Summit Announces Effectiveness of Scheme of Arrangement and Completion of Redomiciliation to Delaware, USA

Summit Therapeutics Inc.

(“Summit” or the “Company”)

Summit Announces Effectiveness of Scheme of Arrangement and Completion of Redomiciliation to Delaware, USA

Cambridge, MA, September 18, 2020 – Summit (NASDAQ: SMMT) today announces the completion of the company’s redomiciliation to Delaware, USA. Previously, Summit Therapeutics plc announced that the High Court of Justice in England and Wales had sanctioned the scheme of arrangement under Part 26 of the Companies Act 2006 (the “Scheme”) pursuant to which Summit Therapeutics Inc. is becoming the new Delaware, USA incorporated holding company of Summit Therapeutics plc and its subsidiaries.  Following the delivery today of the Court Order to the Registrar of Companies in the U.K., the Scheme has become effective and every five ordinary shares, £0.01 par value per share, of Summit Therapeutics plc were exchanged for one share of common stock, $0.01 par value per share, of Summit Therapeutics Inc. The entire issued share capital of Summit Therapeutics plc is now owned by Summit Therapeutics Inc.

It is expected that the last day of trading in the Summit Therapeutics plc American Depositary Shares on the Nasdaq Global Market will be on September 18, 2020 and trading in the shares of common stock of Summit Therapeutics Inc. on the Nasdaq Global Market will commence on September 21, 2020 under the ticker symbol “SMMT”, which was the symbol for the American Depositary Shares of Summit Therapeutics plc. Since the ratio at which the ordinary shares of Summit Therapeutics plc are being exchanged for shares of common stock of Summit Therapeutics Inc. is equal to the ratio of its ordinary shares to the American Depositary Shares, no adjustment to the Nasdaq trading price is being made in connection with the listing of the common stock of Summit Therapeutics Inc.

About Summit Therapeutics

Summit Therapeutics, empowered by its Discuva Platform, the Company’s innovative antibiotic discovery engine, led by Dr. Ventzislav Stefanov and supported by BARDA and Carb-X funding, intends to be the leader in patient and physician friendly paradigm shifting antibiotic innovation. Our new mechanism antibiotics are designed to become the patient-friendly, new era standard-of-care, by working in harmony with the human microbiome to treat prospective patients suffering from infectious disease, initially focussing on Clostridioides difficile infections (“CDI”) which is estimated to impact over 3 million patients worldwide annually. Commercialization of ridinilazole for the treatment of CDI is subject to regulatory approvals. The overriding objective of Summit Therapeutics is to create value for patients, hospital infectious disease care givers, community based infectious disease healthcare providers, as well as healthcare payors around the world.  Currently, Summit’s lead product candidate ridinilazole is engaged in two global phase III trials, Ri-CoDIFy 1 & 2, each enrolling 680 patients vs standard of care (Vancomycin) for the treatment of C. difficile infections.