Real-World Evaluation of Serum Sodium Levels in Patients With Focal Seizures Treated With Eslicarbazepine Acetate
Guy Mitchell1, David Cantu2, Darshan Mehta2, Todd Grinnell2, David Smith1
1Sumitovant Biopharma, Inc., 2Sunovion Pharmaceuticals Inc.
Objective:
Here we report serum sodium values in patients treated with adjunctive eslicarbazepine acetate (ESL) that were collected in an electronic health record database to assess the effect of ESL on sodium levels in a U.S. real world clinical setting.
Background:
ESL is approved for focal seizure treatment in patients ≥4 years in the US. ESL is a member of the dibenzazepine carboxamide class, a class associated with the development of hyponatremia. In a pooled analysis of 3 clinical trials, incidence of clinically meaningful post-dose sodium levels (≤125 mEq/L) was 1.0% (ESL 800mg), 1.5% (ESL 1200mg) vs 0% (placebo). 
Design/Methods:

The electronic health record database was queried to identify patients with 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, and sodium values available within 3 months prior to ESL initiation (baseline). Serum sodium levels obtained during baseline were compared to levels during ESL treatment (6 months, 1 year). These levels were summarized 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.

Results:

Most patients started ESL at 400 or 800 mg/day. The mean serum sodium level for epilepsy patients during baseline was 138.9±8.6 mEq/L and remained stable through 12 months of ESL treatment (138.8±6.2 mEq/L), similar to focal epilepsy patients (baseline, 139.2±9.6 mEq/L; 12 months, 137.5±6.6 mEq/L). These results remained when assessing the max event. 4 focal epilepsy patients demonstrated serum sodium level ≤125 mEq/L at ≥1 timepoints during 12 months of ESL treatment. All observations were made in the context of routine delivery of care.

Conclusions:

Mean serum sodium values in patients treated with ESL did not change from baseline in a real-world clinical setting over 12 months.

10.1212/WNL.0000000000202318