• 10/22/2004
  • Seattle, WA
  • Press Release
  • Introgen Therapeutics, Inc

Introgen Therapeutics, Inc. (Nasdaq: INGN – News) today announced preclinical data demonstrating the promise of its INGN 225 therapy as a cancer vaccine. The data were presented yesterday at the Third Annual AACR International Conference on Frontiers in Cancer Prevention Research, being held in Seattle. INGN 225 is a therapeutic consisting of a cancer patient’s own immune cells treated with an adenovector carrying the human p53 gene, Ad-p53. INGN 225 is currently in Phase 1/2 trials in patients with small cell lung cancer and breast cancer. Introgen is also developing Ad-p53, or ADVEXIN®, in phase 3 clinical trials for head and neck cancer, and for a variety of other cancers.

Previous studies have shown that p53 is a critical tumor suppressor gene, whose function is to prevent tumor formation. Mutations in p53 are required for tumor formation. These characteristics make p53 protein an ideal target for a cancer vaccine. In normal cells, p53 is found at very low levels and its expression is very tightly controlled. In cancer cells however, p53 fails to function normally and often accumulates to high levels. This high level of abnormal expression of p53 is used by the immune system to identify and destroy tumor cells following INGN 225 vaccination.

“We believe that these studies highlight the great potential of INGN 225 for the treatment of cancer, and we are equally excited by the prospect of using this technology to prevent cancer,” said Sunil Chada, Ph.D., Introgen’s director of Research and Development. “The ability of INGN 225 to stimulate natural immunity and kill cancer cells is an important advance in the development of cancer vaccines. INGN 225 is a good example of how we can combine molecular therapies with the body’s own immune system to develop new cancer vaccine strategies.”

The studies presented today were designed to assess the activity of p53-directed immunotherapy and specifically, the ability of p53-treated immune system cells, termed dendritic cells, to generate immunity against cancer cells that over-express p53. Mice were vaccinated with their own dendritic cells or with INGN 225. After 24 days, the mice were injected with a dose of cancer cells that previously has been shown to give rise to cancer in 100 percent of animals tested. In these studies, up to 85 percent of animals were protected from developing tumors. INGN 225 also was assessed for its effect on existing tumors and demonstrated a significant reduction in tumor growth compared with controls. Importantly, activation of the immune system to recognize high levels of p53 expressed in cancer cells did not result in any damage to normal tissue, indicating that this approach should have a very good safety profile.

“The ability to activate a patient’s immune system is a key advantage of using this type of therapeutic approach,” said Dmitry Gabrilovich, M.D., Associate Professor of Oncology at the H. Lee Moffitt Cancer Center and principal investigator of the INGN 225 lung cancer clinical trial. “In these studies, combining the power of Ad-p53 with dendritic cell technology enabled us to generate potent immune responses and prevent tumor growth in animal models. These data validate the use of tumor suppressor antigens as therapeutic targets, and demonstrate that adenovectors provide an efficient method of stimulating dendritic cells so that they can generate a powerful anti-cancer immune response. We hope to ultimately be able to expand our ongoing therapeutic studies in patients into future prevention of this terrible disease.”

Introgen is a leading developer of biopharmaceutical products designed to induce therapeutic protein expression using non-integrating gene agents for the treatment of cancer and other diseases. Introgen maintains integrated research, development, manufacturing, clinical and regulatory departments and operates a commercial-scale, CGMP manufacturing facility.