A chemical once used to treat sofas — until it was found to cause rashes and blisters in people who sat on them — is now poised to become a major therapy for multiple sclerosis.
The Food and Drug Administration on Wednesday approved the chemical, dimethyl fumarate, which will be sold by Biogen Idec under the name Tecfidera, the third of a spate of oral drugs that are transforming the treatment of multiple sclerosis.
Despite the drug’s seemingly odd history, Wall Street analysts, doctors and patients expect Tecfidera to become a blockbuster because of its combination of efficacy and relative safety and the convenience of being a pill. Doctors and analysts say some patients have been putting off starting treatment until Tecfidera is available.
Feedback from doctors was “highly positive, with a strong consensus that Tecfidera offers a more favorable clinical profile than other oral or injectable first-line options,” Thomas Wei, an analyst at Jefferies, wrote on Monday.
About 400,000 Americans and more than two million people worldwide have multiple sclerosis, many of them women first stricken in their 20s. The disease is believed to occur when the body’s immune system attacks the insulation around nerve fibers, causing symptoms like difficulty walking, blurred vision and fatigue.
The market for MS drugs is already $14 billion annually, with $8.5 billion of that in the United States, according to Sanford C. Bernstein & Company.
While self-injected medicines like Avonex from Biogen and Copaxone from Teva that entered the market in the 1990s are still used by the majority of treated patients, newer oral drugs are making inroads. In addition to Tecfidera, the other two oral drugs are Gilenya from Novartis, approved in 2010, and Aubagio from Sanofi, approved in September.
The approvals will solidify Biogen’s position as a leader in multiple sclerosis drugs. In addition to Tecfidera and Avonex, the company also sells Tysabri, a highly effective intravenous drug but one that can cause a potentially fatal brain infection.
Biogen shares have more than doubled in the last two years, largely because of anticipation about Tecfidera. The shares closed on Wednesday at $182.68, up about 3 percent.
Biogen, which is based in Weston, Mass., did not immediately announce the price of Tecfidera, which was known as BG-12 during its development.
Stock fund portfolio managers polled by the research firm the ISI Group on Wednesday predicted a price of about $51,000 a year, which would be roughly in line with prices of the injectable drugs, but less than the $60,000 a year list price of Gilenya.
The effectiveness of multiple sclerosis drugs is often judged by how much they reduce the frequency of relapses, which are severe flare-ups of symptoms, compared to a placebo in clinical trials.
The injectable drugs reduced the frequency about 30 percent, as did the new oral drug Aubagio. Gilenya cut the rate about 54 percent.
Tecfidera cut the relapse rate 44 percent in one trial and 53 percent in another, which might put it a bit behind Gilenya. Tecfidera is also taken twice a day, while Gilenya is taken only once daily.
But Gilenya has side effects that make it off limits for some patients and require careful testing and monitoring for heart, liver and eye problems. Patients are supposed to remain in a medical facility for at least six hours after taking their first dose to make sure their heart does not slow down too much.
Tecfidera will have fewer restrictions and testing requirements. The prescribing information does recommend that blood cell levels be tested before a patient starts on the drug and annually thereafter. That is because Tecfidera can reduce white blood cell levels, leaving patients potentially vulnerable to infections. And some studies in animals suggest that the drug might cause fetal harm, making it a questionable choice for pregnant women, the label says.
Tecfidera’s most common side effect is flushing, which occurs in about 40 percent of patients. The drug can also cause nausea and diarrhea.
Dimethyl fumarate and some closely related compounds are simple molecules that have been used as food additives. The compound was also used to protect upholstery and shoes from mold during storage. But people in Europe developed skin irritation and other problems, causing its use in consumer goods to be banned there.
The first use of it in medicine was in 1959, when a German chemist treated his own psoriasis. A drug called Fumaderm, which is similar to Tecfidera, was approved to treat psoriasis in Germany in 1994.
It is not quite clear how Tecfidera works. It is thought that one way is to activate a pathway known as Nrf2, which helps protect the body from oxidative stress.
Geoffrey C. Porges, a biotechnology analyst at Sanford Bernstein, said in a note on Monday that he expected global sales to reach $1.7 billion by 2015 and $2.6 billion by 2017. European regulators recommended last week that Tecfidera be approved as well.