March 29, 2004

News Release: Peregrine's VTA &Docetaxel Combination Therapy Inhibits Human Breast Cancer Growth by 93% in Pre-Clinical Studies

Peregrine Pharmaceuticals, Inc. (Nasdaq: PPHM) announced today that researchers at The University of Texas Southwestern Medical Center at Dallas (UT Southwestern) presented pre-clinical data at the American Association of Cancer Research annual meeting demonstrating that its anti-phospholipid antibody 3G4 significantly enhances the efficacy of chemotherapy. In data presented, breast cancer tumors were treated with a combination of 3G4 and Docetaxel, which is among the most widely used chemotherapy agents to treat breast cancer. Combination therapy with 3G4 and Docetaxel resulted in 93% inhibition of human breast cancer growth in pre-clinical models. Peregrine has developed a chimeric 3G4 analog that it is developing under the trade name Tarvacin(R). Tarvacin is part of Peregrine's Vascular Targeting Agent Anti-Phospholipid Therapy (APT) program and is expected to enter human clinical studies later this year. In the study, the authors evaluated the effectiveness of 3G4 to enhance the therapeutic effect of Docetaxel in breast tumor models. Tumor growth was inhibited by 93% in the combination-treated group, as compared with 68% and 60% in groups treated with Docetaxel or 3G4 alone, respectively. The authors concluded, 'These studies indicate that as an adjuvant therapy, 3G4 could enhance the therapeutic efficacy of Docetaxel in breast cancer patients, potentially providing a more effective therapy for breast cancer.'

'These results indicate why we are particularly excited about the Tarvacin program,'said Steven King, Peregrine's president and CEO. 'The results presented, as well as other pre-clinical data, are critical in helping determine the best way to effectively treat cancer using Tarvacin.'Peregrine currently plans to begin conducting human clinical studies later this year that will likely involve using Tarvacin alone and in combination with existing anti-cancer cytotoxic agents.

About Phosphatidylserine (PS)

PS is an aminophospholipid or anionic phospholipid. The main function of phospholipids is the formation of cellular membranes. In normal cells, anionic phospholipids are on the inside of the cellular membrane. Exposure of anionic phospholipids on the cell surface occurs during apoptosis (normal cell death), necrosis, cell injury, cell activation and malignant transformation. Factors in the tumor microenvironment cause a breakdown of asymmetry and exposure of anionic phospholipids on the cell surface of the blood vessel and malignant cells.

Anionic phospholipids are attractive as tumor blood vessel targets for several reasons: they are abundant; they are on the surface of the endothelial cells that line tumor vessels that are accessible to VTAs in the blood; they are present on a significant percentage of endothelial cells in diverse solid tumors, and they appear to be absent from vascular endothelium in all normal tissues.

Peregrine has developed an anti-phosphatidylserine (PS) monoclonal antibody named 3G4. When injected into tumor-bearing mice, 3G4 localizes specifically to tumor endothelium. In pre-clinical studies, 3G4 alone significantly inhibits tumor growth in a variety of rodent tumor models. Up to 50% regressions have been seen in syngeneic and human tumors, including human breast carcinomas.

Anti-PS antibodies may also have uses as anti-viral agents. Anti-PS drugs operate on a new principle in virology. When enveloping viruses egress from a host cell after replication, many capture some of the lipids of the host cell for use as their outer membrane. Lacking the natural mechanism for properly aligning the lipids, the outer membranes of these viruses have lipids that are inside-out. The anti-PS antibodies direct the immune responses to the inside- out components of the viral membrane, or envelope. These drugs could potentially be effective against numerous viruses that have similar outer membranes.

About Peregrine Pharmaceuticals, Inc.

Peregrine's research and development efforts focus on discovering and developing products that affect blood flow to tumors. Peregrine's vascular research programs fall under several different proprietary platforms including Anti-Phospholipid Therapy (APT), Vascular Targeting Agents (VTAs), anti- Angiogenesis and Vasopermeation Enhancement Agents (VEAs). The company has research collaborations with pharmaceutical and biotechnology companies to develop its VTA platform for therapeutic and diagnostic applications and expects to enter its first APT compound into clinical trials for cancer therapy during calendar year 2004.

Peregrine's vascular agents may also have applications in other angiogenesis-dependent diseases besides cancer such as diabetes, arthritis, skin disorders and eye diseases. Peregrine currently has exclusive rights to over 190 U.S. and foreign patents and patent applications that broadly cover its vascular programs. In addition, the company is currently evaluating its proprietary targets for use in treating non-angiogenesis dependent diseases such as viral infections. The company believes that the pre-clinical data generated by the company and the broad nature of its intellectual property may provide many opportunities for product development, partnering and licensing.

Peregrine's most clinically advanced therapeutic program is based on a targeting platform outside vascular biology. This technology platform is known as Tumor Necrosis Therapy (TNT) and targets dead or dying tumor cells that are common to the majority of different tumor types. Cotara(TM), the most clinically advanced TNT program, is currently in a Phase I clinical trial for the treatment of colorectal carcinoma at Stanford University Medical Center. In addition, we have received protocol approval from the U.S. Food and Drug Administration ('FDA') to initiate a registration clinical study for the treatment of brain cancer. The company is currently seeking a development or funding partner to move the brain cancer program forward. The company believes that continuing the clinical development of Cotara(TM) in tumor types other than brain cancer will add significant value to the program. The company has a research collaboration to develop immunocytokines based on the TNT platform and a TNT based agent has been developed and approved for the treatment of lung cancer in China under a licensing agreement.

The company also operates a cGMP contract manufacturing facility for monoclonal antibodies and recombinant proteins through its wholly owned subsidiary Avid Bioservices, Inc. (www.avidbio.com). Avid produces clinical trial materials to support Phase I through Phase III clinical trials for biotechnology companies including Peregrine. Copies of Peregrine press releases, SEC filings, current price quotes and other valuable information for investors may be found on the website www.peregrineinc.com.

Safe Harbor Statement: This release may contain certain forward-looking statements that are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Actual events or results may differ from the company's expectations as a result of risk factors discussed in Peregrine's reports on file with the U.S. Securities and Exchange Commission, including, but not limited to, Peregrine's report on Form 10-Q for the quarter ended January 31, 2004 and on Form 10-K for the year ended April 30, 2003.

Peregrine Investor Relations Frank Hawkins and Julie Marshall Hawk Associates, Inc. (800) 987-8256 or This email address is being protected from spambots. You need JavaScript enabled to view it.

SOURCE Peregrine Pharmaceuticals, Inc.

Frank Hawkins and Julie Marshall, both of Hawk Associates, Inc., +1-800-987-8256, or This email address is being protected from spambots. You need JavaScript enabled to view it., for Peregrine Pharmaceuticals

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