Pharmacokinetics, exposure-cognition, and exposure-efficacy relationships of perampanel in adolescents with in adequately controlled partial-onset seizures

Objective: To characterize, in adolescents aged 12-17, the pharmacokinetic (PK) profile of perampanel, the impact of intrinsic and extrinsic factors on PK, and the relationships between perampanel exposure and cognitive function, seizure frequency, and responder status. Methods: Population PK analysis used plasma concentration data from Phase II study 235 (NCT01161524), in which adolescents with inadequately controlled POS despite treatment with 1-3 antiepileptic drugs (AEDs) were randomized to receive once daily oral placebo or perampanel (8-12 mg/day) for 19 weeks, pooled with data from adolescent patients in perampanel Phase III studies 304, 305, 306. Exposure-cognition and exposure-efficacy relationships were modelled using data from study 235. Results: Population PK results from 152 adolescent patients revealed a perampanel apparent clearance of 0.729 L/h, consistent with previous analyses in adolescents and adults. Clearance was increased with coadministration of inducing AEDs (carbamazepine, oxcarbazepine and phenytoin), and was slightly higher in females. The PK/pharmacodynamics (PD) analysis for cognition (n = 110) showed that increasing perampanel exposure had no significant effect on overall cognition, measured by the Cognitive Drug Research global cognition score. The PK/PD analysis for efficacy (n = 123) showed a significant decrease in seizure frequency and significant increased probability of being a responder, as perampanel concentration increased both in the presence and absence of inducing AEDs. Carbamazepine, oxcarbazepine and phenytoin reduced perampanel exposure in adolescents, but reduced the magnitude of seizure frequency reduction and responder probability to a lesser extent. Significance: Pharmacokinetics of perampanel are similar in adolescents to adults. Increasing perampanel exposure reduces seizure frequency and increases probability of being a responder regardless of concomitant inducers. The lack of relationship between perampanel exposure and cognitive function suggests a benign cognitive profile for this AED in adolescents. We await results from long-term exposure. (C) 2016 Elsevier B.V. All rights reserved.