Treatment of acute
ischaemic stroke aims to recanalize the occluded artery, salvage the at-risk brain tissue and thus minimize neurological sequelae. Efforts a decade ago have led to the only currently approved medical treatment for acute
ischaemic stroke, i.e. intravenous
alteplase given within 3 hours of
stroke onset. Recanalization occurs in only one-half of the patients receiving
alteplase, and only approximately 5% of all
ischaemic stroke patients in industrialized countries receive this treatment. Studies are currently being carried out to determine whether intravenous
alteplase would be safe and effective for up to 4.5 hours after
ischaemic stroke onset, and whether it should be followed by an intra-arterial approach. Two novel
thrombolytic drugs being studied for acute
ischaemic stroke are
desmoteplase and
tenecteplase. Although the first trials were promising, the most recent evidence suggests that
desmoteplase is not superior to placebo, even in carefully selected patients, in the 3- to 9-hour time window after
stroke onset.
Tenecteplase has only been studied for acute
ischaemic stroke in a single noncontrolled, dose-finding trial in the 3-hour time window after
stroke onset, which suggested a similar efficacy to that demonstrated in the historical data from the
alteplase trials. A trial to compare the safety and efficacy of
tenecteplase versus
alteplase is ongoing. Safer and more effective
thrombolytic drugs for the treatment of
ischaemic stroke are thus being sought. Such agents will be welcome, but they are not here yet. While waiting we are likely to see the emergence of additive
therapies, including ultrasound insonation, neuroprotective/regenerative agents and invasive intra-arterial techniques. Novel
thrombolytic drugs, or other novel
therapies, possess great potential to make a difference in the future, but the most urgent priority now is in the organization of
stroke treatment in such a way that more patients receive the currently available optimal treatments.