Research Products Division Continues Independent Operation as Mirus Bio LLC

July 22, 2008

Dear Customers;

You may have read the news that Mirus Bio Corporation is being acquired by F. Hoffmann-La Roche. This letter is to assure you that this transaction will not change the relationship between our research products business and our customers, distributors and collaborators.

Mirus Bio has operated as two divisions for some time. The Discovery division has focused on developing technology for therapeutic delivery of nucleic acids. This division will operate as a unit of Roche following close. The Research Products division will be independently owned and operated as Mirus Bio, LLC. We will be selling the same products, retaining all of our staff, operating from the same facility and maintaining our relationships with our customers and partners. In short, nothing will change with respect to our relationships. We are looking forward to continuing to build on our strong and successful partnerships.

Thank you for your business and ongoing loyalty. Please contact us if you have any questions or concerns.

Best regards,
Richard S. Schifreen, Ph.D.
Vice President Research Products

Questions?

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