GENE THERAPY: Vector Transfers Genes to Bone Marrow - Cell Genesys, Inc's lentivirus vectors - Company Business and Marketing

Applied Genetics News, April, 1999

Cell Genesys, Inc. (342 Lakeside Dr., Foster City, CA 94404; Tel: 650/425-4400, Fax: 650/358-0803), in collaboration with scientists from Children's Hospital Los Angeles and the Markey Cancer Center of the University of Kentucky, has demonstrated efficient long term gene delivery to bone marrow stem cells using the company's lentiviral gene delivery system.

The vector successfully transferred a marker gene to 29% of targeted cells. Unlike a previously used retroviral vector, the lentivirus system was able to deliver genes to non-dividing cells. Stable expression of the introduced gene was observed over the 15- week duration of the study. The data were reported in the March 16, 1999 issue of the Proceedings of the National Academy of Sciences. "Successful gene transfer with lentiviral vectors signifies an important step forward in stem cell gene therapy research and overcomes a major limitation of other viral and non- viral gene delivery systems," says Mitchell H. Finer, vice president of research at Cell Genesys. Effective genetic modification of bone marrow stem cells could be the basis of immune-based strategies for the treatment of AIDS, cancer, and other diseases. Progress in stem cell gene therapy research has been hampered by the inability of previous gene delivery systems to deliver genes to non-dividing stem cells at levels high enough to have therapeutic benefit. The lentivirus vectors employed by Cell Genesys were derived from HIV. Company scientists have enhanced the safety profile of the vectors by using only three of the nine genes present in the parent virus. The genes removed were involved with viral replication and pathogenesis. Removal of these genes did not decrease the gene transfer efficiency of the vector. The newest engineered vectors have a built-in safety mechanism that eliminates the possibility of recombination with infectious virus, reports Cell Genesys. These third generation vectors are believed to have potential in human gene therapy.