A Prospective Longitudinal Study of the Effects of Eslicarbazepine Acetate Treatment on Bone Density and Metabolism in Patients with Focal-Onset Epilepsy.

Background and objectives: Eslicarbazepine acetate (ESL) is a third-generation anti-seizure medication for patients with focal-onset epilepsy. There are known short-term impacts of classic enzyme-inducing drugs on bone health. For oxcarbazepine, which like ESL is a less potent inducer of cytochrome P450 (CYP450) than carbamazepine, some studies have shown that treatment is associated with increased bone metabolic parameters. The effects of ESL on bone health have not been systematically evaluated so the objective of this study was to investigate whether adverse effects of ESL on bone mineral density (BMD) could be measured after a 12-month exposure period. In addition, the effects of ESL on bone turnover were investigated using laboratory indicators of bone metabolism.

Methods: BONAPARTE was a prospective, longitudinal, observational study that enrolled patients with focal-onset epilepsy with or without secondary generalization who started treatment with ESL, either as adjunctive treatment or monotherapy, at two tertiary epilepsy centres in Germany between February 2018 and July 2020. Standardised osteodensitometry and biochemical bone metabolism parameters at the time of ESL initiation and 1 year after continuation of therapy were assessed. Comparisons between biochemical and densitometric parameters at baseline and after 12 months of treatment were performed using the paired samples t test.

Results: In total, 26 patients (15 male; mean age 41.4 ± 12.5 years) newly treated with ESL were evaluated. Six of these patients had osteopenia at baseline. The mean daily dose of ESL at the 12-month follow-up was 1438 ± 1406 mg. At the group level, there were no significant effects of treatment with ESL on laboratory markers or on BMD. Mean values of BMD in g/cm² at baseline and after 12 months of ESL treatment were 1.17 (± 0.16) and 1.16 (± 0.16) in the lumbar spine, and 0.98 (± 0.15) and 0.96 (± 0.15) in the proximal femur, respectively. Intra-individually, two patients developed de novo osteopenia measured at the femoral neck associated with relevant changes in bone metabolic parameters.

Conclusion: Neither osteodensitometry nor bone metabolism parameters showed significant group effects after 1 year of treatment with ESL. Individual fluctuations were observed, however, which may warrant monitoring for longer follow-up periods. The study was registered in the German register for clinical studies under the number DRKS00010430 with the official name BONAPARTE.