This study focuses on individuals living with Progressive Supranuclear Palsy Richardson Syndrome, a rare brain disorder that affects movement, balance, and eye movements. The purpose of the study is to evaluate the effectiveness and safety of a drug called NIO752 compared to a placebo, which is a substance containing sodium chloride. This medication is administered through intrathecal use, meaning it is delivered directly into the fluid surrounding the brain and spinal cord.

During the first part of the study, participants are randomly assigned to receive either NIO752 or the placebo. The study is double-blind, which means neither the participants nor the researchers know which substance is being administered. Throughout this period, various measurements are taken to monitor changes in movement, daily activities, and quality of life. Additionally, an MRI, a specialized imaging test that uses magnets to create detailed pictures of the brain, is used to look at different brain structures.

Following the initial phase, there is an open label extension, where participants may have the opportunity to receive the active medication. The study also monitors safety by tracking any side effects or changes in vital signs and electrocardiogram results, which is a test that records the electrical activity of the heart.