Horizon Discovery : enters into agreement with Roche Diagnostics to support the development of immunohistochemistry assays for oncology

• Horizon to develop and manufacture FFPE Reference Standards that express NTRK fusion biomarkers
• Standards to be derived from custom gene edited cell lines
• Agreement builds upon Horizon's pre-existing partnership with Roche Diagnostics

Cambridge, UK, 18 December, 2017: Horizon Discovery Group plc (LSE: HZD) ('Horizon' or 'the Company'), a global leader in gene editing and gene modulation technologies, today announces that it has entered into an agreement with Roche Diagnostics to assist in the development of immunohistochemistry (IHC) assays.

Under the terms of the agreement, Horizon will develop and provide Reference Standard material expressing neurotrophic tropomyosin receptor kinase (NTRK) fusion biomarkers. NTRK gene rearrangements have recently emerged as promising targets for cancer therapy, and a number of novel compounds have been developed against the fusion proteins that arise from these molecular alterations. Their effective application, however, depends upon the accurate determination of the genotype of patients, which is primarily carried out through IHC-based diagnostic testing.

Horizon's Reference Standards will be derived from cell lines generated using the Company's industry-leading gene editing platform to include knock-ins (KI) of NTRK 1,2 and 3 fusion cDNA (each under the control of multiple promoters), to achieve low to high levels of protein expression in selected cell lines. The cells will be supplied in FFPE (formalin-fixed paraffin embedded) format, thereby mimicking real patient samples for better control of variability across the complete diagnostic workflow. The project is expected to be completed within 12 months.

This agreement builds on the Horizon-Roche partnership announced in September 2016, which comprised the development, manufacture and commercialisation of cell line derivative materials for use as IHC Reference Standards in cancer tissue diagnostics, to support the development and validation of IHC assays.

Dr. Darrin M Disley, Chief Executive Officer, Horizon Discovery Group,commented:'Horizon continues to establish itself as a leading supporter of the development and validation of molecular diagnostics by providing reliable and high quality reference standards to assay developers. We are very pleased to announce this agreement, further strengthening our ongoing partnership with Roche, and we look forward to continuing to work alongside them as they develop additional important diagnostic assays in areas of significant need.'