BOSTON - Treatment with interferon beta-1a or glatiramer acetate, if used long term, has the potential to be cost effective and to alter the natural history of relapsing-remitting multiple sclerosis, according to findings from a 6-year observational study.
In 4,137 patients with relapsing-remitting MS who were followed for a median of 6 years, the observed increase in the Expanded Disability Status Scale (EDSS) scores was lower than the increase seen in a natural history cohort that served as a comparator group (relative rates, 0.76 using a continuous Markov model and 0.61 using a multilevel model). The observed progression for utility – a quality of life measure derived from the EDSS scores, and the primary outcome of the study – was consistent with this finding (relative rates of 0.58 and 0.56 according to the two models, respectively), Dr. Jacqueline Palace reported at the joint meeting of the European and Americas Committees for Treatment and Research in Multiple Sclerosis.
The outcome – essentially a reduction of about 42% on the primary outcome measure, compared with the natural history cohort – was better than the 38% reduction that was predicted, said Dr. Palace, leader of the multiple sclerosis and neuromyelitis group at Oxford University Hospitals Trust in England.
A range of sensitivity analyses that examined the potential for various biases consistently demonstrated better outcomes in the treated patients, compared with the natural history cohort, Dr. Palace noted.
If sustained over 20 years, the magnitude of the treatment effect observed in this study would be consistent with a predefined cost-effectiveness target of about $58,400 per quality-adjusted life-year, she said.
Patients included in this study were adults with a mean age of 38 years and a mean age at disease onset of 31 years. Most (76%) were women. Disease duration was a mean of 7.7 years at baseline, and the patients had a mean of three relapses over the prior 2 years. Baseline EDSS score was 3.06.