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During the past two decades , clinical trials focused on combined antiplatelet therapies for the prevention of secondary events following acute coronary syndromes and very recently on the new oral anticoagulants in combination with antiplatelet therapy .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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