- Bavituximab Equivalent Combined With Radiation Reduced Tumor Growth by 80% in Preclinical Lung Cancer Model -

- Findings Confirm Key Aspects of Bavituximab's Mechanism of Action in Combination with Radiation Therapy -

- Results Further Support Future Clinical Trials Testing Bavituximab in Combination With Radiation Therapy -

TUSTIN, Calif., Sept. 4 /PRNewswire-FirstCall/ -- Peregrine Pharmaceuticals, Inc. (Nasdaq: PPHM), a clinical stage biopharmaceutical company developing targeted monoclonal antibodies for the treatment of cancer and hepatitis C virus infection, today reported that researchers have published a new study in a lung cancer model showing that the combination of a mouse equivalent of bavituximab and radiation is significantly more effective in reducing tumor growth than either therapy alone. The study was published in the September 1 issue of Clinical Cancer Research. Bavituximab, Peregrine's lead anti-phosphatidylserine (anti-PS) immunotherapy, is currently in clinical trials for the treatment of solid tumors including lung cancer.

"This new publication further supports the concept that radiation therapy and bavituximab may work synergistically to treat solid tumors." said Steven W. King, president and CEO of Peregrine. "We are particularly pleased to see these positive results in a model of radiation resistant lung cancer, by far the leading cause of U.S. cancer deaths. This is the latest in a series of preclinical studies that have demonstrated the potential of either radiation or chemotherapy to enhance bavituximab's anti-tumor effects. We look forward to evaluating a combination of bavituximab plus radiation therapy in future clinical studies."

Peregrine completed a pilot Phase I study evaluating bavituximab in combination with chemotherapy in advanced cancer patients earlier this year and reported promising results. Based on these results, Peregrine recently submitted a Phase II clinical protocol to test bavituximab plus carboplatin/paclitaxel in lung cancer patients and plans to file several additional combination therapy clinical protocols this year.

Lung cancer is the leading cause of cancer deaths in the U.S. with a 5-year survival rate of only about 15%. With more than one million new cases diagnosed worldwide each year, lung cancer is also the leading cause of cancer deaths globally. About half of all lung cancer patients receive radiation therapy, but many become resistant to its tumor-killing effects. In this study, researchers tested a bavituximab equivalent combined with radiation therapy in a radiation-resistant mouse model of lung cancer.

The UT Southwestern Medical Center researchers found that in this lung cancer model, radiation therapy increased by over six-fold the percentage of tumor blood vessel cells that exposed bavituximab's PS target on the external surfaces. As a result, more of the bavituximab equivalent antibodies became concentrated in the tumor blood vessels. This increased localization may have contributed to the finding that the density of tumor blood vessels was reduced by more than 90% and tumor growth was reduced by 80% in animals treated with combination therapy, significantly greater efficacy than was achieved with either treatment alone.

"Approximately 50% of all cancer patients receive radiation therapy, so these findings could potentially apply to millions of patients," noted Dr. Philip Thorpe, professor of pharmacology at UT Southwestern and a member of Peregrine's Scientific Resource Board. "We are also pleased that these results confirm our previous work that demonstrated that the enhanced therapeutic effects of bavituximab combination therapy do not appear to be accompanied by an increase in side effects, offering the possibility of more effective and less toxic anti-cancer regimens."

Bavituximab is a monoclonal antibody that binds to a phospholipid called phosphatidylserine that is normally located inside normal cells, but which becomes exposed on the outside of the cells that line the blood vessels of tumors, creating a specific target for anti-cancer treatments. Bavituximab is believed to help mobilize the body's immune system to destroy the blood vessels needed for tumor growth and spread. In a Phase lb trial in advanced cancer patients bavituximab plus chemotherapy appeared to have a safety profile consistent with chemotherapy alone and showed positive signs of clinical activity. In the study, objective response or disease stabilization was achieved in 50% of patients evaluated for tumor response. A protocol for a Phase ll trial of bavituximab in combination with chemotherapy in patients with non-small cell lung cancer (NSCLC) has been filed and is currently undergoing regulatory review. Bavituximab is also in clinical trials in the U.S. in patients with advanced solid tumors and in patients co-infected with HCV and HIV.

The study, titled 'Radiation-Enhanced Vascular Targeting of Human Lung Cancers in Mice with a Monoclonal Antibody That Binds Anionic Phospholipids," was co-authored by Philip Thorpe, Jin He, and Troy A. Luster. The research was funded with assistance from the Gillson Longenbaugh Foundation and the American Cancer Society.

About Peregrine Pharmaceuticals

Peregrine Pharmaceuticals, Inc. is a biopharmaceutical company with a portfolio of innovative product candidates in clinical trials for the treatment of cancer and hepatitis C virus (HCV) infection. The company is pursuing three separate clinical programs in cancer and HCV infection in the U.S. and India with its lead product candidates bavituximab and Cotara®. Peregrine also has in-house manufacturing capabilities through its wholly owned subsidiary Avid Bioservices, Inc. (http://www.avidbio.com), which provides development and bio-manufacturing services for both Peregrine and outside customers. Additional information about Peregrine can be found at http://www.peregrineinc.com.

Safe Harbor Statement: Statements in this press release which are not purely historical, including statements regarding Peregrine Pharmaceuticals' intentions, hopes, beliefs, expectations, representations, projections, plans or predictions of the future are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. The forward-looking statements involve risks and uncertainties including, but not limited to, the risk that results of human studies will not correlate to the results achieved in connection with the preclinical lung cancer model, the uncertainty as to whether the results of future clinical studies will support moving this product candidate forward for the treatment of lung cancer. It is important to note that the company's actual results could differ materially from those in any such forward-looking statements. Factors that could cause actual results to differ materially include, but are not limited to, uncertainties associated with completing preclinical and clinical trials for our technologies; the early stage of product development; the significant costs to develop our products as all of our products are currently in development, preclinical studies or clinical trials; obtaining additional financing to support our operations and the development of our products; obtaining regulatory approval for our technologies; anticipated timing of regulatory filings and the potential success in gaining regulatory approval and complying with governmental regulations applicable to our business. Our business could be affected by a number of other factors, including the risk factors listed from time to time in the Company's SEC reports including, but not limited to, the annual report on Form 10-K for the year ended April 30, 2007. The Company cautions investors not to place undue reliance on the forward-looking statements contained in this press release. Peregrine Pharmaceuticals, Inc. disclaims any obligation, and does not undertake to update or revise any forward-looking statements in this press release.

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SOURCE Peregrine Pharmaceuticals, Inc.

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