The arrival of generic copies of Sanofi-Aventis’ and Bristol-Myers Squibb's top-seller Plavix makes genetics a hot topic scientifically and commercially. One study found AstraZeneca's Brilinta, unlike Plavix, requires no genetic testing to check if it will work, while another showed Eli Lilly’s and Daiichi Sankyo's Effient also worked irrespective of gene variations. On the face of it, the results of the two company-sponsored trials give the firms valuable ammunition in a looming marketing war. "Physicians don't like complications, so if there was an alternative to clopidogrel (Plavix) that worked the same way that did not have these variations then most people would jump on it," said Alfred Bove of Temple's School of Medicine.