Responders: number of subjects with a 50 percent (%) or greater reduction in partial seizure frequency from Baseline to Final visit. Seizure frequency in treatment period = total number of partial seizures in maintenance treatment phase * 28 divided by total number of days in the maintenance treatment phase. Missing category includes subjects with missing attack date, insufficient length of treatment period or no seizures in both baseline and treatment periods. Subjects with zero seizures in the baseline period and some seizures in the treatment period were treated as non-responders.

Full Analysis Set: all subjects who received at least 1 dose of study drug and had at least 1 efficacy measurement.

Antiepileptic drug history: number of subjects who took each class of antiepileptic drug prior to entering the study. Subjects who took more than one antiepileptic drug were counted for each of the drug classes.

Safety analysis set: all subjects who received at least 1 dose of study medication.

Change in 28-day partial seizure frequency between the baseline period and treatment period. Baseline period = the 4 weeks (28 days) prior to Baseline visit. Treatment period = last 12 weeks (84 days) of the study (maintenance treatment phase excluding 4-week titration phase). Seizure frequency in baseline period = total number of partial seizures in baseline phase * 28 divided by total number of days in the baseline phase. Seizure frequency in treatment period = total number of partial seizures in maintenance treatment phase * 28 divided by total number of days in maintenance treatment phase.

FAS. Subjects who discontinued less than 4 weeks into the treatment period or with missing date of the attack were excluded from analyses.

Seizure Freedom (responders): subjects with no seizures (partial or other) during the last 4 weeks of the study. Non-responders: subjects with seizures (partial or other)during the last 4 weeks of the study. Subjects, who discontinued less than 4 weeks into the observation period were excluded from analysis. The 4 week period excludes the titration phase of the study. Missing category includes subjects with missing attack date or insufficient length of treatment period.

FAS

Concomitant drugs treatments (drugs other than, and in addition to study medication): number of subjects who took each concomitant drug during the study (baseline through end of study). World Health Organization (WHO) Drug (v02Q2) coding dictionary applied.

Safety analysis set.

Average doses of pregabalin in milligrams per day (mg/day) taken at baseline and final visit shown by number of participants at each dose.

Safety analysis set.

Visual Analog Scale of anxiety self assessment: metric measurement (in 2 mm interval) from the visual analog scale; 0 mm = no anxiety, 100 mm = extreme anxiety at each visit.

FAS; Last observation carried forward (LOCF) method: subject's last available post-baseline observation was used if data were missing. In this case, data from Visit 2 were carried forward if final visit data were missing.

Visual Analog Scale of anxiety self assessment: metric measurement (in 2 mm interval) from the visual analog scale; 0 mm = no anxiety, 100 mm = extreme anxiety. Change from Baseline to Final Visit: score at final visit minus score at baseline.

FAS; Last observation carried forward (LOCF) method: subject's last available post-baseline observation was used if data were missing. In this case, data from Visit 2 were carried forward if final visit data were missing.

CGI-S scale: physician's global impression of a subject's clinical condition, at baseline in terms of severity. Numerical scale ranging from 1 (normal, not at all ill) to 7 (among the most extremely ill subjects). Numbers of subjects in each category are presented.

FAS

CGI-C scale: physician's global impression of a subject's clinical condition in terms of change from baseline. Improvement = CGI response of very much improved, much improved, or minimally improved. No Change = CGI response of no change. Worsening = CGI response of very much worse, much worse or minimally worse.

FAS

MOS-S: subject reported measure with 12 items that assess key constructs of sleep over the past week. Scoring based on 7 subscales: sleep disturbance, snoring, awakened short of breath or with headache, sleep adequacy, and somnolence (range:0-100); sleep quantity (range:0-24), and optimal sleep (yes:1, no:0). Six(6) and 9 item index measures of sleep disturbance were constructed to provide composite scores. Scores are transformed (actual raw score minus lowest possible score divided by possible raw score range * 100); total score range: 0 to 100; higher score = greater intensity of attribute.

FAS. A subscale was classified as missing if any of the questions used in the calculation were missing. Abbreviations: BL = Baseline, SOB = short of breath.

MOS: subject rated questionnaire to assess sleep quality and quantity. Optimal sleep subscale is derived from Sleep Quantity average hours of sleep each night during the past week. Number of subjects with response: YES (Optimal) if sleep quantity was 7 or 8 hours per night, or response = NO (Non-Optimal) if sleep quantity was less than (<) 7 hours per night. Number of participants with shift in response categories from Baseline to Final Visit.

FAS. Abbreviations: BL = Baseline; FV = Final Visit.