Peregrine Pharmaceuticals, Inc reported that its lead product candidate bavituximab achieved the pre-specified Stage A primary endpoint in an ongoing phase-II clinical trial in patients with advanced breast cancer. The phase-II trial is an open-label, Simon two-stage design to evaluate the safety and efficacy of bavituximab in combination with the chemotherapy drugs carboplatin and paclitaxel in locally advanced or metastatic breast cancer patients. Fourteen of the 15 patients enrolled in Stage A were deemed evaluable for tumour response, with seven patients achieving an objective response by approximately eight weeks, after completing two treatment cycles. Six of the patients achieved partial tumour responses and one patient achieved a complete tumour response, according to Recist criteria.

With the Stage A pre-specified primary endpoint achieved, the design of the clinical trial allows for an additional 31 study patients to be enrolled.

"We have now achieved early success in all of our ongoing phase-II bavituximab cancer trials, surpassing our pre-specified primary endpoint criteria for the number of patients achieving an objective tumour response in each of the three clinical studies," said Steven W King, president and CEO of Peregrine. "The results reported today reinforce the positive early data seen in our phase-II breast cancer trial assessing bavituximab in combination with docetaxel, as well as the promising early data we reported last week from our phase-II bavituximab lung cancer trial. We will continue assessing patients for anti-tumor activity as treatment and follow-up progress, and we look forward to sharing more data from these trials in the coming months."

The primary objective of this multi-center phase-II trial is to assess overall tumour response rate. Secondary objectives include measuring time to tumour progression, duration of response, overall patient survival and safety parameters. All tumour responses in the trial are being evaluated using Recist criteria. Patients may continue to receive bavituximab alone after completion of chemotherapy as long as the cancer does not progress and side effects are acceptable. The trial is being conducted in India according to International Conference on Harmonization (ICH) and Good Clinical Practices (GCP) guidelines.

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 US women were diagnosed with breast cancer in 2008 and 40,480 women died of the disease in the US alone.

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 tumours, 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 tumour and the tumour 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.

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.