Mobilizing the Immune System
Gene immunotherapy stimulates a patient's own immune system to attack tumors. Many other gene therapy techniques work by causing cancer cells to self-destruct, requiring delivery of a drug into every cancer cell. By eliminating this requirement, gene immunotherapy shows tremendous promise for treating metastatic disease or inaccessible tumors.
Genzyme Molecular Oncology applies three technological approaches to gene immunotherapy: cancer vaccines, stress genes, and the use of dendritic/cancer cell fusion technology. These approaches seek to stimulate the patient's immune response to attack and kill cancerous cells.
Cancer vaccines combine a tumor antigen gene with a delivery vector. Tumor antigens are proteins produced by tumors but not by normal cells. Genzyme Molecular Oncology is focused on the discovery of tumor antigens that prompt a potent cellular immune response against the tumor. We use SAGE™ and other proprietary technologies to identify and optimize tumor antigens for the development of cancer vaccine products. These technologies may allow us to discover novel antigens more quickly and in much greater quantities than previously possible.
Working with the National Cancer Institute, we have completed two phase I clinical studies in melanoma, the most serious type of skin cancer. These studies demonstrated that our adenoviral vectors containing melanoma tumor antigens MART 1 and gp100 genes were safe and well-tolerated. In addition, a small number of patients showed clinically significant tumor regression. We have designed additional phase I studies, in order to better understand how to consistently elicit this powerful immune response. We plan to use the knowledge gained from these trials, along with novel antigens identified in our research program, to target other cancer indications.
A second and complementary gene immunotherapy approach is the use of stress genes to stimulate an immune response. Delivery of stress genes to tumor cells appears to make these cells more recognizable by the immune system. We have formed a joint venture with StressGen Biotechnologies Inc. to develop stress genes for the treatment of ovarian and other cancers.
Genzyme Molecular Oncology has an option to license technology from the Dana Farber Cancer Institute that may be developed as a cell-based immunotherapy. This technology combines dendritic cells, a type of antigen-presenting cell, with tumor cells. The resulting "fusion" cell is administered to the patient with the purpose of eliciting a strong immune response against tumor cells that contain the same tumor antigens that are present on the fusion cell. |
