This study looks at the effects of a new treatment called **SAR445399** for adults with **hidradenitis suppurativa (HS)**, a skin condition causing painful lumps. A **placebo** is a substance with no active medicine, used to compare against the real treatment. This study is **double-blind**, meaning neither doctors nor participants know who gets the real treatment or placebo, ensuring fair results. Participants will be in the study for about **30 weeks** and visit the clinic **12 times**. The actual treatment with SAR445399 lasts **16 weeks**.

• Participants must have had HS for at least 6 months with certain symptoms.
• The study includes adults who didn't respond well to antibiotics for HS.
• People with certain health conditions, like active skin diseases or serious infections, cannot join.

This study will help researchers understand how safe and effective SAR445399 is for treating HS. Participation involves multiple visits and certain criteria must be met. Always talk to your doctor to see if joining this study is a good idea for you.