Comparative Long-Term Effectiveness of a Monotherapy with Five Antiepileptic Drugs for Focal Epilepsy in Adult Patients: A Prospective Cohort Study

OBJECTIVE To evaluate and compare long-term effectiveness of five antiepileptic drugs (AEDs) for monotherapy of adult patients with focal epilepsy in routine clinical practice. METHODS Adult patients with focal epilepsy, who were prescribed with carbamazepine (CBZ), valproate (VPA), lamotrigine (LTG), topiramate (TPM), or oxcarbazepine (OXC) as monotherapy, during the period from January 2004 to June 2012 registered in Wenzhou Epilepsy Follow Up Registry Database (WEFURD), were included in the study. Prospective long-term follow-up was conducted until June 2013. The endpoints were time to treatment failure, time to seizure remission, and time to first seizure. RESULTS This study included 654 patients: CBZ (n=125), VPA (n=151), LTG (n=135), TPM (n=76), and OXC (n=167). The retention rates of CBZ, VPA, LTG, TPM, and OXC at the third year were 36.1%, 32.4%, 57.6%, 37.9%, and 41.8%, respectively. For time to treatment failure, LTG was significantly better than CBZ and VPA (LTG vs. CBZ, hazard ratio, [HR] 0.80 [95% confidence interval: 0.67-0.96], LTG vs. VPA, 0.53 [0.37-0.74]); TPM was worse than LTG (TPM vs. LTG, 1.77 [1.15-2.74]), and OXC was better than VPA (0.86 [0.78-0.96]). After initial target doses, the seizure remission rates of CBZ, VPA, LTG, TPM, and OXC were 63.0%, 77.0%, 83.6%, 67.9%, and 75.3%, respectively. LTG was significantly better than CBZ (1.44 [1.15-1.82]) and OXC (LTG vs. OXC, 0.76 [0.63-0.93]); OXC was less effective than LTG in preventing the first seizure (1.20 [1.02-1.40]). CONCLUSION LTG was the best, OXC was better than VPA only, while VPA was the worst. The others were equivalent for comparisons between five AEDs regarding the long-term treatment outcomes of monotherapy for adult patients with focal epilepsy in a clinical practice. For selecting AEDs for these patients among the first-line drugs, LTG is an appropriate first choice; others are reservation in the first-line but VPA is not.