Ischaemic strokes are caused by a blockage cutting off the blood supply to the brain, and account for about 85% of all strokes.
In the first few hours after the onset of an ischaemic stroke, giving the patient “clot busting” drug treatment (thrombolysis) greatly improves their chances of recovering to independence. The quicker that treatment can be given, the greater the benefit.
In recent years, stroke units in the UK (and worldwide) have organised themselves to deliver thrombolysis to as many people as possible, and up to 20% of stroke patients can now be treated at major centres. Nevertheless, it may be possible to improve upon the drug that is currently used in thrombolysis, called alteplase (also known as rtPA).
Newer clot-busting drugs have been developed, and have already replaced alteplase in other fields of medicine. One of these drugs is called tenecteplase, which has also been investigated in small studies for its use in the thrombolysis of stroke patients (including the first ATTEST trial). These studies support the possibility that tenecteplase is potentially more effective and also safer than alteplase, causing less disruption of the body’s blood-clotting system, and possibly fewer brain bleeds (haemorrhages) as a risk of thrombolysis treatment.
ATTEST 2 aims to test tenecteplase in a large clinical trial to establish whether it is a better drug than alteplase for use in thrombolysis. This will involve a large number of hospitals in the UK, and possibly overseas. People who are considered suitable for thrombolysis will be allocated at random to receive either the current standard treatment with alteplase, or tenecteplase, and will be followed up for the first 90 days to measure the effects on recovery.
Even if there are no significant differences between between the two drugs, tenecteplase is less expensive and much easier to give to patients than alteplase, needing a single injection only. Alteplase has to be given as an injection followed by a longer injection over an hour. This advantage of tenecteplase alone would have worthwhile benefits to the patient.