Randomized study of once-weekly interferon beta-1la therapy in relapsing multiple sclerosis: three-year data from the...

Area of Science:

• Neurology
• Immunology
• Pharmacology

Background:

• The Once Weekly Interferon beta-1a for Multiple Sclerosis (OWIMS) study initially showed modest MRI benefits but no relapse reduction with once-weekly interferon (IFN) beta-1a.
• An extension study aimed to assess the long-term efficacy and safety of this dosing regimen in relapsing-remitting multiple sclerosis (RRMS).

Purpose of the Study:

• To evaluate the longer-term efficacy and safety of once-weekly interferon beta-1a in RRMS patients.
• To assess magnetic resonance imaging (MRI) lesion activity and relapse rates over an extended treatment period.

Main Methods:

• Patients initially on placebo were rerandomized to receive either 22 or 44 mcg of IFN beta-1a once weekly for two additional 48-week periods.
• The primary outcome was MRI lesion activity, with relapse rates and other MRI measures as secondary outcomes.

Main Results:

• After three years, no significant differences in median T2 lesion counts were observed between the 44 mcg, 22 mcg, and placebo groups.
• Annualized relapse rates were similar across all groups, with the lowest rate in the 44 mcg group (0.77) but not statistically significant.
• While neutralizing antibodies did not impact relapse rates, MRI active lesions increased in antibody-positive patients on 44 mcg compared to antibody-negative patients.

Conclusions:

• Once weekly interferon beta-1a, particularly at 44 mcg, demonstrated a significant MRI effect but not a significant relapse effect compared to placebo in RRMS.
• No significant dose-dependent effect was observed.
• The study concluded that once-weekly dosing of interferon beta-1a does not provide meaningful clinical benefit in RRMS, unlike three-times-weekly subcutaneous administration.