OPAL‐1 2010.

Methods	Randomised, partially blind, active controlled trial
Participants	448 people recruited in the Asian‐Pacific region with documented non‐valvular AF
Interventions	Darexaban (30 mg, 60 mg, 120 mg or 240 mg once daily; n = 354) versus dose‐adjusted warfarin (target INR 2.0 to 3.0 in participants less than 70 years and 1.6 to 2.6 in participants 70 years or older) during a predefined period of 12 weeks (n = 94)
Outcomes	Primary safety outcome: composite of major or clinically relevant non‐major bleeding Secondary safety outcome: adverse events, liver function tests (ALT and AST) and renal function (serum creatinine) Primary efficacy outcome: composite of stroke, TIA, systemic embolic events and all‐cause death
Notes	Study sponsored by Astellas
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomly assigned to treatment groups
Allocation concealment (selection bias)	Low risk	Participants were randomly assigned to treatment groups
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label administration of both darexaban and warfarin. Different doses of darexaban administered in double‐blind fashion
Blinding of outcome assessment (detection bias) All outcomes	High risk	Adjudication of outcomes not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcomes reported in ITT population. Number of participants that discontinued during study and reasons for discontinuation stated
Selective reporting (reporting bias)	Low risk	All predefined outcomes reported for ITT population
Other bias	Unclear risk	Randomisation into 240 mg darexaban arm terminated early after recommendation from DSMB due to increased bleeding