# EDGAR Filing Document

**Accession Number:** 0001599298
**File Stem:** 0001599298-25-000156
**Filing Date:** 2025-10
**Character Count:** 117692
**Document Hash:** f2eace2a04fe2b856253a06c6942767e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001599298-25-000156.hdr.sgml**: 20251020

**ACCESSION NUMBER**: 0001599298-25-000156

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 66

**CONFORMED PERIOD OF REPORT**: 20251017

**ITEM INFORMATION**: Results of Operations and Financial Condition

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251020

**DATE AS OF CHANGE**: 20251020

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Summit Therapeutics Inc.
- **CENTRAL INDEX KEY:** 0001599298
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 371979717
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-36866
- **FILM NUMBER:** 251402323

**BUSINESS ADDRESS:**
- **STREET 1:** 601 BRICKELL KEY DRIVE
- **STREET 2:** SUITE 1000
- **CITY:** MIAMI
- **STATE:** FL
- **ZIP:** 33131
- **BUSINESS PHONE:** 305-203-2034

**MAIL ADDRESS:**
- **STREET 1:** 601 BRICKELL KEY DRIVE
- **STREET 2:** SUITE 1000
- **CITY:** MIAMI
- **STATE:** FL
- **ZIP:** 33131

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Summit Therapeutics plc
- **DATE OF NAME CHANGE:** 20150219

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Summit Corp plc
- **DATE OF NAME CHANGE:** 20140205

?xml version='1.0' encoding='ASCII'? smmt-20251017

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 8-K**

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934**

Date of Report (Date of Earliest Event Reported): <u>October 17, 2025</u>

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| | | |
|:---|:---|:---|
| Summit Therapeutics Inc. | Summit Therapeutics Inc. | Summit Therapeutics Inc. |
| (Exact Name of Registrant as Specified in Its Charter) | (Exact Name of Registrant as Specified in Its Charter) | (Exact Name of Registrant as Specified in Its Charter) |
| Delaware | 001-36866 | 37-1979717 |
| (State or Other Jurisdiction<br>of Incorporation) | (Commission<br>File Number) | (IRS Employer<br>Identification No.) |
| 601 Brickell Key Drive, Suite 1000, Miami, FL | 601 Brickell Key Drive, Suite 1000, Miami, FL | 33131 |
| (Address of Principal Executive Offices) | (Address of Principal Executive Offices) | (Zip Code) |

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Registrant's Telephone Number, Including Area Code: <u>(305) 203-2034</u>

Not applicable <br> (Former Name or Former Address, If Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (*see* General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| Title of Each Class | Trading Symbol(s) | Name of Each Exchange on Which Registered |
| Common stock, $0.01 par value per share | SMMT | The Nasdaq Stock Market LLC |

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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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| | |
|:---|:---|
| **Item 2.02** | **Results of Operations and Financial Condition.** |

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On October 20, 2025, Summit Therapeutics Inc. (the "Company") issued a press release announcing its financial results and operational progress for the third quarter ended September 30, 2025. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference into this Item 2.02 as if fully set forth herein.

In accordance with General Instruction B.2 of Form 8-K, the information set forth under Item 2.02 and in Exhibit 99.1 shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

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| | |
|:---|:---|
| **Item 8.01** | **Other Events.** |

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On October 17, 2025, the Company issued a press release announcing the expansion of the ivonescimab global phase III development program with the initiation of a new clinical study, HARMONi-GI3, in 1L colorectal cancer. A copy of the press release is attached as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated by reference herein.

On October 19, 2025, the Company issued a press release noting that its partner, Akeso, Inc., ("Akeso") announced that ivonescimab in combination with chemotherapy reduced the risk of disease progression or death by 40% compared to tislelizumab (PD-1 inhibitor) plus chemotherapy in first line treatment of patients with squamous non-small cell lung cancer in the Phase III clinical trial, HARMONi-6 or AK112-306. HARMONi-6 is a single region, multi-center Phase III study conducted in China sponsored by Akeso with all relevant data exclusively generated, managed, and analyzed by Akeso. Additionally, the press release announced that the Company sponsored HARMONi-3 global study will be split into two analyses by histology. A copy of the press release is attached as Exhibit 99.3 to this Current Report on Form 8-K and is incorporated by reference herein.

On October 20, 2025, the Company announced that, based on the results of the HARMONi clinical trial, it plans to submit a Biologics License Application in order to seek approval for ivonescimab plus chemotherapy for this proposed indication in the fourth quarter of 2025. The Company also announced its intention to expand its ivonescimab clinical development program with an additional set of Phase III clinical studies, with additional color planned to be provided in the first quarter of 2026.

The Company will utilize slides during its conference call scheduled for 8:00am ET on October 20, 2025. A copy of the slides is attached as Exhibit 99.4 to this Current Report on Form 8-K and is incorporated by reference herein.

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| | |
|:---|:---|
| **Item 9.01** | **Financial Statements and Exhibits.** |

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(d) Exhibits

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| | |
|:---|:---|
| **<u>Exhibit Number</u>** | **<u>Description</u>** |
| 99.1 | <u>[Press Release, dated](a2025_prx1020xq32025earn.htm)[October 20,](a2025_prx1020xq32025earn.htm)[2025](a2025_prx1020xq32025earn.htm)</u> |
| 99.2 | <u>[Press Release, dated October 17, 2025](a2025_prx1017xannounceme.htm)</u> |
| 99.3 | <u>[Press Release, dated October 19, 2025](a2025_prx1019xesmoharmon.htm)</u> |
| 99.4 | <u>[Presentation Slides for October 20, 2025 Conference Call](a20251020esmoupdateq3202.htm)</u> |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |

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**SIGNATURE**

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

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| | | |
|:---|:---|:---|
| | **SUMMIT THERAPEUTICS INC.** | **SUMMIT THERAPEUTICS INC.** |
| Date: October 20, 2025 | By: | /s/ Manmeet S. Soni |
|  |  | Chief Operating Officer, Chief Financial Officer and Director |
|  |  | (Principal Financial Officer) |

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## Exhibit 99.1

![](a2025_prx1020xq32025earn001.jpg)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1 Summit Therapeutics Reports Financial Results and Operational Progress for the Third Quarter and Nine Months Ended September 30, 2025 Summit Plans to Submit a BLA in Q4 2025 for Ivonescimab based on HARMONi Global Phase III Study Results Expansion of Summit's Global Phase III Development Program Starts with Initiation of HARMONi-GI3, a New Study in 1L CRC: Summit to Initiate an Additional Set of Phase III Clinical Trials with Details to Come in Q1 2026 Ivonescimab with Chemotherapy Reduces the Risk of Disease Progression or Death by 48% Compared to Chemotherapy Alone in Global Phase III HARMONi Trial Evaluating Patients with EGFRm NSCLC after EGFR TKI Therapy with Consistent Data across Regions Ivonescimab with Chemotherapy Reduced the Risk of Disease Progression or Death by 40%, Median PFS of 11.14 Months, Compared to Tislelizumab (PD-1 Inhibitor) Plus Chemotherapy, Median PFS 6.90 Months, in 1L Treatment of Patients with Squamous NSCLC in Phase III HARMONi-6 Study Conducted by Akeso in China HARMONi-3 Global Phase III Study Analyses Will Be Split by Histology: Squamous NSCLC Cohort Expected to Complete Enrollment First Half of 2026 with Data Readout Expected Second Half 2026; Non-Squamous NSCLC Cohort Expected to Complete Enrollment Second Half of 2026 Miami, Florida, October 20, 2025 - Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") today reports its financial results and provides an update on operational progress for the third quarter ended September 30, 2025. Planned BLA Submission for Ivonescimab in Q4 2025 Today, Summit announces that, based on the results of the HARMONi clinical trial, it plans to submit a Biologics License Application (BLA) in order to seek approval for ivonescimab plus chemotherapy for this proposed indication. We intend to submit the BLA in the fourth quarter of 2025. The positive results of the multiregional Phase III study are detailed further below. As previously noted, the FDA noted that a statistically significant overall survival benefit is necessary to support marketing authorization in this setting. After careful consideration of the safety and efficacy profile of the current FDA-approved options for patients in this setting, the positive results of the Phase III multiregional study, including regional consistency, as well as discussions with key opinion leaders and those physicians who have administered ivonescimab to patients in a clinical study setting, we believe that the safety and efficacy data generated in the HARMONi study demonstrates that patients suffering from epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) in this setting can benefit from the ivonescimab regimen despite the lack of a statistically significant showing on overall survival. Further Expansion of the Phase III Ivonescimab Clinical Development Program In addition to the announcement HARMONi-GI3, a new global Phase III study in first-line unresectable metastatic colorectal cancer (CRC), Summit today announces its intention to expand its ivonescimab clinical development program with an additional set of Phase III clinical studies. We intend to provide additional color with respect to these Phase III studies in the first quarter of 2026.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2 Other Operational & Corporate Updates Operational progress continues with ivonescimab (SMT112), an investigational, potentially first-in-class bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule: • Since in-licensing ivonescimab (SMT112), from Akeso Inc. (Akeso, HKEX Code: 9926.HK) in January 2023, over 3,000 patients have been treated with ivonescimab in clinical studies globally, and over 40,000 patients when considering those treated in a commercial setting in China as noted by Akeso. Summit has rights to develop and commercialize ivonescimab in the United States, Canada, Europe, Japan, Latin America, including Mexico and all countries in Central America, South America, and the Caribbean, the Middle East, and Africa while Akeso retains development and commercialization rights for the rest of the world, including China. • Summit is developing ivonescimab in NSCLC, specifically conducting Phase III clinical trials in the following proposed indications: ▪ HARMONi: Ivonescimab combined with chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who were previously treated with a third- generation EGFR tyrosine kinase inhibitor (TKI) ▪ HARMONi-3: Ivonescimab combined with chemotherapy in patients with first-line metastatic NSCLC ▪ HARMONi-7: Ivonescimab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression • In addition, Summit plans to start developing ivonescimab in CRC with an intention to begin a Phase III clinical study in the following proposed indication: ▪ HARMONi-GI3: ivonescimab combined with chemotherapy in patients with first-line metastatic CRC • In September 2025, we announced detailed results from our multiregional, double-blinded, placebo- controlled, Phase III study, HARMONi, including data from the study's prespecified primary analysis as well as results from longer-term follow up in western patients.  At the prespecified primary data analysis, ivonescimab in combination with chemotherapy demonstrated a statistically significant improvement in progression-free survival (PFS), the magnitude of which we believe to be clinically meaningful , with a hazard ratio (HR) of 0.52 (95% CI: 0.41 – 0.66; p<0.00001); median PFS was 6.8 months for those patients receiving ivonescimab plus chemotherapy compared to 4.4 months for those receiving chemotherapy. In a longer-term follow-up of PFS, which included all western patients, ivonescimab plus chemotherapy demonstrated a consistent improvement in PFS with an observed HR of 0.57 (95% CI: 0.46 – 0.71). We believe the PFS HR that was observed in both Asian and western sub-populations to be clinically meaningful. In both the primary analysis as well as longer-term follow-up analysis, consistency of the magnitude of PFS benefit was demonstrated between patients randomized in Asia and ex-Asia. PFS was assessed by blinded independent central radiology review committee (BICR) compared to placebo in combination with chemotherapy. The longer-term follow-up analysis of PFS was performed at the time of the primary overall survival (OS) analysis.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3 ▪ In the prespecified primary analysis, a positive trend in OS was observed without achieving a statistically significant benefit with an HR of 0.79 (95% CI: 0.62 – 1.01; p=0.057). Median OS was 16.8 months for those patients administered ivonescimab plus chemotherapy vs. 14.0 months for those receiving placebo plus chemotherapy. Analysis from longer-term follow-up in western patients, resulted in an OS HR consistent with the primary analysis with an improved nominal p- value (HR=0.78; 95% CI: 0.62 – 0.98; nominal p=0.0332). Median OS in the longer-term follow- up analysis remained the same in both arms from the primary analysis, 17.0 months in western patients receiving ivonescimab compared to 14.0 months for those receiving placebo (HR=0.84). Median OS in North American patients, specifically, had not yet been reached in the ivonescimab arm compared to 14.0 months in the placebo arm (HR=0.70). The HRs for western patients in totality, as well as patients from the North American and European regions individually, improved from the primary OS analysis to the analysis with longer-term follow-up of western patients. Consistent benefit was observed across pre-defined subgroups, with both Asian and North American patients demonstrating a positive trend in OS. ▪ These trends provide further support for ivonescimab's use in 2L+ EGFRm NSCLC, a setting where high unmet need continues to exist with limited approved options in the United States and other western territories. Currently there are no FDA-approved regimens that have demonstrated a statistically significant OS benefit in this patient setting. The results of the primary and longer- term follow up analysis in this multiregional study were consistent with that of the single-region HARMONi-A study, which demonstrated an OS HR of 0.80 at 52% data maturity in a similar patient population. ▪ The dual primary endpoints were allocated separate alpha levels and tested individually. The alpha was recycled from the PFS to the OS analysis upon the successful achievement of the PFS endpoint. ▪ Observed overall response rates (ORR) were 45% in the ivonescimab arm vs. 34% in the placebo arm; median duration of response (DoR) was longer in those patients administered ivonescimab plus chemotherapy (7.6 months) compared to those receiving placebo and chemotherapy (4.2 months). ▪ The safety profile of ivonescimab in combination with chemotherapy was acceptable and manageable in the context of the observed clinical benefit, with comparable rates of discontinuation and death between both arms. There were 16 patients (7.3%) who discontinued ivonescimab due to treatment-related adverse events (TRAEs) compared to 11 patients (5.0%) who discontinued placebo due to TRAEs. There were four patients (1.8%) in the ivonescimab plus chemotherapy arm and five patients (2.3%) in the chemotherapy alone arm who died as a result of TRAEs. In the ivonescimab plus chemotherapy arm, 50.0% of patients experienced Grade 3 or higher TRAEs compared to 42.2% in the chemotherapy arm. Of note, 0.9% of patients in the ivonescimab plus chemotherapy arm experienced Grade 3 or higher hemorrhage (bleeding) events. • Last week, we announced the expansion of our Phase III clinical development program into CRC with the planned initiation of the global Phase III HARMONi-GI3 trial. The trial will evaluate ivonescimab plus chemotherapy compared to bevacizumab plus chemotherapy as first line therapy in patients with unresectable metastatic CRC. Clinical trial sites for HARMONi-GI3 are planned to begin activating in the

