Researchers Report Peregrine's Phospholipid-Targeted Antibodies Fused With Cytokines Reduce Tumor Growth in Animals by Over 90

- Data Demonstrates Potential of New Class of Targeted Fusion Therapies -

- Combines Peregrine's Proprietary Vascular Targeting Agent (VTA) and Anti-Phospholipid Technology Platforms -

TUSTIN, Calif., Sept. 19 /PRNewswire-FirstCall/ -- Peregrine Pharmaceuticals, Inc. (Nasdaq: PPHM), a biopharmaceutical company with a portfolio of innovative, clinical stage products for the treatment of cancer and hepatitis C virus (HCV) infection, today reported new research showing that a fusion protein approach that combines two proprietary Peregrine technology platforms -- its Vascular Targeting Agent (VTA) and anti- phospholipid (anti-PS) technologies -- has demonstrated significant anti-tumor potential. In a presentation at the Angiogenesis and Vascular Targeting Agents Conference, researchers presented data showing that a fusion protein combining an antibody from Peregrine's anti-phospholipid therapy program with immunostimulatory cytokines such as interferon or interleukin reduced tumor growth in animal cancer models by more than 90%, with no discernable increase in toxicity. These studies represent an important validation of a new class of compounds in Peregrine's proprietary VTA platform, which uses agents targeted to tumor blood vessels to kill tumors by depriving them of the nutrients and oxygen needed for continued growth.

"We have long thought that our anti-phospholipid platform would be ideal for the delivery of cytokines for cancer therapy, and the data presented today strongly supports the concept of using a cytokine fusion protein to 'supercharge' the ability of anti-phospholipid antibodies to stimulate the immune system," said Steven W. King, president and CEO of Peregrine. "The potential power of this approach is evident from the fact that our collaborators were able to reduce tumors in these animals by more than 90%, with no evidence of cytokine-induced toxicity. Based on this promising data and its good fit with our ongoing development efforts, we plan on working with our collaborators to conduct the studies needed to advance this technology toward human clinical studies."

In the research presented today by Dr. Xianming Huang, assistant professor of pharmacology at UT Southwestern Medical Center, interleukin 2 and interferon alpha proteins fused with an anti-phosphatidylserine monoclonal antibody were tested. The fusion proteins retained full antibody binding and cytokine activity, and combinations of the anti-PS antibody linked to the different cytokines had better anti-tumor effects than either agent alone, inhibiting tumor growth by over 90% in some B-cell lymphoma and melanoma tumor models.

"The anti-tumor efficacy of interferons in clinical trials has been limited by their very short half-life and significant systemic toxicity," said Dr. Huang. "To overcome these obstacles, we engineered immunocytokine fusion proteins combining an anti-PS antibody with various interferons. The resulting fusion proteins were able to target tumor blood vessels and displayed potent anti-cancer effects in tumor models without causing any observable toxicity. These studies demonstrate that this approach could have significant potential for targeted immunotherapy of solid tumors."

The new class of fusion protein agents falls under Peregrine's VTA technology platform that includes over 200 patents and patent applications covering broad concepts of tumor therapy using agents that target tumor blood vessels. Because interferon is currently part of standard-of-care therapy for hepatitis C virus infection, Peregrine also intends to assess the utility of the new class as a second-generation treatment for HCV infection.

Peregrine's lead anti-phospholipid agent bavituximab is currently being studied in Phase l clinical trials in the U.S. for the treatment of solid tumors and chronic hepatitis C infection. Clinical data collected to date have shown that bavituximab is safe and well tolerated, and the company has reported promising signs of anti-viral activity in the hepatitis C trial. A solid cancer trial in India combining bavituximab and chemotherapy regimens is expected to start shortly.

The presentation, "Targeting Inside-Out Phosphatidylserine (PS) on Tumor Vascular Endothelium," was presented today at 2:45 pm EDT by Dr. Xianming Huang of UT Southwestern Medical Center at the 4th Annual Angiogenesis and Vascular Targeting Agents Conference in Boston, MA.

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 trials in cancer and HCV infection with its lead product candidates bavituximab and Cotara®. Peregrine also has in-house manufacturing capabilities through its wholly owned subsidiary Avid Bioservices, Inc. (www.avidbio.com), which provides development and bio-manufacturing services for both Peregrine and outside customers. Additional information about Peregrine can be found at 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 which include statements with respect to the potential therapeutic benefits and successful development of drug candidates, involve risks and uncertainties including, but not limited to, that risk that any such drug candidate will not be well tolerated or the risk that preclinical animal model results regarding tumor reduction or lack of toxicity will not correlate with subsequent human studies. 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, 2006 and the Form 10-Q for the fiscal quarter ended July 31, 2006. 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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