AstraZeneca has signed a deal with the UK’s Silence Therapeutics that is worth up to £200 million and sees the Anglo-Swedish drugmaker branch out into RNA interference.

The three-year deal will see the firms attempt to develop short interfering RNA (siRNA) molecules against up to five targets provided by AstraZeneca, primarily in the respiratory field. Silence brings its proprietary siRNA technology to the table in return for an initial access fee of £7.5 million, comprising a payment of £2.5 million plus an equity investment of £5 million, which gives AstraZeneca a near-3% stake. The £200 million figure is dependent on clinical development and commercial milestone payments and does not include potential royalties.

Jan Lundberg, executive vice president of discovery research at

AstraZeneca, said the deal highlights the firm’s determination “to access new technologies that hold future promise” and this siRNA technology deal will enable it “to target disease mechanisms intractable to small molecules and other approaches."

RNAi is a naturally occurring mechanism within cells and potentially forms the basis for a new class of therapeutic products that can selectively silence genes within the cell. Since many diseases are caused by the inappropriate activity of specific genes, the ability to regulate such genes selectively through RNAi has led to great excitement in the scientific community.

The two discoverers of the technology, Andrew Fire and Craig Mello, won the Nobel Prize for Medicine last year but some observers have noted that as with antisense before it - which while operating by a similar mechanism has failed to emerge as a major treatment option - the main obstacle to using siRNAs as therapeutics lies in delivery inside the cell. However, Silence has developed its own systemic delivery system, AtuPLEX. which it claims can enable the delivery of siRNA molecules to targeted diseased tissues and cells in the body, whilst increasing their bioavailability and circulation times.

The Silence deal is another example of AstraZeneca looking to the future and seeking out new technologies, though some analysts are more worried about the gaps in its near-term pipeline. Aside from the $15.6 billion MedImmune acquisition, a number of smaller alliances have been entered into this year, including an antibody agreement with the USA’s Regeneron Pharmaceuticals, as well as pacts with Argenta Discovery (chronic obstructive pulmonary disease) and the USA's Palatin Technologies (obesity). AstraZeneca also bought UK antiviral specialist Arrow Therapeutics at the beginning of the year for $150 million.