Celladon's first Phase II trial of MYDICAR for advanced heart failure meets primary endpoint

Targeted Genetics Corporation (Pink Sheets:TGEN) (the "Company") announced today that its licensing partner, Celladon Corporation, has reported today that Celladon's first Phase II trial with MYDICAR® for the treatment of advanced heart failure has met its primary safety and efficacy endpoints, as prospectively defined in the Phase II trial protocol.

“We look forward to disclosure of the full data from Celladon's clinical trial at the Heart Failure Congress 2010 on May 30, 2010, and to the plans for future development of MYDICAR”

The Company and Celladon first entered into collaboration and manufacturing agreements in 2004. In 2009, Targeted Genetics licensed its adeno-associated virus (AAV) vector serotype and manufacturing technology to Celladon and manufactured clinical supplies of MYDICAR. If MYDICAR is developed and commercialized by Celladon, then the Company could receive multiple milestone payments totaling up to $20 million, starting with a milestone payment should a MYDICAR Phase III human clinical trial commence. In addition, the Company could receive up to a 10% royalty on commercial sales of MYDICAR, subject to certain conditions. Alternatively, if Celladon enters into a partnering or other strategic transaction related to MYDICAR, the Company could receive a percentage of future partnering income or strategic transaction value received by Celladon and, in certain circumstances, a royalty of up to 10% on sales of MYDICAR.

Although Targeted Genetics' AAV technology has been utilized to develop and manufacture MYDICAR, the MYDICAR clinical trials are sponsored, managed, funded, and the data are analyzed by Celladon without participation from Targeted Genetics. Targeted Genetics has not reviewed the data obtained by Celladon in its Phase II clinical trial. Please refer to the press release issued by Celladon as seen at www.celladon.net for additional information regarding the development of MYDICAR and Celladon's MYDICAR clinical trial results.

"We look forward to disclosure of the full data from Celladon's clinical trial at the Heart Failure Congress 2010 on May 30, 2010, and to the plans for future development of MYDICAR," said Susan Robinson, President and CEO of Targeted Genetics. Ms. Robinson continued, "Should the product candidate MYDICAR proceed successfully through development and onto commercialization, it could provide a much needed advancement for the treatment of patients with heart failure, a significant clinical validation for the field of gene therapy, and a revenue stream for Targeted Genetics."