Targeted Genetics Enhances Patent Portfolio Related to AAV Serotype 1.

SEATTLE -- Targeted Genetics Corporation (Nasdaq:TGEN) today announced the issuance of a new patent that further strengthens the company's leadership in developing adeno-associated virus (AAV)-based therapies. U.S. Patent 7,105,345, titled "Adeno-Associated Virus Serotype 1 Nucleic Acid Sequences, Vectors And Host Cells Containing Same" covers compositions of AAV vectors that encode capsid proteins derived from AAV serotype 1 (AAV1) and host cells into which such vectors are introduced. The patent is a continuation of U.S. Patent #6,759,237 that provides additional protection around recombinant AAV vectors that Targeted Genetics is utilizing in several product development programs. The patent was issued to the University of Pennsylvania and is exclusively licensed to Targeted Genetics. The patent covers both AAV1 serotype and AAV1 pseudotyped vectors. Vectors of one serotype that are engineered to express capsid proteins of a different serotype are said to be "pseudotyped."

"A growing body of data shows that the use of AAV1 pseudotyped vectors improves the efficiency of delivery of recombinant AAV vectors to various tissues including muscle and brain. This increase efficiency of delivery leads to increased expression of the gene product. We have made significant advances in the development, manufacture, and purification of AAV1 vectors at commercial scale," said Barrie J. Carter, Ph.D., chief scientific officer of Targeted Genetics. "Earlier this year we presented preclinical data at the American Society of Gene Therapy Annual Meeting demonstrating the persistence of an AAV1 pseudotyped HIV vaccine candidate following administration to muscle. The patent issued today enhances our intellectual property around AAV vectors, which may expand our product development opportunities."

AAV naturally exists as several different serotypes, which differ physically in the composition of their capsid proteins and genome structures. AAV vectors containing different AAV capsid serotypes have been reported to transduce certain tissues more efficiently and with different specificity. The patent announced today covers compositions of AAV vectors with AAV1 serotype capsids. AAV1 vectors have been reported to result in higher levels of expression of the gene of interest when delivered to muscle compared to other AAV capsid serotypes such as AAV2 or AAV5.

"We, in collaboration with our partners, are currently evaluating AAV1 pseudotyped vectors in our HIV/AIDS vaccine, congestive heart failure and Huntington's disease product development programs," said H. Stewart Parker, president and chief executive officer of Targeted Genetics. "Additionally, we have leveraged our expertise in AAV manufacturing to develop a commercial scale manufacturing and purification process for AAV1 pseudotyped vectors for use in the clinic. We believe that these activities will enhance our commercial opportunities and support our position as the partner of choice for other biopharmaceutical companies that wish to access our robust AAV technologies."

Targeted Genetics was the first to bring AAV vectors into clinical trials. AAV is a naturally occurring virus that is not associated with any disease in humans. AAV vectors can efficiently deliver genetic information to numerous cell types and can be engineered to carry a variety of DNA sequences. These vectors are highly stable, persist in cells for extended periods of time, and carry an extremely low frequency of integration into host-cell DNA.

About Targeted Genetics

Targeted Genetics Corporation is a biotechnology company committed to the development and commercialization of innovative targeted molecular therapies for the prevention and treatment of inflammatory arthritis, HIV/AIDS and other acquired and inherited diseases with significant unmet medical need. Targeted Genetics uses its considerable knowledge and capabilities in the development and manufacturing of gene delivery technologies to advance a diverse product development pipeline. Its product development efforts target inflammatory arthritis, HIV/AIDS, congestive heart failure, Huntington's disease, and hyperlipidemia. To learn more about Targeted Genetics, visit its website at www.targetedgenetics.com.

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This release contains forward-looking statements regarding our business strategy, our product development and other statements about our plans, objectives, intentions and expectations. In particular, the statements regarding the Company's future plans are forward-looking statements. These 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 forward-looking statements. Factors that could affect our actual results include, but are not limited to, our ability to obtain, maintain and protect our intellectual property, the timing, enrollment of patients, nature and results of our clinical trials, potential development of alternative technologies or more effective products by competitors, our ability to obtain and maintain regulatory or institutional approvals, and our ability to raise capital when needed, as well as other risk factors described in Item 1A. Risk Factors in our report on Form 10-K for the year ended December 31, 2005, and updated in Item 1A. Risk Factors in our subsequent reports on Form 10-Q. You should not rely unduly on these forward-looking statements, which apply only as of the date of this release. We undertake no duty to publicly announce or report revisions to these statements as new information becomes available that may change our expectations.