Exercise of Restricted Stock Units

Summit Therapeutics plc 
(‘Summit’ or the ‘Company’)

Exercise of Restricted Stock Units

Oxford, UK, and Cambridge, MA, US, 27 January 2020 – Summit Therapeutics plc (NASDAQ: SMMT, AIM: SUMM), a leader in new mechanism antibiotic innovation, announces that following the exercise of restricted stock units by former directors, the Company has issued 269,230 new ordinary shares of one penny each (the “New Ordinary Shares”).

Application has been made for the admission to trading on AIM of the New Ordinary Shares, which will rank pari passu with the Company’s existing ordinary shares, and admission is expected to occur on or around 30 January 2020.

Following admission of the New Ordinary Shares to trading on AIM, the total number of ordinary shares with voting rights in issue will be 336,159,511. This figure may be used by shareholders as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, the Company under the FCA's Disclosure and Transparency Rules.

About Summit Therapeutics
Summit Therapeutics is a leader in antibiotic innovation. Our new mechanism antibiotics are designed to become the new standards of care for the benefit of patients and create value for payors and healthcare providers. We are currently developing new mechanism antibiotics for infections caused by C. difficile, Enterobacteriaceae and N. gonorrhoeae and are using our proprietary Discuva Platform to expand our pipeline. For more information, visit www.summitplc.com and follow us on Twitter @summitplc.

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