Cell Genesys exclusively licenses technology for liver-directed Aav gene therapy from University of Washington.

Cell Genesys, Inc. (Foster City, CA; 650-425-4542) announced that it has entered into an exclusive worldwide license agreement with the University of Washington (Seattle, WA) to license the University's interest in a patent filing covering adeno-associated viral (AAV) gene therapy to the liver. The licensed patent filing is jointly owned with Cell Genesys and has a priority date of December 23, 1997. In addition, Cell Genesys' AAV patent portfolio currently includes more than 80 issued or granted patents and patent applications including a broad patent (United States Patent 5,753,500) issued in 1998 covering all gene therapy products that utilize AAV vectors to deliver genes.

"This new license agreement further strengthens Cell Genesys' proprietary position for AAV gene therapy of hemophilia and other diseases where liver-directed therapy is appropriate," stated Stephen A. Sherwin, MD, chairman and chief executive officer of Cell Genesys. "Moreover, our scientists have continued to advance our AAV technology platform by evaluating new approaches to delivering AAV vectors to a variety of treatment sites including the central nervous system as well as the liver."

Cell Genesys is currently evaluating liver-directed AAV gene therapy in animal studies of both types of hemophilia -- hemophilia A and B -- which result from genetic deficiencies in blood clotting factors VIII and IX, respectively. Since the liver is the natural production site for blood clotting factors, Cell Genesys has emphasized liver-directed AAV gene delivery in its preclinical hemophilia program and is currently planning to utilize this method of gene therapy for human clinical trials of hemophilia, which are expected to begin in 2001. At the American Society of Gene Therapy Meeting in June 2000, Cell Genesys reported that in non-human primate models of hemophilia B, therapeutic levels of factor IX were restored following a single administration of AAV gene therapy to the liver. In addition, in studies published in 1999 in the journal, Nature Genetics, an 85 percent reduction in bleeding episodes in a canine model of hemophilia B was achieved with a single administration of liver-directed AAV-factor IX gene therapy. Moreover, 24 months after the injection, the treated animals continued to produce the factor IX protein, which was deficient prior to treatment.

Cell Genesys has demonstrated successful gene delivery using AAV vectors in multiple preclinical studies in addition to hemophilia including studies in neurologic disorders such as Parkinson's disease. In these studies, long term gene expression has been achieved with AAV vectors since these vectors can insert a therapeutic gene into the DNA of the target cells thereby potentially allowing long term therapeutic benefit. A single administration of AAV-mediated gene therapy may therefore eliminate the need for repetitive treatment regimens.

Cell Genesys has four different gene delivery systems to employ in gene therapy product development including AAV, lentiviral, adenoviral and retroviral vectors. The choice of vector depends upon such considerations as the disease indication, production efficiencies and the size of the gene. For example, in Cell Genesys' preclinical gene therapy program for hemophilia A, the company has the option of employing either its proprietary AAV vector system if a shorter form of the factor VIII gene can be successfully applied, or its proprietary lentiviral vector system if the full length gene is required for the optimal production of the clotting factor protein. In contrast, Cell Genesys plans to employ its AAV vector system for hemophilia B gene therapy since the factor IX gene is small enough to fit in this vector.

Cell Genesys currently has one of the largest patent portfolios in the gene therapy field including more than 235 issued or granted patents and over 330 pending patent applications. The portfolio includes issued or granted patents for multiple gene delivery systems, specific therapeutic genes and gene therapy applications and multiple genetically modified cell types used in gene therapy independent of the gene delivery system or therapeutic gene.

Cell Genesys is focused on the development and commercialization of cancer vaccines and gene therapies to treat major, life-threatening diseases. The company is conducting two multicenter Phase II human clinical trials for its GVAX cancer vaccine in prostate cancer, a multicenter Phase I/II trial of GVAX vaccine in lung cancer and expects to initiate additional GVAX vaccine trials in pancreatic cancer, myeloma and leukemia during the coming year. Preclinical stage programs include gene therapy for hemophilia, cancer, cardiovascular disorders and Parkinson's disease. Cell Genesys' assets outside gene therapy include its approximately 12 percent ownership of Abgenix, Inc. and the company's licensing program in gene activation technology.