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4 United States prior to the end of the year. The study intends to enroll 600 patients in this multiregional study. The primary endpoint for this study is PFS. ▪ Each year, approximately 48,000 patients are estimated to be diagnosed with or have unresectable recurrent metastatic microsatellite stable (MSS) CRC (also known as mismatch repair-proficient colorectal cancer, or pMMR CRC).1 There have been limited options approved in the United States in the last 20 years for those first-line patients whose tumors are not positive for certain biomarkers or other activating mutations. MSS CRC is a setting where monoclonal PD-1 inhibitors such as pembrolizumab and nivolumab have failed to show a clinically meaningful benefit. Anti-VEGF therapy (e.g., bevacizumab) plus chemotherapy is the standard of care for many patients with first-line metastatic MSS CRC. • In April 2025, Akeso announced that HARMONi-6, which evaluated ivonescimab combined with platinum- based chemotherapy vs. tislelizumab, a PD-1 inhibitor, with the same chemotherapy in patients with locally advanced or metastatic squamous NSCLC, regardless of PD-L1 expression. met its primary endpoint of PFS. Yesterday, additional HARMONi-6 data were presented as part of the Presidential Symposium at the European Society for Medical Oncology 2025 Congress (ESMO 2025) and featured in a manuscript published in The Lancet simultaneously. The presentation and publication are based on the results of HARMONi-6, a single region, multi-center, Phase III study conducted in China sponsored by Akeso, Inc., with data generated and analyzed by Akeso. ▪ In the HARMONi-6 planned interim analysis of progression-free survival (PFS), ivonescimab in combination with chemotherapy demonstrated a statistically significant improvement in the primary endpoint, PFS, by Independent Radiologic Review Committee (IRRC), when compared to tislelizumab in combination with chemotherapy, achieving a hazard ratio (HR) of 0.60 (95% CI: 0.46, 0.78; p<0.0001). A clinically meaningful benefit was demonstrated across clinical subgroups, including those with either PD-L1 negative or positive expression. ▪ Both the overall response rate (ORR) measured according to RECIST v1.1 criteria, as well as the duration of response (DoR) were higher in patients treated with ivonescimab plus chemotherapy compared to those treated with tislelizumab plus chemotherapy. ▪ Ivonescimab demonstrated an acceptable and manageable safety profile in the HARMONi-6 study, which was consistent with previous Phase III studies conducted studying ivonescimab. In squamous NSCLC, VEGF-A monoclonal antibodies have not been approved by health authorities including the FDA and have had limited clinical development based on historical early phase clinical trials, primarily due to significant risks of toxicity, including hemorrhage and other life-threatening, bleeding-related complications. The results of this study further validate the unique mechanism of action of ivonescimab, including key differences as compared to separately administering an anti-PD-1 monoclonal antibody and an anti-VEGF monoclonal antibody. ▪ In this Phase III study, there were nine patients (3.4%) who discontinued ivonescimab plus chemotherapy due to treatment-related adverse events (TRAEs) compared to 11 patients (4.2%) who discontinued tislelizumab plus chemotherapy due to TRAEs. There were eight patients (3.0%) in the ivonescimab plus chemotherapy arm and 10 patients (3.8%) in the tislelizumab plus chemotherapy arm who died as a result of TRAEs in this Phase III study. The most frequent TRAEs for ivonescimab treatment in combination with chemotherapy were common chemotherapy- related AEs, including alopecia, anemia, and various laboratory abnormalities, including

