We hear about ‘breakthroughs’ frequently in MS, and mostly of course, they are not! On this occasion, despite the drug that researchers were testing being an old drug commonly prescribed for hayfever, they found definite evidence of improved neurological function after taking the drug, and the improvement persisted when the drug was stopped. It seems highly likely, given what the researchers have previously tested, that the drug promoted remyelination, something which no agent has previously been able to do.
The research team at University of California, San Francisco (UCSF), led by Prof Jonah Chan tested the drug clemastine (trade name Tavist) which has been licensed by the FDA for 40 years now for use in hayfever and allergies and is now a cheap generic. Importantly they tested the drug in people with chronic longstanding MS who had quite a bit of central nervous system damage. To their surprise they used a sensitive test of the speed of transmission of nerves in the visual pathways and showed that is speeded up substantially, meaning that transmission through the whole central nervous system was likely to be speeded up for those taking this medication. The dose of drug used was 5.36mg twice daily, for a daily dose of 10.72mg, whereas for allergy, the recommended dose is no more than 2.68mg three times daily, for a daily dose of 8.04mg. The only important side effect of large doses is sleepiness, and in this study, participants were more likely to report fatigue, which may reflect that.
While much more work needs to be done before this drug could be licensed in MS, the research is really a breakthrough, showing that repairing damaged myeline is now a realistic possibility. Read the full paper here