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

OBJECTIVE

A protocol system is being used in Spain for the prescription of innovative drugs including interferon beta-1b (IFNbeta-1b). Petitions for dispensing and reimbursement are based on the inclusion and exclusion criteria of pivotal trials, and are reviewed individually for approval by specialist committees. To estimate the performance of IFNbeta-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 individuals, were compiled in a common database for analysis.

METHODS

Data comprise demographic and disease characteristics at the time of petition and at follow-up 3 months after treatment initiation and every 6 months thereafter. Efficacy was estimated by mean number of relapses per year, proportion of relapse-free patients, and disease progression as measured by the Expanded Disability Status Scale (EDSS). Safety parameters included adverse events and laboratory analyses.

RESULTS

Between September 1995 and database cutoff in mid-1998, petitions of 1419 patients were approved for IFNbeta-1b treatment. Patients were homogenous across the three databases and in the subgroups of patients completing 1 year (n = 940) and 2 years (n = 302) of treatment. There was a marked decrease in the mean number of relapses in the first 12 months of IFNbeta-1b treatment for the 938 patients documented for 12 months, with a mean of 0.4 (+/- 0.7 SD) relapses per patient and year, 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 > or = 12 months, 505 (53.8%) were documented as being relapse-free during 12 months of treatment, and 146 (48.3%) of the 302 patients followed for > or = 24 months, were relapse-free during 24 months of treatment. There were no differences in mean or median EDSS scores between baseline and months 12 and 24. Skin disorders were the most frequent adverse events, reported in over one-third of all patients; there were 159 injection site events, most frequently erythema (115 events). Systemic AEs pointing towards flu-like symptoms were reported in 288 of 1419 patients (20.3%). Leukopenia was the most frequently reported laboratory event. Elevations in liver transaminases were noted for 12 patients (0.8%) with SGOT increase and 7 (0.5%) with SGPT increase.

CONCLUSION

The protocol system has helped make IFN treatment available to 8-10% of the estimated 15,000-18,000 MS patients in the regions studied. In terms of efficacy, IFNbeta-1b performed in line with the pivotal study results. The safety profile of IFNbeta-1b was consistent with the published findings and the drug labelling, and no new side effects or increased incidence of known side effects was observed.