Summit Therapeutics Inc.

An investment in our common stock or other securities involves a number of risks. In addition to other information set forth in this Quarterly Report on Form 10-Q, you should carefully consider each of the risks described in our Annual Report, which includes a detailed discussion of the Company’s risk factors. If any of the risks described therein or other uncertainties currently unknown to us, or that we currently deem to be immaterial, develop into actual events, our business, financial condition, or results of operations could be negatively affected, the market price of our common stock or other securities could decline, and you may lose all or part of your investment.

We do not currently have sufficient working capital to fund our planned operations for the next twelve months. There is uncertainty regarding our ability to raise additional capital and as such, there is substantial doubt regarding our ability to continue as a going concern.

Our unaudited financial statements have been prepared under the assumption that we would continue as a going concern. However, we have concluded that there is substantial doubt about our ability to continue as a going concern, because without additional sources of funding, our cash and cash equivalents at September 30, 2025 is not sufficient for us to fund our working capital needs for the next twelve months after the date that the unaudited financial statements included in this Quarterly Report on Form 10-Q are issued. Management’s plans concerning these matters, including raising additional capital, are described in Part I - Item 2 – Management’s Discussion and Analysis of Financial Condition and Results of Operation - Liquidity and Capital Resources – Sources of Liquidity of our unaudited financial statements included within this Quarterly Report on Form 10-Q. We continue to evaluate options to further finance our operating cash needs for our product candidates through a combination of some, or all, of the following: equity and debt offerings, collaborations, strategic alliances, grants and clinical trial support from government entities, philanthropic, non-government and not-for-profit organizations, and marketing, distribution or licensing arrangements. However, we cannot guarantee that we will be able to obtain any or sufficient additional funding or that such funding, if available, will be obtainable on terms satisfactory to us. If we are unable to raise capital in the near term or on attractive terms, we could be forced to delay or reduce our research and development programs or any future commercialization efforts, or even curtail or cease operations.

There have been no material changes to the risk factors disclosed in Item 1A of our Annual Report other than disclosed above.