Objective: To evaluate the efficacy and safety of adjunctive lacosamide treatment in Chinese and Japanese adults with uncontrolled focal (partial-onset) seizures (POS), with or without secondary generalization. Methods: A 24-week, randomized, double-blind, placebo-controlled study (EP0008; NCT01710657) was conducted in patients (aged 16-70 years) with uncontrolled POS and taking 1-3 concomitant antiepileptic drugs from 72 sites across China and Japan. Following an 8-week Baseline period, randomized patients received lacosamide 200 mg/day (100 mg twice daily), 400 mg/day (200 mg twice daily), or placebo for 4-week Titration and 12-week Maintenance periods. The primary efficacy variable was the change in POS frequency per 28 days from Baseline to Maintenance. Results: Overall, 692 patients were screened; 548 were randomized to placebo (n = 184), lacosamide 200 mg/day (n = 183), or lacosamide 400 mg/day (n = 181); 485 (88.5%) completed the study. The median change (range) in POS frequency per 28 days from Baseline to Maintenance was -3.33 (-754.3 to 165.2), -4.50 (-97.5 to 28.2), and -1.22 (-93.0 to 39.8) in the lacosamide 200 mg/day, 400 mg/day, and placebo groups, respectively. Significant percentage reductions in POS frequency over placebo per 28 days from Baseline to Maintenance were observed for lacosamide 200 mg/day (29.4% [ 95% CI 18.7-38.7%], p < 0.001) and 400 mg/day (39.6% [30.5-47.6%], p < 0.001). Higher >= 50% and >= 75% responder and seizure freedom rates were observed in lacosamide-treated patients vs placebo. Treatment-emergent adverse events reported by >= 10% of all lacosamide-treated patients occurring at >= 2% difference compared with placebo were dizziness (25.9% vs 9.2%) and somnolence (10.2% vs 3.8%). Dose-proportional pharmacokinetics were consistent with earlier global pivotal trials. Conclusions: Adjunctive lacosamide (200 and 400 mg/day) was efficacious in reducing POS frequency in Chinese and Japanese patients with a safety and tolerability profile consistent with the three global pivotal studies. (C) 2016 Published by Elsevier B. V.