characteristics, and PD characteristics of IBI3013 in healthy trial participants and active non-segmental vitiligo trial participants and severe alopecia areata trial participants. The study is divided into 2 parts, with Part 1 involving healthy trial participants lasting up to 24 weeks, and Part 2 involving active non-segmental vitiligo trial participants and severe alopecia areata trial participants lasting up to 48 weeks.

The purpose of this clinical trial is to learn about long-term safety and long-term effects of the study medicine (called ritlecitinib) for the potential treatment of severe alopecia areata, a condition that causes hair loss. This study is seeking participants who have: * previously completed one of Pfizer's pediatric studies for Alopecia Areata (B7981027 or B7981031). * at least 50% scalp hair loss due to alopecia areata (for participants enrolling from the study B7981031). * received varicella vaccination (2 doses) or have been infected by varicella zoster virus before based on blood test reports. All participants in this study will receive the study medicine (ritlecitinib). Participants who received ritlecitinib higher or lower doses in the parent Study B7981027 will continue receiving the same ritlecitinib dose in this trial. Participants who received placebo in the parent Study B7981027 and all participants from parent Study B7981031 will receive either higher or lower dose of ritlecitinib in this trial. The study medicine is a capsule that is taken by mouth. It is taken 1 time each day at home. The study will help see if ritlecitinib is safe and effective. Participants will take part in this study for a duration of up to 3 years (36 months). During this time, they will have 17 study visits at the study clinic. The study team will also call participants once a month over the phone.

The purpose of this study is to evaluate the efficacy and safety of different doses of SYHX1901 tablets in the treatment of severe alopecia areata.