Natalizumab in Early Relapsing-Remitting Multiple Sclerosis: A 4-Year, Open-Label Study

INTRODUCTION: STRIVE was a 4-year, multicenter, observational, open-label, single-arm study of natalizumab treatment in anti-JC virus antibody-negative (JCV-negative) relapsing-remitting multiple sclerosis (RRMS) patients with disease duration ≤ 3 years. The objective of STRIVE was to examine no evidence of disease activity (NEDA) status and predictors of NEDA in natalizumab-treated patients with early RRMS. METHODS: Proportions of patients with NEDA were evaluated along with baseline predictors of NEDA, annualized relapse rate, 24-week confirmed disability worsening (CDW), magnetic resonance imaging assessments (T2 and gadolinium-enhancing lesions), and serious adverse events. RESULTS: In years 1 and 2, 56.1% (95% confidence interval [CI] 48.7–63.4%) and 73.6% (95% CI 66.2–80.2%) of patients (intent-to-treat population [N = 222]), respectively, achieved NEDA. In years 3 and 4, 84.6% (95% CI 78.0–89.9%) and 91.9% (95% CI 86.4–95.8%) of patients, respectively, achieved Clinical NEDA (no relapses or 24-week CDW). Baseline predictors of NEDA in year 4 were Expanded Disability Status Scale score ≤ 2.0 (odds ratio [OR] = 3.85 [95% CI 1.54–9.63]; p = 0.004) and T2 lesion volume > 4 cc (OR = 0.39 [95% CI 0.15–0.98]; p = 0.046), with the latter also predicting Clinical NEDA in year 4 (OR = 0.21 [95% CI 0.05–0.92]; p = 0.038). The cumulative probability of CDW at year 4 was 19.3%. Serious adverse events were reported in 11.3% of patients. CONCLUSION: These results support the long-term safety and effectiveness of natalizumab. Baseline predictors of NEDA help to inform benefit-risk assessments of natalizumab treatment in JCV-negative patients with early RRMS. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01485003. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12325-021-01722-w.