Summit Therapeutics plc : Holding(s) in Company

TR-1: S tandard form for notification of major holdings

NOTIFICATION OF MAJOR HOLDINGS
1a. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached ii :			Summit Therapeutics PLC Sedol BN40HZ0
1b. Please indicate if the issuer is a non-UK issuer   (please mark with an "X" if appropriate)
Non-UK issuer
2. Reason for the notification (please mark the appropriate box or boxes with an "X")
An acquisition or disposal of voting rights						X
An acquisition or disposal of financial instruments
An event changing the breakdown of voting rights
Other (please specify) iii : Participation in placing						X
3. Details of person subject to the notification obligation iv
Name			1 Lansdowne Partners International Limited 2 Lansdowne Partners Limited 3 Lansdowne Partners (UK) LLP
City and country of registered office (if applicable)			London, United Kingdom
4. Full name of shareholder(s) (if different from 3.) v
Name			HSBC Client Holdings Nominee (UK) Ltd, HSBC Bank Plc Lansdowne Markets   (Registered Shareholders)
City and country of registered office (if applicable)			n/a
5. Date on which the threshold was crossed or reached vi :			19/09/2017
6. Date on which issuer notified (DD/MM/YYYY):			20/09/2017
7. Total positions of person(s) subject to the notification obligation
	% of voting rights attached to shares (total of 8. A)	% of voting rights through financial instruments (total of 8.B 1 + 8.B 2)		Total of both in % (8.A + 8.B)	Total number of voting rights of issuer vii
Resulting situation on the date on which threshold was crossed or reached	15.75%	11.35%		27.11%	70,316,908
Position of previous notification (if applicable)	17.95%	7.53%		25.48%

9. Information in relation to the person subject to the notification obligation (please mark the applicable box with an "X")
Person subject to the notification obligation is not controlled by any natural person or legal entity and does not control any other undertaking(s) holding directly or indirectly an interest in the (underlying) issuer xiii
Full chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held starting with the ultimate controlling natural person or legal entity xiv (please add additional rows as necessary)				X
Name xv	% of voting rights if it equals or is higher than the notifiable threshold	% of voting rights through financial instruments if it equals or is higher than the notifiable threshold	Total of both if it equals or is higher than the notifiable threshold
Lansdowne Partners International Limited			27.11%
Lansdowne Partners Limited
Lansdowne Partners (UK) LLP			27.11%
10. In case of proxy voting, please identify:
Name of the proxy holder
The number and % of voting rights held
The date until which the voting rights will be held
11. Additional information xvi

Place of completion	London
Date of completion	20 September 2017

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