AMG 706 Shows Activity in Phase 2 Study of Patients with Advanced Imatinib-Resistant Gastrointestinal Stromal Tumors

Broad Clinical Development Program for AMG 706 Under Way

THOUSAND OAKS, Calif.--(BUSINESS WIRE)--Nov. 4, 2006--Amgen (NASDAQ:AMGN) today announced results from a multicenter, single-arm, Phase 2 study of AMG 706, an investigational oral targeted VEGF receptor inhibitor. In this study, AMG 706 showed encouraging clinical activity in patients with advanced high-dose imatinib-resistant gastrointestinal stromal tumors (GIST). These data were presented in an oral session at the Connective Tissue Oncology Society (CTOS) meeting in Venice, Italy.

"AMG 706 targets tyrosine kinases, a family of proteins thought to play an important role in controlling cell development and tumor growth," said Robert Benjamin, M.D. Chair, Sarcoma Medical Oncology Professor, MD Anderson Cancer Center. "This study evaluated the safety and efficacy of AMG 706 given for at least eight weeks to patients whose disease progressed or relapsed while receiving imatinib. Based on these encouraging findings, we believe that further study of AMG 706 is warranted."

One hundred thirty-eight patients received at least one dose of AMG 706. Patients received 125mg per day orally until progressive disease or toxicity. Independent central radiographic review confirmed 120 patients as protocol eligible. Responses were measured by RECIST, fluorodeoxyglucose -positron emission tomography (FDG-PET) and Choi criteria (defined as a 10 percent decrease in tumor size or a 15 percent decrease in tumor density by contrast-enhanced computed tomography scan).

The primary endpoint of the trial was objective response per RECIST assessed by an independent review. Secondary efficacy endpoints included an assessment of AMG 706 on duration of response, progression-free survival, time to progression, survival and adverse events. Additional secondary endpoints explored the utility of FDG-PET, target tumor size/density changes and assessed the pharmacokinetics of AMG 706.

The RECIST assessment of the 120 evaluable patients showed a clinical benefit rate of 27 percent (three percent partial response plus 24 percent durable stable disease greater than or equal to 22 weeks). At week eight, 23 percent of patients demonstrated an objective response by FDG-PET (28/120) and 33 percent showed an objective response by Choi criteria (39/120). The median progression-free survival was 16 weeks, with 26 week progression-free survival of 27 percent. Median survival was 59 weeks.

Treatment-related adverse events that occurred in 15 percent or more of all patients were: diarrhea (55 percent), hypertension (48 percent), fatigue (45 percent), headache (47 percent) and nausea (35 percent).

About VEGF

The VEGF pathway plays a central role in tumor angiogenesis (the process of developing new blood vessels) with the VEGFr1-2 pathway driving angiogenesis and VEGFr3 driving lymphangiogenesis (the formation of lymphatic vessels from pre-existing lymphatic vessels, in a method believed to be similar to angiogenesis). Targeting the entire VEGF pathway may potentially lead to improved control of angiogenesis in cancer.

About AMG 706

AMG 706 is an oral, highly selective inhibitor of the VEGF pathway, targeting all of the VEGF receptors that demonstrate both antiangiogenic and direct antitumor activity (including inhibition of Platelet Derived Growth Factor receptor and Kit, two proteins involved in the regulation of cell proliferation). AMG 706 demonstrated the ability to induce objective responses and prolonged stable disease in phase 1 trials of heavily pre-treated patients with a variety of small tumors. The results of the phase 1 trials have led to the initiation of a broad clinical program in a variety of solid tumors including breast and non-small lung cancer, and that will document the utility of AMG 706 both as a monotherapy and in combination with commonly used therapies. AMG 706 is also being evaluated as a monotherapy in refractory differentiated or medullary thyroid cancer, where there exist no effective therapeutic options.

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 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.

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SOURCE: Amgen