Amgen Submits Supplemental Biologics License Application for Aranesp Extended Dosing; Phase 3 Study Evaluated Aranesp Dosed Once Every Three Weeks in Patients with Chemotherapy-Induced Anemia.

THOUSAND OAKS, Calif. -- Amgen Inc. (Nasdaq:AMGN), the world's largest biotechnology company, today announced the submission of a supplemental Biologics License Application (sBLA) to the U.S. Food and Drug Administration (FDA) for Aranesp(R) (darbepoetin alfa). The sBLA is based on Phase 3 data that Amgen believes will demonstrate Aranesp administered every three weeks is safe and effective in the treatment of chemotherapy-induced anemia in patients with non-myeloid malignancies. If approved, Aranesp will be the first therapy indicated in the United States for once every three week dosing in the treatment of anemia in these patients.

"As the first company to clone erythropoietin and develop recombinant EPO as a therapy, Amgen is deeply committed to improving the chemotherapy experience for cancer patients and their families," said Willard Dere, M.D., chief medical officer and senior vice president of global development at Amgen. "Since chemotherapy is most commonly given to patients every three weeks, an extended dosing schedule for Aranesp has the potential to reduce the amount of patient, physician and caregiver time required for anemia therapy."

About Chemotherapy-Induced Anemia

Chemotherapy can reduce the bone marrow's ability to produce red blood cells that transport oxygen from the lungs to all of the body's muscles and organs. Anemia occurs when there are too few red blood cells and the body's tissues are "starved" of oxygen, which can make a patient feel short of breath, very weak, faint and tired.

This year, an estimated 1.3 million cancer patients will undergo chemotherapy in the United States; approximately 800,000 (67 percent) will become anemic. More than half of these patients report that fatigue associated with anemia affects their daily lives more than any other side effect of treatment, including nausea, pain and depression.

Although anemia is a common and often debilitating side effect of chemotherapy, it is often not recognized and frequently under-treated. In fact, 42 percent of patients with a hemoglobin (Hb) level less than the recommended target level of 11 to 12 g/dL in the National Comprehensive Cancer Network(R) (NCCN) guidelines for "Cancer and Treatment-Related Anemia" are never treated with erythropoietic therapy.

About Aranesp

Aranesp is a recombinant erythropoietic protein (a protein that stimulates production of oxygen-carrying red blood cells). Amgen revolutionized anemia treatment with the development of recombinant erythropoietin, Epoetin alfa, which is currently marketed in the United States by Amgen as EPOGEN(R) (Epoetin alfa)(i) and by Ortho Biotech Products, LP, as Procrit(R) (Epoetin alfa)(ii). Building on this heritage, Amgen developed Aranesp, a unique erythropoiesis stimulating protein, which contains two additional sialic acid-containing carbohydrate chains than the Epoetin alfa molecule and remains in the bloodstream longer than Epoetin alfa because it has a longer half-life. By virtue of its longer half-life, Aranesp should be administered less frequently than Epoetin alfa in patients with chronic kidney disease (CKD).

Aranesp is approved for multiple indications with varying dosage instructions in both the United States and in Europe. Aranesp was approved by the FDA in September 2001 for up to every two week dosing for the treatment of anemia associated with chronic renal failure, also known as CKD, for patients on dialysis and patients not on dialysis. In July 2002, Aranesp was approved by the FDA for weekly dosing for the treatment of chemotherapy-induced anemia in patients with non-myeloid malignancies. In 2004, the European Committee for Medicinal Products for Human Use approved Aranesp for extended dosing intervals of once every three weeks in the treatment of anemia in adult cancer patients with non-myeloid malignancies who are receiving chemotherapy and monthly in the treatment of anemia associated with CKD.

Important Safety Information

Aranesp(R) is contraindicated in patients with uncontrolled hypertension. Erythropoietic therapies may increase the risk of thrombotic events, and other serious events. The target hemoglobin (Hb) should not exceed 12 g/dL. If the Hb increase exceeds 1.0 g/dL in any 2-week period, dose reductions are recommended. In a study with another erythropoietic product, where the target Hb was 12-14 g/dL, an increased incidence of thrombotic events, disease progression and mortality was seen.

Pure red cell aplasia (PRCA) has been observed in patients treated with recombinant erythropoietins. This has been reported predominantly in patients with CRF. Aranesp(R) should be discontinued in any patient with evidence of PRCA and the patient evaluated for the presence of antibodies to erythropoietin products. The most commonly reported side effects in clinical trials were fatigue, edema, nausea, vomiting, diarrhea, fever and dyspnea.

About Amgen

Amgen is a global biotechnology company that discovers, develops, manufactures and markets important human therapeutics based on advances in cellular and molecular biology.

Forward-Looking Statement

This news release contains forward-looking statements that involve significant risks and uncertainties, including those discussed below and others that can be found in Amgen's Form 10-K for the year ended December 31, 2004, and in Amgen's periodic reports on Form 10-Q and Form 8-K. Amgen is providing this information as of the date of this news release and does not undertake any obligation to update any forward-looking statements contained in this document as a result of new information, future events or otherwise.

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Aranesp prescribing information can be accessed by calling 800-772-6436 or by logging on to www.aranesp.com.

(i)  EPOGEN(R) is a registered trademark of Amgen, Inc.
(ii) Procrit(R) is a registered trademark of Ortho Biotech Products,
     L.P.