Horizon Discovery next-generation synthetic lethality targets collaboration
In December 2018, C4X Discovery entered into an exclusive target discovery partnership with Horizon Discovery Group plc (“Horizon”, AIM: HZD), a global leader in the application of gene editing and gene modulation technologies. The partnership aims to validate novel synthetic lethal oncology targets that have been identified by Horizon’s cutting-edge CRISPR-Cas9 technology leading to the generation of potential new drugs for patients with limited effective treatments such as colorectal and lung cancer. C4X aims to apply its proprietary 4D shape-based chemistry technology (Conformetrix) to discover drug candidates directed against these high value, novel, synthetic lethality targets and out-license them to clinical development partners.
The therapeutic concept of harnessing synthetic lethality in cancer with tumour-specific mutations has been demonstrated with the recent approval of the poly(ADP-ribose) polymerase (PARP) inhibitors Lynparza® Zejula® and Rubraca®. These drugs are effective in indications that are poorly served by immunotherapy drugs, such as checkpoint inhibitors, and have become an established treatment in ovarian cancer. They work by targeting a specific DNA repair pathway that cancer cells, with mutations such as BRCA, become over-reliant on. Inhibiting this critical DNA repair pathway causes the tumour cells to self-destruct, resulting in the terminology ‘synthetic lethality’. The pharmaceutical industry is now rushing to fill its clinical pipelines with investigational drugs, identified by empirical research, that might produce similar efficacy in cancers where PARP inhibitors are not effective.
However, recent advancements in the gene-editing tool, CRISPR-Cas9, has enabled systematic ‘functional genomic’ screening to identify novel synthetic lethal genes in cancer cells with specific mutations. Horizon has utilised its target discovery platform to conduct high quality CRISPR gene knock-out studies across multiple cancer cell lines, screening around ~3000 genes suitable as the basis for small molecule drug targets. This cutting-edge approach has identified a shortlist of ~20 novel, high value synthetic lethal genes following a secondary screen to further validate them as targets. The partnership has been established to complete the target validation package for these novel targets, leading to the initiation of drug discovery programmes by C4XD should it exercise its options on a target-by-target basis. C4XD provides the funding for the work plan and Horizon will receive a share of all future revenues C4XD receives should any drug discovery programmes emerging from the partnership be out-licensed for clinical development.