By Louise Gagnon
MONTREAL -- September 20, 2008 -- Glatiramer acetate has been shown to be efficacious in several outcomes among patients with relapsing-remitting multiple sclerosis (RRMS) when a scale other than the Expanded Disability Status Scale (EDSS) was used, according to research presented here at the World Congress on Treatment and Research in Multiple Sclerosis (WCTRMS).
A study of 251 patients was presented by investigator Joseph Herbert, MD, New York University, New York, New York, who described the EDSS as not truly reflective of clinical patient outcomes.
In the pivotal study, glatiramer acetate resulted in a 29% decrease in relapse rates compared with placebo. While patients treated glatiramer acetate did show improvement in their EDSS score, Dr. Herbert described the scale as an insufficiently sensitive measure of disease progression.
He presented the study findings in a poster session here on September 19
In this study, Dr. Herbert employed a Multiple Sclerosis Severity Score (MSSS) algorithm that relates MS disability as measured by EDSS to disease duration from the time of first symptom.
"This measure is a more useful outcome measure, because it corrects for certain flaws in the EDSS," said Dr. Herbert in an interview. "It accounts for duration of disease. The EDSS needs to be considered in the context of duration of disease."
This study enrolled patients who had EDSS scores of between 0 and 5. The researchers randomised 125 patients to subcutaneous injections of glatiramer acetate at 20 mg/day and 126 to placebo. Patients were followed for approximately 35 months.
Subjects in this study were divided into 6 groups according to their disease severity, explained Dr. Herbert. At study entry, the median MSSS scores for patients treated with glatiramer acetate and those treated with placebo were similar (4.59 vs 4.29; P = .1). At the end of the study, the median MSSS change from study entry was significantly greater in patients treated with glatiramer acetate compared with those treated with placebo (-0.73 vs -0.19; P = .0019).
With the revised grading of patients according to the MSSS, fewer patients who received glatiramer acetate were categorised as having severe disease. Specifically, more patients treated with glatiramer acetate were reclassified as having less severe illness (49% vs 31%) and fewer patients were reclassified as having more severe illness (16% vs 26%; P < .0014).
"There was a significant drop in severity for the treated patients," said Dr. Herbert. "There was a reassignment toward the higher grades with placebo patients."
The data support the use of the MSSS scale to measure changes in disability in patients with RRMS.
"We are suggesting that, since EDSS and duration of disease must be collected to begin with, that [MSSS] should be used as an outcome measure," said Dr. Herbert. "There is a true change in the intrinsic severity of the disease over 3 years, which is quite dramatic."
Funding for this study was provided by Teva Pharmaceutical Industries Ltd.
[Presentation title: Glatiramer Acetate Reduces Multiple Sclerosis Severity: Analysis of Patients From the US Pivotal Study Using the Multiple Sclerosis Severity Score. Abstract P454]
