Discontinuation of interferon beta therapy in multiple sclerosis patients with high pre-treatment disease activity leads to prompt return to previous disease activity.

BACKGROUND: A recommendation for the duration of interferon beta (IFNβ) treatment in multiple sclerosis (MS) patients with a good response to this therapy has not been defined. Very limited data exist with regard to the effect of IFNβ discontinuation on the subsequent course of MS.
OBJECTIVE: To assess clinical activity in MS relapsing-remitting (MS RR) patients with high pre-treatment activity who discontinued IFNβ treatment after approximately 2 years of treatment.
METHODS: We determined the relapse rate and disability progression in 43 patients who discontinued IFNβ after ~25 months of treatment.
RESULTS: Within ~34 months post-treatment 28 patients (65%) experienced at least one severe relapse, and 8 MS patients experienced a relapse within 30 days post IFNβ discontinuation. Disability progression measured by EDSS in the post-treatment period was 1.45±0.8 points per patient.
CONCLUSION: These results indicate that IFNβ did not induce a prolonged remission in MS patients and that disease activity returned to the previous rate within a short time after treatment cessation. Discontinuation of IFNβ treatment in high activity pre-treatment MS patients with good response to this therapy is not recommended.