Metformin is used to treat type 2 diabetes. It is now being tested in combination with clemastine (a hay fever drug) as a myelin repair treatment for MS.
- Current phase of trial:
- Phase 2
- Type of MS:
- Relapsing MS
How does metformin work?
Metformin is a drug used to treat type 2 diabetes. It works by reducing the amount of sugar the liver releases into the blood and makes the body respond better to insulin.
In rats, researchers have shown that when rats were given an alternate day fasting diet (meaning they ate every other day) oligodendrocyte precursor cells were able to transform into special myelin-making cells more effectively, leading to an increase in myelin repair. Metformin was shown to mimic these effects without any actual fasting.
How is metformin taken?
Metformin and clemastine trial
In September 2020 we announced our new clinical trial, which will be testing metformin in a Phase 2a clinical trial in combination with clemastine, a drug which is already used to treat hay fever.
This trial will recruit 50 participants with relapsing MS. Half will take a placebo (dummy drug) and the other half will take both metformin and clemastine. Researchers want to know if the combination of metformin and clemastine could repair myelin damage in relapsing MS.
Although both metformin and clemastine have been trialled in people with MS before, the effects of metformin on myelin repair in people has not been tested. And evidence from animal studies has shown that metformin enhances the effect of clemastine on myelin repair, but the two drugs have never been tested in combination.
In 2019, researchers at the MS Society Cambridge Centre for Myelin Repair showed that metformin could promote myelin repair in rats. Cells called ‘oligodendrocyte precursor cells’ transform into special myelin-making cells. But in MS and as we age, this stops happening as well as it should. So new myelin isn’t made. The researchers found that when rats were given an alternate day fasting diet (meaning they ate every other day) OPCs were able to transform into myelin-making cells more effectively. This led to an increase in myelin repair. Metformin was able to mimic these effects without any actual fasting.
One clinical trial has tested metformin in people, but did not look at effects on myelin repair. These researchers gave metformin to 20 people with relapsing MS who were obese, and demonstrated a significant reduction in lesions on MRI scans.
What are the side effects of metformin?
Metformin has not been widely tested in people with MS so its side effects specifically for people with MS are not yet known. However, when used to treat type 2 diabetes, side effects nausea, stomach ache, loss of appetite and vomiting or diarrhoea.
How does metformin compare with current therapies?
Metformin has not been widely tested in people with MS so it isn’t yet known how it compares to existing MS treatments.
When is metformin likely to be available?
Metformin is already licensed for other conditions but will need to undergo larger phase 2 and phase 3 trials to definitively test its effectiveness in MS. This process will take several years. Currently, metformin is being tested with people with relapsing MS, but we hope eventually myelin repair treatments will help people with progressive MS too.