Peregrine Pharmaceuticals reports on phase II trial of Bavituximab plus Docetaxel in advanced breast cancer

Peregrine Pharmaceuticals, Inc. has announced that updated preliminary data from the first stage of its Phase II trial evaluating bavituximab in combination with docetaxel showed that 10 of 14 (71%) evaluable breast cancer patients achieved an objective tumor response according to RECIST criteria.

The company also reported that patient screening has begun in the second stage of this trial, which will enroll 31 patients.

"Early data from the first stage of this bavituximab Phase II cancer study had already exceeded our expectations, so the positive updated results reported today are especially encouraging as we proceed with patient enrollment in the second stage of the trial," said Steven W. King, president and CEO of Peregrine. "We look forward to reporting more results from this study and a second ongoing Phase II breast cancer trial as we continue to learn more about bavituximab's potential in this important, hard-to-treat disease."

The main objective of the multi-center, open label Phase II study is to assess patients' overall response rate to bavituximab and docetaxel. In the trial's Simon two-stage design, 15 patients with advanced breast cancer were enrolled in Stage A. With 10 Stage A patients demonstrating objective tumor responses, the results have exceeded the pre-specified primary efficacy endpoint of six patients with objective tumor responses needed to proceed to Stage B. In Stage B, the trial is being expanded to include an additional 31 patients, for a total of 46 patients overall. Secondary objectives of the study include assessing time to tumor progression, duration of response, overall patient survival and safety parameters. Patients in the study are evaluated regularly for tumor response according to RECIST criteria.

The World Health Organization reports that breast cancer is the most commonly diagnosed cancer in women, and is second only to lung cancer as a leading cause of female cancer deaths. The National Cancer Institute estimates that approximately 182,460 U.S. women will be diagnosed with breast cancer in 2008 and 40,480 women will die of the disease.

Bavituximab is a monoclonal antibody that binds to the cellular membrane component phosphatidylserine (PS) that is usually located inside 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. By binding to PS, bavituximab is believed to help mobilize the body's immune system to destroy the tumor and the tumor blood vessels. Bavituximab currently is in two separate Phase II combination therapy trials for the treatment of advanced breast cancer and a Phase II combination therapy trial for the treatment of non-small cell lung cancer. A Phase I bavituximab monotherapy trial in advanced solid cancers is also continuing.