Study to Evaluate the Safety and Effectiveness of USL261 in Patients With Seizure Clusters

Inclusion Criteria:

• Has a competent, adult caregiver who can recognize and observe the subject's seizure cluster episodes

• Has an established diagnosis of partial or generalized epilepsy that includes the following:

  • A documented history of seizure clusters lasting > 10 minutes and < 6 hours, with a pattern that is observable, stereotyped, and recognizably different from the subject's other non-cluster seizure activity, if any;
  • A seizure cluster pattern composed of multiple (≥ 2) partial or generalized seizures;
  • A seizure cluster pattern established > 3 months before Visit 1;
  • A frequency of ≥ 4 seizure clusters during the year before Visit 1;
  • At least 1 seizure cluster occurring ≤ 3 months before Visit 1;
  • Seizure cluster pattern is confirmed by a central reviewer
• Currently on a stable dosing regimen of AEDs since Visit 1 and for ≥ 7 days before Visit 2, with or without intermittent use of benzodiazepines at a constant dose

Exclusion Criteria:

• Has a neurological disorder that is likely to progress in the next year
• Has had psychogenic, non-epileptic seizure(s) within the 5 years before Visit 1
• Has a history of their stereotypical seizure cluster progressing to status epilepticus within the 2 years before Visit 1 or has a history of seizure clusters progressing to status epilepticus despite therapeutic intervention
• Have a history of acute narrow-angle glaucoma.
• Has had an active suicidal plan/intent or active suicidal thoughts in the 6 months before Visit 1 or any lifetime suicide attempt
• Taking felbamate for less than 18 consecutive months before Visit 1 or has discontinued felbamate within 30 days before Visit 1
• Currently taking or has taken vigabatrin within 1 year before Visit 1
• Taken vigabatrin in the past and has either no documentation of visual field exam or documentation on an abnormal visual field exam
• Currently using a VNS unless the device has been implanted for at least 6 months and the setting stable for 4 weeks before Visit 1