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An Old Antihistamine Demonstrates Myelin Repair in MS Patients

April 14, 2016

Thanks in part to a close collaboration between a scientist and a physician, the prospect of myelin repair therapy in multiple sclerosis is better than it has ever been. In what may be the first demonstration of myelin repair in people with multiple sclerosis, an old antihistamine shows modest improvement in the function of chronically demyelinated optic nerves.

The randomized double-blind study tested the antihistamine Clemastine in 50 people whose relapsing-remitting MS also included long-standing visual system damage known as chronic demyelinating optic neuropathy.

The 5-month crossover design compared twice-daily doses of Clemastine taken for 2 or 3 months to a placebo taken for 2 or 3 months in the same individuals. Patients in the trial averaged 40 years of age, with 5 years of MS, mild disability, and stable disease treated by a disease-modifying therapy or no treatment.

The study met its main endpoint, a small but measurable improvement in the speed with which electrical signals travel from the eye to the brain and back—a repair biomarker known as visual evoked potentials—while people were taking the drug.

Despite the positive results, Clemastine may not be anyone’s favorite candidate to go the distance in large clinical trials for remyelination. At the relatively low doses in the study, people reported a mild worsening of fatigue. At higher and more effective doses for myelin repair, Clemastine has more serious known side effects on the heart and bladder. “At the doses we can imagine using, it is likely to be only partially effective,” said study director Ari Green MD.