Targeted Genetics Corporation Acquires Rights to siRNA Development Program in Huntington's Disease From Sirna Therapeutics

Targeted Genetics Corporation Acquires Rights to siRNA Development Program in Huntington's Disease From Sirna Therapeutics

SEATTLE, WA -- Apr 7, 2008 -- Targeted Genetics Corporation (NasdaqCM:TGEN - News) today announced that it has acquired full exclusive rights to its preclinical Huntington's disease (HD) program from Sirna Therapeutics, a wholly owned subsidiary of Merck & Co., Inc.

In exchange for these rights, which include a license to intellectual property (IP) that Targeted Genetics may find necessary to develop and commercialize an HD product, Targeted Genetics will pay Sirna an undisclosed royalty on future sales. Sirna has also assigned to Targeted Genetics a licensing agreement it has with the University of Iowa that covers certain IP developed by Dr. Beverly Davidson's laboratory related to RNA interference (RNAi) including Adeno-Associated Virus (AAV) expressed RNAi.

In 2005, Targeted Genetics and Sirna Therapeutics formed a collaboration to develop HD therapeutics using an AAV delivered RNAi approach to target the HD gene. This collaboration also involved Dr. Davidson's laboratory and was based on preclinical proof of concept established by University of Iowa researchers. AAV vectors express for long periods of time and allow for infrequent dosing, which is highly desirable when administering a therapeutic directly to the brain.

"This moves all of the key pieces of this program to Targeted Genetics and gives us exclusive rights and direct involvement with the University of Iowa to expedite the program," said H. Stewart Parker, president and chief executive officer of Targeted Genetics. "This program is our primary proof of concept in the area of expressed RNAi, which we believe could present multiple product opportunities to help patients who currently have little hope for treatment, such as those with HD."

"The results we have produced in animal models of HD are very exciting. We have identified and are currently evaluating lead candidates in preclinical studies to move forward into clinical trials," stated Beverly L. Davidson, Ph.D., Roy J. Carver professor of medicine and vice chair of research in the Department of Internal Medicine at the University of Iowa. "Targeted Genetics' approach of using AAV vectors for the delivery of expressed RNAi may have advantages over alternative RNAi delivery approaches due to AAV's proven long-term expression capabilities, stability and safety profile."

HD is a devastating, inherited, neurodegenerative disorder that results from a mutation in the gene that codes for the huntingtin protein. HD generally shows onset in mid-life and, according to the Huntington's Disease Society of America, one of out of every 10,000 Americans has HD and an additional 200,000 are at risk of onset. The disease-causing gene produces a defective huntingtin protein that is toxic to certain brain cells and the subsequent neuronal damage leads to the movement disorders, psychiatric disturbances and cognitive decline that characterize this disease.

"There is a serious unmet medical need for an effective treatment for HD," said Alan Sachs, M.D., Ph.D., vice president RNA therapeutics, Merck Research Laboratories. "This agreement provides Targeted Genetics with the freedom to advance this AAV vector program in the hope of developing a treatment that targets the genetic cause of this devastating condition, not just the symptoms."

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 the Company's liquidity and financial resources, its ability to fund ongoing and future operations, its business strategy and product development, including statements regarding the data collected in the HD program, the timing, continuance or results of trials related to the HD program, the potential impact of the HD program on our results of operations and other statements about the Company's plans, objectives, intentions and expectations. 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 actual future events or results include, but are not limited to, payments anticipated by the Company under product development collaborations and contracts, the Company's actual expenses, the Company's ability to raise capital when needed, the timing, nature and results of the Company's clinical trials, potential development of alternative technologies or more effective products by competitors, the Company's ability to obtain and maintain regulatory or institutional approvals, the Company's ability to maintain its listing on the NASDAQ Capital Market and the Company's ability to obtain, maintain and protect its intellectual property, as well as other risk factors described in its filings with the Securities and Exchange Commission (SEC), including in "Item 1A. Risk Factors" in the Company's most recent annual report on Form 10-K for the year ended December 31, 2007 filed with the SEC. You should not rely unduly on these forward-looking statements, which apply only as of the date of this release. The Company undertakes no duty to publicly announce or report revisions to these statements as new information becomes available that may change the Company's expectations.