-- New Claims Cover Use of Phosphatidylserine-Targeting Antibodies to Image Solid Tumors and Other Malignancies --

-- Supported by Published Data Showing Utility of PS-Targeting Antibodies for the Molecular Imaging of Cancer --

TUSTIN, Calif., June 24 /PRNewswire-FirstCall/ -- Peregrine Pharmaceuticals, Inc. (Nasdaq: PPHM) today reported the issuance of a U.S. patent with broad claims covering vascular imaging applications for phosphatidylserine (PS)-targeting antibodies. The patent represents the first broad coverage of imaging claims under Peregrine's PS-targeting platform, which includes Peregrine's lead antibody bavituximab. PS is a phospholipid that becomes exposed on the surface of tumor blood vessel cells. Since PS is typically not exposed on the surface of normal tissues, it represents a unique target for the vascular imaging of tumors and tumor metastases in patients with cancer.

'PS-targeting antibodies such as bavituximab preferentially bind to tumor blood vessels, which makes them ideal vehicles for imaging the tumor vasculature,' said Dr. Philip Thorpe, professor of pharmacology at UT Southwestern Medical Center and a scientific advisor to Peregrine. 'Last year we published data from preclinical imaging studies confirming bavituximab's high specificity for targeting tumor blood vessels with little or no localization to normal tissue.(1) Bavituximab's ability to achieve unusually clear images of tumors in living animals in these studies supports the concept that PS-targeting antibodies may be useful for the non-invasive detection of tumors and their metastases in cancer patients.'

The new patent claims methods for imaging solid tumors using PS-targeting antibodies coupled to a variety of imaging agents.

'Issuance of this broad vascular imaging patent expands the breadth of our intellectual property around our PS-targeting platform,' said Steven W. King, president and CEO of Peregrine. 'This patent protects expanded use of bavituximab and other PS-targeting antibodies to track disease and treatment status in cancer patients. The growing patent estate around our PS-targeting technology provides us with new options and applications for leveraging our PS-targeting antibodies.'

Bavituximab, Peregrine's most advanced PS-targeting antibody, is currently being tested in combination with chemotherapy in one Phase II trial in advanced lung cancer and two Phase II trials in advanced breast cancer. Interim data from these studies has been promising.

U.S.