Common Allergy Treatment Restores Protective Neuron Coating in MS, Trial Suggests

Common Allergy Treatment Restores Protective Neuron Coating in MS, Trial Suggests

Scientists have been trying to find a way to restore a protective covering around nerve cells whose loss leads to the neuron damage associated with multiple sclerosis.

A team at the University of California, San Francisco may have found a way to do it. And perhaps surprisingly, the possible solution is an over-the-counter allergy drug.

A Phase 2 clinical trial showed that the antihistamine clemastine fumarate helped people with a chronically damaged optic nerve. The therapy led to faster firing of patients’ vision neurons, according to a report in the journal The Lancet. It also slightly improved how well the patients could distinguish contrast.

While the effect was modest, researchers said the study proved that rejuvenation of the protective of the protective neuron coating — the protein myelin — can occur in those with even chronic nerve-cell damage. The findings are a starting point for the development of more effective treatments, they said.

“To the best of our knowledge, this is the first time a therapy has been able to reverse deficits caused by MS,” Dr. Ari Green, principal investigator of the trial, said in a press release. “It’s not a cure, but it’s a first step towards restoring brain function to the millions who are affected by this chronic, debilitating disease.”

The research team focused on vision damage In the Phase 2 ReBUILD trial (NCT02040298) for a simple reason: Vision is commonly affected in MS, and there are reliable ways to measure the speed of neurons in the brain that are linked to vision.

Their study was titled “Clemastine fumarate as a remyelinating therapy for multiple sclerosis (ReBUILD): a randomized, controlled, double-blind, crossover trial.”

How an allergy therapy ended up in the MS field

The team’s choice of compound was not random. Earlier screening of compounds approved for other diseases showed that clemastine fumarate activates oligodendrocyte progenitor cells. These are cells involved in producing and wrapping myelin around nerve cell axons, or long, slender projections of neurons.

Researchers confirmed this finding in lab-grown cells and animals with myelin damage before deciding to test it in patients with chronic neuron damage.

“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,” said Dr. Jonah R. Chan, a Debbie and Andy Rachleff Distinguished Professor of Neurology at UC-San Francisco.

“Intuitively, if myelin damage is new, the chance of repair is strong,” said Chan, the study’s senior author.  “In the patients in our trial the disease had gone on for years.” But “we still saw strong evidence of repair” with clemastine fumarate, he said.

Measuring neuron speed

The team recruited 50 patients with chronic damage to their optic nerve for their study. They used a cross-over design to improve its statistical power.

Participants were split into two groups. One received clemastine fumarate for 90 days and then a placebo for 60 days. The other received a placebo first and then the drug. Then the groups switched, and the procedure was repeated. Neither patients nor the physicians in the study knew which group patients belonged to.

To assess potential effects of the drug, researchers measured what is known as visual-evoked potentials, or how fast neurons that govern sight fire in response to changes in light.

They used scalp electrodes to measure signals in the part of the brain that oversees vision. This area is located in the back of the brain. In people with optic nerve damage, it takes longer for a nerve signal — a response to a flickering pattern on a screen — to travel between the eye and the back of the brain.

Researchers discovered that the speed of the signals was significantly improved in the group that started with clemastine fumarate. The effect persisted after the group was put on a placebo for two months, suggesting that the improved neuronal function was long-lasting.

The team also measured participants’ ability to detect changes in visual contrast. It improved after the treatment, but not enough to reach statistical significance.

Restoration of myelin is called remyelination. The team failed to prove it had occurred because “we still don’t have imaging methods that have been proven to be able to detect remyelination in humans,” Chan said.

But the team said myelin regeneration was the only plausible explanation for the results. That’s because it’s well-known that myelin speeds up nerve signals.

The first step

Although the results were noteworthy, the improvements were “modest and probably not of a clinically meaningful magnitude,” in the opinion of two researchers from the Cleveland Clinic and Case Western Reserve University School of Medicine. They also pointed out that it might be difficult to increase the dose of clemastine fumarate or the duration of treatment because of side effects.

The UC-San Francisco research team is not trying to claim that their study is the final solution to remyelination.

“This is the first step in a long process,” said Green, who is also a Debbie and Andy Rachleff Distinguished Professor of Neurology, chief of the university’s Division of Neuroinflammation and Glial Biology, and medical director of the UCSF Multiple Sclerosis and Neuroinflammation Center.

“By no means do we want to suggest that this is a cure-all,” he said. “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.”

The researchers who wrote the commentary shared this opinion.

“Although clemastine fumarate probably is not the final answer to the search for repair-promoting drugs to treat multiple sclerosis, the ReBUILD trial represents a watershed milestone in that quest,” they wrote.


