An AE is any untoward medical occurrence in a clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability, is a congenital anomaly/ birth defect, other situations and is associated with liver injury or impaired liver function is SAE. TEAE refers to an AE for which the onset was on or after the date of the first RTG dose in this study and on or before 30 days after the last RTG dose date. AEs that started in the parent study that worsened in this study were also considered as TEAEs. Safety population comprised of participants who take at least 1 dose of study medication after they have enrolled into this OLE study. Number of participants with TE-SAEs and non-SAEs (with incidence \>= 5%) have been presented.

An AE is any untoward medical occurrence in a clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. TEAE refers to an AE for which the onset was on or after the date of the first RTG dose in this study and on or before 30 days after the last RTG dose date. Percentage of participants with TEAEs leading to study discontinuation were presented.

The vital signs were evaluated as per PCC Criteria. The vital signs included systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). The vital signs were measured in a seated position after 5 minutes of rest. PCC range for DBP was increase or decrease of \>=20, for SBP was increase or decrease of \>=15 and for heart rate was increase or decrease of \>=15. A Baseline assessment in this OLE study was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Number of participants with vital sign values of PCC at any Post-Baseline visit were presented.

Body weight of participants were measured as a measure of safety. PCC range for body weight was increase or decrease of \>=7 percent. A Baseline assessment in this OLE study was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Number of participants with PCC values of body weight at any Post-Baseline visit were presented.

Single measurements of 12-lead ECGs were obtained in a supine position after at least 10 minutes of rest using an ECG machine that automatically calculates the heart rate (HR) as beats per minute (bpm) and measures PR, QRS, Bazett's correction QT interval (QTcB) and Friedericia's correction QT interval (QTcF) in milliseconds (msec). A Baseline assessment in this OLE study was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Number of participants with PCC values of ECG parameters at any Post-Baseline visit were presented. For the 'Any Post Baseline' value, only the worst case finding was counted for each participant.

Blood samples were collected from participants for evaluation of change from Baseline in hematology parameters including basophils, eosinophils, lymphocytes,monocytes, platelet count, total neutrophils, and WBC. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and standard deviation (SD) were calculated.

Blood samples were collected from participants for evaluation of hematocrit. Hematocrit is a ratio of red blood cells to the total volume of blood. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in hemoglobin and MCHC levels. Baseline assessment in this OLE study was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in MCH levels. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in MCV and MPV levels. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in RBC count. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in RDW. RDW is a parameter that measures variation in red blood cell size or red blood cell volume. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples collected from participants to evaluate change from Baseline in clinical chemistry parameters included ALT, Alk. phosph., AST,CK, GGT and LD. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in albumin and total protein. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in BUN/creatinine. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in calcium, CO2 content/Bicarb, chloride, glucose, magnesium, potassium, sodium, and urea/BUN. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Blood samples were collected from participants to evaluate change from Baseline in creatinine, direct bilirubin, total bilirubin, and uric acid. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Urine samples were collected from participants to evaluate change from Baseline in urine albumin/creatinine ratio. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated. NA indicates data was not available as standard deviation could not be calculated for single participant.

Urine samples were collected from participants to analyze presence of abnormal urinalysis parameters including glucose, ketones, RBC, WBC, occult blood and protein. Abnormal urinalysis values have been presented for all parameters. Only those participants with data available at specific time points were analyzed (represented by n= X in the category titles).

Urine samples were collected to analyze specific gravity of urine. Specific gravity, is a measure of urine concentration and is measured using a chemical test. Specific gravity measurements provide a comparison of the amount of substances dissolved in urine as compared to pure water. If there were no solutes present, the specific gravity of urine would be 1.000 the same as pure water. Specific gravity between 1.002 and 1.035 could be considered as normal. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Urine Samples were collected to analyze pH. pH is a measure of hydrogen ion concentration and used to determine the acidity or alkalinity of urine. pH scale ranges from 0 to 14. A neutral pH is 7.0. The higher number indicates the more basic (alkaline) nature of urine and lower the number indicates the more acidic urine. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Urine samples were collected from participants to evaluate change from Baseline in Urine creatinine concentration. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

The effect of RTG on bladder function was assessed using AUA symptom index. It is a 7-item Likert-scored scale with seven questions, each with six potential responses. Responses to each of 7 questions were scored from 0 (no symptom at all) to 5 (almost always symptoms present) which were summmed to get total possible score ranging from 0 to 35 with higher scores indicating worse symptom severity. The total score for all questions was classified as mild (0-7), moderate (8-19) or severe (\>19). Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

The PVR bladder ultrasound was used to assess the effects of RTG on bladder function. Baseline was defined as the last assessment of that endpoint in parent study RTG114855 taken prior to the first active treatment with RTG IR. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles). Mean and SD were calculated.

