Results from the African American Antiplatelet Stroke Prevention Study (AAASPS), a large multicenter trial of 1,809 African American stroke patients from over 60 sites in the United States, show that aspirin is as effective as ticlopidine for prevention of a second stroke in this population.

The study is sponsored by the National Institute of Neurological Disorders and Stroke (NINDS). Originally scheduled to run until October 2003, the AAASPS was stopped in July 2002, after analyses suggested that there was less than a 1% chance that ticlopidine would be shown to be superior to aspirin if the study were carried to completion.

Looking at the results of previous trials of ticlopidine, a type of clot inhibitor, investigators thought that there was a strong possibility that this agent would be safer and more effective than aspirin in African Americans with a history of stroke. The NINDS funded the AAASPS in order to study this possibility.

"The study shows that aspirin is probably a better choice than ticlopidine for recurrent stroke prevention in African Americans. For those who can tolerate it, aspirin is readily available, inexpensive, and easy to administer. Ticlopidine, on the other hand, is more expensive, more difficult to use, and has the potential for serious side effects," said John R. Marler, Associate Director for Clinical Trials research at the NINDS.

African Americans are at about twice the risk of experiencing a stroke or dying from a stroke, compared to whites, and have a higher prevalence of stroke and cardiovascular disease risk factors such as hypertension, diabetes mellitus, obesity, and cigarette smoking.

The FDA approved ticlopidine, for clinical use in the early 1990s to reduce the risk of fatal or non-fatal stroke in patients with stroke risk factors and in patients who had a completed thrombotic stroke. In North America, ticlopidine was tested in two large trials, the Ticlopidine Aspirin Stroke Study (TASS) and the Canadian American Ticlopidine Study (CATS). A sub-analysis from TASS suggested that ticlopidine might produce fewer side effects and be particularly effective for stroke reduction among non-whites, mostly African Americans. Ticlopidine can cause rash and diarrhea but carries a lower risk of gastrointestinal bleeding and irritation than aspirin. Other adverse effects attributed to ticlopidine include serious blood conditions such as neutropenia and thrombocytopenia.