Ritlecitinib Study for Hidradenitis Suppurativa This study aims to see if the medicine called Ritlecitinib is safe and works well for people with Hidradenitis Suppurativa (HS), which causes painful red skin lumps. People who have moderate to severe HS and didn't get better with antibiotics might join. Participants will either get the real medicine or a placebo, which looks like the medicine but has no drug in it. For the first part, there will be a starting dose, then a regular dose. The study lasts about 24 weeks (6 months) and includes around 10 clinic visits. Visits will include health check-ups like physical exams, blood tests, chest X-rays, and hearing tests. Participants will also keep a diary on their phones about their medicine and symptoms. The study will compare the effects of the medicine with the placebo.

• Study duration: 24 weeks (6 months) with about 10 clinic visits
• Must have moderate or severe HS and have tried antibiotics
• Participants will take medicine daily at home