Summit lung cancer drug improves survival vs pembrolizumab
Partner Akeso’s Phase III HARMONi-2 data show a significant overall survival benefit for ivonescimab versus pembrolizumab, reinforcing Summit’s late-stage oncology strategy.
Rhea-AI Filing Summary
Summit Therapeutics Inc. (SMMT) reported that partner Akeso Inc. announced positive overall survival results from the randomized, double-blind Phase III HARMONi-2 study of ivonescimab monotherapy versus pembrolizumab in PD-L1–positive advanced non-small cell lung cancer in China. Ivonescimab showed a statistically significant overall survival benefit in this preplanned analysis.
Ivonescimab had previously met the primary endpoint of progression-free survival in HARMONi-2, with a hazard ratio of 0.51 (95% CI: 0.38–0.69; p<0.0001), supporting China marketing authorization granted to Akeso in April 2025. Summit highlights a broad late-stage program, including its own positive Phase III HARMONi trial and an accepted Biologics License Application with a goal PDUFA date of November 14, 2026.
Across Summit- and Akeso-sponsored programs, ivonescimab is being studied in multiple Phase III trials in NSCLC and other tumors, with five Phase III trials reported as positive to date and extensive clinical and commercial experience in China. Ivonescimab remains investigational in Summit’s territories, including the United States and Europe.
Positive
- Ivonescimab shows statistically significant overall survival benefit versus pembrolizumab in Akeso’s Phase III HARMONi-2 trial in PD-L1–positive advanced NSCLC, strengthening clinical support for Summit’s lead asset.
- HARMONi-2 previously met its primary PFS endpoint with a hazard ratio of 0.51 and p<0.0001, underpinning Akeso’s China marketing authorization and adding robustness to the ivonescimab dataset.
- U.S. BLA for ivonescimab has been accepted by the FDA with a goal PDUFA date of November 14, 2026, providing a defined regulatory milestone for Summit’s NSCLC program.
- Five Phase III ivonescimab trials have reported positive data across NSCLC and biliary tract cancer, indicating a broad evidence base for the molecule’s activity in multiple tumor types.
Negative
- None.
Filing Explained
The filing places the HARMONi-2 overall-survival result at a reported-but-not-yet-presented stage: Summit says Akeso exclusively generated, managed, and analyzed the data, with results scheduled for an upcoming medical conference.
8-K Event Classification
2 items: 8.01, 9.01
2 items
Item 8.01
Other Events
Other
Voluntary disclosure of events the company deems important to shareholders but not covered by other items.
Item 9.01
Financial Statements and Exhibits
Exhibits
Financial statements, pro forma financial information, or exhibit attachments filed with this report.
Key Figures
Progression-free survival hazard ratio (HARMONi-2): 0.51
Phase III ivonescimab trials with positive data: 5 trials
Phase III ivonescimab studies announced/ongoing/completed: 16 studies
+4 more
7 metrics
Progression-free survival hazard ratio (HARMONi-2)
0.51
Primary endpoint in Phase III HARMONi-2 comparing ivonescimab to pembrolizumab; 95% CI: 0.38–0.69; p<0.0001
Phase III ivonescimab trials with positive data
5 trials
Four in non-small cell lung cancer and one in biliary tract cancer reported as positive
Phase III ivonescimab studies announced/ongoing/completed
16 studies
Five Summit-sponsored global, one cooperative-group study, and ten Akeso-conducted studies in China
Patients treated with ivonescimab in clinical studies
Over 4,000 patients
Global clinical trial exposure reported by Summit with reference to Akeso data
Patients treated with ivonescimab commercially in China
Over 70,000 patients
Commercial use in China as noted by Akeso
China marketing authorization timing
April 2025
Akeso received NMPA marketing authorization for ivonescimab based on HARMONi-2
FDA goal PDUFA date for ivonescimab BLA
November 14, 2026
Goal Prescription Drug User Fee Act decision date for Summit’s Biologics License Application
Key Terms
overall survival, progression-free survival, Biologics License Application, hazard ratio, +2 more
6 terms
overall survival medical
"announced positive overall survival ("OS") results from the randomized, double-blind Phase III HARMONi-2 study"
Overall survival is the average or median length of time patients remain alive after starting a treatment or entering a clinical study, measured regardless of cause of death. Investors care because it is a clear, hard measure of a therapy’s real-world benefit — like timing how long a new battery actually runs — and strong improvements in overall survival can drive regulatory approval, market adoption and revenue potential.
