Methods | Randomised double-blind PCB controlled parallel multicentre (43 in USA and Canada) trial. 3 treatment arms: 1 PCB, 2 PGB. Patients randomised in blocks of 6, each allocated unique ID number. All patients received TDS regimen of blinded capsules (no further information available). Duration of baseline period: 8 weeks. 1-week titration period and 11-week treatment period | |
Participants | Adults aged 17 to 82 years (mean 39.1 years), 50.2% male, all with treatment-resistant partial epilepsy confirmed by history and recent EEG. Patients were on 1 to 4 baseline AEDs. 378 patients screened, 313 patients randomised: 98 patients to PCB (mean baseline 28-day seizure frequency: 25.1), 104 patients to 300 mg PGB BD (mean baseline 28-day seizure frequency: 21.5), and 111 patients to 200 mg PGB TDS (mean baseline 28-day seizure frequency: 21.3) | |
Interventions | Group 1: PCB Group 2: 300 mg PGB BD (1-week titration phase) Group 3: 200 mg PGB TDS (1-week titration phase) |
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Outcomes | Primary outcome: reduction in seizure frequency compared to baseline (response ratio) Secondary outcomes: responder rate, median percentage change in seizure frequency |
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Notes | One patient randomised to the 300 mg BD group failed to take tablets, and therefore was excluded from ITT analysis. Blinding was broken with 1 patient in the PCB arm when she became pregnant | |
Risk of bias | ||
Bias | Authors’ judgement | Support for judgement |
Random sequence generation (selection bias) | Low risk | Patients randomised in blocks of 6 and al located unique ID number |
Allocation concealment (selection bias) | Unclear risk | No details provided |
Blinding (performance bias and detection bias) All outcomes | Low risk | All patients received identical capsules |
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 |