Addressing MS’s unmet need

Three new trials at The Neuro hope to dial down the immune response more precisely, especially for patients with inactive progression

June 17, 2026 || by Sophie Lorenzo

Just a decade ago, it would have been difficult to imagine how dramatically outcomes for many people with Multiple Sclerosis would improve. Today, modern therapies can greatly reduce relapses and new inflammation, allowing many individuals to maintain a high quality of life for years after diagnosis.

But for people with MS who see their disability progress despite current therapies, the future can look very different. Researchers at the Clinical Research Unit at The Neuro (Montreal Neurological Institute-Hospital) are studying new approaches that could help ensure that none of the 90,000 Canadians living with MS are left behind.

Turning down the immune system

The most effective current therapies work by getting rid of a large amount of circulating B cells, a key driver of MS disease activity. A new clinical trial at The Neuro is studying whether by blocking an enzyme called BTK, we could dial down the immune response much more precisely and reach underlying inflammation. BTK plays a key role in what is known as B cell activation and signaling — helping B cells detect targets and coordinate other immune cells to attack.

“We think BTK inhibitors could address some aspects that current treatments can’t. Firstly, by blocking a critical enzyme involved in B cell activation and signaling, they could reduce this activity without removing all B cells,” explains Thebault.

“Secondly, they are small molecules that can enter the central nervous system, where they may be able to target some types of inflammation that aren’t easily reached by current therapies. For example, they may affect microglia, immune cells that remain in the brain and are increasingly thought to contribute to disease progression,” he concludes.

Targeting progression

While this approach is still being studied, early results from other clinical trials on BTK inhibitors have shown some promise, particularly in slowing inactive progression. The Neuro will soon have three clinical trials evaluating the effectiveness of BTK inhibitors for MS, one of which is already open to patients. If successful, the hope is that these therapies could represent an important new treatment option for people with MS.

Individuals, 18 to 65, diagnosed with MS whose disease is not well managed by existing therapies and who are progressing despite a lack of new activity on MRI can reach out to the Clinical Research Unit for more information: ms-cru.neuro@mcgill.ca ; cru.mcgill.ca/ms.