Interferon beta-1b treatment in patients with relapsing-remitting multiplesclerosis under a standardized protocol in Spain

A protocol system is being used in Spain for the prescription of innovative drugs including interferon beta-1b (IFN beta-1b). Petitions for dispensing and reimbursement are based on the inclusion and exclusion criteria of piv otal trials, and are reviewed individually for approval by specialist commi ttees. To estimate the performance of IFN beta-1b in the clinical setting, data collected by the INSALUD and regional health services of Andalusia and Catalonia, together responsible for the healthcare of nearly 30 million in dividuals, were compiled in a common database for analysis. Methods - Data comprise demographic and disease characteristics at the time of petition an d at follow-up 3 months after treatment initiation and every 6 months there after. Efficacy was estimated by mean number of relapses per year, proporti on of relapse-free patients, and disease progression as measured by the Exp anded Disability Status Scale (EDSS). Safety parameters included adverse ev ents and laboratory analyses. Results - Between September 1995 and database cutoff in mid-1998, petitions of 1419 patients were approved for IFN beta- 1b treatment. Patients were homogenous across the three databases and in th e subgroups of patients completing 1 year (n = 940) and 2 years (n = 302) o f treatment. There was a marked decrease in the mean number of relapses in the first 12 months of IFN beta-1b treatment for the 938 patients documente d for 12 months, with a mean of 0.4 (+/-0.7 SD) relapses per patient and ye ar, and a 2-year mean of 0.9 ( +/- 1.20 SD) in the 302 patients documented for 24 months. Of the 938 patients followed for 2 12 months, 505 (53.8%) we re documented as being relapse-free during 12 months of treatment, and 146 (48.3%) of the 302 patients followed for 2 24 months, were relapse-free dur ing 24 months of treatment. There were no differences in mean or median EDS S scores between baseline and months 12 and 24. Skin disorders were the mos t frequent adverse events, reported in over one-third of all patients; ther e were 159 injection site events, most frequently erythema (115 events). Sy stemic AEs pointing towards flu-like symptoms were reported in 288 of 1419 patients (20.3%). Leukopenia was the most frequently reported laboratory ev ent. Elevations in liver transaminases were noted for 12 patients (0.8%) wi th SGOT increase and 7 (0.5%) with SGPT increase. Conclusion - The protocol system has helped make IFN beta treatment available to 8-10% of the estima ted 15,000-18,000 MS patients in the regions studied. In terms of efficacy, IFN beta-1b performed in line with the pivotal study results. The safety p rofile of IFN beta-1b was consistent with the published findings and the dr ug labelling, and no new side effects or increased incidence of known side effects was observed.