To investigate the effects of edaravone on serial serum neurofilament light chain (sNfl) and slow vital capacity (SVC) in patients with amyotrophic lateral sclerosis (ALS).

Edaravone, a free-radical scavenger, has been shown to modestly slow ALS progression. sNfl, a non-specific biomarker of axonal injury, has prognostic and response value in ALS, while SVC reflects the respiratory decline.  However, edaravone’s effects on these objectives remain unclear.

We conducted a single-center retrospective review of 190 edaravone-treated patients with ALS. Thirty-four patients (mean age 62.7 years, 62% male, and 65% limb-onset) had baseline sNfl and SVC measured before and after at least 3 months of therapy. Primary outcomes were changes in sNfl and SVC; the secondary outcome was the change in ALSFRS-R. Patients were stratified into early (≤3 years) and delayed (>3 years) edaravone groups. Statistical analysis included paired and independent t-tests, Pearson correlation, and multivariate logistic regression adjusting for treatment latency, age, gender, and bulbar/limb onset.

No statistically significant change was observed in sNfl (Δ=-0.41pg/mL; p=0.27) or SVC (Δ=-3.21%; p=0.36). Timing of edaravone initiation did not influence the magnitude of sNfl [Δ=-0.44 (early) and -0.38 (delayed); p=0.93] or SVC [Δ=-2.6 (early) and -3.8 (late); p=0.84]. Both groups showed small, non-significant decreases, consistent with disease progression. All correlations, including changes in sNfl with changes in SVC and time from symptom onset with changes in sNfl and SVC, were near zero and non-significant, indicating that changes in sNfl and SVC were independent of each other and of treatment timing. After adjusting for clinical covariates, no variable was independently associated with improvement in either sNfl or SVC. ALSFRS-R scores significantly declined (p<0.05) despite treatment.

Within this real-world ALS cohort treated with edaravone, there was no significant reduction in sNfl or stabilization of SVC, highlighting the need for larger prospective studies to detect subtle treatment effects.