Effects of early treatment with glatiramer acetate in patients with clinically isolated syndrome

Background: The placebo-controlled phase of the PreCISe study showed that glatiramer acetate delayed onset of clinically definite multiple sclerosis (CDMS) in patients with clinically isolated syndrome and brain lesions on MRI. Objective: To compare the effects of early versus delayed glatiramer acetate treatment in the open-label phase of PreCISe. Methods: Patients with a clinically isolated syndrome suggestive of MS with unifocal manifestation and 2 T2-weighted brain lesions were randomized to receive glatiramer acetate 20 mg/d (early-treatment, n=198) or placebo (delayed-treatment, n=211) for 36 months or until conversion to CDMS, followed by open-label glatiramer acetate treatment for two years. Results: Early glatiramer acetate treatment reduced CDMS conversion risk by 41% (hazard ratio 0.59, 95% confidence interval 0.44-0.80; p=0.0005) versus delayed-treatment, and was associated with a 972-day delay (185%) in conversion to CDMS, less brain atrophy (-28%, p=0.0209), fewer new T2 lesions/year (-42%, <0.0001) and lower T2 lesion volume (-22%, p=0.0005) versus delayed treatment. Adverse events were consistent with the established safety profile of glatiramer acetate. Conclusions: Effects of early glatiramer acetate treatment on the rate of conversion to CDMS and on MRI measures of disease activity and lesion burden support initiating glatiramer acetate treatment soon after the first clinical symptoms suggestive of MS and continuing treatment to sustain benefits.