Synthetic siRNA may be used to inhibit the protein expression of any disease-related gene by exploiting the naturally occurring RNAi process of gene regulation.  The potential power and sensitivity of RNAi therapy lies in its ability to silence targeted genes only.  Non-target genes are unaffected, reducing the potential for unwanted side effects. RNAi also has the advantage that it does not require the identification of "drugable" domains on the molecular target or specific target locations at the cell membrane. 

The time to clinic for RNAi-based therapeutics is likely to be rapid as lead identification and optimisation of siRNA molecules takes less than six months (compared with several years for the development of, for example, small molecules) providing a significant reduction in preclinical development time. Unlike most existing therapeutics where each new chemical entity (NCE) has a distinct composition and synthetic protocol, the structure and synthesis of siRNA is similar. Even different siRNA sequences will have similar ADMET profiles implying that once the first siRNAs molecules have been approved for marketing, the regulatory process for subsequent siRNAs molecules will be facilitated and more cost efficient. 

In common with conventional therapeutics, siRNA must be able to penetrate the cell membrane and survive long enough inside the cell in order to exert its effects. These are challenges that have been addressed by Silence Therapeutics’ proprietary ‘AtuPLEX’ delivery system and modified siRNA molecules (‘AtuRNAi’).