{Reference Type}: Journal Article {Title}: Therapeutic interfering particles exploiting viral replication and assembly mechanisms show promising performance: a modelling study. {Author}: Fatehi F;Bingham RJ;Dechant PP;Stockley PG;Twarock R; {Journal}: Sci Rep {Volume}: 11 {Issue}: 1 {Year}: 12 2021 13 {Factor}: 4.996 {DOI}: 10.1038/s41598-021-03168-0 {Abstract}: Defective interfering particles arise spontaneously during a viral infection as mutants lacking essential parts of the viral genome. Their ability to replicate in the presence of the wild-type (WT) virus (at the expense of viable viral particles) is mimicked and exploited by therapeutic interfering particles. We propose a strategy for the design of therapeutic interfering RNAs (tiRNAs) against positive-sense single-stranded RNA viruses that assemble via packaging signal-mediated assembly. These tiRNAs contain both an optimised version of the virus assembly manual that is encoded by multiple dispersed RNA packaging signals and a replication signal for viral polymerase, but lack any protein coding information. We use an intracellular model for hepatitis C viral (HCV) infection that captures key aspects of the competition dynamics between tiRNAs and viral genomes for virally produced capsid protein and polymerase. We show that only a small increase in the assembly and replication efficiency of the tiRNAs compared with WT virus is required in order to achieve a treatment efficacy greater than 99%. This demonstrates that the proposed tiRNA design could be a promising treatment option for RNA viral infections.