Shares in AstraZeneca are on the rise this morning after the company announced positive results from a head-to-head study comparing its investigational oral antiplatelet treatment Brilinta favourably with Sanofi-Aventis/Bristol-Myers Squibb’s blockbuster Plavix.

The Anglo-Swedish drugmaker has presented topline results from its Phase III Plato trial which demonstrate that Brilinta (ticagrelor) has achieved a statistically significant primary efficacy endpoint versus Plavix (clopidogrel), in the prevention of cardiovascular events in patients with acute coronary syndrome. The study measured time to first occurrence of any event from the composite of myocardial infarction, stroke and CV death.

AstraZeneca said that given the size of the Plato trial, which involved 18,624 ACS patients in 43 countries, “further analysis of the entire database, secondary variables, and subgroups is ongoing”. The data will be submitted to a peer-reviewed medical journal and be presented at the European Society of Cardiology meeting in Barcelona in August.

Brilinta is the first reversibly-binding oral adenosine diphosphate (ADP) receptor antagonist and is chemically distinct from thienopyridines like Plavix, AstraZeneca notes. It selectively inhibits P2Y12, a key target receptor for ADP, and the company plans to file the drug for regulatory approval in the fourth quarter of this year.

If approved, Brilinta will compete with Plavix and Eli Lilly/Daiichi Sankyo’s new treatment Effient (prasugrel). Estimates of potential sales vary widely but Paul Mann, an analyst at Morgan Stanley, has issued a research note saying that Brilinta could be worth $3 billion.

However Mr Mann noted that “ahead of presentation of side-effect data and details of the primary endpoint, the full commercial opportunity remains unclear". Investors are excited, however, and at 11.07am UK time, AstraZeneca shares were up 5.6% to £25.31.