Trial shows myelin repair in humans is possible

Friday 25 September 2020

The results from our Phase 2a clinical trial have shown that bexarotene is capable of regenerating lost myelin – the protective coating that surrounds nerve fibres, which is damaged in MS. Now, a new trial of the diabetes drug metformin will build on this work.

Critical to stopping MS

New research presented at the MSVirtual2020 conference has shown that bexarotene, a drug developed to treat cancer, is able to repair myelin in people with relapsing MS. This is a breakthrough that scientists say is critical to their goal of stopping MS.

Professor Alasdair Coles from the University of Cambridge, who led the research, said: “The lessons we’ve learned are incredibly exciting, as we now have further concrete evidence that remyelination in humans is possible. This discovery gives us confidence that we will stop MS, and will swiftly be taken forward into further studies trialling other potential new myelin repair treatments.”

Important lessons learned

In the trial, vision tests and some types of MRI scans showed that bexarotene could repair myelin.

Participants in the trial did experience some serious side effects, including an underactive thyroid gland and high levels of fats in the blood. This means bexarotene won’t be taken forward into a Phase 3 study.

But the lessons we've learned from this trial will now be taken forward into new clinical trials.

Co-investigator Professor Siddharthan Chandran from the University of Edinburgh added: “We now understand much more about myelin repair and are in a significantly better position to measure remyelination in clinical trials. While this work was taking place, further lab research identified new and more tolerable treatments that could repair myelin, and we look forward to these being tested in trials imminently.”

A new trial for myelin repair

Promising results from laboratory studies in October 2019 showed the common diabetes drug metformin could repair myelin in rats. We're proud to announce we're funding a new Phase 2 clinical trial to test metformin in combination with clemastine (an antihistamine). 50 people with relapsing MS will take part.

It’s hoped that together these treatments will be safe and effective at repairing myelin in people living with MS, and could provide a way to prevent disability progression in the condition.

This new clinical trial will be led by Professor Alasdair Coles. It will build on our current understanding of myelin repair, which has been furthered by the bexarotene clinical trial and the work of Professor Robin Franklin and his team at the MS Society Cambridge Centre for Myelin Repair. In studies in rats, they discovered that metformin was able to mimic the effects of fasting and return cells to a “more youthful state”, and encourage the re-growth of myelin.

Professor Robin Franklin said: “Metformin is one of the most exciting developments in myelin repair we have ever seen. Our findings last year shed light on why cells lose their ability to regenerate myelin, and how this process might be reversed. We’re very proud to have done this work and thrilled to see our discovery taken forward so quickly.”

A major milestone in our plan to stop MS

By 2025 we plan to be in the final stages of testing a range of treatments for everyone with MS.

Dr Emma Gray, our Assistant Director of Research, said: "Finding treatments to stop MS progression is our number one priority, and to do that we need ways to protect nerves from damage and repair lost myelin. This new research is a major milestone in our plan to stop MS and we’re incredibly excited about the potential it’s shown for future studies. We look forward to what comes next."

Read more about our plan to stop MS