The study was terminated on September 12, 2010 per protocol following a serious adverse event that occurred with the first subject dosed at 600 mg.

Subjects with epilepsy with a documented photoparoxysmal response to intermittent photic stimulation (IPS) will participate. Four subjects will be enrolled at each dose level and will receive a single dose of placebo and a single dose of ICA-105665 during the study, each followed by intermittent photic stimulation. The effects of ICA-105665 on the photoparoxysmal electroencephalography (EEG) response of each group will be reviewed before the dose is selected for each subsequent group of subjects.

Inclusion Criteria:

• A diagnosis and history of epilepsy for which they are on 0-2 concurrent antiepileptic drugs.
• On a stable dose of their current AED(s) for 4 weeks prior to the Screening Visit.
• Must be in good health (with the exception of epilepsy), as determined by the Primary Investigator via the medical history, a physical examination, and screening laboratory investigations.
• A body mass index (BMI) between 18 and 35.
• Able and willing to give written informed consent prior to participation in the study.
• A reproducible IPS-induced photo-paroxysmal EEG response (PPR) of at least 3 points on a frequency assessment scale in at least one eye condition and no change of more than 3 frequencies in 2 repeated measurements recorded at the Screening Visit.

Exclusion Criteria:

• History of non-epileptic seizures (metabolic, structural, or pseudoseizures).
• History of status epilepticus while on any antiepileptic medication.
• The etiology of the seizures is due to any of the following; progressive degenerative disease, metabolic illness, active infection, demyelination, drugs, alcohol.
• The subject has used benzodiazepines (oral, intra-muscular, or suppository) as escape medication within the past 6 months.
• The subject has taken an investigational medication within 30 days prior to the Day 1.
• Women who are pregnant or lactating.
• An active Central Nervous System (CNS) infection, demyelinating disease, degenerative neurological disease or any CNS disease deemed to be progressive during the course of the study that may confound the interpretation of the study results.
• The subject has a clinically significant (e.g., cancerous, unstable, progressive, functionally disabling, or infectious) medical condition that would interfere with the ability to complete the study or that might interfere with the absorption, distribution, metabolism, and/or excretion of drugs.
• Subjects with impaired hepatic function [ALT (Alanine aminotransferase), AST (Aspartate aminotransferase) =3 times the upper limit of normal] or any clinically significant laboratory abnormality that, in the opinion of the investigator, would increase the risk of participation or interfere with the interpretatio of the study results.
• History of alcoholism, drug abuse, or drug addiction within the last 12 months.
• Clinically significant psychiatric illness, psychological or behavioral problem which, in the opinion of the investigator would interfere with the subject's ability to participate in the study OR the subject is receiving therapy with neuroleptic drugs.
• Subject experiences a clinical seizure during any IPS procedure performed during the screening period.