Biogen Idec is currently sponsoring a clinical trial evaluating its therapy Tysabri (natalizumab) in patients with secondary-progressive multiple sclerosis. Although relapse-remitting multiple sclerosis is more common and well-researched, the National Multiple Sclerosis Society estimates approximately half of relapse-remitting patients will transition to secondary-progressive within 19 years of diagnosis.
The Phase 3b clinical trial is a multicenter, international study known as “A Clinical Study of the Efficacy of Natalizumab on Reducing Disability Progression in Subjects With Secondary Progressive Multiple Sclerosis,” or simply “ASCEND in SPMS.” It is a two-part study, with part one placebo-controlled and part two open-label.
The primary objective of the placebo-controlled study is to evaluate slowed disability progression in patients treated with natalizumab. Patients will be evaluated with the Expanded Disability Status Scale, Timed 25-Foot Walk, and/or 9-Hole Peg Test. Secondary objectives will focus on clinical outcomes such as brain volume using MRI scans.
During the open-label extension study, patients will be monitored for adverse and serious adverse effects to solidify the safety profile of natalizumab. Secondary measures will continue to evaluate disability progression.
An estimated 856 patients are participating in the trial, and natalizumab will be administered once a month intravenously. Patients will receive treatment for a total of 96 weeks, and the study duration is 108 weeks. The trial is predicted to end in December 2014.
The difference between relapse-remitting and secondary-progressive multiple sclerosis is the presence or absence of periods of relapse, respectively. Whereas relapse-remitting patients go through periods of partial recovery, secondary-progressive patients see a continual worsening of symptoms due to steady nerve damage. Consequently, they generally have greater losses of independence and quality of life.
“There are limited treatment options available to people living with secondary-progressive multiple sclerosis, and there is a high unmet need for effective therapies,” stated Aaron Miller, MD, a member of the ASCEND advisory board, in a press release from Biogen Idec at the beginning of the study. “The ASCEND trial is investigating whether treatment with Tysabri may prevent worsening in walking, hand movement and daily functioning in these patients.”