Monday, September 22, 2008
September 19, 2008
BOSTON—One of two European patients, who developed a potentially deadly brain infection after taking the multiple sclerosis drug Tysabri, is deteriorating and likely to suffer brain damage, according to a researcher involved in their care.
The other patient diagnosed with the infection in July is recovering, the researcher said Friday.
The drug, made by Biogen Idec Inc and Elan Corp , was temporarily withdrawn from the market in 2005 after being linked with three cases of an often lethal infection known as progressive multifocal leukoencephalopathy, or PML.
Due to its advantages over older MS treatments and patient willingness to take on the risks, Tysabri was reintroduced with stricter warnings in 2006. No new cases were reported until the end of July, when Biogen announced that two patients had developed the infection.
Biogen said on Friday that no further new PML cases have been confirmed and its shares closed up 6 percent. Elan shares closed up more than 1 percent.
Dr. Ralf Gold of Ruhr University Bochum, Germany, said in an interview that a German patient, hospitalized near the town of Freiburg, is close to a coma and being fed through tubes, though he is breathing on his own.
The other patient, a 37-year-old Swede, is in a rehabilitation center near Stockholm and suffering only from mild weakness on one side of his body.
Gold said the 52-year-old German patient was not diagnosed until at least three months after developing the disease, whereas the Swedish patient's condition was identified in less than a month. As a result, the German patient had a higher level of the virus in his brain.
The two were treated through plasmapheresis, a procedure in which a patient's blood is removed, cleared of the drug, and replaced.
Gold presented an update on the two cases at the World Congress on Treatment and Research in Multiple Sclerosis in Montreal.
Investors have been watching the patients' progress to see whether PML can be reversed. They are also watching to see how many cases of the infection develop among patients taking the drug, which is considered a critically important growth driver for both companies.
Tysabri had second-quarter sales of $200 million, but its fortunes have been inextricably linked to PML concerns.
"The drug's strong efficacy profile should keep it as a preferred agent, in our opinion," Leerink Swann analyst William Tanner wrote in a research note.
In a report ahead of Gold's update, Geoff Porges, an analyst at Sanford Bernstein, said that if the disease becomes manageable through plasmapheresis then the impact of these cases will be blunted.
He said experts interviewed at the meeting have confirmed that in Europe and North America there are a number of patients with suspected PML whose physicians discontinued Tysabri use.
"We believe it is incumbent on Biogen to disclose this information to physicians in order for them to fully evaluate and disclose the risks associated with the product," he said.
Biogen spokeswoman Naomi Aoki said, "We have disclosed the only two cases of diagnosed PML that we have seen so far."
Gold added that while certain databases pick up cases in which a doctor suspects PML and discontinues Tysabri, the cases have not been confirmed either through an MRI or any other scientific measures.
Gold said the virus appears to be leaving the German patient's brain, but he is suffering from brain damage brought about by a condition known as immune reconstitution inflammatory syndrome, or IRIS. This occurs when the immune system, in eliminating an infection, produces an excessive inflammatory response that can worsen symptoms.
It is most likely the patient will be permanently brain damaged, Gold said. The only question is by how much.
The patient was started on a course of corticosteroids on Friday, the standard treatment for IRIS.
It typically becomes clear within a few days whether such a treatment is likely to work, Gold said. In the meantime, the patient is in a critical condition but not in intensive care.
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