Glatiramer acetate in treatment-naive and prior interferon-β-1b-treated multiple sclerosis patients

Objective - This prospective, open-label study evaluated the efficacy, safety, and tolerability of glatiramer acetate (GA) in treatment-naive relapsing-remitting multiple sclerosis (RRMS) patients and in patients who had previously received interferon-beta (IFN-beta)-1b therapy. Methods - Two treatment cohorts were defined based on prestudy IFN-beta-1b use. At entry, prior IFN-beta-1b patients (n = 247) were older, had longer disease duration, and had higher mean Expanded Disability Status Scale (EDSS) scores, relapse rates, and ambulation indexes than treatment-naive patients (n = 558). Safety was assessed every 3 months and EDSS every 6 months for up to 3.5 years. Results - Overall, 247 treatment-naive and 107 prior IFN-beta-1b patients discontinued before study end. Median GA treatment durations were 36 and 24 months in treatment-naive and prior IFN-beta-1b patients, respectively. At last observation, annual relapse rates had declined by 75% in both cohorts (0.42 +/- 0.84 and 0.34 +/- 0.71 in treatment-naive and prior IFN-beta-1b groups, respectively, P = 0.1482). Mean changes in EDSS were less than 0.5 in both cohorts, regardless of entry EDSS, at 12 and 18 months and at last observation. Conclusions - Prior IFN-beta-1b treatment does not negatively influence the efficacy, safety, or tolerability of subsequent GA therapy. Switching to GA can benefit patients who discontinue IFN-beta therapy.