AstraZeneca drug tops Plavix in sickest patients

* Astra's Brilinta tops Plavix in heart attack patients

* No increased major bleeding risk seen with Brilinta

* 18 pct reduction in all cause death seen with Brilinta

* Data from sickest 40 pct from larger PLATO trial

ORLANDO, Fla., Nov 15 (Reuters) - Heart attack patients in need of emergency procedures were less likely to suffer further serious cardiovascular events, including deaths, when given AstraZeneca's experimental Brilinta blood clot preventer than those who received used Plavix, according to a study.

Importantly, the Brilinta patients also were found to be at no greater risk for major bleeding than those taking Plavix -- an encouraging sign for such drugs that work by preventing blood cells called platelets from clumping together.

The lack of increased bleeding risk seen with AstraZeneca's (AZN.L) new medicine could provide comfort that safety was not compromised in order to obtain its greater ability to prevent cardiovascular death, heart attack and stroke for up to a year.

The findings are an important new slice of data from a more than 18,000-patient comparative trial called PLATO unveiled earlier this year in which Brilinta also proved superior to Plavix, one of the world's most widely used medicines sold by Bristol-Myers Squibb (BMY.N) and Sanofi-Aventis (SASY.PA) with annual sales of some $9 billion. (Reporting by Bill Berkrot and Ransdell Pierson; Editing by Will Dunham)