progression-free survival medical
"primary endpoint, progression-free survival (PFS) by Independent Radiologic Review Committee"
Progression-free survival is the length of time during and after a treatment that a patient's disease does not get worse, measured from the start of treatment until the disease shows measurable signs of progression or the patient dies. Investors care because longer progression-free survival in clinical trials often signals that a drug is effective, improving chances of regulatory approval, market adoption, and revenue potential—think of it as a stopwatch showing how long a therapy can keep the illness at bay.
Biologics License Application regulatory
"a Biologics License Application (BLA) was submitted to the United States Food and Drug Administration"
A biologics license application is a formal request submitted to regulatory authorities seeking approval to market a new biological medicine, such as vaccines or treatments made from living organisms. It is a comprehensive review process that evaluates the safety, effectiveness, and manufacturing quality of the product. For investors, receiving approval signals that a biological therapy can be sold to the public, potentially leading to revenue growth and market success.
hazard ratio medical
"achieving a hazard ratio (HR) of 0.51 (95% CI: 0.38, 0.69; p<0.0001)"
A hazard ratio is a way scientists compare the chance of something happening over time between two groups, like patients taking different medicines. If the ratio is high, it means one group is more likely to experience the event sooner or more often, which helps determine how effective a treatment is or how risky a situation might be.
tetravalent structure medical
"specifically engineered tetravalent structure (four binding sites) enables higher avidity"
tumor microenvironment medical
"higher avidity in the TME (Zhong, et al, iScience, 2025)"
The tumor microenvironment is the immediate area surrounding a cancer cell, made up of nearby cells, blood vessels, and support structures that influence how the cancer grows and spreads. It functions like a bustling neighborhood that can either help or hinder the tumor’s development. For investors, understanding changes in this environment can signal the effectiveness of treatments and potential shifts in a cancer-related market.
FAQ
What did Summit Therapeutics (SMMT) disclose about the HARMONi-2 trial?
Summit reported that partner Akeso’s Phase III HARMONi-2 trial in PD-L1–positive advanced NSCLC showed a statistically significant overall survival benefit for ivonescimab monotherapy versus pembrolizumab. This was based on a preplanned overall survival analysis conducted and analyzed by Akeso in China.
How strong were the progression-free survival results cited by SMMT from HARMONi-2?
In the primary HARMONi-2 analysis, ivonescimab monotherapy achieved a hazard ratio of 0.51 for progression-free survival versus pembrolizumab, with a 95% CI of 0.38–0.69 and p<0.0001, indicating a statistically significant improvement as assessed by an Independent Radiologic Review Committee.
How extensive is the clinical and commercial experience with ivonescimab mentioned by SMMT?
Summit notes that over 4,000 patients have received ivonescimab in clinical studies globally and over 70,000 patients have been treated in commercial use in China, according to Akeso. This reflects broad real-world and trial experience with the drug.
How many Phase III trials of ivonescimab have shown positive data according to SMMT?
Summit states that five Phase III ivonescimab clinical trials have read out with positive data so far: four in non-small cell lung cancer and one in biliary tract cancer. All three Akeso NSCLC Phase III trials in China are reported to show statistically significant overall survival benefits.
What is Summit Therapeutics’ broader development plan for ivonescimab?
Summit describes 16 Phase III ivonescimab studies that are announced, ongoing, or completed, including five Summit-sponsored global trials, one cooperative-group study, and 10 Akeso-run trials in China across NSCLC, colorectal cancer, urothelial carcinoma, biliary tract cancer, and other tumors.
Is ivonescimab approved in Summit’s territories such as the United States or Europe?