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5 neutrophil, white blood cell, and platelet count decreases. Grade 3 or higher immune-related adverse events occurred in 9.0% of patients receiving ivonescimab in combination with chemotherapy and 10.2% of patients receiving tislelizumab in combination with chemotherapy. Grade 3 or higher adverse events that were possibly VEGF-related in the ivonescimab plus chemotherapy arm were 7.5% vs. 2.3% for tislelizumab plus chemotherapy. Most of the possibly VEGF-related adverse events occurring in the ivonescimab plus chemotherapy arm were classified as Grade 1 or 2. Of note, Grade 3 or higher hemorrhage events were observed in five patients in the ivonescimab plus chemotherapy arm compared to two patients in the tislelizumab plus chemotherapy arm in this study. ▪ This marks the first known Phase III trial in NSCLC to show significant improvement over PD-(L)1 inhibitor therapy combined with chemotherapy in a head-to-head setting. Following the success of Akeso's HARMONi-2 study in China, this is the second instance where ivonescimab-based regimens have demonstrated a statistically significant benefit compared to standard-of-care PD- (L)1 inhibitor-based regimens in a Phase III trial. • Yesterday, we announced an update to our HARMONi-3 Phase III clinical trial evaluating ivonescimab combined with chemotherapy compared to pembrolizumab, a PD-1 inhibitor, combined with chemotherapy in patients with first-line metastatic, squamous and non-squamous NSCLC. The primary endpoints for this study are PFS and OS. ▪ Summit has amended the protocol for the HARMONi-3 study in order to separate the statistical analysis (i.e., the outcome) of the primary endpoints by histology. Therefore, there will be separate analyses conducted to evaluate ivonescimab plus chemotherapy compared to pembrolizumab plus chemotherapy in patients with squamous NSCLC and in patients with non-squamous NSCLC. ▪ As a result of having two separate intention-to-treat analyses within the HARMONi-3 study, the analyses for squamous tumors and non-squamous tumors may be conducted at separate times, as each analysis will be conducted upon the prespecified numbers of events being reached in the separate cohorts. ▪ Summit currently expects to complete enrollment in the squamous cohort of HARMONi-3 in the first half of 2026 and expects to reach the prespecified number of events for the PFS primary endpoint analysis for this cohort in the second half of 2026. An interim analysis for overall survival may be conducted at a similar time. ▪ At present time, Summit expects to complete enrollment in the non-squamous cohort of HARMONi-3 in the second half of 2026 and expects to reach the prespecified number of events for the PFS primary endpoint analysis for this cohort in the first half of 2027. An interim analysis for overall survival is planned to be conducted based upon reaching a prespecified number of events. ▪ In order to sufficiently power each of the dual primary endpoints in both cohorts of this study, Summit plans to enroll 600 patients with squamous NSCLC and 1,000 patients with non- squamous NSCLC.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6 • Clinical trial collaborations and investigator sponsored trials with leading organizations, including MD Anderson, the Memorial Sloan Kettering Cancer Center, and the Dana Farber Cancer Institute, among others, continue to progress and expand evaluating ivonescimab in solid tumor settings outside of metastatic NSCLC. • In June 2025, we announced a clinical collaboration with Revolution Medicines to evaluate ivonescimab in combination with three RAS(ON) inhibitors, including the multi-selective inhibitor daraxonrasib (RMC- 6236), G12D-selective inhibitor zoldonrasib (RMC-9805), and G12C-selective inhibitor elironrasib (RMC- 6291), in solid tumor settings with RAS mutations. We expect that clinical trials associated with this collaboration will begin in early 2026. • Enrollment continues in Summit's global Phase III trials, HARMONi-3 and HARMONi-7. In addition to the enrollment in multiregional studies conducted and sponsored by Summit, our partners at Akeso are also enrolling several single-region Phase III studies exclusively in China in multiple indications, including biliary-tract cancer, triple-negative breast cancer, head and neck squamous cell carcinoma, colorectal cancer, and pancreatic cancer. Financial Highlights Cash and Cash Equivalents and Short-term Investments • Aggregate cash and cash equivalents and short-term investments were $238.6 million and $412.3 million at September 30, 2025 and December 31, 2024, respectively. GAAP and Non-GAAP Operating Expenses • GAAP operating expenses were $234.2 million for the third quarter of 2025, compared to $58.4 million for the same period of the prior year. The increase in GAAP operating expenses was due to the increase in stock-based compensation expense of $111.4 million primarily related to modification to our performance- based stock option awards which occurred earlier during the current fiscal year. • Non-GAAP operating expenses were $103.4 million for the third quarter of 2025, compared to $39.0 million for the same period of the prior year. The increase in Non-GAAP operating expenses due to expansion of clinical studies and development costs related to ivonescimab. GAAP and Non-GAAP Research and Development (R&D) Expenses • GAAP R&D expenses were $131.1 million for the third quarter of 2025, compared to $37.7 million for the same period of the prior year. The increase was due to the increase in stock-based compensation expense of $34.8 million primarily related to modification to our performance-based stock option awards which occurred earlier during the current fiscal year. • Non-GAAP R&D expenses were $90.5 million for the third quarter of 2025, compared to $31.9 million for the same period of the prior year. The increase is primarily related due to expansion of clinical studies and development costs related to ivonescimab.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7 GAAP and Non-GAAP General and Administrative (G&A) Expenses • GAAP G&A expenses were $103.1 million for the third quarter of 2025, compared to $20.7 million for the same period of the prior year. The increase was due to the increase in stock-based compensation expense of $76.6 million primarily related to modification to our performance-based stock option awards which occurred earlier during the current fiscal year. • Non-GAAP G&A expenses were $12.9 million for the third quarter of 2025, compared to $7.1 million for the same period of the prior year. The increase is related to building our infrastructure to support the development of ivonescimab. GAAP and Non-GAAP Net Loss • GAAP net loss in the third quarter of 2025 and 2024 was $231.8 million or $(0.31) per basic and diluted share, and $56.3 million or $(0.08) per basic and diluted share, respectively. • Non-GAAP net loss in the third quarter of 2025 and 2024 was $101.0 million or $(0.13) per basic and diluted share, and $36.9 million or $(0.05) per basic and diluted share, respectively.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8 Use of Non-GAAP Financial Measures This release includes measures that are not in accordance with U.S. generally accepted accounting principles ("Non-GAAP measures"). These Non-GAAP measures should be viewed in addition to, and not as a substitute for, Summit's reported GAAP results, and may be different from Non-GAAP measures used by other companies. In addition, these Non-GAAP measures are not based on any comprehensive set of accounting rules or principles. Summit management uses these Non-GAAP measures for internal budgeting and forecasting purposes and to evaluate Summit's financial performance. Summit management believes the presentation of these Non-GAAP measures is useful to investors for comparing prior periods and analyzing ongoing business trends and operating results. For further information regarding these Non-GAAP measures, please refer to the tables presenting reconciliations of our Non-GAAP results to our U.S. GAAP results and the "Notes on our Non-GAAP Financial Information" that accompany this press release. About Ivonescimab Ivonescimab, known as SMT112 in Summit's license territories, North America, South America, Europe, the Middle East, Africa, and Japan, and as AK112 in China and Australia, is a novel, potential first-in-class investigational bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule. Ivonescimab displays unique cooperative binding to each of its intended targets with multifold higher affinity to PD-1 when in the presence of VEGF. This could differentiate ivonescimab as there is potentially higher expression (presence) of both PD-1 and VEGF in tumor tissue and the tumor microenvironment (TME) as compared to normal tissue in the body. Ivonescimab's specifically engineered tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, SITC, 2023). This tetravalent structure, the intentional novel design of the molecule, and bringing these two targets into a single bispecific antibody with cooperative binding qualities have the potential to direct ivonescimab to the tumor tissue versus healthy tissue. The intent of this design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, SITC, 2023) increasing to approximately 10 days at steady state dosing, is to improve upon previously established efficacy thresholds, in addition to side effects and safety profiles associated with these targets. Ivonescimab was engineered by Akeso Inc. (HKEX Code: 9926.HK) and is currently engaged in multiple Phase III clinical trials. Over 3,000 patients have been treated with ivonescimab in clinical studies globally, and over 40,000 treated in a commercial setting in China as noted by Akeso. Summit began its clinical development of ivonescimab in NSCLC, commencing enrollment in 2023 in two multiregional Phase III clinical trials, HARMONi and HARMONi-3. In early 2025, the Company began enrolling patients in the United States for HARMONi-7. Summit intends to open clinical trial sites in the United States for the Phase III study in CRC by the end of 2025. HARMONi is a Phase III clinical trial which intends to evaluate ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non- squamous NSCLC who were previously treated with a 3rd generation EGFR TKI (e.g., osimertinib). Enrollment in HARMONi was completed in the second half of 2024, and top-line results were announced in May of 2025, with detailed results provided in September 2025.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9 HARMONi-3 is a Phase III clinical trial which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab combined with chemotherapy in patients with first-line metastatic, squamous or non- squamous NSCLC, irrespective of PD-L1 expression. HARMONi-7 is a Phase III clinical trial which is intended to evaluate ivonescimab monotherapy compared to pembrolizumab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression. HARMONi-GI3 is a planned Phase III clinical trial evaluating ivonescimab in combination with chemotherapy compared with bevacizumab plus chemotherapy in patients with first-line unresectable metastatic CRC. In addition, Akeso has recently had positive read-outs in three single-region (China), randomized Phase III clinical trials for ivonescimab in NSCLC: HARMONi-A, HARMONi-2, and HARMONi-6. HARMONi-A was a Phase III clinical trial which evaluated ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with an EGFR TKI. HARMONi-2 is a Phase III clinical trial evaluating monotherapy ivonescimab against monotherapy pembrolizumab in patients with locally advanced or metastatic NSCLC whose tumors have positive PD-L1 expression. HARMONi-6 is a Phase III clinical trial evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, an anti-PD-1 antibody, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous NSCLC, irrespective of PD-L1 expression. Akeso is actively conducting multiple Phase III clinical studies in settings outside of NSCLC, including biliary tract cancer, colorectal cancer, breast cancer, pancreatic cancer, small cell lung cancer, and head and neck cancer. Ivonescimab is an investigational therapy that is not approved by any regulatory authority in Summit's license territories, including the United States and Europe. Ivonescimab was initially approved for marketing authorization in China in May 2024. Ivonescimab was granted Fast Track designation by the US Food & Drug Administration (FDA) for the HARMONi clinical trial setting. About Summit Therapeutics Summit Therapeutics Inc. is a biopharmaceutical oncology company focused on the discovery, development, and commercialization of patient-, physician-, caregiver- and societal-friendly medicinal therapies intended to improve quality of life, increase potential duration of life, and resolve serious unmet medical needs. Summit was founded in 2003 and our shares are listed on the Nasdaq Global Market (symbol "SMMT"). We are headquartered in Miami, Florida, and we have additional offices in Menlo Park, California, and Oxford, UK. For more information, please visit https://www.smmttx.com and follow us on X @SMMT_TX.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10 Contact Summit Investor Relations: Dave Gancarz Chief Business & Strategy Officer Nathan LiaBraaten Senior Director, Investor Relations investors@smmttx.com media@smmttx.com Summit Forward-looking Statements Any statements in this press release about the Company's future expectations, plans and prospects, including but not limited to, statements about the clinical and preclinical development of the Company's product candidates, entry into and actions related to the Company's partnership with Akeso Inc., the Company's anticipated spending and cash runway, the therapeutic potential of the Company's product candidates, the potential commercialization of the Company's product candidates, the timing of initiation, completion and availability of data from clinical trials, the potential submission of applications for marketing approvals, the expected timing of BLA submissions, potential acquisitions, statements about the previously disclosed At-The-Market equity offering program ("ATM Program"), the expected proceeds and uses thereof, the Company's estimates regarding stock-based compensation, and other statements containing the words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "should," "target," "would," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the Company's ability to sell shares of our common stock under the ATM Program, the conditions affecting the capital markets, general economic, industry, or political conditions, including the effects of geopolitical developments, domestic and foreign trade policies, and monetary policies, the results of our evaluation of the underlying data in connection with the development and commercialization activities for ivonescimab, the outcome of discussions with regulatory authorities, including the Food and Drug Administration, the uncertainties inherent in the initiation of future clinical trials, availability and timing of data from ongoing and future clinical trials, the results of such trials, and their success, global public health crises, that may affect timing and status of our clinical trials and operations, whether preliminary results from a clinical trial will be predictive of the final results of that trial or whether results of early clinical trials or preclinical studies will be indicative of the results of later clinical trials, whether business development opportunities to expand the Company's pipeline of drug candidates, including without limitation, through potential acquisitions of, and/or collaborations with, other entities occur, expectations for regulatory approvals, laws and regulations affecting government contracts and funding awards, availability of funding sufficient for the Company's foreseeable and unforeseeable operating expenses and capital expenditure requirements and other factors discussed in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of filings that the Company makes with the Securities and Exchange Commission. Any change to our ongoing trials could cause delays, affect our future expenses, and add uncertainty to our commercialization efforts, as well as to affect the likelihood of the successful completion of clinical development of ivonescimab. Accordingly, readers should not place undue reliance on forward-looking statements or information. In addition, any forward-looking statements included in this press release represent the Company's views only as of the date of this release and should not be relied upon as representing the Company's views as of any subsequent date. The Company specifically disclaims any obligation to update any forward-looking statements included in this press release.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11 Summit Therapeutics and the Summit Therapeutics logo are trademarks of Summit Therapeutics Inc. Copyright 2025, Summit Therapeutics Inc. All Rights Reserved

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12 Summit Therapeutics Inc. GAAP Condensed Consolidated Statements of Operations (Unaudited) (in millions, except per share data) Three Months Ended September 30, Nine Months Ended September 30, 2025 2024 2025 2024 Operating expenses: Research and development $131.1 $37.7 $390.4 $99.4 Acquired in-process research and development — — — 15.0 General and administrative 103.1 20.7 479.1 46.0 Total operating expenses 234.2 58.4 869.5 160.4 Other income, net 2.4 4.6 9.1 9.0 Interest expense — (2.5) — (8.7) Net loss $(231.8) $(56.3) $(860.4) $(160.1) Net loss per share attributable to common shareholders per share, basic and diluted $(0.31) $(0.08) $(1.16) $(0.22) Summit Therapeutics Inc. GAAP Condensed Consolidated Balance Sheet Information (in millions) Unaudited September 30, 2025 December 31, 2024 Cash and cash equivalents and short-term investments $238.6 $412.3 Total assets $261.7 $435.6 Total liabilities $69.5 $46.8 Total stockholders' equity $192.3 $388.7

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summit Therapeutics Inc. GAAP Condensed Consolidated Statement of Cash Flows Information (in millions) Unaudited Nine Months Ended September 30, 2025 2024 Net cash used in operating activities $(221.0) $(93.4) Net cash provided by (used in) investing activities 310.8 (288.8) Net cash provided by financing activities 43.7 404.8 Effect of exchange rate changes on cash 0.1 0.1 Increase in cash, cash equivalents and restricted cash $133.6 $22.7

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summit Therapeutics Inc. Schedule Reconciling Selected Non-GAAP Financial Measures (Unaudited) (in millions, except per share data) Three Months Ended September 30, Nine Months Ended September 30, 2025 2024 2025 2024 Reconciliation of GAAP to Non-GAAP Research and Development Expense GAAP Research and Development $131.1 $37.7 $390.4 $99.4 Stock-based compensation (Note 1) (40.6) (5.8) (173.2) (11.7) Non-GAAP Research and development $90.5 $31.9 $217.2 $87.7 Reconciliation of GAAP to Non-GAAP General and Administrative Expenses GAAP General and Administrative $103.1 $20.7 $479.1 $46.0 Stock-based compensation (Note 1) (90.2) (13.6) (447.4) (28.2) Non-GAAP General and administrative $12.9 $7.1 $31.7 $17.8 Reconciliation of GAAP to Non-GAAP Operating GAAP Operating Expenses $234.2 $58.4 $869.5 $160.4 Stock-based compensation (Note 1) (130.8) (19.4) (620.6) (39.9) Non-GAAP Operating expense $103.4 $39.0 $248.9 $120.5 Reconciliation of GAAP Net Loss to Non-GAAP Net GAAP Net Loss $(231.8) $(56.3) $(860.4) $(160.1) Stock-based compensation (Note 1) 130.8 19.4 620.6 39.9 Non-GAAP Net Loss $(101.0) $(36.9) $(239.8) $(120.2) Reconciliation of GAAP Net Loss to Non-GAAP Net Loss Per Common Share GAAP Net Loss Per Basic and Diluted Common Share $(0.31) $(0.08) $(1.16) $(0.22) Stock-based compensation (Note 1) 0.18 0.03 0.83 0.06 Non-GAAP Net loss Per Basic and Diluted Common Share $(0.13) $(0.05) $(0.33) $(0.16) Basic and Diluted Common Shares 743.4 726.7 741.4 712.2

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summit Therapeutics Inc. Schedule Reconciling Selected Non-GAAP Financial Measures (in millions) Unaudited Three Months Ended September 30, 2025 June 30, 2025 March 31, 2025 December 31, 2024 September 30, 2024 Reconciliation of GAAP to Non-GAAP Operating Expenses GAAP Operating Expenses $234.2 $568.4 $66.8 $65.6 $58.4 Stock-based compensation (Note 1) (130.8) (478.8) (11.1) (11.0) (19.4) Non-GAAP Operating Expense (Note 2) $103.4 $89.6 $55.7 $54.6 $39.0 Reconciliation of GAAP Net Loss to Non-GAAP Net Loss GAAP Net Loss $(231.8) $(565.7) $(62.9) $(61.2) $(56.3) Stock-based compensation (Note 1) 130.8 478.8 11.1 11.0 19.4 Non-GAAP Net Loss (Note 2) $(101.0) $(86.9) $(51.8) $(50.2) $(36.9)

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summit Therapeutics Inc. Notes on our Non-GAAP Financial Information Non-GAAP financial measures adjust GAAP financial measures for the items listed below. These Non-GAAP measures should be viewed in addition to, and not as a substitute for Summit's reported GAAP results, and may be different from Non-GAAP measures used by other companies. In addition, these Non-GAAP measures are not based on any comprehensive set of accounting rules or principles. Summit management uses these Non- GAAP measures for internal budgeting and forecasting purposes and to evaluate Summit's financial performance. Summit management believes the presentation of these Non-GAAP measures is useful to investors for comparing prior periods and analyzing ongoing business trends and operating results. Each of Non-GAAP Research and Development Expense, Non-GAAP General and Administrative Expenses, Non-GAAP Operating Expenses, Non-GAAP Net Loss and Non-GAAP EPS differ from GAAP in that such measures exclude the non-cash charges and costs associated with stock-based compensation. Note 1: Stock-based compensation is a non-cash charge and costs calculated for this expense can vary year- over-year depending on the stock price of awards on the date of grant as well as the timing of compensation award arrangements. Note 2: Beginning in the fourth quarter of 2024, the Company's Non-GAAP financial measures will no longer exclude acquired in-process research and development expenses ("IPR&D"). Non-GAAP financial measures for the three months ended June 30, 2024 previously excluded $15.0 million of IPR&D which represented an upfront payment made to Akeso under an amendment to the Collaboration and License Agreement. Prior period amounts have been revised to conform to the current period presentation.

