Investigational Therapy Denosumab Increased Bone Mineral Density with Twice-Yearly Dosing; One Year Data Published in New England Journal of Medicine

Amgen (NASDAQ: AMGN), the world's largest biotechnologycompany, announced today the publication of Phase 2 data demonstratingtwice-yearly injections of denosumab (previously referred to as AMG162), a RANK Ligand inhibitor, significantly increased bone mineraldensity (BMD) in the total hip, lumbar spine, distal 1/3 radius andtotal body compared to placebo. The results of this one-year studyappeared in the Feb. 23, 2006 issue of the New England Journal ofMedicine. Data results also included an open-label FOSAMAX(R)(alendronate)(a) arm of the same clinical trial.

Researchers reported that subcutaneous injections of denosumabsignificantly increased BMD at the total hip from 1.9 to 3.6 percentin women who were administered the therapy twice yearly as comparedwith a decrease of 0.6 percent in the placebo group (p less than0.001) at one year. The open label FOSAMAX(R) group receiving 70 mgweekly had an increase of 2.1 percent during the same time frame.Results also indicated that denosumab had a rapid onset of action. Asignificant decrease in serum levels of C-telopeptide, a biomarker ofbone resorption, was achieved within 72 hours after dosing.

"These exciting data suggest that denosumab, when administered intwice-yearly injections, may show promise in the treatment ofosteoporosis," said Michael McClung, MD, FACP, principal investigatorof the denosumab study, Providence Portland Medical Center, anddirector of the Oregon Osteoporosis Center, Portland, Ore. "Continuedresearch will further our understanding of the potential of denosumabin bone loss management."

Denosumab targets RANK Ligand, a protein that acts as the primarymediator of osteoclast (cells that break down bone) activity. Thisinvestigational therapy is the first RANK Ligand inhibitor in latestage development.

Amgen is studying denosumab for its potential in a broad range ofconditions associated with bone destruction including osteoporosis,treatment-induced bone loss, bone metastases, multiple myeloma andrheumatoid arthritis. Data recently presented at the American Collegeof Rheumatology 2005 Annual Scientific Meeting show further increasein bone mineral density in postmenopausal women with osteoporosisafter two years of treatment.

"These data reinforce the essential role that RANK Ligandinhibition plays in decreasing bone loss," said Willard Dere, MD,senior vice president of global development and chief medical officer,Amgen. "We are committed to expanding our data on denosumab with anextensive Phase 3 clinical program to evaluate the effect of denosumabon preventing fractures in men and women."

In the one-year trial results, researchers also reportedtwice-yearly subcutaneous injections of denosumab significantlyincreased lumbar spine BMD from 3.0 to 6.7 percent after 12 months ascompared with a decrease of 0.8 percent in the placebo-treatedpatients (p less than 0.001). Across all doses and dosing intervals,distal 1/3 radius BMD increased from 0.4 to 1.3 percent as comparedwith a decrease of 2.0 percent in those taking placebo (p less than0.001), and total body BMD increased from 0.6 to 2.8 percent ascompared with a decrease of 0.2 percent in the placebo group (p lessthan 0.01).

The incidence of adverse events was similar among the denosumab,placebo, and FOSAMAX(R) groups, with the exception of dyspepsia.Dyspepsia occurred in 7 percent of placebo patients, 6-15 percent ofdenosumab patients and 26 percent of open-label FOSAMAX(R) patients.The most common adverse events among all groups included upperrespiratory infection (common cold), arthralgia (joint pain),nasopharyngitis (sore throat), back pain and headache. No neutralizingantibodies to denosumab were observed.

Denosumab Study Design

This is an ongoing, multi-center dose-ranging trial. Investigatorsrandomized 412 healthy postmenopausal women, average age 63, with lowBMD to receive denosumab, placebo or FOSAMAX(R). The purpose of thestudy was to determine the safety and efficacy of denosumab on lumbarspine BMD compared with placebo at 12 months. The doses of denosumabevaluated included 6, 14 or 30 mg every three months or 14, 60, 100 or210 mg every six months. The researchers administered all doses ofdenosumab via subcutaneous injection. Patients receiving FOSAMAX(R)followed the approved indication and oral dosing instructions of 70 mgonce weekly.

At entry, the average lumbar spine T score ranged from -2.0 to-2.2 across dose groups, consistent with a diagnosis of osteopenia(thinning bone). Approximately a quarter of the patients hadosteoporosis as defined by a T score equal to or below -2.5 at thelumbar spine.

About RANK Ligand

Bone is constantly formed and removed through a natural process ofremodeling. Bone resorption is dependent on RANK Ligand, the proteinthat acts as the primary mediator of osteoclast formation, functionand survival. Osteoclasts are cells responsible for bone removal.

Preclinical models have demonstrated that inhibiting RANK Ligandsignificantly improves cortical and trabecular bone density, volumeand strength. Cortical bone is the protective outer shell around everybone in the body. Trabecular bone is known as spongy bone and issurrounded by the harder cortical layer.

The Need for Bone Loss Treatments

Osteoporosis

Bone loss represents a significant clinical and economic burden.Osteoporosis is a major public health threat for an estimated 44million Americans, or 55 percent of the population 50 years of age andolder. In the U.S. today, 10 million individuals are estimated toalready have the disease and almost 34 million more are estimated tohave low bone mass, placing them at increased risk for osteoporosis.

Of the 10 million Americans estimated to have osteoporosis, eightmillion are women and two million are men. In addition, one in twowomen and one in four men over age 50 will have anosteoporosis-related fracture in their remaining lifetime.

In Europe, recent estimates have stated that approximately 3.8million people have experienced bone fractures related toosteoporosis.

About Amgen

Amgen discovers, develops and delivers innovative humantherapeutics. A biotechnology pioneer since 1980, Amgen was one of thefirst companies to realize the new science's promise by bringing safeand effective medicines from lab, to manufacturing plant, to patient.Amgen therapeutics have changed the practice of medicine, helpingmillions of people around the world in the fight against cancer,kidney disease, rheumatoid arthritis, and other serious illnesses.With a broad and deep pipeline of potential new medicines, Amgenremains committed to advancing science to dramatically improvepeople's lives. To learn more about our pioneering science and ourvital medicines, visit www.amgen.com.

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(a) FOSAMAX(R) is a registered trademark of Merck & Co., Inc.

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