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Targeted Genetics Licenses Technology for Gene Transfer

Study Published Today Reports Improved Gene Transfer Efficiency

SEATTLE - Nov. 21, 1997 - Targeted Genetics Corporation (Nasdaq: TGEN) and Fred Hutchinson Cancer Research Center (Hutchinson Center) today announced a sublicense agreement with Genetic Therapy, Inc. (GTI). The agreement grants GTI a limited non-exclusive, worldwide sublicense to the patent covering a retroviral packaging cell line, called PG13. Retroviral vectors produced by the PG13 cell line are useful for stable gene transfer into various target cells. Financial terms of the agreement were not disclosed. The technology covered under the agreement is protected under U.S. patent 5,470,726 which issued in 1996, and is co-owned by the Hutchinson Center and the National Institutes of Health, and is exclusively licensed to Targeted Genetics.

"We continue to be very excited about the potential of PG13 for use in a number of gene therapy indications," said H. Stewart Parker, president and CEO at Targeted Genetics. "We plan to collaborate or license the technology to other parties for those indications not of primary interest to Targeted Genetics."

The utility of the PG13 cell line is reported in the December 1 issue of the journal Blood. The study, conducted by the Hutchinson Center, found that the PG13 cell line offers the potential for more efficient gene transfer rates in human gene therapy targeting hematopoietic stem cells (cells from which all blood cells are derived), and potentially T-cells (immune system regulators).

Specifically, the study showed that retroviral vectors produced from the PG13 cell line are capable of transducing stem cells in primates, and do so at a higher gene transfer efficiency rate than vectors produced from the PA317 cell line. PA317 is a cell line that produces amphotropic retroviral vectors which are commonly used for transducing stem cells, and have shown limited success for in vivo applications. Vectors produced by the PG13 cell line recognize a receptor that is present at three to five fold higher levels in human cells, than amphotropic receptors. The in vivo strategy of this research study directly compared gene transfer into stem cells by vectors produced by PG13 and PA317 cell lines. Results of the comparison demonstrated that vectors produced by PG13 target human repopulating cells at efficiency rates high enough to generate production of therapeutically significant quantities of genetically modified blood cells.

"We are finally seeing gene transfer efficiencies that may allow us to actually treat a variety of genetic disorders such as Gaucher disease, as well as acquired diseases such as AIDS," said Hans-Peter Kiem, M.D., study investigator at the Hutchinson Center.

The retroviral vector produced by the PG13 cell line was designed by A. Dusty Miller, Ph.D., molecular biologist at the Hutchinson Center and Scientific Advisory Board member at Targeted Genetics. Additional data on the study published today in Blood will be presented in December at the American Society of Hematology's annual scientific meeting in San Diego.

Fred Hutchinson Cancer Research Center is an independent, non-profit research institution dedicated to the development and advances in medical technology to eliminate cancer and other potentially fatal diseases. The Hutchinson Center is one of 27 National Cancer Institute-designated comprehensive cancer centers, and the only one in the Northwest.

Targeted Genetics Corporation develops gene and cell therapy products for the treatment of certain acquired and inherited diseases. The company has three lead product development programs targeting cystic fibrosis, cancer, and HIV cell therapy, as well as an extensive technology platform for gene delivery and expression.

NOTE: Additional written materials, recent press releases and company information are available through a variety of sources, including the Targeted Genetics World Wide Web site at www.targen.com, and 24 hours a day at no charge by calling PR Newswire's Company News On-Call at 800-758-7804, extension 832075.

Contacts:

Susan Edmonds
Media relations manager
Phone: (206) 667-2896
Pager: (206) 994-6833
Fax: (206) 667-7005
E-mail: sedmonds@fhcrc.org

Amy Hampson
Media relations specialist
Phone: (206) 667-5095
Pager: (206) 609-0671
Fax: (206) 667-7005
E-mail: ahampson@fhcrc.org

Alberta L. Garvin
Targeted Genetics Corporation
(206) 521-7824 

Fred Hutchinson Cancer Research Center is a world leader in research to prevent, detect and treat cancer and other life-threatening diseases.