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## Exhibit 99.2

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&nbsp;&nbsp;&nbsp;&nbsp;1 Summit Therapeutics Announces Expansion of Ivonescimab Global Phase III Development Program with HARMONi-GI3 Study in 1L Colorectal Cancer HARMONi-GI3 is the Fourth Global Phase III Study of Ivonescimab and First Global Study beyond NSCLC Clinical Trial Site Activations Planned to Begin This Quarter in the United States Conference Call to be Held at 8:00am ET on Monday, October 20, 2025 Miami, Florida, October 17, 2025 – Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") today announced the expansion of its Phase III clinical development program of the novel, potential first-in-class investigational bispecific antibody, ivonescimab, into colorectal cancer (CRC) with the initiation of the global Phase III HARMONi-GI3 trial. Summit is starting a Phase III clinical study, HARMONi-GI3, to evaluate ivonescimab plus chemotherapy compared to bevacizumab plus chemotherapy as first line therapy in patients with unresectable metastatic colorectal cancer (CRC). Clinical trial sites for HARMONi-GI3 are planned to begin activating in the United States prior to the end of the year. The multiregional study intends to enroll approximately 600 patients. The primary endpoint for this study is progression-free survival. Each year, approximately 48,000 patients are estimated to be diagnosed with or have unresectable recurrent metastatic MSS CRC (also known as mismatch repair-proficient colorectal cancer, or pMMR CRC).1 There have been limited options approved in the United States in the last 20 years for those first-line patients whose tumors are not positive for certain biomarkers or other activating mutations. MSS CRC is a setting where monoclonal PD-1 inhibitors such as pembrolizumab and nivolumab have failed to show a clinically meaningful benefit. Anti-VEGF therapy (e.g., bevacizumab) plus chemotherapy is the standard of care for many patients with 1L metastatic MSS CRC. At the 2024 Annual Congress of the European Society of Medical Oncology (ESMO 2024), Akeso presented encouraging Phase II data of ivonescimab in combination with FOLFOXIRI chemotherapy demonstrating an objective response rate (ORR) of 81.8% (95% CI: 59.7% – 94.8%) and a disease control rate (DCR) of 100% (95% CI: 84.6% – 100.0%) in 22 patients. This Phase II study, AK112-206, was conducted in China and sponsored by Akeso with all relevant data exclusively generated, managed, and analyzed by Akeso. In the ivonescimab plus FOLFOXIRI chemotherapy arm, there were no treatment emergent adverse events that led to permanent discontinuation of ivonescimab as of the data cutoff from the ESMO 2024 presentation. Subsequently, AK112-206 was expanded to include additional patients from the US and China to study ivonescimab in combination with FOLFOX chemotherapy. FOLFOX in combination with a monoclonal antibody such as bevacizumab represents a preferred treatment regimen for physicians treating patients in the United States and other western territories. The data from the initial patient cohort presented at ESMO 2024 have continued to 1 Malla, Midhun, et. al.; Journal of the National Comprehensive Cancer Network: JNCCN, 01 May 2023, Vol. 21, Issue 5.5, pages 567 – 571; Buchler T.; Microsatellite Instability and Metastatic Colorectal Cancer - A Clinical Perspective. Front Oncol. 2022 Apr 28;12:888181; Cohen R, Platell CF. Metachronous colorectal cancer metastasis: who, what, when and what to do about it. J Surg Oncol. 2024; 129: 71-77; SEER data (provided by the US Department of Health and Human Services; US National Institutes of Health; US National Cancer Institute).

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&nbsp;&nbsp;&nbsp;&nbsp;2 mature, in addition to the global Phase II data generated in combination with FOLFOX in the United States and China, which support the Phase III HARMONi-GI3 study design using FOLFOX. "As promised earlier in the year, we sought to expand the ivonescimab clinical development program beyond non- small cell lung cancer in order to continue to explore the potential benefits of its specifically-engineered, novel design and mechanism of action, including its cooperative binding attributes," stated Robert W. Duggan and Dr. Maky Zanganeh, Co-Chief Executive Officers of Summit. "Microsatellite stable colorectal cancer represents a global unmet need whereby ivonescimab has the potential to bring the benefits of immunotherapy to solid tumors where PD-1 monoclonal antibodies have not been able to successfully improve upon existing standards of care. We are thrilled by the potential of ivonescimab to make a significant difference to these patients with few front-line options available today." Conference Call Summit Therapeutics Inc. will host a conference call and live webcast to discuss recent updates related to ivonescimab, including data released at ESMO, on Monday, October 20, 2025, at 8:00am ET. Conference call and webcast information will be accessible through our website www.smmttx.com. An archived edition of the webcast will be available on our website later in the day on Monday. About Ivonescimab Ivonescimab, known as SMT112 in Summit's license territories, North America, South America, Europe, the Middle East, Africa, and Japan, and as AK112 in China and Australia, is a novel, potential first-in-class investigational bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule. Ivonescimab displays unique cooperative binding to each of its intended targets with multi-fold higher affinity to PD-1 when in the presence of VEGF. This could differentiate ivonescimab as there is potentially higher expression (presence) of both PD-1 and VEGF in tumor tissue and the tumor microenvironment (TME) as compared to normal tissue in the body. Ivonescimab's specifically engineered tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, SITC, 2023). This tetravalent structure, the intentional novel design of the molecule, and bringing these two targets into a single bispecific antibody with cooperative binding qualities have the potential to direct ivonescimab to the tumor tissue versus healthy tissue. The intent of this design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, SITC, 2023) increasing to approximately 10 days at steady state dosing, is to improve upon previously established efficacy thresholds, in addition to side effects and safety profiles associated with these targets. Ivonescimab was engineered by Akeso Inc. (HKEX Code: 9926.HK) and is currently engaged in multiple Phase III clinical trials. Over 3,000 patients have been treated with ivonescimab in clinical studies globally. Summit began its clinical development of ivonescimab in non-small cell lung cancer (NSCLC), commencing enrollment in 2023 in two multiregional Phase III clinical trials, HARMONi and HARMONi-3. In early 2025, the Company began enrolling patients in the United States for HARMONi-7. Summit intends to open clinical trial sites in the United States for the Phase III study in colorectal cancer (CRC) by the end of 2025. HARMONi is a Phase III clinical trial which intends to evaluate ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non- squamous NSCLC who were previously treated with a 3rd generation EGFR TKI (e.g., osimertinib). Enrollment in

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&nbsp;&nbsp;&nbsp;&nbsp;3 HARMONi was completed in the second half of 2024, top-line results were announced in May of 2025, with detailed results provided in September 2025. HARMONi-3 is a Phase III clinical trial which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab combined with chemotherapy in patients with first-line metastatic, squamous or non- squamous NSCLC, irrespective of PD-L1 expression. HARMONi-7 is a Phase III clinical trial which is intended to evaluate ivonescimab monotherapy compared to pembrolizumab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression. HARMONi-GI3 is a planned Phase III clinical trial evaluating ivonescimab in combination with chemotherapy compared with bevacizumab plus chemotherapy in patients with first-line unresectable metastatic CRC. In addition, Akeso has recently had positive read-outs in three single-region (China), randomized Phase III clinical trials for ivonescimab in NSCLC: HARMONi-A, HARMONi-2, and HARMONi-6. HARMONi-A was a Phase III clinical trial which evaluated ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with an EGFR TKI. HARMONi-2 is a Phase III clinical trial evaluating monotherapy ivonescimab against monotherapy pembrolizumab in patients with locally advanced or metastatic NSCLC whose tumors have positive PD-L1 expression. HARMONi-6 is a Phase III clinical trial evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, an anti-PD-1 antibody, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous NSCLC, irrespective of PD-L1 expression. Akeso is actively conducting multiple Phase III clinical studies in settings outside of NSCLC, including biliary tract cancer, colorectal cancer, breast cancer, pancreatic cancer, small cell lung cancer, and head and neck cancer. Ivonescimab is an investigational therapy that is not approved by any regulatory authority in Summit's license territories, including the United States and Europe. Ivonescimab was initially approved for marketing authorization in China in May 2024. Ivonescimab was granted Fast Track designation by the US Food & Drug Administration (FDA) for the HARMONi clinical trial setting. About Summit Therapeutics Summit Therapeutics Inc. is a biopharmaceutical oncology company focused on the discovery, development, and commercialization of patient-, physician-, caregiver- and societal-friendly medicinal therapies intended to improve quality of life, increase potential duration of life, and resolve serious unmet medical needs. Summit was founded in 2003 and our shares are listed on the Nasdaq Global Market (symbol "SMMT"). We are headquartered in Miami, Florida, and we have additional offices in Menlo Park, California, and Oxford, UK. For more information, please visit https://www.smmttx.com and follow us on X @SMMT_TX.

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&nbsp;&nbsp;&nbsp;&nbsp;4 Contact Summit Investor Relations: Dave Gancarz Chief Business & Strategy Officer Nathan LiaBraaten Senior Director, Investor Relations investors@smmttx.com media@smmttx.com Summit Forward-looking Statements Any statements in this press release about the Company's future expectations, plans and prospects, including but not limited to, statements about the clinical and preclinical development of the Company's product candidates, entry into and actions related to the Company's partnership with Akeso Inc., the Company's anticipated spending and cash runway, the therapeutic potential of the Company's product candidates, the potential commercialization of the Company's product candidates, the timing of initiation, completion and availability of data from clinical trials, the potential submission of applications for marketing approvals, potential acquisitions, statements about the previously disclosed At-The-Market equity offering program ("ATM Program"), the expected proceeds and uses thereof, the Company's estimates regarding stock-based compensation, and other statements containing the words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "should," "target," "would," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the Company's ability to sell shares of our common stock under the ATM Program, the conditions affecting the capital markets, general economic, industry, or political conditions, the results of our evaluation of the underlying data in connection with the development and commercialization activities for ivonescimab, the outcome of discussions with regulatory authorities, including the Food and Drug Administration, the uncertainties inherent in the initiation of future clinical trials, availability and timing of data from ongoing and future clinical trials, the results of such trials, and their success, global public health crises, that may affect timing and status of our clinical trials and operations, whether preliminary results from a clinical trial will be predictive of the final results of that trial or whether results of early clinical trials or preclinical studies will be indicative of the results of later clinical trials, whether business development opportunities to expand the Company's pipeline of drug candidates, including without limitation, through potential acquisitions of, and/or collaborations with, other entities occur, expectations for regulatory approvals, laws and regulations affecting government contracts and funding awards, availability of funding sufficient for the Company's foreseeable and unforeseeable operating expenses and capital expenditure requirements and other factors discussed in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of filings that the Company makes with the Securities and Exchange Commission. Any change to our ongoing trials could cause delays, affect our future expenses, and add uncertainty to our commercialization efforts, as well as to affect the likelihood of the successful completion of clinical development of ivonescimab. Accordingly, readers should not place undue reliance on forward-looking statements or information. In addition, any forward-looking statements included in this press release represent the Company's views only as of the date of this release and should not be relied upon as representing the Company's views as of any subsequent date. The Company specifically disclaims any obligation to update any forward-looking statements included in this press release.

