250 μg or 500 μg interferon beta-1b versus 20 mg glatiramer acetate in relapsing-remitting multiple sclerosis: a prospective, randomised, multicentre study

Background The aim of the Betaferon Efficacy Yielding Outcomes of a New Dose (BEYOND) trial was to compare the efficacy, safety, and tolerability of 250 mu g or 500 mu g interferon beta-1b with glatiramer acetate for treating relapsing-remitting multiple sclerosis. Methods Between November, 2003, and June, 2005, 2447 patients with relapsing-remitting multiple sclerosis were screened and 2244 patients were enrolled in this prospective, multicentre, randomised trial. Patients were randomly assigned 2:2:1 by block randomisation with regional stratification to receive one of two doses of interferon beta-1b (250 mu g or 500 mu g) subcutaneously every other day or 20 mg glatiramer acetate subcutaneously every day. The primary outcome was relapse risk, defined as new or recurrent neurological symptoms separated by at least 30 days from the preceding event and that lasted at least 24 h. Secondary outcomes were progression on the expanded disability status scale (EDSS) and change in T1-hypointense lesion volume. Clinical outcomes were assessed quarterly for 2.0-3.5 years; MRI was done at screening and annually thereafter. Analysis was by per protocol. This study is registered, number NCT00099502. Findings We found no differences in relapse risk, EDSS progression, T1-hypointense lesion volume, or normalised brain volume among treatment groups. Flu-like symptoms were more common in patients treated with interferon beta-1b (p<0.0001), whereas injection-site reactions were more common in patients treated with glatiramer acetate (p=0.0005). Patient attrition rates were 17% (153 of 888) on 250 mu g interferon beta-1b, 26% (227 of 887) on 500 mu g interferon beta-1b, and 21% (93 of 445) for glatiramer acetate. Interpretation 500 mu g interferon beta-1b was not more effective than the standard 250 mu g dose, and both doses had similar clinical effects to glatiramer acetate. Although interferon beta-1b and glatiramer acetate had different adverse event profiles, the overall tolerability to both drugs was similar.