AstraZeneca has entered an R&D pact with Silence Therapeutics in the respiratory field. Silence will receive initial access fees, clinical development and commercial milestone payments as much as $400 million, plus royalties on product sales.

The three-year collaboration is designed to discover and develop proprietary siRNA molecules against as many as five specific targets provided by AZ. The companies will collaborate in the early phase of identification and optimisation of novel siRNA molecules, while AZ will retain full responsibility for clinical development and commercialization. The agreement is primarily in the respiratory field but includes an option to allow for targets that extend the collaboration into other disease areas of interest to AZ.

Silence will provide a license to its proprietary siRNA technology in return for an initial access fee of $15 million, which includes an equity investment of $10 million. AstraZeneca will hold nearly 3% of the voting rights of Silence Therapeutics.

Iain Ross, chairman of Silence, said, “This transaction provides further validation of the potential application of our proprietary AtuRNAi molecules and our leading position in the fast-developing field of RNAi therapeutics.”

Jan M. Lundberg, AZ’s executive vice president, discovery research, said, “SiRNA technology will enable AstraZeneca to target disease mechanisms intractable to small molecules and other approaches.”