Methods	Randomised double-blind PCB and active drug controlled parallel multicentre (97 in Europe, Canada and Australia) trial. 3 treatment arms: 1 PCB, 1 PGB and 1 LTG. Patients randomised to 1 of 3 treatment arms (no further information available). Duration of baseline period: 6 weeks. 12-week treatment period with 5-week titration phase before treatment (1 week of titration for PGB and 5 weeks of titration for LTG)
Participants	Adults aged 16 to 82 years (mean 39.4 years), 48.5% male, all with treatment-resistant partial epilepsy confirmed by history and recent EEG. Patients were on 1 to 3 baseline AEDs. 546 patients screened, 434 patients randomised: 141 patients to PCB (mean baseline 28-day seizure frequency: 16.38), 152 patients to 150 mg to 300 mg PGB BD (mean baseline 28-day seizure frequency: 21.32), and 141 patients to 150 mg to 300 mg LTG BD (mean baseline 28-day seizure frequency: 21.80)
Interventions	Group 1: PCB Group 2: PGB 150 mg to 300 mg BD (1-week titration phase) Group 3: LTG 150 mg to 300 mg BD (5-week titration phase)
Outcomes	Primary outcome: change in seizure frequency compared to baseline (response ratio) Secondary outcomes: responder rate, seizure freedom, adverse events
Notes	One patient randomised to the PCB group failed to take > 1 dose of medication, and therefore was excluded from ITT analysis. No information provided on methods of randomisation, concealment or blinding
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details of method of randomisation
Allocation concealment (selection bias)	Unclear risk	No details of concealment of allocation
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Same number of capsules administered per study day per group. No further details provided
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition rates reported. ITT analysis employed
Selective reporting (reporting bias)	Unclear risk	All outcomes stated in methods section of paper were reported in the results; however, there was no protocol available to check a priori outcomes
Other bias	High risk	Sponsored by same pharmaceutical company (Pfizer Ltd.) as with all the other included trials