Amgen Release: Interim Long-Term Follow-Up Data Show AMG 531 Increases Platelets In Patients With Immune Thrombocytopenic Purpura; Results Suggest Once-Weekly Dosing Of AMG 531 Results In Sustained Platelet Response

ATLANTA--(BUSINESS WIRE)--Dec. 12, 2005--Amgen (NASDAQ: AMGN), the world's largest biotechnology company, today announced interim results from the first multi-center, randomized, double-blind, placebo-controlled, Phase 3 trial of Aranesp(R) (darbepoetin alfa) administered every three weeks in cancer patients with chemotherapy-induced anemia. The study revealed that Aranesp increased and maintained patient hemoglobin levels to the target level of greater than or equal to 11 grams per deciliter (g/dL) and reduced the need for red blood cell transfusions by almost half compared to placebo. The data were presented at the American Society of Hematology (ASH) 47th Annual Meeting and Exposition. (Abstract #3556)