Roche and Mirus Bio Corporation have entered into a definitive agreement under which Roche will acquire Mirus Bio Corporation, a privately-owned US company based in Madison, Wisconsin

Mirus Bio Corporation focuses on the discovery and development of innovative nucleic acid based technologies, including a proprietary RNAi (Ribonucleic Acid interference) delivery platform.

RNAi (RNA interference) is a revolution in biology, representing a breakthrough in understanding how genes are turned on and off in cells.  It is a natural mechanism that the body uses to 'silence' certain genes – represents a potential whole new class of therapeutics for difficult to treat diseases. The major challenge of this promising technology has so far been the transport of RNAi molecules into the target cell. Mirus' delivery platform provides an innovative way of effectively getting RNAi therapeutics to specific disease targets.

Roche's mission is to find novel solutions for patients who suffer from difficult to treat diseases. RNAi therapeutics provides the capabilities to target complex diseases such as cancer, respiratory or metabolic disorders. In 2007, Roche already announced a major alliance with the US-based company Alnylam Pharmaceuticals, Inc., which included the acquisition of Alnylam's European research site located in Kulmbach, Germany. This is now Roche's established Centre of Excellence for RNAi therapeutic research.

Under the terms of the agreement, Roche will fully acquire Mirus for USD 125 million and will maintain an RNAi research site in Madison. Mirus' transfection reagents business will be divested into a standalone business to be known as Mirus Bio LLC, without any anticipated effect on existing customers. Employees will be offered a transition into their respective business unit. Closing of the transaction is subject to standard conditions. Completion is expected during the second half of 2008.