Shares of Biogen Idec (BIIB) are leading the S&P 500 gainers on Friday after the drugmaker said that it was won 10 years of market exclusivity in the European Union with its new multiple sclerosis drug Tecfidera. 

Regulators at the European Medicines Agency determined that dimethyl fumarate in Tecfidera is a “new active substance,” meaning that generic drugmakers will not be able to compete with generics for at least a decade. The designation follows a positive opinion by the Committee for Medicinal Products for Human Use, or CHMP, in March recommending approval of Tecfidera. 

The U.S. Food and Drug Administration approved Tecfidera on March 27, 2013. A once-daily, oral drug Tecfidera was approved to treat adults with relapsing forms of multiple sclerosis.

“No drug provides a cure for multiple sclerosis so it is important to have a variety of treatment options available for patients,” said Dr. Russell Katz, director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research, upon approval of Tecfidera early this year.

Multiple sclerosis is a chronic, inflammatory, autoimmune disease of the central nervous system that disrupts communication between the brain and other parts of the body. The disease is often characterized by muscle weakness, difficulty with balance and coordination, impaired vision and numbness, amongst other things.

Massachusetts-based Biogen’s clinical trials showed that MS patients treated with Tecfidera had fewer relapses compared to the placebo arm.

If officially approved in the EU as anticipated, Tecfidera will be Biogen’s fourth multiple sclerosis drug approved for the 27-nation region, including its blockbuster Tysabri (natalizumab). In February, Biogen agreed to spend $3.25 billion, plus future considerations, to acquire full rights to the drug from Ireland-based Elan Corp. PLC (ELN) .  Previously, the two companies had split profits on Tysabri 50/50.  Tysabri sales were $1.6 billion in 2012, up 8 percent from 2011.

“We are heartened by the CHMP’s [new active substance] determination, which brings us closer to our goal of providing this important new treatment to multiple sclerosis patients in Europe. We are ready to introduce TECFIDERA in EU countries shortly after anticipated approval,” said Dr. Douglas Williams, executive vice president of Research and Development at Biogen Idec., in a statement today.

The news has catapulted shares of BIIB to all-time highs on Friday, printing as high as $289.97 in morning trading. Shares have had a strong 2013, rising more than 70 percent through Thursday’s close.

In some separate drug news out of Europe, the CHMP adopted a positive opinion on Gilead Sciences, Inc.’s (GILD) application for marketing approval for Sovaldi for chronic hepatitis C. Shares of GILD have surged ahead about 5 percent to all-time highs at $75.21.