New Data Presented on Immunocytokine Fusion Protein Further Supports Broad Anti-Cancer Potential Of Peregrine's Anti-PS Technology Platform
- Immunocytokine Combining Peregrine's Anti-PS Antibodies and IL-2 Protected 80% of Animals From a Lethal Challenge With a Highly Aggressive Form of Breast
Cancer - - New Data Presented at International Conference on Vascular Targeted Therapies in Oncology Further Supports a Second Mechanism of Action for Anti-PS Antibodies -
MANDELIEU, France and TUSTIN, Calif., Oct. 5 /PRNewswire-FirstCall/ -- Peregrine Pharmaceuticals, Inc. , a clinical stage biopharmaceutical company developing targeted therapeutics for the treatment of cancer and hepatitis C virus infections, today reported that data presented at the International Conference on Vascular Targeted Therapies in Oncology showed that a fusion protein combining interleukin-2 (IL-2) and 2aG4, an anti-phosphatidylserine (anti-PS) antibody similar to Peregrine's bavituximab, was effective in stimulating a strong protective immune response when added to a cancer vaccine. The combination was effective in protecting animals against a lethal challenge with a highly aggressive form of breast cancer. The new data is being presented by Dr. Philip Thorpe, professor of pharmacology at UT Southwestern Medical Center in Dallas and a member of the Peregrine Scientific Resource Board.
In the study reported today, breast cancer cells were irradiated to inactivate them and to expose the anti-PS target on their surface. The irradiated cancer cells were then treated with the 2aG4-IL-2 fusion protein to increase their immunogenicity before being used to vaccinate the study animals. Eighty percent of the immunized mice survived a subsequent lethal challenge with live versions of these aggressive breast cancer cells. In contrast, no animals immunized with untreated irradiated breast cancer cells survived the subsequent lethal challenge.
"We are encouraged by the results of this study in a very challenging model of breast cancer that further support the broad potential of our anti-PS targeting platform," said Dr. Thorpe. "In view of these results, we are eager to learn more about the anti-cancer utility of these immunocytokine fusion proteins in combination with vaccines and as direct therapeutic agents."
The results of this study also suggest that anti-PS antibodies may be stimulating the immune system by a second mechanism. Phosphatidylserine that has become exposed on the external surface of cells has been shown to dampen the body's natural immune response. Researchers have demonstrated that anti-PS antibodies can block this immune-suppressing signal by binding to and neutralizing the exposed phosphatidylserine, allowing the immune system to mount a more vigorous response.
"This data further supports the broad potential of our anti-PS platform, building on earlier data demonstrating that anti-PS antibodies have the ability to recognize tumors and then initiate a robust immune response," said Steven W. King, president and CEO of Peregrine. "Previously we reported that our fusion proteins demonstrated excellent anti-tumor activity in a number of cancer models as a therapeutic agent. This new research shows that these same agents also have the potential to enhance cancer vaccines, priming the body's immune system to prevent the development of cancer in animals challenged with a normally lethal dose of cancer cells by enhancing the immune response to the tumor."
The new class of immunocytokine fusion protein agents is part of Peregrine's Vascular Targeting Agent (VTA) technology platform for cancer therapy that includes over 200 patents and patent applications covering broad concepts of tumor therapy using agents that target tumor blood vessels.
This study, "Enhancement of Tumor Immunogenicity by 2aG4-IL2 Fusion Protein," was conducted by Dr, Xianming Huang, assistant professor of pharmacology in the laboratory of Dr. Philip Thorpe. Study results are being presented by Dr. Thorpe at the International Conference on Vascular Targeted Therapies in Oncology, Mandelieu, France, October 05, 2007th, 2007 at 3:10pm local time (9:10am ET).
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(R). 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 this preclinical breast cancer animal model, and the uncertainty as to whether the results of future clinical studies will support moving this product candidate forward for the treatment of breast 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 and the quarterly report on Form 10-Q for the quarter ended July 31, 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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Posted: October 2007