Biotech Values

[DewDiligence]

Blood-Cleansing Treatment Could Make Tysabri Safer

[The ‘plasma exchange’ technique described here is old hat, but an article about it was published today in Neurology.]

http://www.bloomberg.com/apps/news?pid=20601103&sid=afWzOTYu40VQ

›February 2, 2009 18:02 EST
By Rob Waters

Feb. 2 (Bloomberg) -- A blood-washing treatment may whisk Biogen Idec Inc.’s Tysabri from the bloodstreams of patients with multiple sclerosis, potentially neutralizing a rare side effect before it turns deadly.

Tysabri was pulled from the market in February 2005 by Biogen and its marketing partner, Elan Corp., after three patients developed a viral brain disease called progressive multifocal leukoencephalopathy, or PML, and two of them died.

Since U.S. regulators allowed the companies to resume selling the drug in July 2006, four new cases of the brain disease have been reported among Tysabri users. All four patients were treated with the blood-washing method and only one of them died, said Robert Fox, medical director of the Mellen Center for Multiple Sclerosis at the Cleveland Clinic. A study led by Fox, funded by Biogen, and published today in the journal Neurology showed that blood-washing reduced Tysabri to acceptable levels within two weeks.

“If you decide that a patient needs to get rid of the drug, you want to do it as fast as you can,” Fox said in a telephone interview today. “We were able to reduce Tysabri levels by 92 percent” with the treatment.

Tysabri, Biogen’s second-best-selling medicine, is approved to treat multiple sclerosis patients who aren’t helped by other drugs. Tysabri generated $597 million in sales in the first nine months of 2008, and sales growth slowed in the fourth quarter, Chief Executive Officer James Mullen told investors on Jan. 13 at the JPMorgan Healthcare Conference in San Francisco.

Purifying Plasma

The blood-washing method, known to doctors as plasmapheresis or plasma exchange, draws blood from a patient’s arm. Purified plasma, the liquid component of blood, is then returned to the other arm during a two- to three-hour process. In Fox’s study, 12 Tysabri users who didn’t have the brain disease had three blood- washing sessions to see if the approach could work. In all 12, Tysabri levels were lowered by an amount that Fox said may stop the progression of the brain illness if they had it.

Because Fox and his colleagues had presented early results from the study at medical meetings in 2007 and 2008, doctors used the technique on the four patients who developed the brain disease last year.

The technique could improve clinical outcomes for Tysabri patients who develop PML, said Shannon Altimari, a Biogen spokeswoman.

Medical consultants advising Leerink Swann & Co. said they believe the report “could make physicians more comfortable with prescribing Tysabri,” said William Tanner, a Leerink analyst, in a note to investors today. The decline in the number of new patients starting Tysabri may have stabilized, “perhaps providing an opportunity for regrowth in the next few quarters,” he said.‹