Generex Biotechnology to Test Novel RNAi-Based Immune-Response Strategy in Cancer Patients
News Mar 27, 2007
Generex Biotechnology Corporation has announced that its Antigen Express subsidiary has entered into an agreement with Beijing Daopei Hospital in Beijing, China to conduct clinical trials on a novel immunotherapeutic strategy using the Company's proprietary methods of RNAi stimulation of the immune response against the patients' immune cells.
The trials will be conducted under the direction of Dr. Daopei Lu. Dr. Lu was the first to perform bone marrow transplantations in China, has been involved in many clinical trials, and has authored over 200 articles in peer-review journals.
RNAi (RNA interference) refers to the introduction of homologous double stranded RNA (dsRNA) to specifically target a gene's product, resulting in null or hypomorphic phenotypes. The technology is being viewed as a possible groundbreaking improvement over current therapies, such as chemotherapy for cancer, which uses a broad stroke method, destroying the cancer cells but damaging healthy cells in the process.
The strategy pioneered by Antigen Express involves modifying the patient's cancer cells to increase their immunogenicity and thereby enable the immune system to fight off the cancer anywhere in the patient's body. Antigen Express scientists and others have shown that cancer cells expressing MHC class II molecules but not the MHC class II associated invariant chain (Ii protein) can be used as robust vaccines in pre-clinical models.
The Ii protein serves to block MHC class II molecules from associating with aberrant tumor-associated peptides in the cancer cell which it could otherwise present on the surface of the cell to activate T helper immune cells. Normally, the expression of MHC class II molecules and the Ii protein are strongly linked; such that if one is expressed so is the other.
While some groups have used cloning methods to introduce genes for a MHC class II molecule into cancer cells without a gene for Ii (thereby creating a potent cancer cell vaccine) these methods are not practical for clinical application.
Antigen Express has developed proprietary methods using RNAi to specifically inhibit expression of the Ii protein in cancer cells already expressing MHC class II molecules that are amenable to clinical use. Cancer cells from patients with acute myelogenous leukemia will be transfected with a vector expressing RNAi to silence Ii expression. After lethal irradiation, the cells are re-introduced as a subcutaneous immunization to the patient.
"We are very pleased to be working with Dr. Daopei Lu and his team," said Dr. Eric von Hofe, President of Antigen Express. "The results from our pre-clinical studies with Dr. Lu, together with our prior studies, clearly show the potential of this immunotherapy strategy."
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