The PROMiSe trial: baseline data review and progress report

Abstract

The PROMiSe trial is a multinational, multicentre, double-blind, placebo-controlled trial evaluating the effects of glatiramer acetate treatment over 3 years in patients with primary progressive multiple sclerosis (PPMS). A total of 943 patients were enrolled, and all those remaining on-study had completed at least 24 months as of October 2002. Baseline clinical and MRI characteristics and select correlations are reported here. A total of 3.9% of patients exhibited confirmed relapse over 1904 patient-years of exposure, indicating success of efforts to exclude relapsing MS types. Of the 26.3% of patients who have prematurely withdrawn from the study, only 36% discontinued after meeting the study primary endpoint of disease progression. The progression rate in patients in the low Expanded Disability Status Scale (EDSS) stratum (3.0-5.0) observed thus far is markedly lower than the 50% annual progression rate estimate used for determining size and statistical power of the trial; progression was observed in 16.1% of patients with 12 months of study exposure. These early findings raise some concern about the ability of the trial to demonstrate a significant treatment effect, and suggest that the short-term natural history of PPMS may not be as aggressive as previously assumed.