Assessing Efficacy in Clinical Trials of Treatments for Multiple Sclerosis

Abstract

No single sensitive clinical outcome measure is capable of reliably reflecting the broad spectrum of clinical manifestations seen in multiple sclerosis (MS). Disease activity in groups of patients with MS is more readily detected by magnetic resonance imaging (MRI) of the brain and spinal cord than by neurological examination. However, the appearance of new lesions and progression of total lesion area as detected by MRI fails to predict reliably sustained progression of neurological impairment in individual patients. For this reason MRI is accepted as a primary outcome measure in exploratory clinical trials, while sustained progression of neurological impairment is the preferred primary outcome measure for pivotal phase II/III trials that lead to the approval of new treatments for MS.