Background: Not all patients with multiple sclerosis (MS) experience a satisfactory treatment response and may require treatment adjustment. Indicators for assessing treatment effectiveness need to be sought and validated.
Objective: To prospectively validate MRI activity and neutralizing anti-interferon antibody (NAb) status during the first 6 months of interferon-beta (IFN-β) treatment as response indicators in MS.
Methods: Patients with relapsing-remitting MS were prospectively followed during the first 2 years of treatment. Neurological assessments were performed every 3 months or when a relapse was suspected. MRI scans performed at baseline and Months 3, 4, 5, and 6 after start of treatment were centrally assessed for disease activity: new T2 or gadolinium-enhancing T1 lesions. NAb were assessed using the MxA protein assay; positivity was defined as two consecutive titers ≥20 NU/mL. We evaluated the sensitivity and specificity of an active scan, NAb positivity, or both during the first 6 months of treatment to predict clinical disease activity (relapses or confirmed disability progression) in the following 18 months.
Results: 147 patients were assessed at 16 centers. Predictivity parameters (with confidence intervals) were: active scan, sensitivity 52% (34% to 69%), specificity 80% (65% to 91%), p = 0.002; NAb positivity, sensitivity 71% (45% to 88%), specificity 66% (55% to 76%), p = 0.01; active scan and NAb positivity, sensitivity 71% (38% to 91%), specificity 86% (73% to 94%), p = 0.0003.
Conclusions: MRI activity and NAb occurrence during the first 6 months of IFN-β treatment are reliable predictors of long-term clinical response, particularly when combined.
- MRI activity
- interferon beta
- multiple sclerosis
- treatment response indicators
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