MORE THAN A DOZEN TREATMENTS HAVE BEEN APPROVED for multiple sclerosis (MS) in recent decades, but none of them have helped much in treating the most severe form of the disease, primary progressive multiple sclerosis (PPMS), which strikes about 15% of MS patients. A handful of new treatments may soon be available, however—including a high dose of a common supplement that can be acquired without a physician’s prescription.

The first drug to cross the line, with much fanfare, was Ocrevus, approved by the U.S. Food and Drug Administration in March. “Ocrevus is a very important advance,” says Bruce Cree, clinical research director at the UCSF Multiple Sclerosis Center in San Francisco. “But the drug was only tested on patients 55 or younger,” he adds. That means some of those with PPMS will need different options.

Among the small handful of other new drugs for PPMS that are seeking FDA approval, perhaps the most talked-about is MD1003—also called Qizenday—produced by French biotech startup MedDay Pharmaceuticals. The drug is a high-dose, water-soluble form of vitamin B7, also known as biotin.

During a pilot study published in 2015, biotin helped all but two of 23 patients with more severe forms of MS experience measurable, notable improvements. A later phase III trial saw significant gains for those on the drug during a year of treatment, and these results were sustained in the second year of the study. “Our results were in marked contrast with the natural history of progressive forms of MS, where almost no spontaneous or sustained improvement occurs,” says Frédéric Sedel, a neurologist and neuroscientist formerly with Salpêtrière Hospital in Paris, now chief executive officer of MedDay.

The drug is already available in limited early-access programs in France, Switzerland, Luxembourg and Sweden. Its earliest European approval could come next year. In the United States, Cree is principal investigator for a trial of biotin that will ultimately enroll 600 patients in approximately 70 sites around the world. “We’re very excited about it,” he says. “I’ve been following the biotin story for quite some time, and we all saw unprecedented results from the initial studies.” If all goes well, the drug might be approved in the United States by 2020.

What sets biotin apart from other treatments for severe MS are its price and its easy availability. While MD1003 wends its way through trials and awaits approval, many aren’t waiting. A closed Facebook group, Biotin for Progressive MS, has over 5,800 members, some of whom purchase the high-dose form of biotin directly from vitamin companies or specialty compounding pharmacies. Whereas Ocrevus, the MS drug approved in March, will initially cost $65,000 a year, the therapeutic dose of biotin can be acquired online for about $50 for a 30-day dose.

Joseph Guarnaccia, assistant clinical professor in the neurology department at Yale School of Medicine and director of the Multiple Sclerosis Treatment Center at Griffin Hospital in Derby, Conn., provides high-dose biotin to his patients and others through MetaBiome LLC, a company he cofounded last year. “With biotin’s known effects on energy metabolism and myelin production,” he says, “I think it’s worth trying.” Because the FDA considers high-dose biotin a supplement, not a drug, Guarnaccia says neurologists can simply refer patients to companies that supply it—or write a prescription for the high dose to be formulated at a specialty compounding pharmacy.

Sedel says that he expects Qizenday to be reasonably priced in comparison to other MS drugs. He also warns that vitamins such as biotin are not held to the same standard of pharmaceutical purity as a drug, which means that patients should be cautious about attempting self-treatment at this point. His company, for instance, is affiliated with a large pharmaceutical partner, “so we know our biotin meets all regulatory thresholds for purity,” he says.

Another concern with patients sourcing their own biotin is that at certain doses, the vitamin interferes with some medical tests. Patients can get falsely high results in steroid or thyroid tests, for instance, or falsely low results for peptide hormones. In 2016, Harvard Medical School physicians and researchers reported three cases of high-dose biotin interference in laboratory tests, and wrote in a report, “We anticipate more cases of biotin interference. In the month these cases were being reviewed, a local compounding pharmacy dispensed 370 one-month prescriptions of high-dose biotin.”

In practice, this can lead to unnecessary further testing or treatment if physicians aren’t aware of the issue or don’t know a patient is taking high doses of the supplement. But research suggests that if patients stop treatment for a few days to a few weeks, the biotin will fall below levels that interfere with test results.

Whether these patients find relief with Ocrevus, biotin or one of the promising drugs in trials, these new approaches may mark a sea change for PPMS. “I really feel we are entering a new research and treatment era for severe MS,” says Cree.