Medicines Co. blood thinner still has hope: doctors

* Researchers say new trials warranted

* Say lower mortality, stent clots justify further study

* Caution that cangrelor failed earlier main study goals

By Ransdell Pierson and Bill Berkrot

ORLANDO, Fla., Nov 15 (Reuters) - An experimental Medicines Co blood thinner that failed two late-stage clinical trials earlier this year still holds great promise and deserves to be tested in new studies, researchers said on Sunday.

The company discontinued two large trials of the intravenous drug, called cangrelor, in May after an independent monitoring board deemed it unlikely to prove to be superior to the widely used pill Plavix.

Cangrelor had been tested against Bristol-Myers Squibb Co's (BMY.N) Plavix among patients undergoing procedures to clear their heart arteries of plaque, to see if it was better within 48 hours at reducing incidence of death, heart attack or a need for new heart procedures.

Cangrelor failed the trials because it was not satisfying that combination of study goals, or endpoints. Even so, it sharply reduced overall mortality and the occurrence of blood clots associated with new stents -- tiny scaffold-like devices used to prop open arteries cleared of plaque, researchers said.

Some 0.7 percent of patients taking Plavix by itself died within 48 hours of treatment, compared with 0.2 percent of those who received cangrelor in combination with Plavix, representing a 67 percent reduction for the cangrelor group.

Clotting from stents was reduced from 0.6 percent in the Plavix group, to 0.2 percent of those taking both cangrelor and Plavix, and the reduced clotting may help explain the lower death risk, researchers said.

The data were presented at the American Heart Association scientific meeting in Orlando.

Dr. Deepak Bhatt, chief of cardiology at the Veterans Administration Boston Healthcare System -- who helped lead one of the two large failed trials -- said he believes Medicines Co will likely conduct new big trials of cangrelor in view of the favorable secondary data on survival and stent blood clots.

"I think it should be tested again in large Phase III trials because there is a clinically meaningful benefit" in those secondary trial goals, even though the earlier studies failed to achieve their combined main goals.

Bhatt and other researchers said cangrelor may post better results if patients receive longer intravenous infusions, should new trials commence.

He said an older clot preventer, Merck & Co's (MRK.N) Integrilin, failed initial trials only to succeed in later studies after its dosage was increased.

Cangrelor belongs to a newer class of agents that includes Plavix, Eli Lilly's (LLY.N) Effient and AstraZeneca Plc's (AZN.N) Brilinta. They use the same mechanism to prevent blood cells called platelets from clumping together to form clots, and all are pills, with the exception of cangrelor.