A prospective open-label study of glatiramer acetate: over a decade of continuous use in multiple sclerosis patients

Abstract

A decade of continuous glatiramer acetate (GA) use by relapsing remitting multiple sclerosis (RRMS) patients was evaluated in this ongoing, prospective study, and the neurological status of ‘Withdrawn’ patients was assessed at a 10-year long-term follow-up (LTFU) visit. Modified intention-to-treat (mITT, n=232) patients received ≥ 1 GA dose since 1991; ‘Ongoing’ patients ( n=108) continued in November 2003. Of 124 patients, 50 Withdrawn patients returned for LTFU. Patients were evaluated every six months (EDSS). Mean GA exposure was 6.99, 10.1 and 4.26 years for mITT, Ongoing, and Withdrawn/LTFU patients, respectively. While on GA, mITT relapse rates declined from 1.18/year prestudy to ∼1 relapse/5 years; median time to ≥ 1 EDSS point increase was 8.8 years; mean EDSS change was 0.739±1.66 points; 58% had stable/improved EDSS scores; and 24, 11 and 3% reached EDSS 4, 6 and 8, respectively. For Ongoing patients, EDSS increased 0.509±1.65; 62% were stable/improved; and 24, 8 and 1% reached EDSS 4, 6 and 8, respectively. For Withdrawn patients at 10-year LTFU, EDSS increased 2.249±1.86; 28% were stable/improved; and 68, 50 and 10% reached EDSS 4, 6 and 8, respectively. While on GA nearly all patients (mean disease duration 15 years) remained ambulatory. At LTFU, Withdrawn patients had greater disability than Ongoing patients.