Number of participants with suicidal ideation or behavior during treatment were assessed using the C-SSRS score scale. It is a brief questionnaire designed to assess severity and change in suicidality by integrating both behavior and ideation using a semi-structured interview to probe participant responses. It consists of an assessment of suicidal ideation (ranging from "desire to be dead" to "active suicidal ideation with specific plan and intent") and an assessment of suicidal behavior (ranging from "preparatory acts or behavior" to "completed suicide").

The number of participants who discontinued from RTG treatment has been presented.

Percentage of participants with abnormal findings after eye examination were evaluated. Abnormalities detected on-treatment in study RTG114873 were presented. Retinal pigmentary abnormalities included abnormalities in the macula, peripheral retina and unspecified location.

Percentage of participants with abnormal findings after eye examination were evaluated. Abnormalities detected on-treatment in study RTG114873 were presented. Pigmentation of non-retinal ocular tissues included pigmentation of the sclera and/or conjunctiva, cornea, iris and lens.

Percentage of participants with abnormal findings after skin examination (including the skin around the eyes and the eyelids, lips, nails, or mucosa) were evaluated.

Percentage of participants with a clinically significant decrease in visual acuity from initial examination were evaluated. Only abnormalities occurring on-treatment in study RTG114873 were presented.

Percentage of participants with decrease in confrontational visual field from initial examination were evaluated. Only abnormalities occurring on-treatment in study RTG114873 were presented.

A responder was defined as a participant experiencing a \>=50 percent reduction in 28 day total POS frequency from Baseline. A responder rate was calculated overall and based on duration of exposure. As this was an OLE study, Baseline was defined by the parent study Baseline period. Percentage of responders were evaluated from study RTG114873 Day 1 through the last dosing day, excluding the Taper Phase.

The 28-day total POS frequency was calculated as the number of total POS reported during the treatment phase, divided by the number of applicable days in the treatment phase, then multiplying this ratio by 28. In this formula, innumerable seizures were counted as 10 seizures and status epilepticus was counted as 1 seizure. As this was an OLE study, Baseline was defined by the parent study Baseline period. The percent change from Baseline was calculated as the 28-day total POS on-treatment frequency (during dosing in this study, not including the taper phase) minus the Baseline 28-day total POS frequency, with this difference being divided by the Baseline 28-day partial seizure rate, and the resulting quantity multiplied by 100. It was calculated as overall and by duration of exposure. Mean and SD were presented.

The ophthalmologist/retina specialist determined the presence or absence of retinal and non-retinal ocular abnormalities. Retinal abnormalities included abnormalities in the macula and/or the peripheral retina. This analysis was performed on the All SFUCP Subjects population which comprised of all participants who enter the SFUCP.

The skin examination included assessment of the skin around the eyes and the eye lids, lips, nails, and mucosa. Participants who enter the SFUCP who had on-treatment finding(s) of abnormal discoloration of skin, lips, nails or mucosa confirmed by a dermatologist, underwent assessments performed by a dermatologist at 6-monthly intervals.

An AE is any untoward medical occurrence in a clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability, is a congenital anomaly/ birth defect or is associated with liver injury or impaired liver function. TEAE refers to an AE for which the onset was on or after the date of the first retigabine dose in this study and on or before 30 days after the last retigabine dose date. AEs that started in the parent study that increased in severity during this study were also considered treatment-emergent. The analysis was performed on Safety Population, which included participants who took at least one dose of study medication after they had enrolled into this OLE study.

An AE is any untoward medical occurrence in a clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability, is a congenital anomaly/ birth defect or is associated with liver injury or impaired liver function. The following AEs were collected in the SFUCP: AEs related to the finding(s) of pigmentation/, discoloration of the eye/skin, AEs related to unexplained vision loss, SAEs, Deaths and Pregnancies. SFUCP collected AEs are those for which onset was 31 days or more after the last dose of retigabine. The analysis was performed on the All SFUCP Subjects population which comprised of all subjects who enter the SFUCP.

An AE is any untoward medical occurrence in a clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolonged existing hospitalization, results in disability, is a congenital anomaly/birth defect or is associated with liver injury or impaired liver function. TEAE refers to an AE for which the onset was on or after the date of the first retigabine dose and on or before 30 days after the last retigabine dose date.

