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Title: Investigational Motesanib Provides Clinical Benefit in Phase 2 Trial: Presented at ASCO-GI

"Investigational Motesanib Provides Clinical Benefit in Phase 2 Trial: Presented at ASCO-GI"

By Ed Susman ORLANDO, FL -- January 27, 2008 -- The investigational multikinase inhibitor motesanib diphosphate appears to be active among patients as a second-line therapy for treatment of progressive gastrointestinal stromal tumors (GISTs). The phase 2 study enrolled patients in Japan who were progressing despite treatment with imatinib mesylate, but had received no other kinase-inhibitor treatments. "Treatment with motesanib diphosphate was reasonably well tolerated, with hypertension, diarrhea, and fatigue being the most frequently occurring adverse events," said Tomoko Ohtsu, MD, PhD, Medical Researcher, Amgen KK, Tokyo, Japan, who presented the study here at the American Society for Clinical Oncology's 2008 Gastrointestinal Cancers Symposium (ASCO-GI). The symposium is cosponsored by ASCO with the American Gastroenterological Association Institute, the American Society for Therapeutic Radiology and Oncology, and the Society for Surgical Oncology Of the 35 patients who developed progressive GISTs after treatment with imatinib, one patient achieved a confirmed partial response and seven other patients achieved disease stabilization that was durable for at least 6 months. "We saw that 23% of the patients in this group achieved some clinical benefit from treatment with motesanib," said Dr. Ohtsu during her poster presentation on January 25. Motesanib (formerly known as AMG 706) attacks GISTs by blocking vascular endothelial growth factor receptors 1, 2, and 3; kinase stem cell factor receptor; and platelet-derived growth factor receptor. These mechanisms are involved in angiogenesis and cell proliferation. Patients were eligible for the study if they were older than 20 years of age and had disease progression despite at least 8 weeks of treatment with imatinib 400 mg a day. The GIST also had to express CD117 or activating mutations of platelet-derived growth factor receptors. Dr. Ohtsu reported that the median progression-free survival time was 113 days for these patients, who were receiving 125 mg of motesanib daily until disease progression or intolerable toxicity occurred, the researchers said. The only grade 4 toxicity occurred in a single patient who developed hyperuricemia, Dr. Ohtsu reported. Seven patients discontinued treatment due to adverse events. Funding for this study was provided by Amgen. [[Presentation title: Phase II Study of Motesanib Diphosphate (AMG 706) in Japanese Patients With Advanced Gastrointestinal Stromal Tumors (GISTs) Who Developed Progressive Disease or Relapsed While on Imatinib Mesylate. Abstract 107]

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