Introgen Therapeutics Inc announced the publication of preclinical data from studies of two oncolytic viruses that have potential as novel cancer therapies. Introgen has licensed rights to these oncolytic viruses and other related technologies from VirRx, Inc. The studies were conducted in the laboratory of William S.M. Wold, chairman of the Department of Microbiology and Immunology at the Saint Louis University School of Medicine and founder and chief executive officer of VirRx, and are published in the current issue of Cancer Research.

INGN 007 (VRX-007) and VRX-009 are novel oncolytic adenoviruses that have been engineered to kill cancer cells via viral replication. These viruses can be engineered so that they are active in specific types of cancer cells.

The data published indicate that INGN 007 and VRX-009 efficiently killed cancer cells in culture. VRX-009, which has been designed to kill cells that carry a mutation common in many colon cancers, efficiently killed cultured colon cancer cells, but not lung cancer cells. INGN 007 effectively killed both types of cancer cells.

In an animal model of colon cancer, injection of either INGN 007 or VRX-009 into tumours suppressed tumor growth more efficiently than a negative control (five-fold and ten-fold suppression, respectively). INGN 007 also completely suppressed tumor growth in a lung cancer model of disease.

Louis Zumstein, Ph.D., director of research at Introgen, said "These preclinical data are very promising, and support our belief that oncolytic adenoviruses have enormous potential as a new class of cancer therapies that may provide potent and selective killing of cancer cells. These data also illustrate the flexibility of engineered oncolytic adenoviruses to target selected tumor types with great specificity. Our expertise in developing adenoviral-based cancer therapies, including Advexin in Phase 3 trials and INGN 241 in Phase 2 trials, positions us to be the leader in tumor-specific oncolytic adenoviruses. We are conducting additional studies to support the continued development of our oncolytic adenovirus programmes."

INGN 007 and VRX-009 are replicating adenovirus vectors that over-express ADP, an adenoviral protein that plays a key role in the release of viral particles from infected cells. This release kills the cell, and also yields a pool of new viral particles capable of infecting additional cells within the tumor. The ability to overexpress the ADP gene sets this technology apart from other existing oncolytic viruses and has been shown to provide a powerful antitumour effect. Introgen holds an exclusive license to this technology from VirRx.

"Oncolytic adenoviruses kill cancer cells through a mechanism that is completely different from chemotherapy or radiation," said Dr. Wold. "These viruses have the potential to treat many cancers that are resistant to currently available therapeutics. Additionally, it may be possible to use these viruses in combination with other therapies to create novel treatment regimens."