Cancer drug rebuilds myelin in humans with MS

A recent clinical trial of a cancer drug showed it repaired the myelin sheath that multiple sclerosis (MS) attacks, but the findings are bittersweet as the drug’s side effects are too serious for it to be used as treatment.

The clinical trial of bexarotene has, however, given doctors hope that remyelination is possible in humans, and they say the findings suggest other drugs or drug combinations may be able to halt MS.

One such drug is metformin, a diabetes drug, which has already been shown to help remyelination in animals when combined with an antihistamine, clemastine. It is hoped that a postponed human trial of these drugs will take place this year.

During the bexarotene trial, brain scans showed that neurons had regrown their myelin sheaths, which was confirmed with tests showing signals sent from the retina to the visual cortex at the back of the brain had got quicker, which can only be due to remyelination. The side effects were severe, however, including thyroid disease and raised levels of fats in the blood which can cause dangerous inflammation of the pancreas.