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( Posted by-Desinie Smith )

Biogen Seeks Test for Brain Disease Linked to MS Drug (Update1)

By Elizabeth Lopatto
April 9 (Bloomberg) -- Biogen Idec Inc. wants to take the fear out of prescribing its multiple sclerosis treatment Tysabri with a test that can tell patients their odds of getting a deadly brain illness from the drug.

The screening tool could be marketed as early as 2011 if clinical trials involving 9,000 people, set to start this year, show a low rate of false findings, said Naomi Aoki, a spokeswoman for the Cambridge, Massachusetts-based biotechnology company. The test is designed to detect the JC virus that causes progressive multifocal leukoencephalopathy, or PML, a brain-cell destroyer that can lead to disability and death.

Tysabri, which generated $1.1 billion in sales in 2009, has been linked to 42 PML cases, the company has reported. While it’s approved for use only after other drugs fail, 61 percent of 285 neurologists surveyed by RBC Capital Markets in San Francisco said Tysabri’s ability to slow MS progression would make it their first choice if they could assess the risk of PML.

If the test works, it is “absolutely a game changer,” said Patricia O’Looney, vice president of biomedical research at the New York-based National Multiple Sclerosis Society, in a telephone interview. “If Biogen can validate it, that takes out the guessing game.”

‘Longer-Term Positive’

It’s too early to set a dollar amount on the potential gain in drug sales based on such a test until the clinical trials are completed, said Geoffrey Meacham, an analyst for J.P. Morgan in New York, in a telephone interview. A successful test that determines Tysabri is safe to use in some patients would be “a longer-term positive” for the company, he said.

Biogen rose 20 cents to $56.63 at 9:53 a.m. New York time in Nasdaq Stock Exchange composite trading. The stock, which sold for $67.28 on the last trading day before Tysabri was removed from the market, plunged 43 percent on the withdrawal. The shares had fallen 16 percent since Feb. 27, 2005.

Biogen first tested their assay using blood samples taken from 11 patients who later developed PML, said Al Sandrock, senior vice president of neurology research and development. The findings from that study and research on the prevalence of JC virus will be presented next week at the American Academy of Neurology meeting in Toronto.

Behind Goal

Since the therapy returned to the market in 2006, the company hasn’t reached its goal to have 100,000 patients use it by the end of 2010. Tysabri is used by about 48,800 patients as of the end of 2009, according to Biogen. The company backed away from the goal last year, after a fifth patient developed PML.

Biogen plans two clinical trials to determine the rates of false positives and false negatives. For patients who test positive, the risk of PML will be about 1 in 500, said Robert Fox, a neurologist at the Cleveland Clinic in Ohio. For those who test negative, though, the risk is “quite low,” Biogen’s Sandrock said.

In February, the FDA updated Tysabri’s labeling to clarify its risks. The number of infections and deaths from PML remains about 1 in 1,000 overall. The rate is higher outside the U.S., with 2 of every 1,000 patients contracting the illness. The reason for the difference is unknown, the FDA said.

JC Virus

The test is designed to detect the presence of an antibody to the JC virus in the blood of patients, signaling that the patient has been infected.

With a false-negative rate of 2 percent, patients who are free of the virus would lower their risk of getting the brain disorder PML to 1 in 25,000 for the first three years of their Tysabri therapy, wrote analyst Joshua Schimmer of Leerink Swann, in a March 25 note to investors.

Since a patient may become infected with the JC virus at any time (it is passed through the air), part of Biogen’s task in its clinical trials is to determine how many patients become infected over time. This determination changes the odds that any one patient may get the disease.

Probably about 1 to 2 percent of patients will be infected yearly, Sandrock said.
Antibody Reliability
Eugene Major, a researcher at the National Institutes of Health in Bethesda, Maryland, said that when the NIH and others tested for the presence of the virus, rather than antibodies, they found that at least 70 percent of the population probably is infected. The company, based on antibody testing, has put that number at 50 percent.

“They’re underestimating the number of people who’ve been exposed,” Major said in a telephone interview. “We have strong evidence that the overwhelming majority, especially after the third and fourth decade, have been exposed.”

Biogen is looking at other biological signs of PML risk that may be incorporated to improve the test, Sandrock said. In those who test positive, Biogen is testing for markers to further determine which patients are at high risk, Sandrock said. Those markers may include certain genes that increase the risk of a brain infection, or viral mutation that allows JC virus to live in brain tissue.

“We know a lot about the benefits of Tysabri, and we know something about the risk,” said Sandrock. “If we can be specific about an individual’s risk versus an individual’s benefit, that would help patients make better-informed treatment decisions. Patients want to know, ‘what’s my risk?’”

To contact the reporter on this story: Elizabeth Lopatto in New York at

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