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&nbsp;&nbsp;&nbsp;&nbsp;5 Summit Therapeutics and the Summit Therapeutics logo are trademarks of Summit Therapeutics Inc. Copyright 2025, Summit Therapeutics Inc. All Rights Reserved

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## Exhibit 99.3

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&nbsp;&nbsp;&nbsp;&nbsp;1 Ivonescimab with Chemotherapy Reduced the Risk of Disease Progression or Death by 40% Compared to Tislelizumab (PD-1 Inhibitor) Plus Chemotherapy in 1L Treatment of Patients with Squamous NSCLC in the HARMONi-6 Study Conducted by Akeso in China Ivonescimab in Combination with Chemotherapy Is the First Known Regimen to Achieve a Clinically Meaningful Benefit over an anti-PD-(L)1 Antibody Combined with Chemotherapy in a Phase III Clinical Trial in 1L NSCLC: Median PFS of 11.14 Months vs. 6.90 Months, Respectively, for Patients Receiving Ivonescimab Plus Chemotherapy vs. Tislelizumab Plus Chemotherapy; Hazard Ratio of 0.60 Tolerable Safety Profile Reaffirmed for PD-1 / VEGF Bispecific in Squamous NSCLC: Comparable Serious Treatment-Related Adverse Events and TRAE-Led Discontinuation & Death Rates Were Observed in the Two Arms of HARMONi-6 Summit-Sponsored HARMONi-3 Global Study Will be Split into Two Analyses by Histology: Squamous NSCLC Cohort Expected to Complete Enrollment in First Half 2026 with Data Readout Expected in Second Half 2026; Non-Squamous NSCLC Cohort Expected to Complete Enrollment in Second Half 2026 Simultaneous Ivonescimab Manuscript for HARMONi-6 Clinical Trial Results Published in The Lancet Conference Call to be Held at 8:00am ET on Monday, October 20, 2025 Miami, Florida, October 19, 2025 – Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") today announced results from the Phase III HARMONi-6 trial, conducted in China and sponsored by our partner, Akeso, Inc. (HKEX Code: 9926.HK), featuring the novel, potential first-in-class investigational bispecific antibody, ivonescimab. The data was presented today as part of the Presidential Symposium at the European Society for Medical Oncology 2025 Congress (ESMO 2025) in Berlin, Germany. The HARMONi-6 presentation, Phase III Study of Ivonescimab plus chemotherapy versus Tislelizumab plus chemotherapy as First-line Treatment for advanced squamous non-small cell lung cancer (HARMONi-6), evaluated ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, a PD-1 inhibitor, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous non- small cell lung cancer (NSCLC) irrespective of PD-L1 expression. HARMONi-6 is a single region, multi-center, Phase III study conducted in China sponsored by Akeso with all relevant data exclusively generated, managed, and analyzed by Akeso. The trial results were presented by Dr. Shun Lu, MD, PhD, Chief of Shanghai Lung Cancer Center at Shanghai Chest Hospital, Professor of Medicine at Shanghai Jiaotong University, and associate editor for the Journal of Thoracic Oncology. In major markets globally, first-line therapy for patients with advanced non-small cell lung cancer without driver mutations is most commonly a PD-1 inhibitor plus platinum-based chemotherapy. Prior to HARMONi-6, there were no known Phase III clinical trials in advanced NSCLC which have shown a statistically significant and clinically meaningful improvement compared to PD-(L)1 inhibitor therapy in combination with chemotherapy in a head-to- head setting.

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&nbsp;&nbsp;&nbsp;&nbsp;2 Clinically Meaningful Efficacy In the HARMONi-6 planned interim analysis of progression-free survival (PFS), ivonescimab in combination with chemotherapy demonstrated a statistically significant improvement in the primary endpoint, PFS, by Independent Radiologic Review Committee (IRRC), when compared to tislelizumab in combination with chemotherapy, achieving a hazard ratio (HR) of 0.60 (95% CI: 0.46, 0.78; p<0.0001). A clinically meaningful benefit was demonstrated across clinical subgroups, including those with either PD-L1 negative or positive expression. Both the overall response rate (ORR) measured according to RECIST v1.1 criteria, as well as the duration of response (DoR) were higher in patients treated with ivonescimab plus chemotherapy compared to those treated with tislelizumab plus chemotherapy. HARMONi-6 ITT (n=532): Median Follow-up: 10.28 mos Ivonescimab + Chemo (n=266) Tislelizumab + Chemo (n=266) Median PFS 11.14 mos (95% CI: 9.86, NE) 6.90 mos (95% CI: 5.82, 8.57) PFS Stratified HR 0.60 (95% CI: 0.46, 0.78; p<0.0001) ORR 75.9% 66.5% DoR 11.20 mos (95% CI: 8.54, NE) 8.38 mos (95% CI: 5.72, NE) ITT: Intention-to-Treat population; mos.: months; NE: not established HARMONi-6 PD-L1 Subgroup Analyses Ivonescimab + Chemo vs. Tislelizumab + Chemo PD-L1 Negative (PD-L1 TPS <1%) PFS stratified HR Ivonescimab + Chemo n=105; Tislelizumab + Chemo n=105 0.55 (95% CI: 0.37, 0.82) PD-L1 Positive (PD-L1 TPS >1%) PFS stratified HR Ivonescimab + Chemo n=161; Tislelizumab + Chemo n=161 0.66 (95% CI: 0.46, 0.95) Overall survival (OS) data was not yet mature at the time of the data cutoff and will be evaluated in the future. Manageable Safety Profile Ivonescimab demonstrated an acceptable and manageable safety profile in the HARMONi-6 study, which was consistent with previous Phase III studies conducted studying ivonescimab. In squamous NSCLC, VEGF-A monoclonal antibodies have not been approved by health authorities including the FDA and have had limited clinical development based on historical early phase clinical trials, primarily due to significant risks of toxicity, including hemorrhage and other life-threatening, bleeding-related complications. The results of this study further validate the unique mechanism of action of ivonescimab, including key differences as compared to separately administering an anti-PD-1 monoclonal antibody and an anti-VEGF monoclonal antibody. In this Phase III study, there were nine patients (3.4%) who discontinued ivonescimab plus chemotherapy due to treatment-related adverse events (TRAEs) compared to 11 patients (4.2%) who discontinued tislelizumab plus chemotherapy due to TRAEs. There were eight patients (3.0%) in the ivonescimab plus chemotherapy arm and

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&nbsp;&nbsp;&nbsp;&nbsp;3 10 patients (3.8%) in the tislelizumab plus chemotherapy arm who died as a result of TRAEs in this Phase III study. The most frequent TRAEs for ivonescimab treatment in combination with chemotherapy were common chemotherapy-related AEs, including alopecia, anemia, and various laboratory abnormalities, including neutrophil, white blood cell, and platelet count decreases. Grade 3 or higher immune-related adverse events occurred in 9.0% of patients receiving ivonescimab in combination with chemotherapy and 10.2% of patients receiving tislelizumab in combination with chemotherapy. Grade 3 or higher adverse events that were possibly VEGF-related in the ivonescimab plus chemotherapy arm were 7.5% vs. 2.3% for tislelizumab plus chemotherapy. Most of the possibly VEGF-related adverse events occurring in the ivonescimab plus chemotherapy arm were classified as Grade 1 or 2. Of note, Grade 3 or higher hemorrhage events were observed in five patients in the ivonescimab plus chemotherapy arm compared to two patients in the tislelizumab plus chemotherapy arm in this study. HARMONi-6 Ivonescimab + Chemo (n=266) Tislelizumab + Chemo (n=265) Serious TRAEs (TRSAEs) 32.3% 30.2% TRAEs Leading to Drug Discontinuation 3.4% 4.2% TRAEs Leading to Death 3.0% 3.8% Grade 3+ Immune-related 9.0% 10.2% Grade 3+ Possibly VEGF-related\* 7.5% 2.3% \*In the ivonescimab plus chemotherapy arm, possibly VEGF-related Grade 3+ events were largely driven by conditions such as hypertension (3.0%) and proteinuria (2.3%) and largely did not lead to the discontinuation of ivonescimab. TRAE: treatment-related adverse event "The novel mechanism of action of ivonescimab may allow for an improved clinical profile and longer duration of therapy, which help improve outcomes – this distinguishes ivonescimab from other PD-1 monoclonal antibodies and PD-(L)1 plus VEGF treatments administered separately," added Dr. Maky Zanganeh, Co-Chief Executive Officer and President of Summit. "No more striking is this result than in squamous NSCLC where the benefit of anti-VEGF therapy has been largely unrealized. Combined with the improved benefit in patients across all levels of PD-L1 expression, implying a true improvement in the immunotherapy activity, this study of ivonescimab in combination with chemotherapy provides rich context as to the potential benefit of ivonescimab across solid tumors, reaffirming its incredible potential to help a wide variety of patients suffering from cancer." HARMONi-6 Clinical Trial Results Published in The Lancet Today The Lancet published a manuscript titled, "Ivonescimab plus chemotherapy versus tislelizumab plus chemotherapy as first-line treatment for advanced squamous non-small-cell lung cancer (HARMONi-6): a randomised, double-blind, phase 3 trial." The publication is based on the results of HARMONi-6, a single region, multi-center, Phase III study conducted in China sponsored by Akeso, with data generated and analyzed by Akeso. "HARMONi-6 is yet another meaningful milestone for ivonescimab, Team Summit, and our partners at Akeso, and most importantly, continues to advance a potential treatment option for patients living with difficult-to-treat cancers," said Robert W. Duggan, Chairman and Co-Chief Executive Officer of Summit. "We remain extraordinarily proud of our partnership with Akeso and their ongoing clinical accomplishments and advancement of ivonescimab in solid tumors. We also would like to express our heartfelt appreciation to those physicians and patients in China who

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&nbsp;&nbsp;&nbsp;&nbsp;4 participated in this important study, who are helping to advance the treatment of patients around the world with this incredibly innovative therapy." HARMONi-3 Clinical Trial Update Summit is currently enrolling patients in the HARMONi-3 study. HARMONi-3 is a multiregional Phase III clinical trial sponsored by Summit which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab, an anti-PD-1 antibody, combined with chemotherapy in patients with first-line metastatic, squamous and non-squamous NSCLC. HARMONi-3 is currently enrolling patients globally and is conducted with registrational intent for the United States and other regions within Summit's license territories. The dual primary endpoints for this study are PFS and OS. Summit has amended the protocol for the HARMONi-3 study in order to separate the statistical analysis (i.e., the outcome) of the primary endpoints by histology. Therefore, there will be separate analyses conducted to evaluate ivonescimab plus chemotherapy compared to pembrolizumab plus chemotherapy in patients with squamous NSCLC and in patients with non-squamous NSCLC. As a result of having two separate intention-to-treat analyses within the HARMONi-3 study, the analyses for squamous tumors and non-squamous tumors may be conducted at separate times, as each analysis will be conducted upon the prespecified numbers of events being reached in the separate cohorts. Summit currently expects to complete enrollment in the squamous cohort of HARMONi-3 in the first half of 2026 and expects to reach the prespecified number of events for the PFS primary endpoint analysis for this cohort in the second half of 2026. An interim analysis for overall survival may be conducted at a similar time. At present time, Summit expects to complete enrollment in the non-squamous cohort of HARMONi-3 in the second half of 2026 and expects to reach the prespecified number of events for the PFS primary endpoint analysis for this cohort in the first half of 2027. An interim analysis for overall survival is planned to be conducted based upon reaching a prespecified number of events. In order to sufficiently power each of the dual primary endpoints in both cohorts of this study, Summit plans to enroll 600 patients with squamous NSCLC and 1,000 patients with non-squamous NSCLC. Reference Comparison of Results of 1L Squamous NSCLC Studies Evaluating Pembrolizumab or Tislelizumab Plus Chemotherapy Compared to Chemotherapy Study Data at Initial Readout Study Regions Median PFS (PD-1 + Chemo Arm) Hazard Ratio vs. Chemo\* Median Follow-up Time Source KEYNOTE-407 (n=559) Multiregional Study 6.4 months HR=0.56 7.8 months Paz-Ares, NEJM, 2018 RATIONALE-307 (n=360) China Regional Study 7.6 months HR=0.52\* 8.6 months Wang, JAMA Oncology, 2021 \*RATIONALE-307 compared tislelizumab + carboplatin + paclitaxel (Arm A) vs. carboplatin + paclitaxel (Arm C) and separately tislelizumab + carboplatin + nab-paclitaxel (Arm B) vs. carboplatin + paclitaxel (Arm C). The study randomized patients 1:1:1 between the three arms. The median PFS results for tislelizumab + carboplatin + paclitaxel (Arm A) and tislelizumab + carboplatin + nab-paclitaxel (Arm B) were the same. The hazard ratios were 0.52 for Arm A vs. Arm C and 0.48 for Arm B vs. Arm C. KEYNOTE-407 randomized patients to receive either pembrolizumab or placebo plus carboplatin and either paclitaxel or nab-paclitaxel; the study was stratified by the choice of taxane.

