ASGT results from ENMD collaboration:
>>SEATTLE, June 1 /PRNewswire/ -- Cell Genesys, Inc. (Nasdaq: CEGE - news) and EntreMed, Inc. (Nasdaq: ENMD - news) today reported encouraging preclinical data demonstrating the feasibility of gene therapy as a strategy to inhibit tumor growth by delivering genes that block the growth of tumor blood vessels. In these studies, Cell Genesys' proprietary AAV (adeno-associated viral) and adenoviral gene delivery systems were used to deliver EntreMed's Angiostatin and Endostatin genes to lung tumors in a mouse tumor model. Each of the vector and antiangiogenic gene combinations demonstrated at least 50 percent inhibition of tumor growth as well as microscopically documented inhibition of tumor blood vessel growth. These data were reported by James G. McArthur, Ph.D., principal scientist and senior director of preclinical biology and immunology of Cell Genesys, at the American Society for Gene Therapy Meeting (ASGT) in Seattle, WA.
Various combinations of the gene delivery systems and antiangiogenesis genes were tested in a mouse lung tumor model. The delivery of Angiostatin with an adenoviral vector resulted in 60 percent inhibition of lung tumor growth. Administration of either the Angiostatin or Endostatin genes using the AAV vector resulted in greater than 50 percent inhibition of tumor growth with the most potent combination of AAV-Angiostatin resulting in greater than 80 percent reduction in tumor metastases compared to mice not receiving treatment. No treatment related toxicity was observed following AAV-Angiostatin gene therapy, and stable levels of the Angiostatin protein were maintained throughout the four-month study following a one-time delivery of the gene. These findings suggest that prolonged expression of Angiostatin or Endostatin through gene therapy could potentially obviate the need for repeated injections of the protein product. In the gene therapy studies in mice, all vectors were delivered intravenously by a single injection.
``We are encouraged by the data we have observed in initial preclinical studies of antiangiogenesis gene therapy and are intending to select a product candidate for potential human clinical studies by the end of this year,'' stated Joseph J. Vallner, Ph.D., executive vice president and chief operating officer at Cell Genesys. ``Cell Genesys' preclinical programs in cancer gene therapy combined with the company's extensive clinical programs for multiple GVAX® cancer vaccines demonstrate the depth of the company's product pipeline in cancer.''
``As we have observed in earlier preclinical studies for Angiostatin and Endostatin protein products, the administered gene therapies evaluated in these studies were well tolerated at doses producing significant antitumor activity,'' stated Dr. Edward Gubish, EntreMed's president and chief operating officer. ``We believe that evaluating the delivery of our antiangiogenic genes using gene delivery systems could be an important complement to direct injection of antiangiogenesis proteins.''
Angiostatin and Endostatin are naturally occurring proteins that have been shown to block tumor growth by preventing the development of the tumor blood supply through a process called antiangiogenesis. Direct administration of Endostatin and Angiostatin was shown to be safe and well tolerated in EntreMed's Phase I clinical trials in multiple types of cancer, and Phase II trials to determine the efficacy of the proteins are being planned.
Cell Genesys' proprietary AAV and adenoviral gene delivery systems, which have previously been shown to deliver genes safely and efficiently in a wide range of studies, are being used to deliver the antiangiogenic genes and may provide added benefit over direct administration of the proteins. Gene delivery systems are the means by which therapeutic genes are introduced into target cells or tissues to induce a therapeutic effect and are a critical component of any successful gene therapy.
In August 1999, Cell Genesys and EntreMed entered into a research collaboration to evaluate the use of EntreMed's Angiostatin and Endostatin in combination with Cell Genesys' AAV and adenoviral gene delivery systems in preclinical studies designed to assess whether the gene therapy can treat tumors by inhibiting their blood supply. Based on the results of the preclinical studies, a potential business collaboration will be considered.<<
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Cheers, Tuck |
