Data Shows ENBREL Provides Sustained Clinical Improvements for People with Ankylosing Spondylitis for up to Three Years.

Data Show Sustained Improvements in Clinical Measures for up to Three Years

THOUSAND OAKS, Calif. -- Amgen (NASDAQ:AMGN), today announced that data from an ongoing open-label, multinational, phase 4 extension study showed that patients with ankylosing spondylitis (AS) who received treatment with Enbrel([R]) (etanercept) experienced sustained improvement in signs and symptoms, spinal mobility and physical function over 148 to 160 weeks of therapy. These results are consistent with an ENBREL phase 3 clinical trial at 24 weeks. The 160-week results will be presented at the American College of Rheumatology (ACR) Scientific Meeting in Washington, D.C.

"These data demonstrate that ENBREL can provide substantial long-term improvement in AS symptoms such as total back pain and spinal mobility," said Joachim Sieper, M.D., professor of rheumatology, Charite University in Berlin, Germany. "Because AS is a chronic inflammatory disease that requires ongoing management, it is important to offer patients a treatment option that is effective, has an established safety profile, and can be used over the long-term."

Data presented at ACR showed that 59 patients who received open-label ENBREL treatment for up to 160 weeks experienced sustained clinical improvements. Overall, 78 percent of patients (n=46) continuing treatment with ENBREL achieved a 20 percent improvement in the Assessment on Ankylosing Spondylitis Response Criteria (ASAS 20) after 160 weeks of treatment. ASAS is a composite measure of improvement in AS symptoms that include total back pain, patient assessment of disease activity, inflammation and physical function. Thirty-one percent of patients (n=18) achieved partial remission at week 160. Partial remission, as defined by ASAS, is a low disease activity level (score < 20 units out of 100 in each of the four ASAS criteria).

Additional ENBREL data presented at ACR from this phase 4 extension study show that improvement in spinal mobility was also sustained through 148 to 160 weeks of treatment with ENBREL.

Patients with ankylosing spondylitis have reported that their condition has negatively impacted their ability to perform daily activities including exercising, rising from a seated position and climbing stairs without aid. Overall, patients treated with ENBREL achieved a 46 percent improvement in physical function, as measured by the Bath Ankylosing Spondylitis Functional Index (BASFI), and these results were sustained through 160 weeks. The BASFI is a 10-question, patient self-assessment instrument consisting of 8 specific questions regarding physical function in AS and 2 questions reflecting the patient's ability to cope with everyday life. Each question is answered on a 10 cm horizontal visual analog scale, the mean of which gives the BASFI score (0-10).

ENBREL was generally well tolerated over 148 to 160 weeks of therapy.

This study was designed to assess the safety and long-term efficacy of ENBREL in patients with AS, using clinical measures to assess disease activity, physical function, improvement in AS symptoms, and ongoing surveillance to assess the incidence of adverse events. The study is a 96-week open-label, multinational, phase 4 extension study in 59 patients with AS who completed each of two earlier trials, a 12-week randomized, double-blind, placebo-controlled study and a 96-week open-label study. The data presented at ACR is from the first 52-weeks of an ongoing 96-week extension study (total ENBREL treatment 148 - 160 weeks).

Enbrel received FDA approval to treat the signs and symptoms of active AS in 2003 following a randomized, double-blind, placebo-controlled phase 3 study in 277 patients with active ankylosing spondylitis. Treatment with ENBREL (n=138) resulted in significant clinical improvements through 24 weeks, compared to placebo (n=139). At 12 weeks, the ASAS 20 response was achieved by 60 percent of patients receiving ENBREL, compared to 27 percent of patients receiving placebo (p en 0.0001, ENBREL vs. placebo). These results were maintained through 24 weeks. Patients in this study were between 18 and 70 years of age and had ankylosing spondylitis as defined by the modified New York Criteria for Ankylosing Spondylitis. Patients with complete ankylosis of the spine were excluded from study participation. Patients taking hydroxychloroquine, sulfasalazine, methotrexate, or prednisone (en 10 mg/day) could continue these drugs at stable doses for the duration of the study. Doses of 25 mg ENBREL or placebo were administered subcutaneously twice a week for 6 months. The primary measure of efficacy was a 20 percent improvement in the Assessment in Ankylosing Spondylitis (ASAS) response criteria.