Number of participants with abnormal findings after eye examination were evaluated. Only retinal pigmentary abnormalities detected on-treatment with retigabine were presented. Retinal pigmentary abnormalities included abnormalities in the macula, peripheral retina and unspecified location.

Number of participants with abnormal findings after eye examination were evaluated. Pigmentation of non-retinal ocular tissue (s) detected on-treatment with retigabine were presented. Non-retinal pigmentary abnormalities included abnormalities in the sclera and/ or conjunctiva, cornea, iris and lens.

Number of participants with Dermatologist-Confirmed abnormal discoloration of skin including skin around the eyes and eyelids, lips, nails, or mucosa were evaluated. Only abnormalities occurring on-treatment with retigabine were presented.

Number of participants with a clinically significant decrease in visual acuity from initial examination were evaluated. Only abnormalities occurring on-treatment with retigabine were presented.

Number of participants with a clinically significant decrease in confrontational visual field from initial examination were evaluated. Only abnormalities occurring on-treatment with retigabine were presented.

Vital signs including systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured after at least 5 minutes of rest. Body weight was measured without shoes and wearing light clothing. Baseline assessments in this OLE study were defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was calculated by subtracting the Baseline value from the post-baseline value. Increase or decrease of \>=20 in SBP, increase or decrease of \>=15 in DBP and HR were considered as PCC values. Number of participants with PCC values of vital signs for any visit post-Baseline are presented.

Single measurements of 12-lead ECG were obtained in supine position after at least 10 minutes of rest using an ECG machine to measure HR. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Single measurements of 12-lead ECG were obtained in supine position after at least 10 minutes of rest using an ECG machine to measure parameters including PR interval, QRS duration, uncorrected QT interval, QTcB, QTcF and RR interval. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Number of participants with chemistry parameters of PCC at 'any visit post-Baseline' are presented. Chemistry parameters for which PCC values were identified were alanine aminotransferase (ALT) (if value \>=3 \* upper limit of normal \[ULN\]), alkaline phosphatase (alk.phosphatase) (if value \>=3\*ULN), aspartate aminotransferase (AST) (if value \>=3\*ULN), calcium (if value \<=1.8962 or \>=2.8692), carbon-di-oxide (CO2) (if value \<=18 or \>=36), chloride (if value \<=92 or \>=112), creatine kinase (if value \>=3\*ULN), direct bilirubin (if value \>=1.5\*ULN), glucose (if value \<=2.7755 or \>=11.102), lactate dehydrogenase (LD) (if value \>=3\*ULN), magnesium (if value \<0.36 or \>2.50), potassium (if value \<=3.0 or \>=6.0), sodium (if value \<=127 or \>=153), total bilirubin (if value \>=1.5\*ULN), total protein (if value \<45 or \>100), blood urea nitrogen (BUN) (if value \>=14.28). Only those participants with data available at specific time points were analyzed (represented by n=X in the category titles).

Blood samples were collected from participants to evaluate hematology parameters. Number of participants with clinical hematology parameters of PCC at 'any visit post-Baseline' are presented. Hematology parameters for which PCC values were identified were eosinophils (if value is \>0.8), hematocrit (if value is \<=0.32 for males and \<=0.28 for females), platelet count (if value is \<=100 or \>=550), total neutrophils (if value is \<=1.8), white blood cells (WBC) (if value is \<=2.8 or \>=16). Only those participants with data available at specific time points were analyzed (represented by n=X in the category titles).

Urine samples were collected from participants at specific time points. Number of participants with urinalysis parameters of PCC at 'any visit post-Baseline' are presented. Urinalysis parameters for which PCC values were identified were albumin/creatinine ratio (if value is \>11.3), red blood cells (RBC) (if value is 3-5 or higher), WBC (if value is 5-10 or higher for male and 10-15 or higher for females), specific gravity (if value is \<1.001 or \>1.035) and potential of hydrogen (pH) (if value is \<4.6 or \>8.0). Only those participants with data available at specific time points were analyzed (represented by n=X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical chemistry parameters including alk. phosphatase, ALT, AST, creatine kinase and LD. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical chemistry parameters including direct bilirubin, total bilirubin and creatinine. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical chemistry parameters including BUN/creatinine ratio. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical chemistry parameters including calcium, chloride, CO2, glucose, potassium, magnesium, sodium and BUN. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including absolute basophils, eosinophils, lymphocytes, monocytes, neutrophils, platelet count and WBC count. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including hemoglobin and MCHC. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including hematocrit. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including MCH. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including MCV and MPV. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including RBC count. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Blood samples were collected from participants for evaluation of change from Baseline in clinical hematology parameters including percent basophils, eosinophils, lymphocytes, monocytes, neutrophils and RDW. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Urine samples were collected from participants for evaluation of change from Baseline in urinalysis parameters including albumin creatinine ratio. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Urine samples were collected from participants for evaluation of change from Baseline in urinalysis parameters including albumin levels. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Urine samples were collected from participants for evaluation of change from Baseline in urinalysis parameters including creatinine levels. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

