The FDA gave the green light to AstraZeneca’s Brilinta (ticagrelor) anti-platelet for heart attack prevention, but the brand will carry a black box warning, a Risk Evaluation and Mitigation Strategy requirement and an obligation to educate doctors about possible risks of use in users of high-dose aspirin. 

The drug, a likely blockbuster, outperformed Sanofi and Bristol-Myers Squibb’s Plavix at preventing heart attacks and deaths, but has been dogged by a discrepancy in a head-to-head study known as PLATO which found that advantage blunted in the US. Both the company and the agency pinned the blame on a tendency toward higher doses of aspirin, which seem to blunt the drug’s effectiveness. Accordingly, the boxed warning advises against use in patients taking more than 100 milligrams of aspirin daily, and FDA required the company to “conduct educational outreach to physicians to alert them about the risk of using higher doses of aspirin.”

An AstraZeneca spokesperson said of the REMS program: “The key components of the Brilinta REMS program include a medication guide that will be dispensed with each prescription, letters to healthcare professionals and select professional organizations and a website specifically for HCPs so that they can learn more details about the REMS program.

Plavix, a $7 billion behemoth that loses patent exclusivity next year, presents the most formidable threat to Brilinta, which will be bolstered in the battle to gain formulary coverage by the PLATO study’s finding of superior efficacy but may falter in the doctor’s office amid fears over bleeding and the higher dose of aspirin. That’s led analysts to mark down their expectations for the drug’s sales.

“While Brilinta’s approval is clearly a good thing, we continue to believe that the product will disappoint commercially,” wrote Bernstein’s Tim Anderson in an analyst note. Anderson projects $750 million in sales for the drug in 2015 – well below the $2 billion he characterizes as the consensus view elsewhere. 

AstraZeneca is counting on the drug to as its great hope to replace lost revenues with Seroquel losing exclusivity next year and Crestor facing generic competition in 2016.