Peregrine's PS-targeting antibodies highlighted in AACR Annual Meeti...( DENVER Colorado and TUSTIN Calif. Ap...)

DENVER, Colorado and TUSTIN, Calif., April 21, 2009--Peregrine Pharmaceuticals, Inc. (Nasdaq: PPHM), a clinical stage biopharmaceutical company developing monoclonal antibodies for the treatment of cancer and serious virus infections, today reported that two preclinical studies presented during the AACR 100th Annual Meeting 2009 provided further confirmation of the immunomodulatory mechanisms contributing to the anti-tumor activity of its phosphatidylserine (PS) targeting antibodies. One study confirms the anti-tumor effects and immune stimulating ability of a fully human anti-PS antibody and the other demonstrates the ability of a second fully human anti-PS antibody to stimulate development of a critical component of the adaptive immune system.

These human PS-targeting antibodies, which are currently being evaluated for both anti-cancer and anti-viral applications, increase the number of product candidates in Peregrine's anti-PS pipeline. Peregrine's lead anti-PS antibody bavituximab is currently in Phase II clinical trials in advanced breast and lung cancers.

"These preclinical studies further elucidate the unique immunomodulatory mechanisms contributing to the observed anti-tumor activity of anti-PS antibodies in preclinical and clinical studies," said Dr. Philip Thorpe, professor of pharmacology at UT Southwestern Medical Center in Dallas, a scientific advisor to Peregrine and co-author of one of the AACR presentations. "These presentations provide additional insight into the mechanisms that act to selectively destroy the blood vessels supporting tumor growth and spread and also to reverse the ability of tumors to suppress the body's natural immune response, resulting in the mobilization of important inflammatory and other anti-tumor components of the immune system. Together, the studies provide compelling evidence suggesting that PS-targeting antibodies facilitate an important cytokine shift in the tumor environment that subsequentl
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