The effect of retigabine on bladder function was assessed using AUA symptom index. It is a 7-item Likert-scored scale ranging from 0 (no symptom at all) to 5 (almost always symptoms present) with a total possible score of 35. AUA SS score is the sum of the responses to these seven questions. The total score for all questions was classified as mild (0 to 7), moderate (8 to 19), or severe (\>19). Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

The PVR bladder ultrasound was used to assess urinary retention. Baseline was defined by and taken directly from the Baseline assessments in the parent study NCT01336621. Change from Baseline was defined as post-Baseline value minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n= X in the category titles).

Number of participants with suicidal ideation or behavior during treatment were assessed using the C-SSRS score scale. It is a brief questionnaire designed to assess severity and change in suicidality by integrating both behavior and ideation using a semi-structured interview to probe participant responses. Participants are classified with respect to extent of suicidal ideation, extent of suicidal behavior, and with respect to self-injurious behavior.

Number of participants experiencing new seizure type that is seizure not experienced before were summarized. New seizure types were classified into 5 classes including type A (simple partial seizure), type B (complex partial seizure), type C (Partials, evolving to Secondary Generalized Seizures), type D (Generalized, excluding Myoclonic Seizures), type D2 (Myoclonic Seizures) and type E (Unclassified Seizures).

Worsening of seizures was defined as an increase in seizure frequency or the occurrence of a new, more severe seizure type, or status epilepticus occurring in a participant without a history of status epilepticus. An increase in seizure frequency was defined as doubling of the 28-day seizure frequency compared to the 28-day Baseline seizure frequency established in the parent study. Number of participants experiencing worsening of seizure during study period are presented.

Duration of exposure was calculated from the first dose through the last dose during study including the Taper Phase and presented using median and full range.

The ophthalmologist/retina specialist determined the presence or absence of retinal and non-retinal ocular abnormalities. Retinal abnormalities included abnormalities in the macula and/or the peripheral retina and non-retinal ocular pigmentary abnormality.

Participants who enter the SFUCP who had an on-treatment finding(s) of abnormal discoloration of skin, lips, nails or mucosa confirmed by a dermatologist entered the SFUCP and underwent assessments performed by a dermatologist at 6-monthly intervals. The assessment of the participant's skin included assessment of the skin around the eyes and the eyelids, lips, nails, and mucosa.

Retinal pigmentary abnormality was determined by either an ophthalmologist or retina specialist. Retinal pigmentary abnormality included abnormality of macula, peripheral retina and unspecified location. If a participant had pigmentary abnormality of macula and pigmentary abnormality of the peripheral retina both should be resolved in order for retinal pigmentary abnormality to be considered resolved. If a participant had non-retinal ocular pigmentary abnormality in more than one location (conjunctiva, sclera, cornea, iris or lens), all should be resolved for non-retinal pigmentary abnormality to be considered resolved.

Assessments were at approximately 6-monthly intervals (timed relative to the participants previous dermatology assessment) until the abnormal discoloration either resolved or stabilized (as defined by no changes over 2 consecutive 6-monthly assessments performed by the dermatologist over at least 12 months after discontinuation of retigabine). The assessment of the participant's skin included assessment of the skin around the eyes and the eyelids, lips, nails, and mucosa. Only participants with resolution of the specified tissue are included in this analysis.

The number of participants experiencing a \>=50% reduction from Baseline (BL) in POS frequency during the Treatment Phase (TP) (i.e., Titration Phase and Flexible Dose Evaluation \[FDE\] Phase) was measured. A POS has its onset in a limited area on one side of the brain. POSs may remain limited or may spread to involve both sides of the brain. For both the Baseline Phase and the TP, seizure frequency was calculated as a 28-day rate using the following formula: 28 x {\[(number of countable partial seizures in Phase) + (10 x number of days with innumerable seizures in Phase) + (number of occurrences of status epilepticus in Phase)\] / number of applicable days in the Phase}, where all days in the Phase are considered applicable (including days with 0 seizures), except for days on which the participant failed to complete the Seizure Diary. \>= 50% reduction from BL is calculated as 100 x (28-day partial seizure rate \[PSR\] for the TP - 28-day PSR for the BL Phase) / 28-day PSR for the BL Phase.