Targeted Genetics and its Collaborators Reports Advances in HIV Vaccine Manufacturing Capabilities at ASGT

May 31, 2007

Targeted Genetics Corporation (Nasdaq: TGEN) announced today that its academic collaborators at Columbus Childrens Research Institute (CCRI) and Childrens Hospital of Philadelphia (CHOP) presented data describing a novel cell line-based method for manufacturing AAV-based vaccines. The data are to be presented today in a poster session (Abstract #84) at the 10th Annual Meeting of the American Society of Gene Therapy in Seattle (ASGT). Researchers at Targeted Genetics also presented a poster (Abstract #87) demonstrating the utility of an assay that can be used for testing the stability and relative potency of different lots AAV-HIV gag based vaccines.

Abstract #84 describes the development of a cell line-based AAV manufacturing process that utilizes Vero cells, which are derived from African green monkeys. Vero cell lines are used for the production of numerous approved human vaccines, including poliovirus and rabies.  In this small-scale study, the Vero-based method has a similar yield compared with the HeLa-based manufacturing process developed by Targeted Genetics and its collaborators.  A manufacturing process for AAV-based vaccines that utilizes a cell substrate common to commercial vaccine production processes may have regulatory advantages.

Abstract #87 describes a relative potency assay for a candidate AAV serotype 1 (AAV1)-based vector encoding gag genes from HIV.  The assay is an in vitro method that tests the capacity of a recombinant AAV1 vector to transduce cells and express the HIV protein gag p24. Such assays are a critical component of the vaccine manufacturing process and are required by the U.S. Food and Drug Administration (FDA) for approval of all vaccine products.

These data highlight our focus on developing commercially viable products, said H. Stewart Parker, president and chief executive officer at Targeted Genetics. Even as we evaluate vaccine candidates and conduct clinical trials, we continue to develop, implement and validate critical components of an approvable manufacturing process. The knowledge and process enhancements gained through this collaborative work take the field of AAV manufacturing to a new level.  Importantly, these advances can be applied to our portfolio of proprietary and partnered AAV-based product candidates.

The research described in both abstracts is focused on a comprehensive development program for AAV-based HIV/AIDS vaccines and is funded by the International AIDS Vaccine Initiative (IAVI) and by a contract awarded by the National Institute of Allergy and Infectious Diseases (NIAID) to CCRI in collaboration with CHOP and Targeted Genetics.

About AAV-Based Vaccines for HIV/AIDS
AAV-based prophylactic vaccine candidates for HIV/AIDS are designed to protect against HIV infection in HIV negative individuals and/or prevent progression to AIDS in people who become infected with HIV.  AAV-based vaccines are used to deliver HIV antigens that are intended to stimulate the immune system and fight against HIV infection.  Targeted Genetics, in collaboration with IAVI, CHOP and CCRI currently are conducting Phase II trials of tgAAC09, an AAV-based vaccine for use in the developing world. Under the NIAID sub-contract, an AAV-based candidate vaccine for use in the developed world is currently undergoing preclinical tests ?before advancing into clinical trials in healthy volunteers.

About Targeted Genetics
Targeted Genetics Corporation is a biotechnology company committed to the development of innovative targeted molecular therapies for the prevention and treatment of acquired and inherited diseases with significant unmet medical need. Targeted Genetics proprietary Adeno-Associated Virus (AAV) technology platform allows it to deliver genes that encode proteins to increase gene function or RNAi to decrease or silence gene function.  Targeted Genetics product development efforts target inflammatory arthritis, AIDS prophylaxis, congestive heart failure and Huntington's disease. To learn more about Targeted Genetics, visit Targeted Genetics website at

Safe Harbor Statement under the Private Securities Litigation Reform Act of 1995:
This release contains forward-looking statements regarding preclinical results,  the potential of Targeted Genetics gene delivery technology and other statements about the plans, objectives, intentions and expectations of Targeted Genetics. These forward-looking statements involve current expectations, forecasts of future events and other statements that are not historical facts. Inaccurate assumptions and known and unknown risks and uncertainties can affect the accuracy of these forward-looking statements. Actual results or developments may be materially different from the results projected or implied in these forward-looking statements. Factors that could affect our actual results include, but are not limited to, the risk of preclinical results not advancing into clinical or therapeutic benefit, Targeted Genetics ability to obtain, maintain and protect its intellectual property, Targeted Genetics dependence on the efforts of third parties, the timing, nature and results of research and clinical trials, potential development of alternative technologies or more effective processes by competitors, and, whether  regulatory or institutional approvals can be obtained and maintained, as well as other risk factors described in Item 1A. Risk Factors in Targeted Genetics report on Form 10-K for the year ended December 31, 2006 as updated in its Form 10-Q for the quarter ended March 31, 2007. You should not rely unduly on these forward-looking statements, which apply only as of the date of this release. Targeted Genetics undertakes no duty to publicly announce or report revisions to these statements as new information becomes available that may change these expectations.

Investor and Media Contact:
Stacie D. Byars
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Targeted Genetics Corporation
(206) 521-7392

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