SAN DIEGO and TUSTIN, Calif., April 14 PeregrinePharmaceuticals, Inc. (Nasdaq: PPHM) announced today that a preclinical studybeing presented by an independent team of investigators at the 2008 AnnualMeeting of the American Association for Cancer Research (AACR) furtherillustrates the broad anti-tumor potential of its anti-phosphatidylserine(anti-PS) vascular targeting antibodies. The study by Dr. Yayun Liang, Dr.Salman Hyder and colleagues at the University of Missouri describes promisinganti-cancer activity observed when a mouse equivalent to the company's PhaseII anti-PS antibody bavituximab was combined with an investigational agentthat re-activates the tumor suppressor p53, which is turned off in manytumors. Bavituximab is a monoclonal antibody that is believed to work byselectively destroying the blood vessels supporting tumor growth and spreadand by reversing the ability of tumors to suppress the body's natural immuneresponse.
"This study highlights the broad anti-cancer potential of our anti-PSvascular targeting platform," said Steven W. King, president and CEO ofPeregrine. "Numerous preclinical studies have shown the potential efficacy ofour anti-PS antibodies in combination with both existing and novel therapiesfor the treatment of cancer. This new study further illustrates the potentialversatility of our anti-PS antibodies in combination cancer therapy. We lookforward to future clinical studies of bavituximab and other anti-PS antibodiesin a broad range of anti-cancer regimens."
Dr. Liang and her colleagues reported on their study of a bavituximabequivalent antibody, 2aG4, in combination with a clinical stage small moleculeagent, PRIMA-1. PRIMA-1 restores the normal function of mutant forms of thetumor suppressor p53, enabling it to induce tumor cell death. The combinationtherapy resulted in additive and synergistic anti-tumor effects in two mousemodels of advanced breast cancer, enhancing tumor regression and elimination,while also reducing the incidence of lymph node metastases in some subjects.
Dr. Liang noted, "These results indicate that PRIMA-1 plus 2aG4combination therapy has a complementary and potent anti-tumor activity andcould define a new strategy for suppression of advanced breast cancers."
Bavituximab is a monoclonal antibody that binds to a phospholipid calledphosphatidylserine that is usually located inside normal cells, but whichbecomes exposed on the outside of the cells that line the blood vessels oftumors, creating a specific target for anti-cancer treatments. Bavituximabhelps mobilize the body's immune system to destroy the blood vessels neededfor tumor growth and spread. In a Phase lb pilot trial in advanced cancerpatients, bavituximab plus chemotherapy appeared to have a safety profileconsistent with chemotherapy alone and showed positive signs of clinicalactivity, achieving objective response or disease stabilization in 50% of theevaluable patients. Peregrine has received regulatory approval to conductthree Phase II trials to study the anti-tumor effects of bavituximab incombination with chemotherapy. These include two breast cancer protocols anda non-small cell lung cancer protocol. One of the bavituximab breast cancertrials is currently enrolling and dosing patients and the two other trials areexpected to begin shortly. Bavituximab is in clinical trials in the U.S. inpatients with advanced solid tumors and in patients co-infected with HCV andHIV.
No. 2341: Yayun Liang, Salman M. Hyder, Cynthia L. Besch Williford,Indira Benakanakere, Sandra L. Brandt, Philip E. Thorpe. Targeting mutant p53protein and tumor vasculature: An effective combination therapy for advancedbreast tumors, Univ. of Missouri, Columbia, MO, Simmons Cancer Center,University of Texas Southwestern, Dallas, TX, April 14, 2008, 8:00 AM -12:00PM PDT
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