In the ASCLEPIOS I/II trials, ofatumumab significantly lowered serum neurofilament light (sNfL) levels, a marker of disease activity and treatment response, in the first assessment at month 3 and at all subsequent visits versus teriflunomide.
To investigate the prognostic value of baseline sNfL for on-study disease activity and worsening in patients with relapsing MS, particularly in newly diagnosed, treatment-naïve patients.
Patients (pooled N=1882) were randomized to ofatumumab or teriflunomide, receiving treatment for up to 30 months. Patients were stratified by median baseline sNfL levels. We assessed annual on-study T2 lesion formation and brain volume loss (BVL, Jacobian integration) by sNfL category in all patients and in the subgroup of newly diagnosed within 3 year of screening without prior disease-modifying treatment (representing natural course of sNfL and disease at baseline) at month 24 or end of study. The annualized rate of new or enlarging T2 (neT2) lesions in year-2 versus year-1 was assessed in all patients by sNfL category (negative binomial model with time [in year] as offset).
Patients with high sNfL (>median) levels at baseline developed more neT2 lesions per year on study than patients with low (≤median) sNfL levels (adjusted mean rate: ofatumumab: 0.95 vs 0.39, relative increase 143%, p<0.001; teriflunomide 5.28 vs 3.02, relative increase 74.5%, p<0.001). The prognostic value of baseline sNfL persists for year-2 (high vs low, ofatumumab: 0.09 vs 0.06, 64.5%, p=0.124; teriflunomide 4.53 vs 3.12, 45.6%, p=0.003. A single sNfL assessment at baseline had no prognostic value for on-study relapses and disability worsening. Patients with high baseline sNfL had higher annualized rate of BVL than patients with low sNfL (ofatumumab: 0.32% vs 0.23%, relative difference 37.3%, p=0.045; teriflunomide: 0.43% vs 0.29%, relative difference 49.4%, p<0.001). The results were consistent in the subgroup of newly diagnosed, treatment-naïve patients. The relative treatment effect of ofatumumab versus teriflunomide was similar across all measures in both the high and low sNfL groups.
Baseline sNfL levels were prognostic for on-study lesion formation and BVL for at least 2 years, in all patients and in the subgroup of newly diagnosed, treatment-naïve patients. sNfL levels can supplement clinical assessments and help identify patients at high risk for future disease activity.