A chemical previously found to cause people to break out in blistery rashes when used on furniture upholstery now shows promise as a treatment for multiple sclerosis, according to two new studies.
The results suggest the compound, called dimethyl fumarate, reduces the likelihood that patients will experience a flare-up of their MS symptoms, and the degree to which those symptoms are disabling.
In people with MS, the immune system attacks the nerve cells of the brain and spinal cord, producing symptoms such as numbness, loss of balance, weakness and tremors. Patients typically experience their symptoms in episodes called "relapses" which last days, weeks or months, and alternate with periods of remission.
In one study, dimethyl fumarate, which is given as an oral drug called BG-12, reduced the percentage of patients experiencing flare-up by about half.The drug reduced the percentage of patients who became more disabled by their MS symptoms over the study period, and reduced signs of the disease in the brain.
Because the drug is given orally, it has an advantage over many of the current treatments for MS, which are given by injection, said Dr. Nicholas LaRocca, vice president of health care delivery at the National Multiple Sclerosis Society, who was not involved in the studies. There are currently nine treatments available to reduce MS symptoms, two of which are oral.
BG-12 has not yet been approved as a treatment for MS by the Food and Drug Administration. If approved, it would provide patients with another treatment option, LaRocca said.
"Every person with MS is unique, and not all therapies work with all people," LaRocca said. "The more options that we have available, the more likely it is that an individual will find something that is the right fit for them."
Both studies were funded by the pharmaceutical company Biogen Idec, and are published Thursday (Sept. 18) in the New England Journal of Medicine.
New MS drug
In one of the new studies, researchers at Ruhr-University Bochum in Germany randomly assigned about 1,200 MS patients to receive two or three doses of BG-12 daily, or a placebo.
After two years, 26 percent of patients who took the drug had experienced a relapse of their symptoms, while 46 percent of those who took the placebo had a relapse.
Sixteen percent of the patients who took the drug twice a day became more disabled over the course of the study, 18 percent of those who took the drug three times a day became more disabled, and 27 percent in the placebo group saw their condition worsen.
In the second study, conducted at the Cleveland Clinic, 1,400 MS patients were randomly assigned to take BG-12 either two or three times a day, take a placebo, or take a different MS drug called Copaxone.
Yearly relapses were reduced by 44 percent in patients who took BG-12 twice a day, 51 percent in patients who took BG-12 three times a day, and 29 percent in patients who took Copaxone, compared with those taking the placebo.
The most common side effects for BG-12 were flushing (experienced by about a third of participants) and gastrointestinal problems, such as diarrhea, nausea and abdominal pain (experienced by 36 to 41 percent of participants). The side effects were considered mild to moderate, the researchers said.
The compound has an interesting history. "In the very curious incident of the 'poison chair,' hundreds of people in several European cities appeared at clinics with [eczema-like sores] that had no apparent cause," writes Dr. Allan Ropper, of Brigham and Women’s Hospital in Boston, in an editorial accompanying the studies in the journal. The sores were traced in 2008 to dimethyl fumarate, the chemical used to prevent fungi from growing in furniture.
As an MS treatment, BG-12 looks favorable in the short term, but it's not yet known whether it can reduce disability over the long term, Ropper said.
Long-term effectiveness is important because, on average, patients are diagnosed with MS in their late 20s, Ropper said.
In addition, it is not clear whether oral drugs to prevent relapse will interact with current therapies, Ropper said.
The FDA is set to make a decision on whether to approve BG-12 as an MS treatment by the end of the year, LaRocca said.