This clinical trial is focused on studying the effects of a medication called Ritlecitinib on a skin condition known as nonsegmental vitiligo. Nonsegmental vitiligo is a condition where patches of skin lose their color, leading to white spots on various parts of the body. The study will use two different doses of Ritlecitinib, 50 mg and 100 mg, taken as capsules. The purpose of the study is to evaluate the long-term safety and how well people tolerate these doses of Ritlecitinib.

Participants in the study will be adults and adolescents who have nonsegmental vitiligo. The study will involve a period where participants will take the medication, and their response to the treatment will be monitored. Some participants may receive a placebo, which is a capsule that looks like the medication but does not contain the active ingredient. The study will help researchers understand how effective Ritlecitinib is in treating nonsegmental vitiligo and whether it is safe for long-term use.

Throughout the study, participants will be regularly checked for any side effects or changes in their condition. The study aims to provide valuable information on the potential benefits and risks of using Ritlecitinib for treating nonsegmental vitiligo, contributing to better treatment options for those affected by this condition.