Oral interferon beta-1 alpha in relapsing-remitting multiple sclerosis: a double-blind randomized study

Background: Interferon beta (IFNbeta) is available in parenteral formulations for treatment of multiple sclerosis (MS). The purpose of this study was to evaluate safety, tolerability and effects on MRI lesions of three different doses of oral IFNB-1alpha compared with placebo over six months in relapsing-remitting (RR) MS patients. Methods: In this multicenter, double-blind randomized trial, RR-MS patients received 0.06, 0.6 or 6 million international units (MIU) IFNB-1alpha or placebo every other day for up to six months. Gadolinium DTPA enhanced brain MRI scans were per formed at screening and monthly during treatment. The primary variable was the cumulative number of newly active lesions. Secondary variables included volume of enhancing lesions on T1-weighted images each month and lesion volume on T2-weighted images at months three and six. Safety measures included adverse events, laboratory variables, vital signs, ECG, physical examination, EDSS and number of relapses. Neopterin was measured in 21 patients and neutralizing antibodies in 24 patients. Results: Of 194 screened patients, 173 were randomized (42-44 patients per group) in 15 centers. Median cumulative numbers of newly active lesions over six months were 4.0 in the placebo and 0.6 MIU groups, compared with 7.5 and 9.0 in the 0.06 and 6 MIU groups (no significant differences). Secondary efficacy endpoints showed small and inconsistent differences between groups. Adverse events showed no notable group differences. Approximately two-thirds of patients in each group remained relapse free. No patients showed neutralizing antibodies. Neopterin levels were comparable between groups. Conclusion: Oral IFNB-1alpha showed neither beneficial effects in RRMS nor any systemic biological effects. Treatment was safe and well tolerated.