Completion of Divestment of In Vivo Business Unit

Horizon Discovery Group plc

Completion of Divestment of In Vivo Business Unit

Cambridge, UK, 4 December 2019: Horizon Discovery Group plc (LSE: HZD) ("Horizon" or "the Group"), a global leader in the application of gene editing and gene modulation technologies, announces that further to its announcement published on 8 November 2019, the divestment of the Group's In Vivo business unit to Envigo RMS LLC completed on 3 December 2019.

Ends

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

Horizon Discovery Group plc

Terry Pizzie, Chief Executive Officer

Jayesh Pankhania, Chief Financial Officer

Jon Davies, Head of Investor Relations

Tel: +44 (0) 1223 655 580

Numis Securities Limited (Broker and NOMAD)

Freddie Barnfield / Tom Ballard / Duncan Monteith

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 5700

Email: [email protected]

Zyme Communications (Trade and Regional Media)

Katie Odgaard

Tel: +44 (0)7787 502 947

Email: [email protected] 

Westwicke, an ICR Company (US Investor Relations)

Stephanie Carrington

Tel. +1 646-277-1282

Email: [email protected]

About Horizon Discovery Group plc www.horizondiscovery.com

Horizon Discovery Group plc (LSE: HZD) ("Horizon") drives the application of gene editing and gene modulation within the global life science market - supporting scientists on the path from research to therapy.

Built upon more than a decade of experience in the engineering of cell lines, Horizon offers an unmatched portfolio of tools and services to help scientists gain a greater understanding of gene function, identify genetic drivers behind human disease, deliver biotherapeutics, cellular and gene therapies for precision medicine as well as develop and validate diagnostic workflows.

Horizon's solutions enable almost any gene to be altered, or its function modulated, in human and other mammalian cell lines.

The Group's customers include many of the world's foremost academic institutes, global pharmaceutical and biotechnology companies as well as clinical diagnostic laboratories. Insight into the challenges faced by these organizations enables Horizon to focus efforts on development of innovative solutions that not only differentiate the Group's offering, but also fuel development of the next wave of precision medicines.

Horizon is headquartered in Cambridge, UK with offices in USA and Japan. The Group is listed on the London Stock Exchange's AIM market under the ticker HZD.

About Envigo www.envigo.com

Envigo provides the broadest range of standard research models to the pharmaceutical and biotechnology industries, government, academia and other life science organizations. The company has over 1,200 devoted employees in more than 20 locations across North America and Europe

As the largest organisation that is solely dedicated to providing research models and related products and services, we are committed to helping researchers realise the full potential of their critical R&D projects as we fulfil our mission to work together to build a healthier and safer world.