Tarvacin shows significant anti-viral activity

Peregrine Pharmaceuticals today announced that there will be two presentations, April 4 and 6, at the American Association of Immunologists (AAI) annual meeting in San Diego, California, indicating the anti-viral potential of its Tarvacin antibody. Dr. Melina Soares of The University of Texas Southwestern Medical Center at Dallas will present pre-clinical data titled "Targeting inside-out phospholipids on viruses in a guinea pig model of Lassa fever."

The data to be presented demonstrates that Tarvacin has significant anti-viral activity in the treatment of Pichinde virus, which is an established model for Lassa fever, a fatal viral hemorrhagic fever that is on the U.S. government's biodefense Category A watch list.

Key Study Findings Include:

• Animals lethally infected with Pichinde virus and then treated with Tarvacin showed a 50 percent survival rate as compared to zero survivors in the control treated group.

• Surviving animals did not show any signs of viral infection several months after treatment with Tarvacin and were considered to have been disease free.

•  Surviving animals had long-term immunity to further infection with the Pichinde virus.

• Tarvacin protected lethally infected animals whether treated at the time of viral challenge or once symptoms had developed indicating an active viral infection.

• Tarvacin binds to both Pichinde viral particles and Pichinde-infected cells.

"The pre-clinical data demonstrate that Tarvacin and related Anti-Phospholipid Therapy agents have anti-viral therapy which, if proven out in the clinic, has far reaching implications for the treatment of infectious disease," said Dr. Philip Thorpe, professor of pharmacology at UT Southwestern, and the co-author on the presentations. "Since Tarvacin targets a basic, universal property of enveloped viruses that is host-derived and independent of the viral genome, it may be effective against a broad spectrum of enveloped viruses. This target may also be difficult for viruses to overcome via resistance mechanisms."

Enveloped viruses account for many of the most concerning viral health risks including HIV, Hepatitis B and C, cytomegalovirus, hemorrhagic fever, SARS and various types of influenza including Avian influenza. The presentations represent a summary of first-year results from an ongoing 3-year, $1.68 million grant from the National Institute of Allergy and Infectious Disease (NIAID), which is part of the National Institutes of Health (NIH). The funded research is investigating the ability of anti-phospholipid antibodies to bind directly to enveloped viruses and to virally infected cells from a number of viruses.

"This data supports a second exciting opportunity for Tarvacin to accompany the broad anti-cancer activities seen with the same compound," said Steven King, president and CEO of Peregrine. "Because we have a complete IND package for manufacturing and pre-clinical safety of Tarvacin that was used to support the upcoming Phase I cancer therapy clinical trial, we may be able to initiate clinical evaluation of Tarvacin in the near future as an anti-viral agent."

Anti-Phospholipid Therapy is Peregrine's novel approach to treating cancer, viral infections and certain ocular diseases. It is based on the finding that aminophospholipids, which are basic components of the inner surface of the cellular membrane, become exposed as antigenic targets in response to certain disease states.

A large number of viruses significant to global health and security possess an "envelope" derived from their host cell membrane. Since viruses lack the means to maintain structural organization of the envelope, amino-phospholipids such as phosphatidylserine (PS) and phosphatidylethanolamine (PE) become exposed on the surface of these viruses, making them a potential therapeutic target. Peregrine, together with its collaborators, has developed a series of monoclonal antibodies directed against aminophospholipids to take advantage of this property.