Stroke is a leading causes of death and disability. At least 20% of strokes occur during sleep, so- called 'wake up stroke'. Thrombolysis with the clot-busting drug alteplase is effective for acute ischaemic stroke, provided that it is given within 4.5 hours of symptom onset. Patients with wake-up stroke are currently ineligible for clot-busting therapy. Previous studies indicate that many wake-up strokes occur just before awakening.

In this study, patients with wake-up stroke will be randomized to thrombolysis with tenecteplase and best standard treatment or to best standard treatment without thrombolysis. Tenecteplase has several potential advantages over alteplase, including very rapid action and that it can be given as a single injection. Prior to thrombolysis, a brain scan must be done to exclude bleeding or significant brain damage as a result from the stroke. We will use a CT scan to inform this decision. CT is used as a routine examination in all stroke patients. Other studies testing clot-busting treatment in wake-up stroke are using alteplase and more complex brain scans, which are not routinely available in the emergency situation in all hospitals.

Background:

One in five strokes occur during sleep, but patients with "wake-up" stroke are not given thrombolytic therapy because time of stroke onset is unknown. On-going trials are testing alteplase, and use MRI techniques for selection of patients. Tenecteplase has many pharmacological advantages over alteplase: greater fibrin specificity, very rapid action, longer half-life, and single bolus administration. In addition, patient selection based on MRI findings risks excluding many patients that might otherwise benefit. TWIST will test tenecteplase and will not use MRI techniques for selection of patients. Plain CT and CT angiography (if possible) will be performed before randomisation, and CT perfusion will be performed at selected centres, as part of a sub-study.

Study design: TWIST is an international, multi-centre, randomised, open-label, blinded-endpoint trial of tenecteplase for acute ischaemic 'wake-up' stroke.

Study questions:

1. Can tenecteplase given <4.5 hours of awakening improve functional outcome at 3 months?
2. Can findings on cerebral plain CT and CT angiography (and CT perfusion, at selected centres) identify patients who benefit from such treatment, compared to other patients?

Patients eligible for treatment who are able to receive tenecteplase within 4.5 hours of waking, will be randomly allocated to treatment with tenecteplase in addition to best standard treatment, versus best standard treatment.

Randomisation and treatment: Central randomisation (over the internet) to tenecteplase 0.25 mg/mg i.v. (maximum dose 25 mg) plus best medical treatment vs. best medical treatment alone.

Imaging: All patients will undergo CT and CT angiography (CTA, if possible) before randomisation and on day 2. CT perfusion (CTP) will be performed at selected centres, as part of a sub-study.

Follow-up and primary effect variable: Centralised follow-up via telephone or mail at 3 months. The primary effect variable is functional outcome (modified Rankin Scale score).

Study size and centers: 600 patients from centers in Norway, Sweden, Denmark, Finland, Estonia, Latvia, Lithuania, United Kingdom, Switzerland and New Zealand.

Inclusion Criteria:

• Stroke symptoms on awakening that were not present before sleep
• Clinical diagnosis of stroke with limb weakness with NIHSS score >=3, or dysphasia
• Treatment with tenecteplase is possible within 4.5 hours of awakening
• Written consent from the patient, non-written consent from the patient (witnessed by non-participating health care personnel), or written consent from the nearest family member

Exclusion Criteria:

• Age <18 years

• NIHSS score >25 or NIHSS consciousness score >2, or seizures during stroke onset

• Findings on plain CT that indicate that the patient is unlikely to benefit from treatment:

  • Infarction comprising more than >1/3 of the middle cerebral artery territory on plain CT or CT perfusion
  • Intracranial haemorrhage, structural brain lesions which can mimic stroke (e.g cerebral tumour)

• Active internal bleeding of high risk of bleeding, e.g.:

  • Major surgery, trauma or gastrointestinal or urinary tract haemorrhage within the previous 21 days, or arterial puncture at a non-compressible site within the previous 7 days
  • Any known defect in coagulation, e.g. current use of vitamin K antagonist with an INR >1.7 or prothrombin time >15 seconds, or use of direct thrombin inhibitors or direct factor Xa inhibitors during the last 24 hours (unless reversal of effect can be achieved by agents such as idarucizumab) or with elevated sensitive laboratory tests (such as activated partial thromboplastin time (aPTT), international normalized ratio (INR), platelet count, ecarin clotting time, thrombin time (TT), or appropriate factor Xa activity assays), or heparins during the last 24 hours or with an elevated aPTT greater than the upper limit of normal
  • Known defect of clotting or platelet function or platelet count below 100,000/mm3 (but patients on antiplatelet agents can be included)
  • Ischaemic stroke or myocardial infarction in previous 3 months, previous intracranial haemorrhage, severe traumatic brain injury or intracranial or intraspinal operation in previous 3 months, or known intracranial neoplasm, arteriovenous malformation or aneurysm

• Contraindications to tenecteplase, e.g., acute bacterial endocarditis or pericarditis; acute pancreatitis; severe hepatic dysfunction, including hepatic failure, cirrhosis, portal hypertension; active hepatitis; systemic cancer with increased bleeding risk; haemostatic defect including secondary to severe hepatic, renal disease; organ biopsy; prolonged cardiopulmonary resuscitation > 2 min (within 2 weeks)

• Persistent blood pressure elevation (systolic ≥185 mmHg or diastolic ≥110 mmHg), despite blood pressure lowering treatment

• Blood glucose <2.7 or >20.0 mmol/L (use of finger-stick measurement devices is acceptable)

• Pregnancy, positive pregnancy test, childbirth during last 10 days, or breastfeeding. In any woman of childbearing potential, a pregnancy test must be performed and the result assessed before trial entry

• Other serious or life-threatening disease before the stroke: severe mental or physical disability (e.g. Mini Mental Status score <20, or mRS score ≥3), or life expectancy less than 12 months

• Patient unavailability for follow-up (e.g. no fixed address)