A Study to Characterise the Efficacy of Natalizumab on Disability (ASCEND) trial is a double-blind placebo-controlled study in which SPMS patients are randomised to receive either Tysabri 300 mg or placebo intravenously every four weeks for 96 weeks.
The ASCEND study is part of the collaboration between Biogen Idec and Elan to improve the well-being of patients with multiple sclerosis.
In the trial, the primary endpoint is to investigate whether treatment with Tysabri slows the accumulation of disability not related to relapses in subjects with SPMS.