Summit Therapeutics plc : Block listing applicatio

Summit Therapeutics plc ("Summit" or the "Company")

BLOCK LISTING APPLICATION

Oxford, UK, 23 October 2017 - Summit Therapeutics plc (AIM: SUMM, NASDAQ: SMMT), the drug discovery and development company advancing therapies for Duchenne muscular dystrophy and C. difficile infection, announces that application has been made to the London Stock Exchange for the block listing of securities in respect of an aggregate total of 7,989,707 ordinary shares of one penny each ("New Ordinary Shares") to be admitted to trading on AIM.

The block listing application relates to 4,454,158 ordinary shares of one penny each to be issued from time to time in order to satisfy the potential exercise of share options granted under the Company's 2005 EMI Scheme, and 3,535,549 ordinary shares of one penny each to be issued from time to time in order to satisfy the potential exercise of share options granted under the Company's 2016 Long Term Incentive Plan.

It is expected that admission will become effective on 26 October 2017.

When issued, the New Ordinary Shares will be credited as fully paid and will rank pari passu in all respects with the existing ordinary shares of one penny each in the capital of the Company ("Ordinary Shares").

As at today, there are 70,629,352 Ordinary Shares in issue with one voting right per share. The Company does not hold any shares in treasury. Summit will notify on a monthly basis when there are changes to the issued share capital of the Company, and these monthly figures may be used by shareholders as the denominator for the calculation by which they will determine if they are required to notify their interest in, or a change in their interest in, the share capital of the Company under the Financial Conduct Authority's Disclosure Guidance and Transparency Rules.

This announcement contains inside information for the purposes of Article 7 of EU Regulation 596/2014.

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