ABOUT AS

Ankylosing spondylitis, which affects up to half a million people in the United States, is a chronic, painful and progressive inflammatory disease affecting joints and ligaments that normally allow a person's back to move and flex. The disease most often occurs in the lower back but can affect the upper spine, chest and neck. In more advanced disease, the spine can fuse, causing loss of motion and a permanent stooped-over posture. AS may also involve other joints, such as the hips, shoulders, knees and ankles. Unlike other forms of arthritis, AS frequently affects individuals between the ages of 17 and 35. It tends to affect more men than women.

ABOUT ENBREL

ENBREL is a fully human soluble TNF receptor. ENBREL has more than 14 years of collective clinical experience.

ENBREL is indicated for:

* reducing signs and symptoms, keeping joint damage from getting worse, and improving physical function in patients with moderate to severe rheumatoid arthritis. ENBREL can be taken with methotrexate or used alone.

* reducing signs and symptoms of moderate to severe polyarticular-course juvenile rheumatoid arthritis in patients who have failed one or more disease modifying anti-rheumatic drugs (DMARDs).

* reducing signs and symptoms, keeping joint damage of active arthritis from getting worse, and improving physical function in patients with psoriatic arthritis. ENBREL can be used with methotrexate in patients who do not respond adequately to methotrexate alone.

* reducing signs and symptoms in patients with active ankylosing spondylitis.

* the treatment of adult patients (18 years or older) with chronic moderate to severe plaque psoriasis who are candidates for systemic therapy or phototherapy.

ENBREL is a type of protein called a tumor necrosis factor (TNF) blocker that blocks the action of a substance your body's immune system makes called TNF. People with an immune disease, such as rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and psoriasis, have too much TNF in their bodies. ENBREL can reduce the amount of TNF in the body to normal levels, helping to treat your disease. But, in doing so, ENBREL can also lower the ability of your immune system to fight infections.

All medicines have side effects, including ENBREL. Possible side effects of ENBREL include:

-- Serious infections
    -- Many occurred in people prone to infection, such as those with
       advanced or poorly controlled diabetes
    -- Some serious infections have been fatal
    -- Rare cases of tuberculosis have occurred
        -- What not to do
            -- Do not start ENBREL if you have an infection, such as
               an open sore or the flu, or are allergic to ENBREL or
               its components
        -- What to do
            -- Tell your doctor if you are prone to infection
            -- Stop ENBREL if a serious infection occurs
            -- Contact your doctor if you have questions about ENBREL
               or develop an infection
            -- Tell your doctor if you have ever been treated for
               heart failure
-- Serious nervous system disorders, such as multiple sclerosis,
   seizures, or inflammation of the nerves of the eyes
    -- Tell your doctor if you have ever had any of these disorders or
       if you develop them after starting ENBREL
-- Rare reports of serious blood disorders (some fatal)
    -- Contact your doctor immediately if you develop symptoms, such
       as persistent fever, bruising, bleeding, or paleness
-- In medical studies of all TNF blockers, including ENBREL, a higher
   rate of lymphoma (a type of cancer) was seen compared to the
   general population. The risk of lymphoma may be up to several-fold
   higher in rheumatoid arthritis and psoriasis patients
    -- The role of TNF blockers, including ENBREL, in the development
       of lymphoma is unknown
-- ENBREL can cause injection site reactions
-- In a medical study of patients with JRA, infections, headaches,
   abdominal pain, vomiting, and nausea occurred more frequently than
   in adults
    -- The kinds of infections reported were generally mild and
       similar to those usually seen in children
    -- Other serious adverse reactions were reported rarely, including
       serious infections (2%) and depression/personality disorder
      (1%)

About Amgen and Wyeth

Amgen and Wyeth Pharmaceuticals, a division of Wyeth, market ENBREL in North America. Wyeth markets ENBREL outside of North America. Immunex Corporation, a wholly owned subsidiary of Amgen, manufactures ENBREL. Additional information about ENBREL, including full Prescribing Information, can be found on the Web site sponsored by the companies at www.enbrel.com or by calling toll free 888-4ENBREL (888-436-2735).

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 broad and deep 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.

Wyeth Pharmaceuticals, a division of Wyeth, has leading products in the areas of women's health care, cardiovascular disease, central nervous system, inflammation, transplantation, hemophilia, oncology, vaccines and nutritional products. Wyeth is one of the world's largest research-driven pharmaceutical and health care products companies. It is a leader in the discovery, development, manufacturing and marketing of pharmaceuticals, vaccines, biotechnology products and non-prescription medicines that improve the quality of life for people worldwide. The Company's major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Healthcare and Fort Dodge Animal Health.

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