  1. Deborah Elam says:

    this actually makes me angry because they pulled Tavist (clemastine) off of the shelves. My guess is that this common OTC allergy medication will no longer be readily available… and that is horribly wrong!!!

  2. charles says:

    the only thing that concerns me about getting on high dose clemastine is the anticholinergic effect. i already have some small difficulty from urinary retention. it’s not serious, but if i take a bunch of clemastine, i may not be able to void my bladder at all. if it were compounded with another drug to counter that effect, then i would be less worried about it. i suppose that one could resort to a catheter…

  3. Megan says:

    It probably isn’t the “answer” because it is off patton. Also, the sife effects are sleepiness, compare that to PML, cancers, liver damage, heart problems and site reactions.
    Also you can order it, stores just don’t carry it anymore.

  4. Jumpy says:

    Clemastine Is still available in some Generic named brands. Walmart can order it for you if they don’t stock the right one or doesage in the store. My son was using it for about 6 months over a year ago and has not had a relapse or hot spot show up on his MRI Since.
    I had found articles of this used on mice over 3 years ago. Glad there are some non profit motivated researchers looking at this. LDN is also helpful and Microbiotics are also proving to be a possible source of immune system problems/diseases.

    • Ruth says:

      I have been taking Low dose Naltrexone since 2002. I came upon the link and my doctor called Dr. Bahri in New York. The reason I took it was I had such bad fatigue. I started at 3mg HCL Naltrexone to be taken after 9 PM and 1 AM. After one month and at a dose of 4.5mg fatigue was gone. There is a book titled The Promise of Low Dose Naltrexone Therapy. Studies are being done with Naltrexone in Cancer, Autoimmune, Neurological and Infectious Disorders. My Neurologist started to prescribe Naltrexone to his other patients. I was lucky to have an open minded specialist. I have given the book to other people I know with MS which they showed to the doctors. Sorry to say Big Pharma won. Just wish they were strong enough to see my specialist. It could have helped them. The only other drug I take is Baclofen for muscle spasms. I have been very lucky. God Bless.

  5. Jack O'Hearn says:

    D you know why was it pulled off the shelves? I have significant vision problems related to M.S. and I would have liked to see what my neurologist thought about me trying this over-the-counter treatment. I have seen a neurological ophthalmologist who said there was nothing that could be done. It sounds like this might be worth a try.

  6. Jane Morton says:

    My husband has been ill for nineteen years with MS and we read these articles constantly but we have never been offered anything in terms of a modifying drug or to try a new drug. I think my husband feels very overlooked. It seems to be something we read about but they never seem to benefit real people.

  7. Eric Woodard says:

    Why even talk about it this was in the news in 2012 and it came an went they continue to put out false hope for people the use the word cure but also say we can’t say that I am so tired of false hope article they receive millions of dollars each year trying to find a treatment not a cure their is no profit in a cure we need to come together to create our own researchers who are working on a cure

  8. Arthur Leeper says:

    Clemastine Fumarate was sold out for several months, while it still was available in the UK. It can also be found in Tavist tablets, which are a smaller and more costly dosage. Clemastine is available in the US again, through Kaiser and other providers.

    It does have some side-effects, but it also has quite important positive effects. In my opinion it would be worth trying, with the knowledge and support of your Neurologist. They should know what dosage you are taking; 2.68 is the standard tablet size, and people are taking one tablet, one and a half, and two tablets in a Clinical Trial at UCSF, where Clemastine was first identified as a myelin repair candidate.

    Until something else comes along (and people are looking like crazy) this is the best bet. Some people can’t tolerate it, others can. It seems to vary considerably.

  9. Arthur Leeper says:

    My one suggestion to those who think they are being overlooked is to pay close attention to the work being done at UCSF (University of California San Francisco) Medical Center and by the Brigham and Women’s Medical Center at Harvard University. People at both locations are working hard to try to find ways to halt… an reverse… the progression of MS. A large study is working to study the gut microbiome of 2,000 people with MS, in three countries. The initial data from some smaller sample groups is quite intriguing. There are good people, working hard to stop MS in its tracks, if they can. Getting into clinical trials is a key way that those with MS can support their work.

    That and getting as much exercise as possible, to keep healthy in the meantime.

  10. Merlin Leine says:

    Has anyone trying this clemanstine formula haď any success with it? It has been around à while,someone should have some results by now.

  11. Ed says:

    Clemastine Furmate is very hard to find right now, only seems to be available in allergy, anti-itch pills for dogs.

    The recall of certain allergy pills was because they contained phenylpropanolamine, or PPA, it has nothing to do with clemastine.

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