Interferon-β-1b slows progression of atrophy in RRMS: Three-year follow-up in NAb- and NAb+ patients

Objective: To determine the effect of interferon-β-1b (IFNβ-1b) treatment on total contrast-enhancing lesions (CEL), white matter lesion load (WMLL), and cerebral atrophy (CA) in patients with relapsing-remitting multiple sclerosis (RRMS) using serial monthly MRI. Methods: An open-label baseline-vs-treatment crossover trial was conducted with 30 RRMS patients monitored during a 6-month baseline and up to 36 months on treatment with IFNβ-1b. Monthly MRI exams and neurologic exams using the Expanded Disability Status Scale (EDSS) were performed. Results: The percentage changes from baseline for years 1, 2, and 3 on IFNβ-1b were as follows: brain volume (BV) = -1.35, -1.48, and -1.68%; CEL = -76.5, -60.1, and -54.7%; WMLL = -12.2, -9.8, and -10.4%. There was no difference in the BV, CEL, or WMLL for between-year comparisons, and the decrease in BV from year 1 to years 2 and 3 was less than the change from baseline to year 1. EDSS did increase (p < 0.001) when comparing the last 3 months of baseline (2.8 ± 2.1) and the last 3 months on IFNβ-1b (3.6 ± 2.1). Eleven patients developed neutralizing antibody (NAb) during the study. The effect of IFNβ-1b on CEL and WMLL was significantly reduced in NAb+ patients compared with NAb- patients (p < 0.003). Conclusion: IFNβ-1b decreases contrast-enhancing lesions and white matter lesion load over 3 years on therapy and slows the progression in cerebral atrophy during years 2 and 3.