Weekly IM interferon beta-1a in multiple sclerosis patients over 50 years of age

Background: Efficacy and safety data have not previously been compiled for intramuscular interferon beta-1a (IM IFN beta-1a) in patients with multiple sclerosis (MS) = 50 years of age. We investigated the efficacy and safety of IM IFN beta-1a in patients segregated by 50 and 40 years of age in separate meta-analyses. Methods: The MS Clinical Research Group Study, the Controlled High-Risk Subjects AVONEX (R) (IM IFN beta-1a) MS Prevention Study, the IFNb-1a European DoseComparison Study, and a multicenter, open-label antigenicity and safety study of human serum albumin-free IM IFNb-1a were analyzed. Results: Overall, 906 patients (68 aged 50 years and 838 aged < 50 years, or 323 aged 40 years and 583 aged < 40 years) received IM IFNb-1a for 24 months. At baseline, patients 50 years had significantly higher Expanded Disability Status Scale scores than patients < 50 years (3.4 vs. 2.8; P < 0.001), but fewer relapses in the three preceding years (2.6 vs. 3.4; P < 0.001); patients 40 years and < 40 years exhibited similar differences. After 2 years of treatment, there were no significant differences in annualized relapse rate, sustained disability progression, time to sustained disability progression, or number of MRI-identified gadolinium-enhanced lesions between age groups in either analysis. The cumulative probability of relapse was significantly lower in patients 40 years versus patients < 40 years (0.601 vs. 0.702; P < 0.001). Adverse event incidence did not differ significantly between age groups in either analysis. Conclusions: IM IFNb-1a is effective and well tolerated in patients with MS 40 and 50 years as well as younger patients.