( --Immunization with a Bavituximab Equiv...)Data Presented at AACR Meeting Show Peregrine's Bavituximab,Equivalent Can Generate Curative Immune Responses as Part of a,Vaccine-Like Regimen in Preclinical Models of Aggressive Brain,Cancer,Health

LOS ANGELES and TUSTIN, Calif., April 18, 2007 /PRNewswire-FirstCall/ -- Peregrine Pharmaceuticals, Inc. , a clinical stage biopharmaceutical company developing targeted monoclonal antibodies for the treatment of cancer and hepatitis C virus (HCV) infection, today announced preclinical studies presented at the Centennial Annual Meeting of the American Association for Cancer Research (AACR) showed that 2aG4, a mouse equivalent to the company's anti-phosphatidylserine (PS) antibody bavituximab has vaccine- like activity and can generate curative responses in an aggressive model of brain cancer. Researchers also presented data demonstrating that this improvement in survival was likely attributable to the ability of 2aG4 to enable the treated animals to mount an effective immune response against this difficult to treat cancer.

To confirm that the bavituximab equivalent 2aG4 acted by enhancing anti- cancer immune responses, researchers injected rats with irradiated glioma cells (inactivated tumor cells) along with 2aG4. This regimen was intended to protect the animals from a subsequent challenge with a large lethal dose of tumor cells -- 10,000 times the number required to produce lethal disease in this model.

Among the animals pre-treated with the 2aG4-treated irradiated cells, 57% achieved long-term survival, versus 0% of animals receiving no prior treatment (P < 0.01). The key role of the bavituximab equivalent's anti-PS activity in protecting these animals was illustrated by the fact that a group receiving irradiated control antibodies that did not block PS only achieved a 16% long- term survival rate.

These data are particularly noteworthy because the glioma cells used in the study are highly aggressive -- fewer than 10 cell
'"/>