OBJECTIVE

To evaluate the efficacy and safety of samPEG-IFN-β1a 180 μg and 240 μg administered once every 2 weeks for the treatment of relapsing remitting multiple sclerosis (RRMS) compared to placebo and low dose interferon beta-1a (LIB) 30 μg administered once weekly. The primary endpoint after 52 weeks of therapy was the time to first relapse, the hypotheses of non-inferiority and superiority to LIB were tested.

MATERIAL AND METHODS

This international, multicenter, double blind, comparative, placebo-controlled clinical study enrolled 399 patients with the diagnosis of RRMS, randomized in 4 groups: samPEG-IFN-β1a180 μg (n=114), samPEG-IFN-β1a 240 μg (n=114), LIB (n=114) and placebo (n=57). Placebo group patients participated in the study for 20 weeks. After 52 weeks of therapy and 4 weeks of follow-up, LIB group patients completed their participation in the study, patients from PEG-IFN-β1a groups continued to receive therapy until week 100 inclusive. The article presents the results of an analysis conducted after the end of 52 weeks of a double-blind, comparative, randomized, placebo-controlled clinical trial.

RESULTS

Final analysis of the efficacy and safety was performed after 52 weeks of study. Main statistical hypothesis testing proved that both doses of samPEG-IFN-β1a were equally effective when compared to LIB by the primary endpoint — «Time to first relapse». Due to detection of statistically significant differences in the primary endpoint between the study drug and the reference drug, indicating a greater efficacy of the study drug, an additional testing was carried out and the hypothesis of superiority of samPEG-IFN-β1a at a dose of 240 μg over the reference LIB was proved. Evaluation of the dynamics of certain key parameters of magnetic resonance imaging (MRI) of the brain and clinical outcomes demonstrated a positive effect of samPEG-IFN-β1a therapy in the form of decreased activity of the demyelinating process in the brain and reduce the number of relapses. The proportion of patients without new T2 lesions after 52 weeks was 87.6% and 90.4% in 180 μg and 240 μg samPEG-IFN-β1a groups, versus 72.6% in the LIB group (p=0.0199 and p=0.0033). No progression of multiple sclerosis was shown based on EDSS scale evaluation. During the study, the most common adverse reactions were flu-like symptoms and injection site reactions.

CONCLUSION

The new drug samPEG-IFN-β1a is an effective and safe agent for relapsing remitting multiple sclerosis treatment, while having an advantage over other low-dose interferons in the form of reduced frequency of intramuscular injections.