AMX0035 is a new medicine being tested to help people with Progressive Supranuclear Palsy (PSP), a brain disease that makes movement and balance hard. The study checks if AMX0035 is safe and effective by comparing it to a placebo (a fake treatment) over 52 weeks. If you join, you might get AMX0035 or the placebo, but you won't know which one. After 52 weeks, there's an optional phase where everyone can try AMX0035. Participants need to be 40-80 years old, have had PSP symptoms for less than 5 years, and be able to walk with little or no help. You also need a partner to attend study visits with you. This study is not for people with other major brain or mental health issues, or those who need a feeding tube.

• The study lasts 52 weeks, with regular visits to a clinic.
• You may receive some compensation for participating.
• Regular MRIs and check-ups are part of the trial.