For many, MS drugs not helpful, study shows
SAN FRANCISCO — Multiple sclerosis drugs from Biogen Idec, Merck KGaA, and Bayer with sales of $6.1 billion work for fewer than three in four patients, and a test can predict which ones, a study found.
Researchers at Stanford University analyzed mice with an induced disorder similar to MS and blood samples saved from humans with the disease. They found two subtypes of disease, each driven by excess activity of a different set of infection-fighting immune cells. Only the patients with one subtype responded to the MS drugs known as beta interferons.
In MS, the body attacks itself, damaging the insulation that protects nerve cells and disrupting their ability to transmit electrical impulses and move muscles. About 2.5 million people worldwide have the disease.
The study, published yesterday in the journal Nature, reveals why beta interferons, widely used drugs that suppress immune-system activity, don’t work for everyone.
“A lot of people are taking beta interferons who should not be and it may make them actually worse,’’ Lawrence Steinman, a neurology professor at Stanford, said last week.
The test measures blood levels of IL1 and of IL17, the two immune cells Steinman and his colleagues linked to different forms of the disease. Patients whose disease is driven by IL1 respond to beta interferon drugs, while patients with IL17-linked disease don’t, Steinman said.
“This information could allow us to better select a group of people who are likely to respond in the first place and to optimize use of the drug,’’ said Dean Wingerchuk, vice chairman of research at the Mayo Clinic in Scottsdale, Ariz.
The leading beta interferons are Avonex from Cambridge, Mass.-based Biogen, with 2009 sales of $2.3 billion; Rebif, from Merck KGaA, of Germany, with $2.1 billion in sales; and Betaferon, by Bayer AG, also of Germany, at $1.7 billion in sales in 2008.
Biogen Idec markets the MS drug Tysabri with Dublin-based Elan Corp. It strives to offer a range of options for multiple sclerosis patients, said spokeswoman Naomi Aoki.
“We’re excited about the prospect of taking a more personalized approach to identifying patients who are most likely to respond to different therapies,’’ Aoki said.