Glatiramer acetate in treatment‐naïve 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‐naïve relapsing–remitting multiple sclerosis (RRMS) patients and in patients who had previously received interferon‐ β (IFN‐ β )‐1b therapy. Methods –  Two treatment cohorts were defined based on prestudy IFN‐ β ‐1b use. At entry, prior IFN‐ β ‐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‐naïve patients ( n  = 558). Safety was assessed every 3 months and EDSS every 6 months for up to 3.5 years. Results –  Overall, 247 treatment‐naïve and 107 prior IFN‐ β ‐1b patients discontinued before study end. Median GA treatment durations were 36 and 24 months in treatment‐naïve and prior IFN‐ β ‐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‐naïve and prior IFN‐ β ‐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‐ β ‐1b treatment does not negatively influence the efficacy, safety, or tolerability of subsequent GA therapy. Switching to GA can benefit patients who discontinue IFN‐ β therapy.