Peregrine Pharmaceuticals, Inc, announced that updated preliminary data from the initial cohort of 21 patients in its phase-II trial evaluating bavituximab in combination with carboplatin and paclitaxel showed that 11 of 17 evaluable patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) achieved an objective tumour response according to RECIST criteria, after completing the maximum six treatment cycles. The company also reported that patient dosing is underway in the expansion stage of the trial, which will enrol an additional 28 patients for a total of 49 patients overall.

"We are very pleased to see these additional objective tumour responses in this difficult-to-treat cancer following the full regimen of six treatment cycles of bavituximab and chemotherapy," said Steven W King, president and CEO of Peregrine. "These updated results build on the impressive data we reported after only four treatment cycles, which had already exceeded the pre-defined number of objective tumour responses needed to expand the trial to the larger cohort."

King added, "The tumour response data to date from this trial compares favourably to published studies with current standard-of-care lung cancer treatments, and we are looking forward to seeing results from the entire study. With dosing now underway in the expanded patient cohort, we expect to resume the brisk pace of enrolment achieved in the first cohort, with the goal of completing patient enrolment around mid-year. We intend to provide further updates as patient treatment and follow-up continue in the coming months."

The primary objective of the multi-center, open-label phase-II study is to assess the overall response rate to bavituximab with carboplatin and paclitaxel. In the trial's Simon two-stage design, 21 patients with previously untreated locally advanced or metastatic NSCLC were initially enrolled and 17 of these patients were deemed evaluable. In this initial cohort, 11 of the 17 evaluable patients achieved an objective tumour response by the time that treatment with the combination of bavituximab, carboplatin and paclitaxel was completed. Eight of the 11 objective tumour responses were confirmed by at least one repeat scan no less than four weeks after the criteria for response were first met.

Secondary objectives of the study include measuring time to tumour progression, duration of response, overall patient survival and safety parameters. Patients in the study are evaluated regularly for tumour response according to RECIST criteria. Patients may continue to receive bavituximab as monotherapy 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.

Lung cancer is a major cause of cancer deaths worldwide. According to the American Cancer Society, lung cancer is the second most commonly diagnosed cancer in men and women in the US and is the leading cause of cancer deaths. It estimates that in 2008, there were approximately 215,020 new cases of lung cancer in the US and an estimated 161,840 lung cancer deaths. NSCLC is the most common type of lung cancer, accounting for approximately 85 to 90 per cent of lung cancer cases.

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 Pharma is a biopharmaceutical company with a portfolio of innovative monoclonal antibodies in clinical trials for the treatment of cancer and serious viral infections.