An Adverse Event (AE) is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product which does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product.

The Safety Population was defined as all randomized subjects who received at least 1 dose of study medication.

Partial (Type I) seizures can be classified into one of the following three groups:

• Simple partial seizures
• Complex partial seizures
• Partial seizures evolving to generalized tonic-clonic convulsions.

Partial Onset Seizure (POS) frequency per week over the Treatment Period (TP) was calculated as:

(Total Type I seizures over the TP)*7/(Total number of days with no missing seizure count in the TP)

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

The responder rate was presented as the percentage of responders and non-responders. A subject is a responder, if the subject has at least 50 % reduction in Partial Onset Seizure frequency per week from Baseline to Treatment Period. Subjects with zero seizure frequency per week at Baseline were considered as non-responders.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

There are three different types of seizures:

• Type I: Partial seizures
• Type II: Generalized seizures
• Type III: Unclassified epileptic seizures. All seizure frequency per week over Treatment Period (TP) was calculated as: (Total number of seizures over the TP)*7/(Total number of days with no missing seizure count in the TP)

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Percent change from Baseline was calculated as percent reduction by:

(weekly seizure frequency Baseline - weekly seizure frequency Treatment)*100/(weekly seizure frequency Baseline).

A negative value in percent Change from Baseline indicates an improvement from Baseline.

The higher the negative values for percent change in Partial Onset Seizure (POS) frequency, the higher the improvement from Baseline.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Subjects were classified in 1 of the following categories based on their percent reduction from Baseline to Treatment Period in Partial Onset Seizure (POS) frequency per week: <-25 %, -25 % to <25 %, 25 % to <50 %, 50 % to <75 %, 75 % to <100 %, and 100 %.

Subjects having zero for Baseline seizure frequency per week were classified in the <-25 % category.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Subjects were considered seizure free if their seizure counts for every day over the Treatment Period (TP) was zero and if they did not discontinue before the end of the TP. Seizure freedom rate was calculated as:

(total number of seizure - free subjects in treatment group during TP)/(total number of evaluable Intent-To-Treat (ITT) subjects in treatment group)

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

The type IC/Type I seizure frequency ratio is represented by the percentage of subjects having a reduction in the ratio of Type IC seizure frequency over Type IA, IB, and IC seizure frequency from Baseline to Treatment Period.

The Intention-to-treat (ITT) population was defined as all randomized subjects who received at least 1 dose of study medication.

Type IC Population consists of those subjects with at least one Type IC seizure during the Baseline period.

Time to first Type I seizure during the 16-week Treatment Period was measured in days.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Time to fifth Type I seizure during the 16-week Treatment Period was measured in days.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Time to tenth Type I seizure during the 16-week Treatment Period was measured in days.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Hospital Anxiety and Depression Scale (HADS) was used to evaluate Anxiety and Depression. The HADS was developed as a self-administered scale to assess the presence and severity of Anxiety and Depression. It consists of 14 items that are scored on a 4-point severity scale ranging from 0 to 3. A score per dimension was calculated with each score ranging from 0 to 21 (higher scores indicating greater problems). A negative value in change from Baseline indicates an improvement from Baseline.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the HADS. Only subjects having values at baseline ans at the considered visit are included.

The Hospital Anxiety and Depression Scale (HADS) was used to evaluate Anxiety and Depression.The HADS was developed as a self-administered scale to assess the presence and severity of Anxiety and Depression. It consists of 14 items that are scored on a 4-point severity scale ranging from 0 to 3. A score per dimension was calculated with each score ranging from 0 to 21 (higher scores indicating greater problems). A negative value in change from Baseline indicates an improvement from Baseline.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the HADS. Only subjects having values at baseline ans at the considered visit are included.

The Patient's Global Evaluation Scale (P-GES) is a global assessment of the disease evolution which was performed using a seven-point scale (1= Marked worsening to 7= Marked improvement) with the start of the study medication as the reference time point. The subject completed it by answering to the following: 'Overall, has there been a change in your seizures since the start of the study medication?'

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Evaluable subjects are subjects who completed the GES at last treatment period visit.

The Investigator's Global Evaluation Scale (I-GES) is a global assessment of the disease evolution which was performed using a seven-point scale (1= Marked worsening to 7= Marked improvement) with the start of the study medication as the reference time point. The Investigator completed it by answering to the following: 'Assess the overall change in the severity of patient's illness, compared to start of study medication.'

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Evaluable subjects are subjects for whom the GES was completed by the investigator at last treatment period visit.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.

The Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) is an adaptation of the original QOLIE-31 instrument that includes 30 items grouped into 7 multi-item subscales: Seizure Worry (5 items), Overall Quality of Life (2 items), Emotional Well-being (5 items), Energy/Fatigue (4 items), Cognitive Functioning (6 items), Medication Effects (3 items) and Daily Activities/Social Functioning (5 items), and a Health Status item. In addition to the 31 items of the QOLIE-31, the QOLIE-31-P contains 7 items asking the subjects to rate the degree of 'distress' related to the topic of each subscale (ie, distress items). The QOLIE-31-P also contains an item asking about the relative importance of each subscale topic (ie, prioritization item). The subscale scores, the total score and the Health Status item score were calculated according to the scoring algorithm defined by the author with scores ranging from 0 to 100 and higher scores indicating better function.

Localization-related epilepsy Intent-To-Treat (ITT) Population (POS). The ITT Population was defined as all randomized subjects who received at least 1 dose of study medication.

Only subjects who are not mentally impaired were to complete the QOLIE-31-P. Only subjects having values at baseline and at the considered visit are included.