Quoted from http://www.reuters.com/article/2011/02/18/biogen-tysabri-idUSN1811430320110218
Biogen reports 10 more Tysabri PML cases, 4 deathsT
Fri Feb 18, 2011 5:10pm EST
NEW YORK Feb 18 (Reuters) - Ten more patients taking Biogen Idec's (BIIB.O) multiple sclerosis drug Tysabri developed the serious brain infection known as PML last month and there were reports of four more deaths, according to a monthly update by the U.S. biotechnology company.
The new cases of potentially fatal progressive multifocal leukoencephalopathy, or PML, were detected between Jan. 7 and Feb. 2, bringing the total number of confirmed cases to 95 and deaths to 20 since the drug was reintroduced into the market in July of 2007, Biogen said.
Biogen, which markets the drug with Ireland-based partner Elan Corp Plc (ELN.I), said the overall rate of PML cases per 1,000 patients has edged slightly higher to 1.16. In November it had been 1.0.
The number of new PML cases per month has been climbing. Four new cases were reported in November and six in December.