The drug tested in the trial, clemastine fumarate, was first identified as a candidate treatment for MS in 2013 by UCSF’s Jonah R. Chan, PhD, Debbie and Andy Rachleff Distinguished Professor of Neurology, vice chief of the Division of Neuroinflammation and Glial Biology, and senior author of the new study. First approved by the U.S. Food and Drug Administration (FDA) in 1977 for allergies, the drug has been available over the counter in generic form since 1993.
Researchers suspect the antihistamine works by repairing MS-related damage to myelin, restoring nervous system function.
The new results are particularly notable, Chan said, because patients in the trial had suffered from MS symptoms caused by injury to myelin for years. “People thought we were absolutely crazy to launch this trial, because they thought that only in newly diagnosed cases could a drug like this be effective – intuitively, if myelin damage is new, the chance of repair is strong. In the patients in our trial the disease had gone on for years, but we still saw strong evidence of repair.”
Though excited about the results, the scientists caution this development is not a cure:
“This is the first step in a long process,” [Ali] Green said. “By no means do we want to suggest that this is a cure-all. We want to ground-truth myelination metrics – we’re designing the crucible that’s going to be used to test any future method for detecting remyelination.”