No increase of serum neurofilament light in relapsing-remitting multiple sclerosis patients switching from standard to extended-interval dosing of natalizumab

Background: Accumulating evidence supports the efficacy of administering natalizumab (NZ) with extended-interval dosing (EID) in patients with relapsing-remitting multiple sclerosis (RRMS). Objectives: We switched NZ dosing from 4-week to 6-week intervals in patients with RRMS, and investigated the effect on serum neurofilament light chain (sNfL) concentrations. Methods: We included two cohorts of patients with RRMS treated with NZ: one received the standard-interval dosing (4 weeks) at baseline, and were switched to 6-week intervals (EID4-6, N = 45). The other cohort received EID (5- or 6-week intervals) both at baseline and during follow-up (EID5/6, N = 25). Serum samples were collected in the EID4-6 cohort at every NZ infusion, for 12 months. The primary outcome was the change in sNfL concentrations after switching to EID. Results: The baseline mean sNfL concentration in the EID4-6 cohort was 10.5 ng/L (standard deviation (SD) = 6.1), and it remained unchanged at 12 months. Moreover, individual sNfL concentrations did not change significantly after extending the NZ dosing intervals. In addition, the EID4-6 and EID5/6 cohorts had similar baseline sNfL concentrations. Conclusion: We concluded that extending the NZ dosing interval did not increase axonal damage, as determined with sNfL, in patients with RRMS.

Automated summary

This study investigated the effect of extending the dosing interval of natalizumab (NZ) from 4 to 6 weeks on serum neurofilament light chain (sNfL) concentrations in patients with relapsing-remitting multiple sclerosis (RRMS). The results showed that extending the NZ dosing interval did not increase axonal damage in patients with RRMS, as determined with sNfL.