Targeted Genetics Corporation acquired full exclusive rights to its preclinical Huntington's disease (HD) programme 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 programme to Targeted Genetics and gives us exclusive rights and direct involvement with the University of Iowa to expedite the programme," said H. Stewart Parker, president and chief executive officer, Targeted Genetics. "This programme 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."

HD is a devastating, inherited, neurodegenerative disorder that results from a mutation in the gene that code 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 characterise this disease.

"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," said 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."