Abstracts

Rationale: In subjects with partial-onset seizures eslicarbazepine acetate (ESL) can be used as an add-on anti-epileptic drug to carbamazepine (CBZ), which is a drug that has been associated with high susceptibility to pharmacokinetic interactions. To gain a thorough understanding of the effect of ESL on the CBZ pharmacokinetics (PK), CBZ plasma concentrations were analyzed in subjects taking ESL or placebo as adjunct therapy to CBZ in a pooled analysis of three Phase III clinical studies. Methods: Trough (i.e. pre-dose) blood samples for the assay of CBZ were taken in subjects with ongoing CBZ treatment at the time of randomization (i.e. before starting concomitant treatment with once-daily ESL 400 mg, 800 mg, 1200 mg or placebo) and after 12 weeks of concomitant treatment. Mean ratios and 95% confidence intervals (CIs) of CBZ trough values at the end versus start of ESL/Placebo treatment were calculated in order to get information regarding the possible influence of ESL on the PK of CBZ. Results: Among 1049 subjects enrolled in the three Phase III studies, 611 (58%) subjects were receiving CBZ as a concomitant antiepileptic drug. CBZ plasma concentrations were available for 414 (68%) subjects treated with CBZ. The mean ratios and 95% CIs are presented in Table I, including information on the number of subjects receiving a given combination. The results did not indicate a major influence of ESL on the PK of CBZ. Conclusions: In this pooled analysis of 3 Phase III studies, no major influence of ESL on the PK of CBZ was observed. The metabolite CBZ-epoxide was not measured. Supported by BIAL- Portela & Co, SA