Comparison of the efficacy and safety of lacosamide and oxcarbazepine monotherapy in young children aged 1month to 4years with focal epilepsy: An ambispective cohort study based on real-world clinical practice in China

Background: In the context of off-label use, this study aimed to compare the efficacy and safety of lacosamide (LCM) and oxcarbazepine (OXC) monotherapy in children aged 1 month to 4 years with focal epilepsy. Methods: This non-randomized, open-label, real-world study included 134 LCM-treated and 132 OXC-treated children. The primary endpoint was the 12-month efficacy rate (≥50% reduction in seizures). Mantel–Haenszel analysis and E-values controlled and assessed confounding; ANCOVA compared Gesell developmental quotients between groups. Results: LCM efficacy rates at 3, 6, 9, and 12 months were 76.9%, 76.9%, 72.4%, and 64.9%, respectively; OXC rates were 84.1%, 87.9%, 88.6%, and 73.5%, with no significant between-group differences. At 12 months, the adjusted ORs ranged from 0.603 to 0.645, with E-values of 1.55 to 1.60. LCM improved all five Gesell domains from baseline (P < 0.05). The language domain favored LCM after baseline adjustment (difference = 2.59, P = 0.043), but this was attenuated after further adjustment. Epilepsy duration and baseline seizure frequency predicted poorer LCM response. The 12-month retention rates were 75.4% and 84.1%, and adverse event rates were 7.46% and 4.55% in the LCM and OXC groups, respectively; most events were mild. Conclusion: In real-world clinical practice in China, LCM monotherapy demonstrated efficacy and safety comparable to those of OXC in young children with focal epilepsy, suggesting that LCM may represent an alternative option for off-label use in this age group. Its potential benefit for language development warrants further investigation.