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&nbsp;&nbsp;&nbsp;&nbsp;5 Conference Call Summit Therapeutics Inc. will host a conference call and live webcast to discuss recent updates related to ivonescimab, including data released at ESMO, on Monday, October 20, 2025, at 8:00am ET. Conference call and webcast information will be accessible through our website www.smmttx.com. An archived edition of the webcast will be available on our website later in the day on Monday. About Ivonescimab Ivonescimab, known as SMT112 in Summit's license territories, North America, South America, Europe, the Middle East, Africa, and Japan, and as AK112 in China and Australia, is a novel, potential first-in-class investigational bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects associated with blocking VEGF into a single molecule. Ivonescimab displays unique cooperative binding to each of its intended targets with multifold higher affinity to PD-1 when in the presence of VEGF. This could differentiate ivonescimab as there is potentially higher expression (presence) of both PD-1 and VEGF in tumor tissue and the tumor microenvironment (TME) as compared to normal tissue in the body. Ivonescimab's specifically engineered tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, SITC, 2023). This tetravalent structure, the intentional novel design of the molecule, and bringing these two targets into a single bispecific antibody with cooperative binding qualities have the potential to direct ivonescimab to the tumor tissue versus healthy tissue. The intent of this design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, SITC, 2023) increasing to approximately 10 days at steady state dosing, is to improve upon previously established efficacy thresholds, in addition to side effects and safety profiles associated with these targets. Ivonescimab was engineered by Akeso Inc. (HKEX Code: 9926.HK) and is currently engaged in multiple Phase III clinical trials. Over 3,000 patients have been treated with ivonescimab in clinical studies globally. Summit began its clinical development of ivonescimab in non-small cell lung cancer (NSCLC), commencing enrollment in 2023 in two multiregional Phase III clinical trials, HARMONi and HARMONi-3. In early 2025, the Company began enrolling patients for HARMONi-7. Summit intends to open clinical trial sites in the United States for the Phase III HARMONi-GI3 study in colorectal cancer (CRC) by the end of 2025. HARMONi is a Phase III clinical trial which intends to evaluate ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with epidermal growth factor receptor (EGFR)-mutant, locally advanced or metastatic non-squamous NSCLC who were previously treated with a third generation EGFR tyrosine kinase inhibitor (TKI) (e.g., osimertinib). Enrollment in HARMONi was completed in the second half of 2024, and top-line results were announced in May of 2025, with detailed results provided in September 2025. HARMONi-3 is a Phase III clinical trial which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab combined with chemotherapy in patients with first-line metastatic, squamous or non- squamous NSCLC, irrespective of PD-L1 expression. HARMONi-7 is a Phase III clinical trial which is intended to evaluate ivonescimab monotherapy compared to pembrolizumab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression.

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&nbsp;&nbsp;&nbsp;&nbsp;6 HARMONi-GI3 is a planned Phase III clinical trial evaluating ivonescimab in combination with chemotherapy compared with bevacizumab plus chemotherapy in patients with first-line unresectable metastatic CRC. In addition, Akeso has recently had positive read-outs in three single-region (China), randomized Phase III clinical trials for ivonescimab in NSCLC: HARMONi-A, HARMONi-2, and HARMONi-6. HARMONi-A was a Phase III clinical trial which evaluated ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with an EGFR TKI. HARMONi-2 is a Phase III clinical trial evaluating monotherapy ivonescimab against monotherapy pembrolizumab in patients with locally advanced or metastatic NSCLC whose tumors have positive PD-L1 expression. HARMONi-6 is a Phase III clinical trial evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, an anti-PD-1 antibody, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous NSCLC, irrespective of PD-L1 expression. Akeso is actively conducting multiple Phase III clinical studies in settings outside of NSCLC, including biliary tract cancer, colorectal cancer, breast cancer, pancreatic cancer, small cell lung cancer, and head and neck cancer. Ivonescimab is an investigational therapy that is not approved by any regulatory authority in Summit's license territories, including the United States and Europe. Ivonescimab was initially approved for marketing authorization in China in May 2024. Ivonescimab was granted Fast Track designation by the US Food & Drug Administration (FDA) for the HARMONi clinical trial setting. About Summit Therapeutics Summit Therapeutics Inc. is a biopharmaceutical oncology company focused on the discovery, development, and commercialization of patient-, physician-, caregiver- and societal-friendly medicinal therapies intended to improve quality of life, increase potential duration of life, and resolve serious unmet medical needs. Summit was founded in 2003 and our shares are listed on the Nasdaq Global Market (symbol "SMMT"). We are headquartered in Miami, Florida, and we have additional offices in Menlo Park, California, and Oxford, UK. For more information, please visit https://www.smmttx.com and follow us on X @SMMT_TX. Contact Summit Investor Relations: Dave Gancarz Chief Business & Strategy Officer Nathan LiaBraaten Senior Director, Investor Relations investors@smmttx.com media@smmttx.com

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&nbsp;&nbsp;&nbsp;&nbsp;7 Summit Forward-looking Statements Any statements in this press release about the Company's future expectations, plans and prospects, including but not limited to, statements about the clinical and preclinical development of the Company's product candidates, entry into and actions related to the Company's partnership with Akeso Inc., the Company's anticipated spending and cash runway, the therapeutic potential of the Company's product candidates, the potential commercialization of the Company's product candidates, the timing of initiation, completion and availability of data from clinical trials, the potential submission of applications for marketing approvals, potential acquisitions, statements about the previously disclosed At-The-Market equity offering program ("ATM Program"), the expected proceeds and uses thereof, the Company's estimates regarding stock-based compensation, and other statements containing the words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "should," "target," "would," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the Company's ability to sell shares of our common stock under the ATM Program, the conditions affecting the capital markets, general economic, industry, or political conditions, including the effects of geopolitical developments, domestic and foreign trade policies, and monetary policies, the results of our evaluation of the underlying data in connection with the development and commercialization activities for ivonescimab, the outcome of discussions with regulatory authorities, including the Food and Drug Administration, the uncertainties inherent in the initiation of future clinical trials, availability and timing of data from ongoing and future clinical trials, the results of such trials, and their success, global public health crises, that may affect timing and status of our clinical trials and operations, whether preliminary results from a clinical trial will be predictive of the final results of that trial or whether results of early clinical trials or preclinical studies will be indicative of the results of later clinical trials, whether business development opportunities to expand the Company's pipeline of drug candidates, including without limitation, through potential acquisitions of, and/or collaborations with, other entities occur, expectations for regulatory approvals, laws and regulations affecting government contracts and funding awards, availability of funding sufficient for the Company's foreseeable and unforeseeable operating expenses and capital expenditure requirements and other factors discussed in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of filings that the Company makes with the Securities and Exchange Commission. Any change to our ongoing trials could cause delays, affect our future expenses, and add uncertainty to our commercialization efforts, as well as to affect the likelihood of the successful completion of clinical development of ivonescimab. Accordingly, readers should not place undue reliance on forward-looking statements or information. In addition, any forward-looking statements included in this press release represent the Company's views only as of the date of this release and should not be relied upon as representing the Company's views as of any subsequent date. The Company specifically disclaims any obligation to update any forward-looking statements included in this press release. Summit Therapeutics and the Summit Therapeutics logo are trademarks of Summit Therapeutics Inc. Copyright 2025, Summit Therapeutics Inc. All Rights Reserved

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## Exhibit 99.4

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Summit Therapeutics ESMO Update & Q3 2025 Earnings Call October 20, 2025 8:00am ET

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Forward Looking Statement Any statements in this press release about the Company's future expectations, plans and prospects, including but not limited to, statements about the clinical and preclinical development of the Company's product candidates, entry into and actions related to the Company's partnership with Akeso Inc., the Company's anticipated spending and cash runway, the therapeutic potential of the Company's product candidates, the potential commercialization of the Company's product candidates, the timing of initiation, completion and availability of data from clinical trials, the potential submission of applications for marketing approvals, the expected timing of BLA submissions, potential acquisitions, statements about the previously disclosed At-The-Market equity offering program ("ATM Program"), the expected proceeds and uses thereof, the Company's estimates regarding stock-based compensation, and other statements containing the words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "should," "target," "would," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the Company's ability to sell shares of our common stock under the ATM Program, the conditions affecting the capital markets, general economic, industry, or political conditions, including the effects of geopolitical developments, domestic and foreign trade policies, and monetary policies, the results of our evaluation of the underlying data in connection with the development and commercialization activities for ivonescimab, the outcome of discussions with regulatory authorities, including the Food and Drug Administration, the uncertainties inherent in the initiation of future clinical trials, availability and timing of data from ongoing and future clinical trials, the results of such trials, and their success, global public health crises, that may affect timing and status of our clinical trials and operations, whether preliminary results from a clinical trial will be predictive of the final results of that trial or whether results of early clinical trials or preclinical studies will be indicative of the results of later clinical trials, whether business development opportunities to expand the Company's pipeline of drug candidates, including without limitation, through potential acquisitions of, and/or collaborations with, other entities occur, expectations for regulatory approvals, laws and regulations affecting government contracts and funding awards, availability of funding sufficient for the Company's foreseeable and unforeseeable operating expenses and capital expenditure requirements and other factors discussed in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of filings that the Company makes with the Securities and Exchange Commission. Any change to our ongoing trials could cause delays, affect our future expenses, and add uncertainty to our commercialization efforts, as well as to affect the likelihood of the successful completion of clinical development of ivonescimab. Accordingly, readers should not place undue reliance on forward-looking statements or information. In addition, any forward-looking statements included in this press release represent the Company's views only as of the date of this release and should not be relied upon as representing the Company's views as of any subsequent date. The Company specifically disclaims any obligation to update any forward-looking statements included in this press release. Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Summit Therapeutics and the Summit Therapeutics logo are trademarks of Summit Therapeutics Inc. Copyright 2025, Summit Therapeutics Inc. All Rights Reserved. 2

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). 19 October 2025 Phase III study of ivonescimab plus chemotherapy versus tislelizumab plus chemotherapy as first-line treatment for advanced squamous non-small cell lung cancer (HARMONi-6) Shun Lu1, Fang Yang2, Zhou Jiang3, Longhua Sun4, Lin Wu3, Zhengxiang Han5, Yun Fan6, Yanqiu Zhao7, Xingya Li8, Haipeng Xu9, Xiangjiao Meng10, Ying Cheng11, Zhiye Zhang12, Zhiwei Chen1, Hui Luo13, Qin Shi14, Xuelei Ma15, Xuezhen Ma16, Zhongmin Zhang17, Michelle Xia18 1Shanghai Chest Hospital, Shanghai, China; 2Harbin Medical University Cancer Hospital, Harbin, China; 3Hunan Cancer Hospital, Changsha, China; 4The First Affiliated Hospital of Nanchang University, Nanchang, China; 5The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China; 6Zhejiang Cancer Hospital, Hangzhou, China; 7Henan Cancer Hospital, Zhengzhou, China; 8The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China; 9Fujian Provincial Tumor Hospital, Fuzhou, China; 10Shandong Cancer Hospital and Institute, Jinan, China; 11Jilin Cancer Hospital, Changchun, China; 12The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, China; 13Jiangxi Cancer Hospital, Nanchang, China; 14Fuzhou pulmonary hospital of fujian, Fuzhou, China; 15West China Hospital of Sichuan University, Chengdu, China; 16Qingdao Central Hospital, Qingdao, China; 17Linyi People's Hospital, Linyi, China; 18Akeso Biopharma, Inc., Zhongshan, China. Akeso Sponsored Trial HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 3

