Master Service Agreement with Top 3 Pharma Company

Horizon Discovery Signs a Master Service Agreement with

a Top Three Pharmaceutical Company

Cambridge, UK, 14 February 2017: Horizon Discovery Group plc (LSE: HZD) ("Horizon" or the "Group"), the world leader in the application of gene editing technologies, today announces the signing of a Master Services Agreement (MSA) with a top three global pharmaceutical company (the "Company"), extending support for their drug discovery and development efforts to Horizon's full suite of services.

Adding to a pre-existing MSA for in vivo services, the terms of this agreement now cover a range of Horizon's in vitro service offerings, defining the pricing and terms that will govern future transactions and facilitating simplified entry into forthcoming agreements. Services included under the MSA are: custom cell line engineering, target identification and validation screening (including the use of CRISPR gene editing technology), drug combination screening, and cell-based assay services.

Horizon is establishing itself as a key provider to an increasing number of major pharmaceutical and biotech companies by delivering reliable, high-quality, high-value services, and by strengthening key relationships within each organisation. In this way, Horizon was able to negotiate this agreement, building trust with the Company and becoming a preferred provider over time. It is now Horizon's single largest customer, contributing over £1.5 million in revenue in 2016 (c£0.6 million FY15) and the current project pipeline indicates there will be an expansion of revenue received in 2017.

Dr. Darrin Disley, Chief Executive Officer Horizon Discovery, commented: "Today's announcement demonstrates the success of Horizon's strategy of deepening relationships with our top customers. By taking a broader and more integrated approach, we are able to identify areas where we can provide significant value and are able to offer unified solutions that involve a range of Horizon's services. In 2016, our top 20 customers provided over £9.8 million to the Group, and in 2017 we are looking to increase our revenue from this segment by at least 20%, with this agreement serving as a template."

ENDS

Glossary:

· Custom cell line engineering: The on-demand development of cell lines that reflect the genetics of disease found in real patients by use of gene editing

· Target identification and validation screening: The process of identifying genes as potential targets for drug development programmes

· Drug combination screening: The process by which potential drug compounds are combined with known drugs under a variety of conditions to identify synergistic and antagonistic interactions

· Cell-based assay services: A range of contract research services based on the direct interrogation of cells under specific conditions (e.g. looking at drug response under low oxygen)

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

Consilium Strategic Communications (Financial Media and Investor Relations)

Mary-Jane Elliott / Susan Stuart / Matthew Neal / Melissa Gardiner

Tel: +44 (0) 20 3709 5701

Email: [email protected]

Zyme Communications (Trade and Regional Media)

Katie Odgaard

Tel: +44 (0)7787 502 947

Email: [email protected]

About Horizon Discovery Group plc www.horizondiscovery.com

Horizon Discovery Group plc (LSE: HZD) ("Horizon"), is a world-leading gene editing company that designs and engineers genetically-modified cells and then applies them in research and clinical applications that advance human health.

Horizon's core capabilities are built around its proprietary translational genomics platform, a highly precise and flexible suite of gene editing tools (rAAV, ZFN and CRISPR) able to alter almost any gene sequence in human or mammalian cell-lines.

Horizon offers over 23,000 catalogue products and related research services, almost all of which are based on the generation and application of cell and animal models that accurately recapitulate the disease-causing genetic anomalies found in diseases like cancer. Horizon's commercial offering has been adopted by c. 1,600 unique research organisations in over 50 countries as well as in the Company's own R&D pipeline to support a greater understanding of the genetic drivers of disease and the development of molecular, cell and gene therapies that can be prescribed on a personalised basis.

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