A simple combination of two anti-clotting drugs, clopidogrel and aspirin, can cut the risk of a stroke in patients who have already experienced a mini-stroke or transient ischemic attack (TIA).
This was the result of a phase 3 clinical trial conducted in China with the help of a US physician who says it could change the standard of care in the US.
The investigators report their findings in the 26 June online issue of the New England Journal of Medicine, NEJM.
The trial took place at several sites in China and was designed in partnership with S. Claiborne Johnston, a professor of neurology and associate vice chancellor of research at University of California - San Francisco (UCSF).
A mini-stroke (minor ischemic stroke) or TIA is where the supply of much needed oxygen-rich blood to the brain is temporarily blocked because of a blood clot that the body naturally disperses, usually within a few minutes.
About 10-20% of people who have a TIA go on to have a subsequent stroke within three months, so patients who suffer TIAs are usually given aspirin to prevent blood clots.
Clopidogrel (marketed as Plavix) has a similar effect as aspirin. Both drugs target blood platelets, that form blood clots, and stop them clumping together.
The US Food and Drug Administration (FDA) approved generic versions of clopidogrel in 2012.
People who have a heart attack are also at higher risk of blood clots afterwards, but they are usually given both aspirin and clopidogrel.
However, until this study there wasn't enough evidence that this might also work after TIA or mini-stroke.
The trial results show that giving clopidogrel in addition to aspirin within 24 hours of the TIA, can reduce the risk of a further stroke by nearly a third over aspirin alone in the ensuing 90 days.
The trial involved 5,170 patients admitted to hospital after suffering mini-stroke or TIA.
They were randomly assigned into two treatment groups. One group received aspirin alone, and the other group received aspirin plus clopidogrel. Treatment in both groups lasted for three months.
The results show that overall, 8.2% of the patients in the combination drug group suffered further strokes during the follow- up compared to 11.7% of the aspirin-only group.
Johnston says in a statement: "the results were striking".
The Chinese trial, called CHANCE, is nearly identical to one called POINT, that is already enrolling patients in the US.
Johnston says if the US trial confirms the Chinese one, "then we're done", and the "two-drug combination becomes the standard of care".
Johnston says it is important to do the US trial as well as the Chinese one because important differences between the two countries's populations, such as different genes, ways of practising medicine, and risk factors, could produce different trial results.
Funds from the Ministry of Science and Technology (MST) of the People's Republic of China helped finance the study.