Tysabri natalizumab autoimmune data

Biogen Idec and Elan reported data from serum samples of Tysabri-treated patients analyzed by the partners' anti-JC virus (JCV) antibody assay to detect anti-JCV antibodies, which are believed to be a risk factor for developing progressive multifocal leukoencephalopathy (PML). An analysis of serum samples from 1,413 U.S. and Canadian patients with MS enrolled in the Tysabri Global Observation Study (TYGRIS) showed that anti-JCV antibodies were detected in 48% of patients using the partners' anti-JCV antibody assay. Furthermore, significant differences in the rates of anti-JCV antibody detection were observed between different age groups - 18-29 (39%), 30-39 (42.6%), 40-49 (49%), 50-59 (51.9%) and 60-75 (60.7%) -, but not between males (52.5%) and females (46.6%). The partners are jointly developing the 2-step ELISA-based test as a risk stratification tool for detecting anti-JCV antibodies to identify a patient's risk of developing PML. Data were presented at the European Committee for Treatment and Research in Multiple Sclerosis meeting in Gothenburg. ...