HealthDay News — After 15 years of follow-up, patients with relapsing-remitting multiple sclerosis (RRMS) who display disease activity despite treatment with interferon (IFN)β-1a tend to have unfavorable long-term outcomes, study results indicate.
Among patients treated with IFNβ-1a, persistent disease activity was associated with an 8.96-fold higher risk of gadolinium-enhancing lesions (P<0.001), a 4.44-fold higher risk of relapse (P= 0.010), and a 2.90-fold higher risk of new T2 lesions (P= 0.080), Robert A. Bermel, MD, of the Cleveland Clinic, and colleagues reported in Annals of Neurology.
“Particular attention should be paid to gadolinium-enhancing lesions on IFNβ therapy, as their presence strongly correlates with severe disability 15 years later,” they wrote.
The researchers conducted a multicenter, observational, 15-year follow-up study involving 136 patients with RRMS, who had initially been treated with either intramuscular IFNβ-1a or placebo, to identify early predictors of long-term outcomes.
The proportion of patients experiencing early disease activity was lower in patients on intramuscular IFNβ-1a than placebo for all disease activity markers (range, 23.5%–29.0% vs. 41.0–45.5%), the researchers found.
Conversely, early disease activity in placebo-treated patients was not associated with long-term outcomes (OR range=1.53–2.62; P=0.069–0.408).
“The results provide rationale for monitoring IFNβ treated patients with magnetic resonance imaging, and for changing therapy in patients with active disease,” the researchers wrote.