Reactions 1217 - 30 Aug 2008

■ The US FDA is informing healthcare professionalsof two recent cases of progressive multifocalleukoencephalopathy (PML) associated with Tysabri[natalizumab; Biogen Idec/Elan] reported to theEMEA.* These new cases of PML are notable for beingthe first to occur in the absence of concomitant orrecent immunomodulatory therapy. They are also thefirst PML cases reported since Tysabri wasreintroduced to the market in June 2006. Both patientswere receiving Tysabri monotherapy (for 14 and17 months); one patient had a history of priorimmunosuppressive therapy with azathioprine and β-interferons. Both cases were diagnosed on the basis ofphysical and MRI findings, and detection of JC viralDNA in the CSF.* see Reactions 1214 p4; 1075330

FDA. Natalizumab injection for intraveneous use (marketed as Tysabri).Internet Document : [4 pages], Aug 2008. Available from: URL: http://www.fda.gov 801075349

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Reactions 30 Aug 2008 No. 12170114-9954/10/1217-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved