Horizon Discovery : Agreement with Roche Diagnostics

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.'

ENDS

About Horizon's Reference Standards:

There are many potential sources of variability that can lead to molecular diagnostic tests providing erroneous results. Horizon's Reference Standards offer a source of genetically defined, quantitative, sustainable and independent third-party reference material, critical to the validation and routine performance monitoring of assays, providing an unprecedented level of control. Horizon Reference Standards are available in a broad range of formats, including Formalin-Fixed Paraffin-Embedded (FFPE) cell line sections, purified genomic DNA (gDNA), and cell-free DNA (cfDNA) on its own or spiked into synthetic plasma.

Glossary:

· Assay: a laboratory procedure measuring the presence, amount, or functional activity of a specific biomarker or analyte

· Immunohistochemistry (IHC): the process of imaging antigens (e.g. proteins) in by exploiting the principle of antibodies binding specifically to antigens in biological tissues

· Biomarker: a naturally occurring molecule, gene, or characteristic by which a particular pathological or physiological process or disease, can be identified

· Fusion proteins: proteins created through the joining of two or more genes that originally coded for separate proteins

· Reference standard: a standardized substance (e.g. DNA, protein) which is used as a measurement base or control for an assay

For further information from Horizon Discovery Group plc, please contact:

Horizon Discovery Group plc

Darrin Disley, Chief Executive Officer

Richard Vellacott, Chief Financial Officer

Chris Claxton, VP Investor Relations

Tel: +44 (0) 1223 655 580

Numis Securities Limited (Broker and NOMAD)

Michael Meade / Freddie Barnfield

Tel: +44 (0) 207 260 1000

Consilium Strategic Communications (Financial Media and Investor Relations)

Mary-Jane Elliott / Matthew Neal / Melissa Gardiner

Tel: +44 (0) 20 3709 5701

Email:horizon@consilium-comms.com

Zyme Communications (Trade and Regional Media)

Katie Odgaard

Tel: +44 (0)7787 502 947

Email: katie.odgaard@zymecommunications.com

About Horizon Discovery Group plc www.horizondiscovery.com

Horizon Discovery Group plc (LSE: HZD) ('Horizon') is a world leader in gene editing and gene modulation technologies. Horizon designs and engineers cells using its translational genomics platform, a highly precise and flexible suite of DNA editing tools (rAAV, ZFN, CRISPR and Transposon) and, following the acquisition of Dharmacon, Inc., its functional genomics platform comprising gene knockdown (RNAi) and gene expression (cDNA, ORF) tools, for research and clinical applications that advance human health. Horizon's platforms and capabilities enable researchers to alter almost any gene or modulate its function in human or mammalian cell lines.

Horizon offers an extensive range of catalogue products and related research services to support a greater understanding of the function of genes across all species and the genetic drivers of human disease and the development of personalised molecular, cell and gene therapies. These have been adopted by over 10,000 academic, drug discovery, drug manufacturing and clinical diagnostics customers around the globe, as well as in the Company's own R&D pipeline.

Horizon is headquartered in Cambridge, UK, and is listed on the London Stock Exchange's AIM market under the ticker 'HZD.'