Amgen Drug Boosts Blood Cells for Clotting

An Amgen Inc. drug increased the number of platelets -- blood cells needed for clotting -- in patients with an uncommon immune disorder, according to research presented at a medical meeting in San Diego.

A larger company-funded study is underway to test AMG 531 in patients with immune thrombocytopenic purpura, which causes the immune system to destroy platelets, said lead investigator David Kuter of Massachusetts General Hospital. About 20,000 people in the U.S. have the disease, which causes spontaneous bruising and bleeding.

Amgen has said that AMG 531 could have peak sales of $250 million.