Tetsuro Fujita's eureka moment about a Himalayan fungus came in 1985. As the scientist was driving over a bridge between Japan's Shikoku and Honshu islands on his way to conduct research on traditional herbal remedies, Fujita was contemplating ways to keep patients' immune systems from rejecting transplanted organs. He was particularly intrigued by the example of a parasitic fungus used in a Chinese medicinal soup. Known in Asia as "winter insect, summer plant," the Cordyceps fungus invades an insect larva during winter, feeds on it for months, and then grows out of the host by summer. Fujita suddenly realized that the fungus must be suppressing the immune system of the insect larvae on which it grew to maturity.
His research on Cordyceps at Kyoto University eventually helped Japanese drugmaker Mitsubishi Tanabe Pharma produce Gilenya, a treatment for multiple sclerosis that Novartis (NVS) licensed and began selling in the U.S. in October. UBS (UBS) says annual sales of the medicine, the first pill to treat the autoimmune disease afflicting more than 2 million people worldwide, may exceed $5 billion annually by 2018. That would rank it among the 10 best-selling drugs worldwide, based on data from researcher IMS Health. Mitsubishi Tanabe will likely book royalties equivalent to 10 percent of sales, based on the median of estimates by four analysts surveyed by Bloomberg News.
"Little did I think that it would be a treatment for multiple sclerosis," says Fujita, 80. "I knew nothing about the disease back then." Multiple sclerosis causes the immune system to attack the myelin sheath, which protects nerve cells, leading to symptoms including numbness, difficulty in coordination, and memory loss. In its severest form, multiple sclerosis also can shorten life.
Gilenya, approved to treat the relapsing-remitting form of multiple sclerosis, the most common, competes with injected drugs including Biogen Idec's (BIIB) Avonex and Teva Pharmaceutical Industries' (TEVA) Copaxone. The Novartis pill cut the number of relapses by more than half compared with Avonex, according to a study published last year in the New England Journal of Medicine.
European regulators are expected to make a decision on the drug by the end of April. Gilenya is also being reviewed by regulators in Japan. In the U.S. the drug is priced at $4,000 for a monthly prescription. A month's supply of prefilled Avonex syringes costs $2,414.99. Analysts expect Gilenya to be cheaper in Europe.
Current medicines require patients to inject themselves every other day or once a week, says Kyoko Nakata, chairman of Japan's MS Cabin, a support group. "Gilenya would make it easier to treat the disease, as it saves time and brings patients closer to having a normal life," says Nakata.
That's gratifying to Fujita, now a professor emeritus at Kyoto University. "Although it took a quarter of a century," he says, "I'm happy it's become a drug while I'm still alive."
The bottom line: According to analysts' estimates, Mitsubishi Tanabe will likely book royalties equivalent to 10 percent of sales from its new pill to treat MS.