United States open-label glatiramer acetate extension trial for relapsing multiple sclerosis: MRI and clinical correlates

After the placebo-controlled extension of the pivotal US trial of glatiramer acetate for the treatment of relapsing multiple sclerosis ended, 208 participants entered an open-label, long-term treatment protocol. Magnetic resonance imaging (MRI) was added to the planned evaluations of these subjects to determine the consequences of long-term treatment on MRI-defined pathology and evaluate its clinical correlates. Of the 147 subjects that remained on long-term follow-up, adequate images were obtained on 135 for quantitative MRI analysis. The initial imaging sessions were performed between June 1998 and January 1999 at 2447+61 days (mean+standard deviation) after the subject's original randomization. Clinical data from a preplanned clinical visit were matched to MRI within 3+51 days. At imaging, 66 patients originally randomized to placebo (oPBO) in the pivotal trial had received glatiramer acetate for 1476+63 days, and 69 randomized to active treatment with glatiramer acetate (oGA) were on drug for 2433+59 ...