Abstracts

This is a Late Breaking abstract

Rationale: Eslicarbazepine acetate (ESL) is an antiseizure medication (ASM) approved for the treatment of partial-onset (focal) seizures in patients aged ≥ 4 years in the U.S. ESL is a member of the dibenzazepine carboxamide class of sodium channel blockers, a class which has been associated with the development of hyponatremia. In a pooled analysis of 3 placebo controlled, double-blind, randomized clinical trials (RCTs) the incidence of clinically meaningful post-dose sodium levels of ≤125 mEq/L was 11/993 (1.1%) in patients treated with adjunctive ESL compared to 0% with placebo. Although this incidence was low, it was important to assess the potential impact of ESL treatment on serum sodium levels in a “real-world” clinical setting over a period of time longer than the typical 12-week RCT. Here we report serum sodium values in epilepsy patients treated with ESL in clinical practice using data collected in an electronic health record database.

Methods: The electronic health record database was queried to identify patients with the following characteristics: a diagnosis of epilepsy (ICD-10 G40*; N=99) or focal epilepsy (ICD-10 G40.0*-G40.2*; n=55), aged ≥ 4 years, currently treated with ESL, with sodium values available within 3 months prior to the ESL initiation (index) date. Serum sodium levels obtained during the 3 months prior to the ESL index were used as baseline and compared to serum sodium levels during ESL treatment at 6 months and at 1 year. Serum sodium levels were analyzed both as the average of all lab values for all patients up to the date of interest and as the single lab value closest to the date of interest (max event) per individual patient. Serum sodium levels were summarized as mean ± SD and range of values.

Results: A total of 99 patients with epilepsy and 55 patients with focal epilepsy who were treated with ESL were identified. Baseline characteristics are shown in the Table. The most common concomitant baseline ASMs were levetiracetam and lacosamide, and the most common comorbidities were bipolar disorder and chronic pulmonary disease. The starting dose of ESL ranged from 200 to 800 mg/day, with most patients starting at 400 or 800 mg/day. In the epilepsy group, mean serum sodium level during baseline was 138.9±8.6 mEq/L and remained stable through 12 months of ESL treatment (138.8±6.2 mEq/L; Figure 1A). Similar results were seen in the patients with focal epilepsy (baseline, 139.2±9.6 mEq/L; 12 months, 137.5±6.6 mEq/L; Figure 1A). These results did not change when assessing the max event (Figure 1B). A total of 4 patients in the focal epilepsy group demonstrated at least one post-dose serum sodium level ≤125 mEq/L at one or more timepoints during 12 months of ESL treatment.

Conclusions: In both epilepsy and focal epilepsy groups, mean serum sodium values in patients treated with ESL aged ≥ 4 years did not change from baseline in a real-world clinical setting over a period of 12 months.

Funding: Sunovion Pharmaceuticals, Inc.