Pivotal Phase 3 Data Show Denosumab Increased Bone Density Throughout Skeleton in...

Pivotal Phase 3 Data Show Denosumab Increased Bone Density Throughout Skeleton in Non-Metastatic Breast Cancer Patients on Adjuvant Aromatase Inhibitor Therapy

A Study Evaluating Twice Yearly Dosing with Denosumab Met All
Primary and Secondary Endpoints
SAN ANTONIO--(Business Wire)--Amgen (NASDAQ:AMGN) today announced results of the first Phase 3
pivotal study to complete in the denosumab oncology development
program. The study evaluated denosumab's effect on bone density across
the skeleton in women with non-metastatic breast cancer who were
receiving adjuvant Aromatase Inhibitor (AI) Therapy. These results
were presented during the Late Breaking Session at this year's 30th
Annual San Antonio Breast Cancer Symposium (SABCS) in San Antonio,
Texas.

Results from the Phase 3 HALT Breast Cancer 135 study show that
denosumab, a fully human monoclonal antibody under investigation as a
twice yearly subcutaneous injection, increased bone density worsened
by AI therapy, including in highly cortical areas of the skeleton. In
addition to increasing bone mineral density (BMD) of the trabecular
bone (spongy bone matrix), denosumab showed increases in cortical
bone, the dense outer shell of the skeleton which is responsible for
the supportive and protective function of the skeleton.

"The risk of bone loss for women with breast cancer is a genuine
concern and needs to be proactively managed when treating with
aromatase inhibitors," said Georgiana Kehr Ellis, M.D., Associate
Professor, Department of Medicine, Division of Oncology, University of
Washington School of Medicine, Seattle, WA. "In this study, denosumab
data looks promising, and as a clinician, I look forward to having a
potential alternative to existing therapies."

Skeletal integrity is normally maintained through complex
biological processes that carefully regulate the bone remodeling
process. However, disruption of these processes with AI therapy in
postmenopausal breast cancer patients, already in a state of
accelerated bone loss, can lead to worsening imbalances in bone
resorption and formation. Bone loss can occur with over stimulation of
osteoclasts; the cells responsible for bone resorption. Too much
resorption causes progressive bone loss and weakens cortical and
trabecular bone throughout the skeleton. RANK Ligand inhibition is
being investigated for the clinical potential to both prevent bone
resorption and halt active bone destruction.

The Phase 3 data show that lumbar spine BMD increased
significantly at all time points with the denosumab group (n=127) as
early as one month. At month 12 (primary endpoint) a 5.5 percent (p
less than 0.0001) difference from placebo (n=125) was observed.
Additionally, a consistent effect of denosumab was demonstrated on the
Total Hip BMD (3.7 percent difference from placebo) and Femoral Neck
BMD (2.5 percent difference from placebo) at 12 months (secondary
endpoints).

In addition, exploratory endpoints evaluated the effect of
denosumab at the distal radius and on total body. A 3.8 percent change
in BMD at the distal radius was observed at month 12 with denosumab
compared to placebo and at 24 months that difference increased to 6.1
percent. A 3 percent increase in BMD on Total Body was shown at month
12 with denosumab compared to placebo and at 24 months BMD in the
denosumab arm increased to 4.2 percent compared to placebo.

In the study, denosumab was generally well tolerated, with overall
rates of adverse events similar to placebo. The most common adverse
events (AEs) were consistent with those usually associated with AI
therapy, and included, arthralgia, pain in extremity, fatigue, back
pain, constipation, cough, and insomnia.

"The results of this pivotal study provide a promising glimpse of
the potential of denosumab to help manage bone disease in multiple
tumor types and stages of disease in the cancer setting," said Roger
M. Perlmutter, M.D., Ph.D., executive vice president of Research and
Development at Amgen. "This data on denosumab evaluating its effect on
BMD throughout the skeleton, including cortical sites, should be
encouraging to clinicians who witness the devastating effects of
cancer and cancer treatment on their patients' bones."

About Denosumab

Denosumab is the first fully human monoclonal antibody in late
stage clinical development that specifically targets RANK Ligand, the
essential mediator of osteoclasts (the cells that break down bone).
Denosumab inhibits all stages of osteoclast activity through a
targeted mechanism that does not incorporate into bone matrix. In the
oncology setting, denosumab is being investigated in treatment-induced
bone loss (in breast cancer and prostate cancer patients) and for its
potential to delay bone metastases as well as inhibit and treat bone
destruction across many stages of cancer.

About RANK Ligand Inhibition

RANK Ligand is found in all parts of trabecular and cortical bone
and RANK Ligand inhibition represents a highly targeted and specific
approach to treating osteoclast-mediated bone destruction.

About Amgen in Bone Biology

Amgen is a leader in bone biology and is committed to developing
medicines to help the millions of patients with osteoporosis,
rheumatoid arthritis and other bone conditions. We have initiated a
robust clinical trial program with more than 18,000 patients worldwide
to evaluate the benefit/risk profile of denosumab across a number of
therapeutic areas. Denosumab is also being studied in a range of
bone-loss conditions outside of the oncology setting including
postmenopausal osteoporosis and in the treatment of bone erosions in
rheumatoid arthritis.

About Amgen

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

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Amgen, Thousand Oaks
Lisa Rooney: (805) 559-0739 (media)
Arvind Sood: (805) 447-1060 (investors)

Copyright Business Wire 2007