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Study Design A multicenter, randomized, double-blind, parallel-controlled phase III study Key Eligibility Criteria • Pathologically confirmed sq-NSCLC • Stage IIIB-IV • No prior systemic therapy • No EGFR mutations or ALK rearrangements • ECOG PS 0 or 1 Tislelizumab (200 mg, Q3W) + Carboplatin (AUC 5, Q3W) + Paclitaxel (175 mg/m2, Q3W) up to 4 cycles Ivonescimab (20 mg/kg, Q3W) up to 24 months or unacceptable toxicity Tislelizumab (200 mg, Q3W) up to 24 months or unacceptable toxicity N=532 Stratification Factors: • Stage: IIIB/IIIC vs. IV • PD-L1 TPS: ≥1% vs. <1% Endpoints: • Primary endpoint: PFS by IRRC per RECIST v1.1 • Key secondary endpoint: OS • Secondary endpoints: PFS by INV, ORR, DCR, DoR, TTR and safety Abbreviation: ALK, anaplastic lymphoma kinase; ECOG PS, Eastern Cooperative Oncology Group performance score; R, randomization; AUC, area under the curve; Q3W, every three weeks; IRRC, independent radiology review committee; RECIST v1.1, response evaluation criteria in solid tumors version 1.1; PFS, progression-free survival; OS, overall survival; INV, investigator; ORR, overall response rate; DCR, disease control rate; DoR, duration of response; TTR, time to response. Data cutoff date: February 28, 2025 Ivonescimab (20 mg/kg, Q3W) + Carboplatin (AUC 5, Q3W) + Paclitaxel (175 mg/m2, Q3W) up to 4 cycles R 1:1 Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 4

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Baseline Characteristics Characteristics, n(%) Ivonescimab + chemo (N=266) Tislelizumab + chemo (N=266) Age, years < 65 135 (50.8) 139 (52.3) ≥ 65 131 (49.2) 127 (47.7) Sex Male 256 (96.2) 238 (89.5) Female 10 (3.8) 28 (10.5) ECOG PS\* 0 42 (15.8) 42 (15.8) 1 224 (84.2) 222 (83.5) Smoking history Never 21 (7.9) 37 (13.9) Current/Former 245 (92.1) 229 (86.1) Disease stage IIIB/IIIC 21 (7.9) 20 (7.5) IV 245 (92.1) 246 (92.5) Tumor characteristics Central type 178 (66.9) 158 (59.4) Major blood vessel encasement 49 (18.4) 44 (16.5) With cavity 24 (9.0) 23 (8.6) With hemoptysis history 86 (32.3) 79 (29.7) PD-L1 TPS <1% 105 (39.5) 105 (39.5) ≥ 1% 161 (60.5) 161 (60.5) 1-49% 112 (42.1) 99 (37.2) ≥ 50% 49 (18.4) 62 (23.3) Metastases sites ≥3 metastatic sites 42 (15.8) 39 (14.7) Liver metastases 28 (10.5) 45 (16.9) Brain metastases 9 (3.4) 17 (6.4) \*Two patients' ECOG PS were missing in the tislelizumab plus chemotherapy arm. Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 5

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Primary endpoint: PFS by IRRC Ivonescimab + chemo (N=266) Tislelizumab + chemo (N=266) mPFS, months (95% CI) 11.14 (9.86, NE) 6.90 (5.82, 8.57) Stratified HR (95% CI) 0.60 (0.46, 0.78) p-value <0.0001 Abbreviation: mPFS, median progression-free survival; NE, not estimable; HR, hazard ratio; CI, confidence interval. Median Follow-up: 10.28 months Ivonescimab+chemo demonstrated a statistically significant improvement in PFS vs. tislelizumab+chemo with HR=0.60, representing a 4.2 months improvement in mPFS. Consistent PFS benefit by investigator-assessment: HR = 0.64 (95% CI: 0.50, 0.84) Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 6

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Favors Ivonescimab+chemo Favors Tislelizumab+chemo Subgroup Analysis of PFS by IRRC • PFS benefit favored ivonescimab across all key subgroups. • Observed important baseline imbalances in the older patient subgroup (Age ≥65), such as target lesion size, brain metastases. After adjusting for these covariates, the adjusted HR for Age ≥65 was 0.69. If the number of events at a level of a subgroup is less than 10, the median PFS and hazard ratio will not be provided. Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 7

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). PFS in different PD-L1 expression Subgroups Ivonescimab showed meaningful PFS improvement over tislelizumab regardless of PD-L1 expression. PD-L1 TPS<1% HR (95% CI) 0.55 (0.37, 0.82) PD-L1 TPS 1-49% HR (95% CI) 0.63 (0.41, 0.98) PD-L1 TPS ≥50% HR (95% CI) 0.71 (0.37, 1.33) Median Follow-up: 10.28 months PD-L1 TPS≥1% HR (95% CI) 0.66 (0.46, 0.95) Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 8

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). ORR and DoR by IRRC Ivonescimab + chemo (N=202) Tislelizumab + chemo (N=177) mDoR, months (95% CI) 11.20 (8.54, NE) 8.38 (5.72, NE) p-value 0.0219 Abbreviation: BOR, best overall response; CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; NE, not estimated. Tumor response was higher and more durable in the ivonescimab arm. Ivonescimab + chemo (N=266) Tislelizumab + chemo (N=266) BOR, n (%) CR 1 (0.4) 0 PR 201 (75.6) 177 (66.5) SD 39 (14.7) 60 (22.6) PD 6 (2.3) 15 (5.6) 75.9 66.5 0 10 20 30 40 50 60 70 80 90 100 O R R (%) 69.5 61.0 0 10 20 30 40 50 60 70 80 90 100 O R R (%) 80.1 70.2 0 10 20 30 40 50 60 70 80 90 100 O R R (%) ORR by IRRC Any PD-L1 PD-L1 TPS<1% PD-L1 TPS≥1% DoR by IRRC p=0.008 Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 9

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Safety Summary b Most common TRAEs (incidence ≥15%) Ivonescimab + chemo (N=266) Tislelizumab + chemo (N=265) TRAE 264 (99.2) 261 (98.5) Grade ≥ 3 TRAE 170 (63.9) 144 (54.3) Serious TRAE 86 (32.3) 80 (30.2) Leading to ivonescimab or tislelizumab discontinuation 9 (3.4) 11 (4.2) Leading to death 8 (3.0) 10 (3.8) Abbreviation: TRAE, treatment-related adverse events. Ivonescimab plus chemotherapy showed a manageable safety profile in squamous NSCLC. Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 10 10

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Immune-Related and VEGF-Related AEs Ivonescimab exhibited similar irAEs to tislelizumab. Immune-related AEs Ivonescimab + chemo (N=266) Tislelizumab + chemo (N=265) Any grade 73 (27.4) 67 (25.3) Grade ≥3 irAE 24 (9.0) 27 (10.2) Serious irAE 23 (8.6) 26 (9.8) Leading to ivonescimab or tislelizumab discontinuation 3 (1.1) 6 (2.3) Leading to death 0 1 (0.4) Possibly VEGF- Related AEs# Ivonescimab + chemo (N=266) Tislelizumab + chemo (N=265) Any Grade Grade ≥3 Any Grade Grade ≥3 Any 123 (46.2) 20 (7.5) 60 (22.6) 6 (2.3) Proteinuria 72 (27.1) 6 (2.3) 29 (10.9) 0 Haemorrhage 57 (21.4) 5 (1.9) 25 (9.4) 2 (0.8) Hypertension 27 (10.2) 8 (3.0) 12 (4.5) 3 (1.1) Arterial thromboembolism 3 (1.1) 3 (1.1) 0 0 Venous thromboembolism 2 (0.8) 0 3 (1.1) 1 (0.4) Fistula 1 (0.4) 0 0 0 Abbreviation: VEGF, vascular endothelial growth factor; AEs, adverse events; irAEs, immune-related adverse events. # AE terms were grouped terms. Possibly VEGF-related AEs occurred more frequently in the ivonescimab arm, most of which were grade 1-2. Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 11

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Conclusion ⚫ Ivonescimab plus chemotherapy significantly improved PFS for advanced squamous NSCLC first-line treatment compared with tislelizumab plus chemotherapy in HARMONi-6 in China. ◼ mPFS: 11.14 vs. 6.90, HR=0.60 (95%CI: 0.46, 0.78), p<0.0001 ◼ PFS benefit favored ivonescimab plus chemotherapy across all key subgroup • PD-L1 TPS＜1%: HR=0.55; TPS≥ 1%: HR=0.66 ⚫ Tumor response was higher and more durable in the ivonescimab plus chemotherapy arm. ⚫ OS was not matured at this time and will be reported later. ⚫ Ivonescimab plus chemotherapy showed a manageable safety profile in squamous NSCLC, consistent with previous experience. Ivonescimab plus chemotherapy showed a statistically significant improvement in PFS with manageable safety profile, which may serve as a future advancement in the standard of care for patients with advanced squamous NSCLC: HARMONi-3 study on-going globally. Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 12

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Acknowledgement ⚫ All patients participating in the study as well as their families. ⚫ All investigators and team members involved in this trial. ⚫ Akeso Biopharma Inc. who sponsored this study. https://doi.org/10.1016/S0140-6736(25)01848-3 Published Online First at https://www.thelancet.com/journals/lancet/onlinefirst Akeso Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 HARMONi-6 conducted in China fully sponsored and managed by Akeso, Inc. 13

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Phase 1-2 Phase 3 1L Biliary Tract: 1L Pancreatic: 1L Colorectal: 1L NSCLC: 2L+ NSCLC EGFR+: 1L TNBC: 2L+ NSCLC: 1L NSCLC: SCLC: 1L HNSCC: Conducted in China Fully Sponsored and Managed by Akeso Breast Head & Neck Gastric / GEJ Hepatocellular Gynecologic Ovarian Phase 3 30+ Approved Trials Being Initiated Investigator Sponsored Trials\* Planned and Ongoing Studies Sponsored by Summit Therapeutics M.D. Anderson Collaboration Initiated\* 5+ Pre-clinical and Clinical Ongoing Trials RAS(ON) + ivonescimab in multiple solid tumors Revolution Medicines Collaboration Enrolling 1L NSCLC: 1L NSCLC: Enrolling 2L+ NSCLC EGFR+: Enrollment Complete 1L CRC: Not Yet Enrolling \*ISTs, M.D. Anderson collaboration trials not sponsored by Summit. Akeso Phase III clinical trials from Akeso's 2025 First Half Interim Results (prnewswire.com; akesobio.com) and/or clinicaltrials.gov; Summit Therapeutics Press Release Revolution Medicines. Jun 30, 2025 Abbreviations: 1L=first-line; 2L=second-line; CDP=clinical development plan; CRC=colorectal cancer; EGFR=epidermal growth factor receptor; GEJ=gastroesophageal junction; HNSCC=head and neck squamous cell carcinoma; NSCLC=non small cell lung cancer; SCLC=small cell lung cancer; TNBC=triple negative breast cancer. Ivonescimab Development Plan Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 14

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). HARMONi-3 Clinical Trial Update ⚫ Protocol Amendment: ◼ PFS and OS statistical analyses for both dual primary endpoints will be conducted separately by histology (i.e., two separate ITT analyses for squamous and non-squamous) ◼ Expected enrollment: 600 squamous, 1,000 non-squamous to sufficiently power each endpoint ◼ Analyses for squamous and non-squamous may be conducted at separate times, once the prespecified number of events in each cohort is reached ⚫ Timing Expectations: ◼ Squamous expected to complete enrollment H1 2026 and reach prespecified number of events for PFS analysis H2 2026 ◼ An interim analysis for OS may be conducted at a similar time ◼ Non-squamous expected to complete enrollment H2 2026 and reach prespecified number of events for PFS analysis in H1 2027 ◼ An interim analysis for OS will be conducted based upon reaching a prespecified number of events Summit Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 15

