Patients hoping for a new alternative to the blockbuster blood thinner Plavix will have to wait a bit longer for a verdict on a promising candidate. The U.S. Food and Drug Administration needs more time to review AstraZeneca’s experimental blood thinner Brilinta (ticagrelor). A decision had been expected Wednesday, the News Journal reports, but the review deadline was pushed back to December 16. Although a panel of advisors to the FDA had voted 7-1 for Brilinta’s approval in July, regulators are not obligated to follow their advice. Brilinta demonstrated greater efficacy than Plavix in U.K.-based AstraZeneca’s PLATO study, which involved 18,624 patients who had been treated for a heart attack or worsening chest pain. However, Brilinta did not work as well in U.S. patients. Brilinta is formulated to prevent clots that can cause heart attacks and strokes in patients with acute coronary syndrome, an umbrella term for any condition caused by sudden, reduced blood flow to the heart. If approved, Brilinta is expected to go head-to-head with bestseller Plavix, marketed by Bristol-Myers Squibb and Sanofi-Aventis. Plavix generated $9.8 billion in revenues in 2009. If Brilinta is approved, industry analysts expect sales of the drug to reach $1.2 billion by 2014, according to Reuters. The New York Times recently reported that pharma giants including Bayer, Pfizer and Boehringer Ingelheim are currently racing to develop the next generation of anti-clotting therapies. Japanese pharmaceutical company Eisai is also developing an anticoagulant, as are smaller companies such as Regado Biosciences, Thrombotech and Portola Pharmaceuticals. Blood thinners are such big business in part because blood clots have so many potential causes. According to the National Heart Lung and Blood Institute, blood clots can be caused by any of the following: an autoimmune disorder known as APS, bone marrow disorders, genetic mutations, atherosclerosis, diabetes, heart failure, atrial fibrillation, diabetes, obesity, smoking, certain medications, extended periods of inactivity, pregnancy and more. Implanted medical devices such as joint implants and catheters can lead to blood clot formation (a problem that Cambridge, Mass.-based device company Semprus BioSciences is currently tackling). Blood clots can form in the legs (a condition known as deep vein thrombosis), travel to the lungs, and block blood flow (a potentially fatal complication known as pulmonary embolism). The National Blood Clot Alliance recently made available a free online curriculum for healthcare professionals to help increase understanding about the diagnosis and treatment of blood clots and blood clotting disorders. According to Randy Fenninger, NBCA Board President, the diagnosis of deep vein thrombosis (DVT) is often delayed, made too late, or not made at all. DVT occurs in approximately 2 million Americans per year, and pulmonary embolism kills up to 300,000 people in the U.S. each year—more than AIDS and breast cancer combined. With such high demand and clinical need for blood thinners in the U.S., it seems the next clot-buster drug can’t reach the market fast enough.