Data Presented at AACR Annual Meeting Show Anti-Tumor Activity of Peregrine's Fully Human Anti-PS Antibody in Prostate Ca...( -Preclinical Results Fur...),Health

-Preclinical Results Further Validate Significant Anti-Tumor Potential of Fully Human Anti-PS Antibodies and Expand the Company's PS-Targeting Platform-

-Treatment with Mouse Equivalent to the Human Antibody Inhibited Tumor Growth in a Prostate Cancer Model by More than 90%-

DENVER and TUSTIN, Calif., April 22 /PRNewswire-FirstCall/ -- Peregrine Pharmaceuticals, Inc. (Nasdaq: PPHM), a clinical stage biopharmaceutical company developing monoclonal antibodies for the treatment of cancer and serious virus infections, today announced that preclinical data presented during the AACR 100th Annual Meeting 2009 shows that one of its fully human phosphatidylserine (PS)-targeting antibodies demonstrated encouraging signs of efficacy in a preclinical model of prostate cancer. These positive new data validate the anti-tumor potential of this human anti-PS antibody, which is similar to Peregrine's lead clinical stage antibody bavituximab and extends Peregrine's anti-PS antibody pipeline. Bavituximab is in Phase II clinical trials for the treatment of advanced breast cancer and non-small cell lung cancer.

Peregrine's PS-targeting antibodies bind to the cellular membrane component PS that is usually located inside cells, but which becomes exposed on the external surface of the cells that line the blood vessels of tumors (the tumor vascular endothelium), creating a specific target for anti-cancer treatments. By binding to PS, the antibodies are believed to help mobilize the body's immune system to destroy the tumor and the tumor blood vessels.

In today's presentation, researchers from UT Southwestern Medical Center in Dallas and Affitech A/S reported that similar to bavituximab, the human antibody PGN635 targets and binds specifically to the tumor vascular endothelium(1). Treatment with androgen deprivation therapy or docetaxel substantially increased the percentage
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