26 May 2016 | FOR IMMEDIATE RELEASE
NEW GLOBAL STUDY IDENTIFIES A SAFER TREATMENT FOR ACUTE STROKE
Singapore, 26 May 16 – Less may be more and even better. That is what researchers who conducted an international study of the use of anti-clotting medication used to treat stroke victims have discovered.
The study covered more than 3,000 patients in hospitals around the world, including Singapore. Asian patients were well represented in the study. It found that patients who received a reduced dosage of Intravenous Thrombolysis with Recombinant tissue plasminogen activator (IV-rTPA), a medication commonly used to treat stroke patients, still received most of the clot-busting benefits of a higher dose, yet had significantly fewer subsequent major intracerebral bleeding and improved survival rates. In the very early hours of stroke, patients who receive it have a better chance of recovery.
What the reduced dose of medication does
The medication works by breaking up clots that suddenly block vital arteries in the brain. IV-rTPA is administered as an initial injection, followed by further continuous intravenous infusion over 1 hour.
In the study, it was found that the benefit of a 33% reduction in dosage was offset by a slight rise in the number of patients suffering post-stroke residual disability: for every 1,000 patients treated with low-dose IV-rtPA compared to the standard dose, 41 more people had physical disabilities that required help with dressing or walking. However, there were also 19 fewer deaths among patients receiving the lower dosage of medication after 90 days.
Proof-of-principle in dose optimisation helps saves lives
Associate Professor Vijay Sharma, a clinician scientist with the National University Health System, who is a principal investigator of the study, said “We now have proof-of-principle: reducing the dose to help the patient recover, whilst reducing the risk of bleeding is now feasible. And being alive with some recovery as a result of lower dose of IV-rTPA is surely preferable to most patients than early death. A reduced-dose regimen could become useful in patients with an exceptionally high risk of bleeding in the brain after thrombolysis.”
Assoc Prof Sharma emphasised that more work is needed. “What we seek is a very high degree of precision in balancing the risks versus benefits of a lower dose of IV-rtPA so that we can act safely and effectively for every patient. New drugs take decades to develop, so we must improve what we have with the standard-of-care medications. Dose optimisation is only one of many strategies to study into. Stroke is on the rise; Asia is in the eye of the storm and IV-rtPA use is rising across the world. Annually, on a global scale, improving a complication rate by just 1 percent has the potential to save tens of thousands of people.”
In Singapore, the National Registry of Diseases Office statistics for 2013 alone cites 6,642 new stroke cases. The annual estimates of new cases of stroke are 40,000 in Australia, 120,000 in the UK, 640,000 in the USA, 1.2 million in India, and 2 million in China.
Assoc Prof Sharma, with the NUS Yong Loo Lin School of Medicine and also a Senior Consultant with National University Hospital, had initiated a search for an ideal balance between effectiveness and safety in stroke treatment in 2010 and designed the study with Professor Craig Anderson of Australia’s George Institute in Sydney in 2012 that paved the way for the international trial, named ENCHANTED.
Funded by a grant from the National Health and Medical Research Council of Australia, the findings were published on 10 May 2016 in the New England Journal of Medicine and presented at the recent European Stroke Organisation conference in Barcelona, Spain.
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