Effect of statins on clinical and molecular responses to intramuscular interferon beta-1a

BACKGROUND:: Findings from a small clinical study suggested that statins may counteract the therapeutic effects of interferon beta (IFNβ) in patients with relapsing-remitting multiple sclerosis (RRMS). METHODS:: We conducted a post hoc analysis of data from the Safety and Efficacy of Natalizumab in Combination With IFNβ-1a in Patients With Relapsing-Remitting Multiple Sclerosis (SENTINEL) study to determine the effects of statins on efficacy of IFNβ. SENTINEL was a prospective trial of patients with RRMS treated with natalizumab (Tysabri^®, Biogen Idec, Inc., Cambridge, MA) plus IM IFNβ-1a (Avonex^®, Biogen Idec, Inc.) 30 μg compared with placebo plus IM IFNβ-1a 30 μg. Clinical and MRI outcomes in patients treated with IM IFNβ-1a only (no-statins group, n ≤ 542) were compared with those of patients taking IM IFNβ-1a and statins at doses used to treat hyperlipidemia (statins group, n ≤ 40). RESULTS:: No significant differences were observed between treatment groups in adjusted annualized relapse rate (p ≤ 0.937), disability progression (p ≤ 0.438), number of gadolinium-enhancing lesions (p ≤ 0.604), or number of new or enlarging T2-hyperintense lesions (p ≤ 0.802) at 2 years. More patients in the statins group reported fatigue, extremity pain, muscle aches, and increases in hepatic transaminases compared with patients in the no-statins group. Statin treatment had no ex vivo or in vitro effect on induction of IFN-stimulated genes. CONCLUSIONS:: Statin therapy does not appear to affect clinical effects of IM interferon beta-1a in patients with relapsing-remitting multiple sclerosis or the primary molecular response to interferon beta treatment.