Interferon beta in secondary progressive multiple sclerosis : daily clinical practice.

BACKGROUND AND OBJECTIVE: Observational studies may provide additional information about the behaviour of different drugs in the post-marketing period. We present the data from a cohort of secondary progressive multiple sclerosis (SPMS) patients treated with interferon beta (IFNbeta-1b) at our MS clinic. METHODS: This was an independent, open-label, non-randomised, observational study. Within the period 1998 to 2005, all patients with SPMS who started therapy with IFNbeta-1b at our centre were studied. Each patient was included in a follow-up protocol collecting demographic and baseline clinical data. RESULTS: We studied 146 SPMS patients with a median follow-up of 60 months. Over the total study period, 62.2% of patients had confirmed progression. The analysis of the time to con- firmed progression showed that patients with two or more relapses in the 2 years before IFNbeta initiation, had a higher risk of disability increase than those patients with less than two relapses (p = 0.002). Multiple regression analysis showed disease activity in terms of relapses as the only factor to predict increase of disability during the follow-up period. A significant proportion of patients (36%) stopped treatment during the follow-up period. IFNbeta was safe, although some unexpected adverse events were observed. CONCLUSIONS: A higher disease activity before the beginning of treatment with IFNbeta in SPMS patients with a given EDSS rank could identify those with faster disability progression after treatment initiation.