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Ivonescimab + Chemo vs. Pembrolizumab + Chemo Randomized, Double-Blind, Phase 3 Study 1L Metastatic Non-Small Cell Lung Cancer (NSCLC) NCT05899608 Summit Sponsored Trial HARMONi-3. ClinicalTrials.gov identifier: NCT05899608 Updated Mar 21, 2025, Accessed on May 20, 2025 Abbreviations: 1L=first-line; chemo=chemotherapy; CNS=central nervous system; DCR=disease control rate; DOR=duration of response; GI=gastrointestinal; ORR=overall response rate; OS=overall survival; PD-1=programmed cell death protein 1; PD-L1=programmed cell death-ligand 1; PFS=progression-free survival; PK=pharmacokinetics; Q3W=every 3 weeks; R=randomization; RECIST=Response Evaluation Criteria in Solid Tumors; TC=tumor cell; TPS=tumor proportion score; vs.=versus. Ivonescimab 20 mg/kg IV + Carboplatin AUC 5 IV + Pemetrexed 500 mg/m2 IV Q3W x 4 cycles Key Inclusions • 1L Stage IV squamous and non-squamous NSCLC Key Exclusions • Known actionable mutations for which 1L approved agents are available • Symptomatic CNS metastases • Major blood vessel or organ invasion • Active autoimmune disease Safety and Survival Follow -up Ivonescimab 20 mg/kg IV + Carboplatin AUC 6 or AUC 5 IV + Paclitaxel 200 mg/m2 IV (or nab- paclitaxel 100 mg/m2 IV) Q3W x 4 cycles Pembrolizumab 200 mg IV + Carboplatin AUC 6 or AUC 5 IV + Paclitaxel 200 mg/m2 IV (or nab- paclitaxel 100 mg/m2 IV) Q3W x 4 cycles Endpoints Primary • OS, PFS by investigator assessment Secondary • ORR, DCR, DOR by investigator assessment, safety, PK, immunogenicity Squamous Cohort Non-Squamous Cohort Maintenance R 1:1 N~600 R 1:1 N~1000 Randomization by NSCLC Histology Cohort (squamous and non-squamous) Pembrolizumab 200 mg IV + Carboplatin AUC 5 IV + Pemetrexed 500 mg/m2 IV Q3W x 4 cycles Ivonescimab 20 mg/kg IV + Pemetrexed 500 mg/m2 IV Q3W Ivonescimab 20 mg/kg IV Q3W Pembrolizumab 200 mg IV Q3W Pembrolizumab 200 mg IV + Pemetrexed 500 mg/m2 IV Q3W Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 16

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). 17 Key Criteria • Metastatic CRC • Not a candidate for surgical resection or local therapy • No prior systemic therapy for metastatic disease • ECOG PS 0-1 • MSI-high/dMMR status excluded • BRAF V600E mutation excluded Bevacizumab 5 mg/kg + mFOLFOX6 Q2W x 8 cycles Ivonescimab 20 mg/kg + mFOLFOX6 Q2W x 8 cycles Bevacizumab 5mg/kg + 5-FU/LV Q2W maintenance Ivonescimab 20 mg/kg + 5-FU/LV Q2W maintenance R 1:1 N=600 Endpoints Primary • PFS by IRRC Secondary • OS, ORR and DOR by IRRC, Safety, PK, Immunogenicity Abbreviations: 5-FU=5-fluorouracil; CRC=colorectal cancer; DCR=disease control rate; dMMR=mismatch repair deficient; DOR=duration of response; ECOG PS=Eastern Cooperative Oncology Group performance status; HRQoL=health-related quality of life; IRRC = independent radiology review committee; LV=leucovorin; mFOLFOX6=modified FOLFOX6 [Oxaliplatin + Leucovorin + 5-fluorouracil (5-FU)]; MSI=microsatellite instability; ORR=objective response rate, OS=overall survival; PFS=progression-free survival; PK=pharmacokinetics; R=randomization; Q2W=every 2 weeks. Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Summit Sponsored Trial Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 Ivonescimab + Chemo vs. Bevacizumab + Chemo Randomized, Double-Blind, Phase 3 Study 1L Unresectable Metastatic Colorectal Cancer (CRC) 17

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). AK112-206: Study Design Phase 2: Akeso Sponsored Study A Study of AK112 With or Without AK117 in Metastatic Colorectal Cancer. ClinicalTrials.gov identifier: NCT05382442. https://clinicaltrials.gov/study/NCT05382442. (Accessed 2024 September 09). Deng et al. ESMO 2024. Mini oral presentation #514MO. Abbreviations: 5-FU=5-fluorouracil; CRC=colorectal cancer; DCR=disease control rate; dMMR=mismatch repair deficient; DOR=duration of response; ECOG PS=Eastern Cooperative Oncology Group performance status; FOLFOXIRI=5-FU/LV + oxaliplatin + irinotecan; h=hour; IV=intravenous; LV=leucovorin; mCRC=metastatic colorectal cancer; MSI=microsatellite instability; ORR=objective response rate, OS=overall survival; PFS=progression- free survival; Q2W=every 2 weeks; R=randomization; RECIST v1.1=Response Evaluation Criteria in Solid Tumors, version 1.1; TTR=time to response a5-FU 2400-2800 mg/m2 as 46-48 h continuous IV infusion starting on day 1 Q2W + LV 400 mg/m2 IV on day 1 Q2W + oxaliplatin 85 mg/m2 IV on day 1 Q2W + irinotecan 150-165 mg/m2 IV on day 1 Q2W b5-FU 2400-2800 mg/m2 as 46-48 h continuous IV infusion starting on day 1 Q2W + LV 400 mg/m2 IV on day 1 Q2W Phase 1 and 2 data generated and analyzed by Akeso. Data Cutoff: Feb 29, 2024 Endpoints Primary • ORR (investigator assessed) based on RECIST v1.1 • Safety Secondary • DCR, DOR, TTR, PFS, OS R 1:1 Key Eligibility Criteria • No prior systemic therapy for recurrent or metastatic CRC • Not suitable for surgical resection or local therapy • ECOG PS 0 or 1 • Measurable disease per RECIST v1.1 • Patients with known MSI-high or dMMR tumors were excluded Ivonescimab 20 mg/kg on day 1 Q2W + FOLFOXIRIa for 8 cycles n=22 Ivonescimab 20 mg/kg on day 1 Q2W + ligufalimab 45 mg/kg on day 1 Q2W + FOLFOXIRIa for 8 cycles n=18 Ivonescimab 20 mg/kg on day 1 Q2W + 5-FU/LVb Ivonescimab 20 mg/kg on day 1 Q2W + ligufalimab 45 mg/kg on day 1 Q2W + 5-FU/LVb N=40 18 Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 AK112-206 conducted in China fully sponsored and managed by Akeso, Inc. (Presented at ESMO 2024)

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). AK112-206: Efficacy Data Deng et al. ESMO 2024. Mini oral presentation #514MO. Abbreviations: CI=confidence interval; CR=complete response; CRC=colorectal cancer; DCR=disease control rate; FOLFOXIRI=5-FU/LV + oxaliplatin + irinotecan; ORR=objective response rate; PR=partial response; SD=stable response Data Cutoff: Feb 29, 2024 Note: One subject did not have post-baseline disease assessment with measurable disease. B es t P er ce nt C ha ng e fr om B as el in e, % Ivonescimab +FOLFOXIRI (n=22) Ivonescimab + ligufalimab + FOLFOXIRI (n=18) -30% 20 0 -20 -40 -60 -80 -100 Best Percent Change From Baseline Responsea Ivonescimab + FOLFOXIRI (n=22) Ivonescimab + ligufalimab + FOLFOXIRI (n=17b) Investigator-assessed ORR n 18 15 ORR (95% CI), % 81.8 (59.7-94.8) 88.2 (63.6-98.5) Investigator-assessed DCR n 22 17 DCR (95% CI), % 100 (84.6-100) 100 (80.5-100) aMedian (range) duration of follow up: 9.0 months (6.3-11.3) for ivonescimab + FOLFOXIRI and 9.6 months (4.6-11.3) for ivonescimab + ligufalimab + FOLFOXIRI. b1 patient had no post-baseline tumor assessment. Summary of Efficacy Ivonescimab plus Chemotherapy in CRC; Phase 2: Akeso Sponsored Study Data Cutoff: Feb 29, 2024 Phase 1 and 2 data generated and analyzed by Akeso. 19 Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 AK112-206 conducted in China fully sponsored and managed by Akeso, Inc. (Presented at ESMO 2024)

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Adverse Event Ivonescimab + FOLFOXIRI (n=22) Ivonescimab + ligufalimab + FOLFOXIRI (n=18) TEAEs with Grade ≥3, n (%) 15 (68.2) 12 (66.7) TESAE, n (%) 5 (22.7) 3 (16.7) TEAEs leading to permanent discontinuation, n (%) 0 1 (5.6) TRAEs with Grade ≥3, n (%) 12 (54.5) 8 (44.4) TRSAE, n (%) 5 (22.7) 2 (11.1) TRAEs leading to permanent discontinuation, n (%) 0 1 (5.6) Deng et al. ESMO 2024. Mini oral presentation #514MO. Abbreviations: ALT=alanine aminotransferase; AST=aspartate aminotransferase; CRC=colorectal cancer; ECG=electrocardiogram; FOLFOXIRI=5-FU/LV + oxaliplatin + irinotecan; TEAE=treatment-emergent adverse event; TESAE=serious TEAE; TRAE=treatment-related adverse event; TRSAE=serious TRAE; WBC=white blood cell. Data Cutoff: Feb 29, 2024 Summary of TRAEs Most Common TRAEs (≥10% overall) Ivonescimab + FOLFOXIRI Ivonescimab + ligufalimab + FOLFOXIRI AK112-206: Safety Data Ivonescimab plus Chemotherapy in CRC; Phase 2: Akeso Sponsored Study Phase 1 and 2 data generated and analyzed by Akeso. 20 (Presented at ESMO 2024) Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025 AK112-206 conducted in China fully sponsored and managed by Akeso, Inc.

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Ivonescimab is an investigational therapy not presently approved by any regulatory authority other than China's National Medical Products Administration (NMPA). Phase 1-2 Phase 3 1L Biliary Tract: 1L Pancreatic: 1L Colorectal: 1L NSCLC: 2L+ NSCLC EGFR+: 1L TNBC: 2L+ NSCLC: 1L NSCLC: SCLC: 1L HNSCC: Conducted in China Fully Sponsored and Managed by Akeso Breast Head & Neck Gastric / GEJ Hepatocellular Gynecologic Ovarian Phase 3 30+ Approved Trials Being Initiated Investigator Sponsored Trials\* Planned and Ongoing Studies Sponsored by Summit Therapeutics M.D. Anderson Collaboration Initiated\* 5+ Pre-clinical and Clinical Ongoing Trials RAS(ON) + ivonescimab in multiple solid tumors Revolution Medicines Collaboration Enrolling 1L NSCLC: 1L NSCLC: Enrolling 2L+ NSCLC EGFR+: Enrollment Complete 1L CRC: Not Yet Enrolling \*ISTs, M.D. Anderson collaboration trials not sponsored by Summit. Akeso Phase III clinical trials from Akeso's 2025 First Half Interim Results (prnewswire.com; akesobio.com) and/or clinicaltrials.gov; Summit Therapeutics Press Release Revolution Medicines. Jun 30, 2025 Abbreviations: 1L=first-line; 2L=second-line; CDP=clinical development plan; CRC=colorectal cancer; EGFR=epidermal growth factor receptor; GEJ=gastroesophageal junction; HNSCC=head and neck squamous cell carcinoma; NSCLC=non small cell lung cancer; SCLC=small cell lung cancer; TNBC=triple negative breast cancer. 21 Ivonescimab Development Plan Summit Confidential & Proprietary Information Do Not Copy or Distribute Presentation Summit Therapeutics ESMO Update & Q3 2025 Earnings Call - October 2025

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