Clinical Parameters to Predict Response to Interferon in Relapsing Multiple Sclerosis

BACKGROUND: To identify clinical parameters of response to beta-interferon (IFN-beta) in relapsing-remitting multiple sclerosis (RRMS) from an East France cohort. METHODS: Data from 2,645 patients, identified by Burgundy and Lorraine multiple sclerosis (MS) networks, were computerized by a neurologist using the European Database for MS software. Patient inclusion criteria were: clinically or laboratory-supported definite RRMS according to Poser's diagnostic criteria and treatment with IFN-beta for at least 6 months. Four criteria were chosen to predict a response to IFN-beta. The first criterion was any patient who had a lower annualized relapse rate under IFN-beta therapy than during the year preceding treatment; the second criterion was a lower relapse rate than during the 2 years preceding treatment. The third was any patient free of relapse during the first 2 years of IFN-beta therapy. The last criterion concerned the variation in the degree of disability measured by the Disability Status Scale during the first year of treatment. Multivariate logistic regression analyses were performed. RESULTS: 751 RRMS cases were included. A higher relapse rate in the year preceding IFN-beta onset, an older age at MS onset and having a polysymptomatic onset of MS were significantly associated with a response for the first criterion. With the 3 other criteria, no parameter predicting response was identified. CONCLUSION: Only the relapse rate in the year before initiation of IFN-beta treatment appears to be able to predict response to treatment but not the one of 2 years before.