WAKE‐UP.

Study characteristics
Methods	Randomised, double‐blinded, placebo‐controlled trial
Participants	503 participants, of whom 449 had wake‐up stroke. The study authors contributed unpublished data on participants with wake‐up stroke. Clinical inclusion criteria Clinical diagnosis of acute ischaemic stroke with unknown symptom onset (e.g. stroke symptoms recognised upon awakening) Last known well (without neurological symptoms) > 4.5 hours of treatment initiation Measurable disabling neurological deficit (defined as an impairment of 1 or more of the following: language, motor function, cognition, gaze, vision, neglect) Age 18 to 80 years Treatment can be started within 4.5 hours of symptom recognition (e.g. awakening) Written informed consent by patient or proxy Imaging inclusion criteria Acute stroke MRI including DWI and FLAIR completed MRI showing a pattern of "diffusion weighted imaging (DWI) and fluid attenuated inversion recovery (FLAIR) ‐mismatch", i.e. acute ischaemic lesion visibly on DWI ("positive DWI") but no marked parenchymal hyperintensity visible on FLAIR ("negative FLAIR") indicative of an acute ischaemic lesion ≤ 4.5 hours of age Clinical exclusion criteria Planned or anticipated treatment with endovascular reperfusion strategies (e.g. intra‐arterial thrombolysis, mechanical recanalisation techniques) Pre‐stroke disability (inability to carry out all daily activities, requiring some help or supervision, i.e. slight disability corresponding to an mRS score > 1) Participation in any investigational study in the previous 30 days Severe stroke by clinical assessment (e.g. NIHSS > 25) Hypersensitivity to alteplase or any of the excipients Pregnancy or lactating (formal testing needed in women of childbearing potential; childbearing potential is assumed in women up to 55 years of age) Significant bleeding disorder at present or within past 6 months Known haemorrhagic diathesis Manifest or recent severe or dangerous bleeding Known history of or suspected intracranial haemorrhage Suspected subarachnoid haemorrhage (even if CT is negative) or condition after subarachnoid haemorrhage from aneurysm History of central nervous system damage (e.g. neoplasm, aneurysm, intracranial or spinal surgery) Recent (within 10 days) traumatic external heart massage, obstetrical delivery, recent puncture of a non‐compressible blood vessel Current use of anticoagulants (e.g. phenprocoumon, warfarin, new anticoagulants such as dabigatran) or current use of heparin and elevated thromboplastin time (low‐dose subcutaneous heparin is allowed) Platelet count < 100,000/mm3 Blood glucose < 50 or > 400 mg/dL (< 2.8 or 22.2 mmol/L) Severe uncontrolled hypertension, i.e. systolic blood pressure > 185 mmHg or diastolic blood pressure > 110 mmHg or requiring aggressive medication to maintain blood pressure within these limits (routine medical treatment is allowed to lower the blood pressure below these limits) Manifest or recent bacterial endocarditis, pericarditis Manifest or recent acute pancreatitis Documented ulcerative gastrointestinal disease during the last 3 months, oesophageal varices, arterial aneurysm, arterial/venous malformations Neoplasm with increased bleeding risk Manifest severe liver disease including hepatic failure, cirrhosis, portal hypertension, and active hepatitis Major surgery or significant trauma in the past 3 months Stroke within 30 days Life expectancy 6 months or less by judgement of the investigator Any condition associated with a significantly increased risk of severe bleeding not mentioned above Any contraindication to MRI (e.g. cardiac pacemaker) Imaging exclusion criteria Poor MRI quality precluding interpretation according to the study protocol Any sign of intracranial haemorrhage on baseline MRI FLAIR showing a marked parenchymal hyperintensity in a region corresponding to the acute DWI lesion indicative of an acute ischaemic lesion with a high likelihood of being > 4.5 hours old Large DWI lesion volume > 1/3 of the MCA or > 50% of the anterior cerebral artery or posterior cerebral artery territory (visual inspection) or > 100 mL Any MRI findings indicative of a high risk of symptomatic intracranial haemorrhage related to potential IV alteplase treatment in the judgement of the investigator
Interventions	IV t‐PA (alteplase) 0.9 mg/kg body weight up to a maximum of 90 mg, 10% as bolus, 90% over 1 hour as infusion Matching placebo
Outcomes	Favourable outcome (mRS 0 to 1) at 90 days follow‐up Mortality at 90 days follow‐up Death or dependency (mRS 4 to 6) at 90 days follow‐up
Notes	ClinicalTrials.gov identifier: NCT01525290 Funding Source: supported by a grant (278276) from the European Union Seventh Framework Program. Trial was terminated after 503 participants of the estimated and planned 800 target sample size for financial reasons.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated
Allocation concealment (selection bias)	Low risk	Web‐based randomisation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, placebo controlled
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	13 participants lost to follow‐up
Selective reporting (reporting bias)	Low risk	Intention‐to‐treat analysis was provided.
Other bias	Unclear risk	Trial was terminated after 503 participants of the estimated and planned 800 target sample size for financial reasons.

aPTT: activated partial thromboplastin time
ASPECTS: Alberta Stroke Program Early Computed Tomography Score
CT: computed tomography
CTA: computed tomography angiography
DWI: diffusion‐weighted imaging
FLAIR: fluid attenuated inversion recovery
ICA: internal carotid artery
INR: international normalised ratio
IV: intravenous
MCA: middle cerebral artery
MRA: magnetic resonance angiogram
MRI: magnetic resonance imaging
mRS: modified Rankin Scale
NIHSS: National Institutes of Health Stroke Scale
PWI: perfusion‐weighted imaging
rt‐PA: recombinant tissue plasminogen activator
t‐PA: tissue plasminogen activator