Developing a method for in vivo quantification and analysis of Sixfold’s Programmable Oligonucleotide Delivery System (PODS) for siRNA cancer therapy

"The project combines Sixfold's Programmable Oligonucleotide Delivery System (PODS) with deep expertise of NML in quantitative bio-measurement and NPL in qualitative and quantitative advanced imaging to determine and optimise PODS in vivo profile. PODS have demonstrated a highly promising safety profile for delivery of Cell&Gene therapeutics such as short-interfering RNA (siRNA) for gene-silencing. The aim now is to complete preclinical studies and meet the requirements of the regulatory agencies by collecting more robust data on PODS' pharmacokinetics/dynamics profile. To that end, the project employs an iterative technical approach, takes advantage of the interdisciplinary expertise of the consortium and leverages NML's/NPL's unique facilities, equipment and know-how. This allows for optimisation, enabling PODS to quickly progress through preclinical development, and expediting commercialisation.

Given their high specificity/selectivity for gene-silencing, siRNAs have the potential to provide effective treatment options for a variety of genetically-driven diseases including cancer. The first ever regulatory approval of Alnylam's siRNA therapy in 2018\[1\] has validated the clinical and commercial opportunity for such therapies. The major limiting factor for their further clinical and commercial success is the lack of safe and effective systems for systemic delivery of siRNAs to specific diseased cells. This is recognised by academia and industry\[2\]. Current approaches (viral-based/lipid-based) are sub-optimal given their limited specificity, toxicity, and complex/expensive manufacturing\[2\], limiting the type and number of addressable disease indications.

PODS can address the drug delivery challenge given their unique, biocompatible design based on a central ""naked"" RNA nanoscaffold, which can be functionalised with multiple therapeutics and highly-specific targeting molecules that recognise biomarkers on cancer -but not healthy- cells.

Preclinical data indicates a highly competitive safety profile of siRNA-PODS cancer therapy. However, to complete the preclinical studies and meet the requirements of the regulatory agencies, Sixfold must collect more robust data on PODS' pharmacokinetics/dynamics profile. Although Sixfold has performed biodistribution studies in rodents, the results of these experiments have not allowed for quantitative analysis on the composition of PODS, their by-products and their exact distribution in tissues.

By utilising NML's and NPL's expertise, the project will enable the necessary advanced in vivo analysis/measurement of:(i)intact PODS versus by-products, (ii)spatial distribution and subcellular localisation in tissue. This would accelerate the completion of preclinical development, unlocking Sixfold's ability to generate first revenue from licensing agreements and expediting clinical development not only for our primary indication but also other diseases, contributing to the competitiveness of the UK's _Advanced Therapies_.

\[1\]Alnylam\_Press Release\_30.08.18.\[2\]Karim\_ME\_et\_al.\_Pharmaceutic 2018"