Study Purpose: This study looks at how well and how safely a new medicine, GIA632, works for people with a skin condition called cutaneous lichen planus (cLP). cLP can cause itchy, purple bumps on the skin. The study will help find the best amount of medicine to use in future research.

Study Process: The study has different parts: a screening period (up to 4 weeks) to check if you can join, a core treatment period (16 weeks) where neither you nor your doctor will know if you are getting GIA632 or a placebo, an extension period (52 weeks) where you might continue treatment, and a safety follow-up period (12 weeks) to check on your health after treatment ends.

• Participants must be 18 years or older with moderate to severe cLP.
• The study lasts for about 1.5 years, including follow-up.
• Participants must be willing to use an electronic diary and complete questionnaires.

Note: Some people cannot join, like those with certain other skin conditions or who have used certain medications. Always check with your doctor to see if this is right for you.