Prospective, randomized, double-blind, placebo-controlled, single-center comparative trial evaluating oral hydroxychloroquine 200 mg BID for reducing microglial activation in the brain of patients with progressive multiple sclerosis (MS)

This study is investigating a drug called hydroxychloroquine, sometimes known by its brand name Oxiklorin, for people living with progressive multiple sclerosis (MS). Progressive MS means that the condition tends to steadily worsen over time. Researchers are particularly interested in seeing if this medicine can reduce something called "microglial activation" in the brain. Microglia are a type of immune cell in the brain, and when they become too active, they can cause inflammation and damage. The scientists think reducing this activity might help slow down the progression of MS.

To see if the drug works, participants will undergo special brain scans, called TSPO-PET scans, at the beginning and end of the study. These scans help scientists measure the amount of microglial activity in different parts of the brain. By comparing the scans, they can see if hydroxychloroquine helps to reduce this activity more than a dummy pill (placebo). This is a 'double-blind' study, meaning neither the participants nor the doctors will know who is getting the real drug and who is getting the placebo, which helps make the results fairer and more reliable.

But the study isn't just about what happens in the brain; it also wants to understand how the drug affects people's daily lives. Researchers will measure changes in things like walking speed, how well people can use their hands, their memory and thinking skills, and their overall quality of life and fatigue levels. They will also collect blood samples to look for signs of nerve damage and use different types of MRI scans to check for changes in the brain. All these different measurements help build a complete picture of whether the treatment is helpful and safe.