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C013 supportive study and reduced frequency of seizures

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The efficacy of adjunctive ONTOZRY® (cenobamate) in clinical trials

The efficacy of adjunctive ONTOZRY® for the treatment of uncontrolled focal onset epilepsy was evaluated in two multicentre, randomised, double-blind, placebo-controlled efficacy and safety studies and in one open-label safety study.1–3

ONTOZRY® (cenobamate) Phase 2 clinical trial: C013 study design

C013 was a Phase II, multicentre, randomised, double-blind, placebo-controlled parallel group efficacy and safety study.2

The patient inclusion criteria included:2

  • Aged 18-65 years.
  • Focal epilepsy, drug resistant as defined by the ILAE*
  • Taking 1-3 concomitant ASMs at stable doses for at least 12 weeks before randomisation
  • NOT having taken phenytoin or phenobarbital because of the potential for drug-drug interaction with ONTOZRY®

The baseline demographic and epilepsy-related characteristics were generally similar in each treatment group:2

Table displaying C013 baseline demographics and epilepsy-related characteristics grouped according to the two treatment groups: SoC + Placebo and SoC + ONTOZRY® 200 mg.

Participants (n=222) were randomised 1:1 to receive either placebo or 200 mg/day ONTOZRY® which was titrated up over 6 weeks.2

Timeline diagram of the C013 study illustrating the titration schedule of ONTOZRY® over a 12-week double-blind period. The schedule is displayed according to the two treatment groups: SoC + Placebo and SoC + ONTOZRY® 200 mg. The study includes an 8-week baseline, 6-week titration, and 6-week maintenance period, followed by an OLE.

Patients who continued to meet study eligibility, with the exception of seizure frequency requirement, could enrol in an OLE.6

*Defined as the failure of two tolerated, appropriately chosen and used anti-epileptic drug schedules (whether as monotherapies or in combination) to achieve sustained seizure freedom.7

**The OLE target dose was initially 200 mg/day but was increased to 400 mg/day ~2 years after OLE initiation.6

Abbreviations

ASM, anti-seizure medication; EMA, european medicines agency; FDA, food and drug administration; ILAE, international league against epilepsy; OLE, open-label extension; SoC, standard of care.

  1. Krauss GL, Klein P, Brandt C, et al. Safety and efficacy of adjunctive cenobamate (YKP3089) in patients with uncontrolled focal seizures: a multicentre, double-blind, randomised, placebo-controlled, dose-response trial. The Lancet Neurology. 2020;19(1):38-48. doi:https://doi.org/10.1016/s1474-4422(19)30399-0
  2. Chung SS, French JA, Kowalski J, et al. Randomized phase 2 study of adjunctive cenobamate in patients with uncontrolled focal seizures. Neurology. 2020;94(22):e2311-e2322. doi:https://doi.org/10.1212/wnl.0000000000009530
  3. Sperling MR, Klein P, Aboumatar S, et al. Cenobamate (YKP3089) as adjunctive treatment for uncontrolled focal seizures in a large, phase 3, multicenter, open‐label safety study. Epilepsia. 2020;61(6):1099-1108. doi:https://doi.org/10.1111/epi.16525
  4. Klein P, Aboumatar S, Brandt C, et al. Long-term Efficacy and Safety From an Open-Label Extension of Adjunctive Cenobamate in Patients With Uncontrolled Focal Seizures. Neurology. 2022;99(10):e989-e998. doi:https://doi.org/10.1212/WNL.0000000000200792
  5. Sander JW, Rosenfeld WE, Halford JJ, Steinhoff BJ, Biton V, Toledo M. Long‐term individual retention with cenobamate in adults with focal seizures: Pooled data from the clinical development program. Epilepsia. 2021;63(1):139-149. doi:https://doi.org/10.1111/epi.17134
  6. Rosenfeld WE, Abou‐Khalil B, Aboumatar S, et al. Post hoc analysis of a phase 3, multicenter, open‐label study of cenobamate for treatment of uncontrolled focal seizures: Effects of dose adjustments of concomitant antiseizure medications. Epilepsia. 2021;62(12):3016-3028. doi:https://doi.org/10.1111/epi.17092
  7. Sperling MR, Abou‐Khalil B, Aboumatar S, et al. Efficacy of cenobamate for uncontrolled focal seizures: Post hoc analysis of a Phase 3, multicenter, open‐label study. Epilepsia. 2021;62(12):3005-3015. doi:https://doi.org/10.1111/epi.17091

MAT-UKI-0451-P | June 2026