Agensys and Seattle Genetics announced that they have initiated a phase I clinical trial of ASG-5ME for the treatment of castration-resistant prostate cancer

SANTA MONICA, CA, USA & BOTHELL, WA, USA | October 20, 2010 | Agensys, Inc., an affiliate of Tokyo-based Astellas Pharma Inc., and Seattle Genetics, Inc. (Nasdaq:SGEN – News) today announced that they have initiated a phase I clinical trial of ASG-5ME for the treatment of castration-resistant prostate cancer. ASG-5ME is an antibody-drug conjugate (ADC) targeting the SLC44A4 antigen and is being co-developed by both companies for the treatment of solid tumors.

"There is significant need for new prostate cancer therapies, given that more than 32,000 men are expected to die of prostate cancer in 2010,” said Leonard Reyno, M.D., Senior Vice President and Chief Medical Officer at Agensys. “We believe ASG-5ME, which is an ADC designed to deliver the potent cytotoxic agent MMAE directly to tumor cells, has the potential to provide a new therapeutic option for men with advanced prostate cancer.”

“This clinical trial, together with our ongoing phase I trial of ASG-5ME for pancreatic cancer, reflects continued progress in expanding our pipeline of clinical-stage ADCs for cancer,” said Jonathan Drachman, M.D., Senior Vice President, Research and Translational Medicine of Seattle Genetics.

The single-agent phase I trial will evaluate the safety, tolerability, pharmacokinetic profile and antitumor activity of escalating doses of ASG-5ME. The study is designed to enroll up to 60 patients at multiple centers in the United States.

ASG-5ME is an ADC composed of a fully human antibody directed to SLC44A4, a solute carrier antigen family member identified by Agensys to be overexpressed in epithelial cancers, including more than 80 percent of samples derived from patients with prostate, pancreatic and gastric cancers. The antibody is attached to a potent, synthetic cell-killing agent, monomethyl auristatin E (MMAE), via an enzyme-cleavable linker using Seattle Genetics’ proprietary technology. The ADC is designed to be stable in the bloodstream, but to release MMAE upon internalization into SLC44A4-expressing tumor cells, resulting in targeted cell-killing. Preclinically, ASG-5ME has demonstrated potent antitumor activity, inducing regressions in models of established prostate, pancreatic and colon cancers.

About Prostate Cancer

Prostate cancer forms in tissues of the prostate, a gland in the male reproductive system. According to the American Cancer Society, more than 217,000 new cases of prostate cancer will be diagnosed in the United States during 2010, making it the second most commonly diagnosed form of cancer. More than 32,000 men are expected to die of prostate cancer in the United States during 2010.

About Agensys

Agensys, Inc., an affiliate of Astellas Pharma Inc., is developing a pipeline of therapeutic fully human monoclonal antibodies (MAbs) to treat solid tumor cancers. The MAb product pipeline is being generated to Agensys’ diverse portfolio of proprietary, clinically relevant cancer targets that encompass 14 types of solid tumors. Agensys’ target portfolio and related products are protected by a large patent estate. The company has full capabilities to generate, develop and manufacture antibody products. Agensys is progressing a pipeline of both naked and antibody-drug conjugated (ADC) therapeutic antibodies, directed at a variety of cancer indications, including those of the prostate, kidney, pancreas, ovary, bladder, lung, colon, breast and skin. ADC products are based on drug platform technologies developed by Seattle Genetics. Agensys is developing a growing pipeline of clinical stage functional MAbs and ADC products.

About Astellas

Astellas Pharma Inc., located in Tokyo, Japan, is a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceutical products. Astellas has approximately 15,000 employees worldwide. The organization is committed to becoming a global category leader by rapidly establishing a business model in urology, immunology & infectious diseases, neuroscience, DM complications & metabolic diseases and oncology. Astellas has discovered a treatment for functional symptoms of benign prostatic hyperplasia (BPH), Vesicare® and an immunosuppressant, Prograf® (tacrolimus), which have enabled Astellas to become an established leader in both Urology and Transplant. For more information on Astellas Pharma Inc., please visit Astellas’ website at http://www.astellas.com/en.

About Seattle Genetics

Seattle Genetics is a clinical-stage biotechnology company focused on the development and commercialization of monoclonal antibody-based therapies for the treatment of cancer and autoimmune disease. The company recently reported positive top-line data from both a pivotal Hodgkin lymphoma trial and phase II anaplastic large cell lymphoma trial with its lead product candidate, brentuximab vedotin, and plans to submit a Biologics License Application to the U.S. Food and Drug Administration in the first half of 2011. Brentuximab vedotin is being developed in collaboration with Millennium: The Takeda Oncology Company. In addition, Seattle Genetics has four other clinical-stage programs: SGN-75, ASG-5ME, dacetuzumab (SGN-40) and SGN-70. Seattle Genetics has collaborations for its ADC technology with a number of leading biotechnology and pharmaceutical companies, including Bayer, Celldex Therapeutics, Daiichi Sankyo, Genentech, GlaxoSmithKline, Millennium: The Takeda Oncology Company and Progenics, as well as ADC co-development agreements with Agensys, an affiliate of Astellas, and Genmab. More information can be found at www.seattlegenetics.com.

SOURCE: Agensys/Astellas