Peregrine Pharmaceuticals, Inc., a biopharmaceutical company with a portfolio of innovative, clinical stage products for the treatment of cancer and hepatitis C virus infection, has reported new research that validates a second phospholipid drug target in Peregrine's proprietary anti-phospholipid platform. The data indicated that the new target, known as PE, can be specifically targeted on tumour blood vessels for anti-cancer applications, similar to the activity of PS (or phosphatidylserine), the target for Peregrine's bavituximab programme. The data were presented by Dr Philip Thorpe, an inventor of the anti-phospholipid technology, at the 2nd European Conference on Tumour Angiogenesis and Antiangiogenic Therapy in Munich, Germany.

"A growing body of preclinical and clinical data indicates that therapies targeting PS have significant potential as novel immunotherapeutics to treat cancer and viral infections," said Dr Thorpe, professor of pharmacology at UT South-western Medical centre and a member of the Peregrine Scientific Resource Board. "These new data confirm that certain other aminophospholipids share these properties, providing us with the opportunity to develop a variety of anti-phospholipid agents designed to target specific disease states. We look forward to continuing these studies and to assessing how we can apply these findings to develop important new drugs."

Data presented at the conference supported that the new target appears to exhibit many of the same qualities that make PS an attractive drug target. The data showed that therapeutic compounds targeting PE were able to specifically localize to tumour blood vessels, signal the immune system and exert anti-tumour effects against a model of the cancer fibrosarcoma, as had been previously demonstrated by antibodies that bind to PS. However, the new research showed that the new PE target could be addressed using a non-antibody drug candidate, unlike the previous PS studies, which all used monoclonal antibodies for targeting. These results open the door to the possibility that orally available agents such as peptides and potentially even small molecule drugs could eventually become second-generation drug candidates using Peregrine's technology.

"As our lead anti-PS agent bavituximab advances in clinical studies for the treatment of cancer and hepatitis C infection, we are increasingly enthusiastic about the clinical potential of its unique mechanism," said Steven W King, president and CEO of Peregrine. "These exciting new data show that our anti-PS approach represents a technology platform rather than a single target, and the new target already is included in our anti-phospholipid intellectual property portfolio. We will work with Dr Thorpe and his colleagues in continuing to explore the potential of these findings for our drug discovery and development efforts."

Peregrine's proprietary anti-phospholipid immunotherapeutic technology uses monoclonal antibodies to target and bind to specific phospholipids that are present on the inner surface of normal cell membranes, but which become exposed for binding on the external surface of cells that line the blood vessels associated with tumours, as well as on certain viruses and the cells they infect. After binding, these agents help stimulate the body's immune defenses to destroy cells that exhibit the specific phospholipid component on their surface.

Peregrine's lead anti-phospholipid agent bavituximab is currently being studied in phase l clinical trials in the US for the treatment of solid tumours and chronic hepatitis C infection. Clinical data collected to date have shown that bavituximab is safe and well tolerated, and the company has reported promising signs of anti-viral activity in the hepatitis C trial. A solid cancer trial in India combining bavituximab and chemotherapy regimens is expected to start shortly.