Lilly shares slump after it stops trials

By Ransdell Pierson

NEW YORK (Reuters) - Eli Lilly and Co (LLY.N: Quote, Profile, Research, Stock Buzz) and Daiichi Sankyo Co (4568.T: Quote, Profile, Research, Stock Buzz) said on Wednesday they had stopped giving their most important experimental medicine, the blood-clot preventer prasugrel, to patients in two small trials because the dosage may need to be changed for certain patients.

Lilly, whose shares fell 4 percent in after-hours trading in response, said developments in the two trials "should not be interpreted to represent the outcome of the overall prasugrel clinical development program."

Daiichi Sankyo shares tumbled 6 percent to 3,290 yen in Thursday morning trade in Tokyo.

Lilly spokesman Joedy Isert said the company does not believe suspension of the small trials, which collectively had enrolled 119 patients, would have a material effect on the drug's future.

"We don't expect this to delay approval," Isert said, noting the trials were not designed to assess prasugrel's effectiveness.

Instead, he said they focused on other measures -- such as its speed of action, the way it is processed by the body and its side effects -- compared with Bristol-Myers Squibb Co's (BMY.N: Quote, Profile, Research, Stock Buzz) multibillion-dollar anti-clot drug, Plavix.

Isert said it was not yet clear what types of patients in the trials might require a different dose of prasugrel, or if indeed any adjustment needs to be made.

Prasugrel is seen by Wall Street as a linchpin of the Indianapolis drugmaker's future earnings growth and a serious potential rival to Plavix, one of the world's biggest-selling medicines.