Two New Reports of PML With Tysabri Use
Friday, August 1st, 2008One again the controversial drug Tysabri is back in the news. This time, two multiple-sclerosis patients treated with Biogen Idec Inc.’s drug Tysabri contracted a potentially deadly brain infection, casting a cloud over the revival of the medicine, which has already been withdrawn from the market once over safety concerns.
Biogen said it had no plans to recall the drug again or restrict its use. The company and its marketing partner, Ireland’s Elan Corp., said that the two patients, who contracted the ailment, Progressive Multifocal Leukoencephalopathy (PML), are alive. Both patients live in Europe. One is ambulatory and at home and the other has been hospitalized.
An estimated 31,800 people take Tysabri, which is also used to treat Crohn’s disease, a digestive condition. The company has forecast 100,000 patients would be on it by 2010, with quarterly sales hitting a $1 billion annual rate by the end of this year. Renewed safety concerns over the drug, which costs about $30,000 a year in the U.S., could slow new patient adoption.
The two Progressive Multifocal Leukoencephalopathy (PML) cases are the first reported since Tysabri returned to the market in July 2006 under strict rules approved by the FDA to monitor its risks. Tysabri was removed from the market in 2005 after three Progressive Multifocal Leukoencephalopathy (PML) cases. MS patients clamored for the drug’s return because of its effectiveness in combating the symptoms of the chronic, often-disabling disease, which attacks the central nervous system.
The companies estimate Tysabri’s Progressive Multifocal Leukoencephalopathy (PML) risk at 1 in 1,000 in the first 18 months of treatment. In clinical trials, two MS patients contracted PML and one died. Another patient with Crohn’s disease also died. “We clearly believe the risk benefit profile continues to be favorable for Tysabri,” said Biogen spokesman Tim Hunt.
The two new Progressive Multifocal Leukoencephalopathy (PML) cases involved patients taking it as “monotherapy,” or with no other drug, as indicated on the Tysabri label. One, however, had a history of taking other medications. Many physicians had hoped that the patients contracting Progressive Multifocal Leukoencephalopathy (PML) had done so because of exposure to multiple medications and that monotherapy was less risky.
In earlier cases, it took more than two years before Progressive Multifocal Leukoencephalopathy (PML) was discovered. In the two new cases of Progressive Multifocal Leukoencephalopathy (PML), one patient had been taking the drug for 14 months and the other for 17.
Despite “the real hope and optimism” that many patients and doctors have about Tysabri, Mr. Schoenebaum said the short time the patients were taking Tysabri and the lack of exposure to other drugs, especially in one of the cases, could lead to reduced usage. Still, he said, “I would be shocked if this is pulled from the market.”