Peregrine Pharmaceuticals Inc. a clinical stage biopharmaceutical company developing targeted therapeutics for the treatment of cancer and hepatitis C virus (HCV) infection, has announced that enrolment of the planned 12 evaluable patients in its phase lb cancer trial has been completed.

This trial at clinical sites in India is designed to assess the safety of bavituximab in combination with common chemotherapy agents in advanced cancer patients with metastatic disease who had failed prior therapy. Data from this study are expected to support the initiation of phase II cancer trials later this year.

To date, the safety profile of bavituximab in combination with chemotherapy appears similar to that seen in advanced cancer patients undergoing chemotherapy treatment alone. Nine patients have completed their course of therapy and have been assessed for tumour response at the eight week scheduled MRI or CT scan. Of these, more than half of the patients achieved either disease stabilization or an objective tumour response. "Disease stabilization" is defined as less than a 20 per cent increase in the size of the tumour up to a 30 per cent reduction in tumour size, while "objective response" is defined as greater than a 30 per cent reduction in tumour size.

Both stable disease and objective response are considered potential signs of anti-tumour activity. Patients demonstrating either an objective tumour response or stable disease have been offered continued treatment with the combination regimen on a compassionate use basis.

"We are encouraged by the results seen to date in this first test of bavituximab in combination with common chemotherapy regimens," said Steven W. King, president and CEO of Peregrine. "Achieving stable disease and objective responses in these very ill advanced cancer patients is a promising sign, and we look forward to reporting top-line results as soon as patient follow-up and data analysis are complete. We are optimistic that these results, in combination with data from our ongoing US phase l cancer trial, will support advancing bavituximab into more extensive combination therapy cancer trials later this year."

The phase Ibo open label trial is designed to characterize the safety, tolerability and pharmacokinetics of bavituximab given in combination with standard chemotherapy regimens including docetaxel, gemcitabine and carboplatin paclitaxel. These regimens are commonly used for treating major solid cancers, and the enrolled patients include those with breast, ovarian and lung cancers. Study patients are considered enrolled and evaluable for safety analysis after completing four of the planned eight weekly doses of bavituximab in combination with chemotherapy.

The chemotherapy agent was administered for up to eight weeks on its standard prescribed administration schedule. Patients are also being evaluated for tumour response according to Response Evaluation Criteria in Solid Tumours (RECIST) parameters, receiving CT or MRI scans prior to therapy and at week eight, although this assessment is not a formal endpoint of the study.

Bavituximab is a monoclonal antibody that targets and binds to a phospholipid called phosphatidylserine, which is located on the inside of normal 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.