Amgen Submitted New Drug Applicatioin for Cinacalcet HCI

THOUSAND OAKS, Calif., (September 8, 2003) — Amgen (NASDAQ: AMGN) filed a new drug application (NDA) with the U.S. Food & Drug Administration for cinacalcet HCl, a first-in-class oral calcimimetic agent, licensed from NPS Pharmaceuticals, Inc., currently being investigated for the treatment of secondary hyperparathyroidism (SHPT) associated with chronic kidney disease. The filing was based upon the successful completion of phase 3 studies, which will be presented at the American Society of Nephrology annual meeting in November. Cinacalcet HCl is the company's first small molecule therapeutic and represents an important milestone for Amgen and furthers the company's commitment to the nephrology community. It also represents a potentially significant advance for chronic kidney disease patients diagnosed with SHPT, a common yet serious metabolic disorder where parathyroid hormone levels are elevated. Patients with this disease can suffer from bone disease, bone pain and fractures, soft tissue calcification, vascular calcification and cardiovascular complications.

Cinacalcet HCl is an oral compound with a unique mechanism of action that modulates the behavior of the calcium-sensing receptor on the parathyroid gland. By increasing sensitivity of the receptors to calcium levels in the bloodstream, cinacalcet HCl may lead to a reduction in the levels of parathyroid hormone, calcium, phosphorous and the calcium-phosphorous product. Currently, there are no therapies available that have these features.

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 Statements This news release contains forward-looking statements that involve significant risks and uncertainties, including those discussed below and others that can be found in our Form 10-K for the year ended December 31, 2002, and in our 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.

No forward-looking statement can be guaranteed and actual results may differ materially from those we project. The Company's results may be affected by our ability to successfully market both new and existing products domestically and internationally, sales growth of recently launched products, difficulties or delays in manufacturing our products, and regulatory developments (domestic or foreign) involving current and future products and manufacturing facilities. In addition, sales of our products are affected by reimbursement policies imposed by third party payors, including governments, private insurance plans and managed care providers, and may be affected by domestic and international trends toward managed care and healthcare cost containment as well as possible US legislation affecting pharmaceutical pricing and reimbursement. Government regulations and reimbursement policies may affect the development, usage and pricing of our product. Furthermore, our research, testing, pricing, marketing and other operations are subject to extensive regulation by domestic and foreign government regulatory authorities. We, or others could identify side effects or manufacturing problems with our products after they are on the market. In addition, we compete with other companies with respect to some of our marketed products as well as for the discovery and development of new products. Discovery or identification of new product candidates cannot be guaranteed and movement from concept to product is uncertain; consequently, there can be no guarantee that any particular product candidate will be successful and become a commercial product. In addition, while we routinely obtain patents for our products and technology, the protection offered by our patents and patent applications may be challenged, invalidated or circumvented by our competitors. Further, some raw materials, medical devices, and component parts for our products are supplied by sole third party suppliers.

For further information, please contact:
Media Inquiries: (805) 447-4587
Investors: (805) 447-1060