UPDATE 2-Biogen says new brain infection linked to Tysabri
12.15.08, 12:51 PM EST
By Ransdell Pierson
NEW YORK, Dec 15 (Reuters) - Biogen Idec Inc
The latest case of the brain infection, known as progressive multifocal leukoencephalopathy (PML), was seen in a European patient who had been taking Tysabri as a stand-alone treatment for 26 months, Biogen said in a regulatory filing.
'The patient is under physician's care,' company spokeswoman Shannon Altimari said, noting it was too soon to speculate on the prognosis for the patient.
Shares of Biogen and Elan fell sharply after the drugmakers disclosed on Oct. 29 that a case of PML had been seen in a U.S. patient. In July, the companies reported two cases had emerged in Europe.
This year's four cases of affected patients, all still alive, are the first to be announced since Tysabri was withdrawn from the market in 2005 after three earlier patients developed the brain infection. Two of the earlier three patients died.
Asked why no cases were seen in 2006 or 2007, Biogen spokeswoman Naomi Aoki on Monday said, 'The drug had been taken off the market for a little over a year, and returned in July 2006.'
She said Biogen and Elan believe the superior effectiveness of Tysabri in preventing relapses of multiple sclerosis symptoms justifies its use, despite the relatively low risk of PML.
68 PCT RELAPSE REDUCTION
Aoki said more than 35,500 patients worldwide are taking Tysabri, and that the drug in clinical trials was able to produce a 68 percent reduction in relapses.
Rival drugs, by contrast, are able to reduce relapses by only about a third, she said.
Tysabri's package insert label cautions that patients taking the drug have a 1-in-1,000 risk of developing PML, but the overall incidence of the brain infections seen so far is 'still well within' that magnitude, JP Morgan analyst Geoffrey Meacham said in a research note.
'Overall, we would characterize this new case as completely in line with expectations at this point,' Meacham said, noting that the infrequent occurrence of PML suggests there is little risk Tysabri will again be pulled from the market.
Third-quarter sales of Tysabri rose 18 percent to $171 million, a slowdown from the 25 percent growth seen in the second quarter. Biogen said growth was tempered as doctors continue to assess the drug's risks versus its benefits.
Even so, Biogen in October reaffirmed it expects 100,000 patients to be taking Tysabri by 2010, a near tripling of the current patient roster. The company on Monday said its ambitious goal remains in place.
Multiple sclerosis, a so-called autoimmune condition that can cause progressive paralysis of limbs, occurs when an overactive immune system attacks the protective myelin sheath around nerves.
Autoimmune drugs work by taming the immune system, but in doing so some of them can leave the body prey to infections that rarely affect the general population.
Aoki said a handful of other drugs, including Biogen's own Rituxan treatment for cancer, carry warnings of increased risk for PML.
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