* Cangrelor reduced serious heart risk by 22 pct vs Plavix * Reduces clots in heart stents by 38 percent * Serious bleeding very low for both drugs By Bill Berkrot SAN FRANCISCO, March 10, The Medicines Co's experimental intravenous blood clot preventer Cangrelor, which is intended for use during angioplasty procedures, solidly outperformed commonly used Plavix in a pivotal late stage study, likely resurrecting the drug's prospects. The aptly named Champion-Phoenix trial, with 11,000 patients undergoing an angioplasty and stenting procedure, was meant to save the potentially important new medicine from the ashes of a pair of prior Phase III studies in which it failed to achieve the primary goal. The third time around, with some trial design changes aimed at more accurately reflecting heart attacks likely associated with the drugs and not the procedure, appears to have been the charm. The company had previously announced that the third study succeeded, but the details were released at the American College of Cardiology scientific meeting in San Francisco on Sunday. The primary goal was a combination of death, heart attack, need for repeat procedures or stent thrombosis, a blood clot forming at the site of the stent, at 48 hours after the procedure. The percentage of patients who suffered one of those serious complications was 4.7 for cangrelor and 5.9 for Plavix, now available generically as clopidogrel. The result, which was statistically significant, represented a 22 percent risk reduction for the Medicines Co drug. "I think it's a significant advance in the care of patients undergoing stent procedures, which of course is one of the most common procedures in the U.S. and worldwide," Dr. Deepak Bhatt, a co-lead investigator of the study, said in an interview. "I think the potential health impact of our findings are substantial and I hope that the result will help change clinical practice." Cangrelor also showed a 38 percent reduction in stent thrombosis alone, a key secondary goal of the study. Both drugs had very low and similar incidence of severe bleeding - 0.16 percent for Cangrelor and 0.11 percent Plavix. Cangrelor has significant clinical advantages over Plavix and other oral blood clot preventers in that it takes effect rapidly and leaves the system in only one hour. The other drugs continue to work for five days or more, which significantly increases serious bleeding risk if a patient needs an emergency or urgent follow-up procedure. In some cases, surgery will be postponed for several days until the oral drug wears off. Cangrelor also would benefit patients unable to swallow pills, researchers said. "The first two trials we thought provided very strong signals of benefit," said Bhatt, chief of cardiology at the VA Boston Health Care system and professor of medicine at Harvard Medical School. Noting a similar important reduction in stent thrombosis in the earlier trials, he said, "That gave us confidence that there really was some benefit to the drug, and that's why we launched the third trial." The Phoenix trial included a broad cross section of patients with conditions that require artery clearing intervention. "The results really do apply to a substantial percentage of patients undergoing stent procedures around the world," Bhatt said, calling the data "compelling." Medicines Co plans to file its application seeking U.S. approval of Cangrelor in the second quarter. "If Cangrelor is approved, we think it will be a significant step forward for patients with cardiovascular disease in an acute setting," said Simona Skerjanec, the company's head of anti platelet therapies. Adnan Butt, an analyst with RBC Capital Markets, is estimating Cangrelor to attain peak sales of about $400 million by 2019.