A leading RNA interference (RNAi) therapeutics company, Silence Therapeutics plc, has successfully completed its research work under the Research Collaboration and Delivery Collaboration with its partner AstraZeneca and its biologics arm, MedImmune.

The first collaboration between Silence and AstraZeneca was initiated in 2007 and was extended in 2010 and includes five research programmes on novel small interfering RNA (siRNA) therapeutic molecules for selected targets. The second collaboration, focusing on the development of novel approaches for the delivery of siRNA molecules, was established in 2008 and was also extended in 2010.

Under the first collaboration, Silence and AstraZeneca successfully identified, optimised and formulated novel siRNA molecules for selected targets and executed certain studies for five research programmes. Three of these programmes have been declared as “Accepted Programmes” by AstraZeneca and can now be advanced into pre-clinical development. AstraZeneca retains the global development and commercial rights to these Accepted Programmes. Silence will retain all rights with respect to the two research programs which did not become Accepted Programs. However, these two programs remain subject to a two-year option with a first right of refusal in favour of AstraZeneca. In addition, Silence acknowledges and agrees that AstraZeneca may continue to work on these two programs solely for its own internal research purposes.

The second collaboration led to the development by Silence of a novel delivery system for siRNA molecules, the DACC delivery system. Full rights to this system have been retained by Silence and complement the company’s unique AtuPLEX and DBTC RNAi delivery systems. The DACC delivery system allows selective functional delivery of siRNA molecules to the lung endothelium with a long duration of target mRNA and protein knock-down, compared to AtuPLEX which is used for broad delivery to the vasculature of several organs and DBTC which enables functional delivery of siRNA molecules selectively to liver cells including hepatocytes.

Commenting on today’s announcement, Thomas Christély, chief executive officer of Silence, said: “We are pleased by the progress that we have made in both collaborations. In particular the delivery collaboration has enabled Silence to make significant progress in developing a new technology that delivers RNAi to target cells. The development of the lung focused RNAi delivery system DACC is an important outcome of the delivery collaboration. The DACC delivery technology is proprietary to Silence and can be applied to the other projects that we are pursuing by ourselves and with partners.”

David Blakey, Chief Scientist Oncology iMed and Chair of Oligonucleotide Strategy Team, AstraZeneca, commented: “AstraZeneca and MedImmune remain committed to the development of new technologies that have the potential to create novel therapeutics. The collaboration with Silence Therapeutics has been excellent and AstraZeneca and  MedImmune will continue to evaluate the novel siRNA molecules and the delivery technologies discovered under the collaboration as part of its overall strategy to explore this important therapeutic approach.”