Abstracts

Rationale:
Patients undergoing surgical treatment for epilepsy may continue to experience focal seizures. Cenobamate is an antiseizure medication (ASM) approved in the United States (XCOPRI®) and Europe (ONTOZRY®) for the treatment of focal seizures in adults. This retrospective observational analysis used data from a national claims database to compare inpatient (IP) and emergency (ER) admissions for patients adding cenobamate or seven other newer ASMs to existing therapy regimens following surgical or neurostimulation therapy for seizure disorders.

Methods:
Patients with an epilepsy diagnosis (ICD-10-CM G40*) taking at least 1 ASM between 1/1/2017 through 12/31/2021 were identified from the HealthVerity Marketplace Private Source 20 database. Patients were required to have 12 months of medical and pharmacy enrollment before the first line of therapy, which was defined as the dispensing of an ASM after ≥30 days without exposure. Mixed-effect Poisson regressions (with log link functions) examined the association between ASM-specific therapy lines and proxy measures of seizure control (IP and ER admissions) in patients with prior evidence of epilepsy surgical resection or implantation of a vagus nerve stimulator (VNS) or a responsive neurostimulation (RNS) device. We compared therapy lines adding cenobamate with those adding brivaracetam, clobazam, eslicarbazepine, lacosamide, lamotrigine, levetiracetam, or perampanel.

Results:
A total of 7835 patients (52.4% female, mean [SD] age = 39.3 [14.9] years) were exposed to 11,771 lines of therapy. Intractable epilepsy was diagnosed in 73.0% (n=5718) of patients; 46.7% (n=3656) had history of status epilepticus. Therapy lines per ASM ranged from 605 for eslicarbazepine (590 patients) to 3400 for lacosamide (3336 patients). Therapy lines included 7.8% (n=915) first-line, 17.9% (n=2103) second-line, and 74.4% (n=8753) later-line. Over 14,874.6 person-years ( >5.4 million days of therapy), patients experienced 202.7 IP days and 47.3 ER admissions per 100 person-years; 23.5% (n=2327) of patients experienced at least one IP or ER admission within 90 days before therapy start. Compared with cenobamate, all other 7 ASMs demonstrated higher ER admission rates. Six ASMs demonstrated higher IP day rates than cenobamate (all P≤ 0.001); eslicarbazepine demonstrated lower IP day rates (P< 0.001). Relative to cenobamate, adjusted mean increases in ER admissions per patient year ranged from 3.4 (brivaracetam) to 9.2 (levetiracetam) per 100 patient-years. Adjusted mean increases in IP days ranged from 0.004 (lamotrigine) to 10.3 (lacosamide) per 100 patient-years, with an adjusted mean decrease of 0.3 IP days per 100 patient-years for eslicarbazepine (Figure 1).

Conclusions:
In a retrospective claims-based analysis of patients who have undergone epilepsy surgery or invasive therapies, cenobamate was associated with lower ER rates than seven leading ASMs, and with lower IP days than all comparators except eslicarbazepine, suggesting that improved seizure control with cenobamate may provide significant cost savings and reductions in seizure-related morbidity and mortality.

Funding:
Funded by SK Life Science, Inc.