No. Summit emphasizes that ivonescimab remains investigational and is not approved by any regulatory authority in its license territories, including the United States and Europe. The drug is, however, approved and commercially available in China for NSCLC based on Akeso’s studies.
AI-generated analysis. How Rhea-AI works. Not financial advice.
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): September 2, 2026
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Registrant’s Telephone Number, Including Area Code: (305) 203-2034
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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):
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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 ☐
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Item 8.01 | Other Events. | ||||
On September 2, 2026, Summit Therapeutics Inc. issued a press release noting that its partner, Akeso Inc., (“Akeso”) announced positive overall survival (“OS”) results from the randomized, double-blind Phase III HARMONi-2 study evaluating ivonescimab monotherapy against pembrolizumab monotherapy in patients with locally advanced or metastatic non-small cell lung cancer whose tumors have positive PD-L1 expression (“HARMONi-2”). HARMONi-2 is a single-region, multi-center Phase III study conducted in China and sponsored by Akeso, with all relevant data exclusively generated, managed, and analyzed by Akeso.
In this preplanned analysis of OS, a secondary endpoint in HARMONi-2, Akeso reported that ivonescimab monotherapy demonstrated a statistically significant improvement compared to pembrolizumab monotherapy. Results from this HARMONi-2 analysis are scheduled to be presented at an upcoming medical conference.
A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference herein.
| Item 9.01 | Financial Statements and Exhibits. | ||||
(d) Exhibits
Exhibit Number | Description | ||||
| 99.1 | Press Release, dated September 2, 2026 | ||||
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) | ||||
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.
| SUMMIT THERAPEUTICS INC. | ||||||||
| Date: September 3, 2026 | By: | /s/ Manmeet S. Soni | ||||||
| Chief Operating Officer, Chief Financial Officer and Director | ||||||||
| (Principal Financial Officer) | ||||||||
1 Ivonescimab Monotherapy Demonstrates Statistically Significant Overall Survival Benefit Compared to Pembrolizumab Monotherapy in PD-L1-Positive Advanced NSCLC in HARMONi-2 Study Conducted by Akeso in China Summit is Conducting HARMONi-7 in Patients with PD-L1 High-Expressing NSCLC Miami, Florida, September 2, 2026 – Summit Therapeutics Inc. (NASDAQ: SMMT) today noted that its partner Akeso Inc. announced positive overall survival (OS) results from the randomized, double-blind Phase III HARMONi-2 study evaluating ivonescimab monotherapy against pembrolizumab monotherapy in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) whose tumors have positive PD-L1 expression. HARMONi-2 (AK112-303) is a single-region, multi-center Phase III study conducted in China and sponsored by Akeso, with all relevant data exclusively generated, managed, and analyzed by Akeso. In this preplanned analysis of OS, a secondary endpoint in the HARMONi-2 study, Akeso reported that ivonescimab monotherapy demonstrated a statistically significant improvement compared to pembrolizumab monotherapy. Results from this HARMONi-2 analysis are scheduled to be presented at an upcoming medical conference. Akeso received marketing authorization for ivonescimab from China’s National Medical Products Administration (NMPA) based on the results of HARMONi-2 in April 2025. In the study’s primary analysis, ivonescimab monotherapy demonstrated a statistically significant improvement in the trial’s primary endpoint, progression-free survival (PFS) by Independent Radiologic Review Committee (IRRC), when compared to pembrolizumab monotherapy, achieving a hazard ratio (HR) of 0.51 (95% CI: 0.38, 0.69; p<0.0001). A clinically meaningful benefit was demonstrated across clinical subgroups, including those with PD-L1 low expression, PD-L1 high expression, squamous, and non-squamous histologies.1 The HARMONi-2 study was conducted by Akeso in China, where ivonescimab is approved and commercially available for indications in NSCLC. Ivonescimab remains investigational and is not approved by any regulatory authority in Summit’s license territories, including the United States and Europe. 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 outside of Summit’s license territories, 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. By design, 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 design is intended to 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. Summit believes ivonescimab’s specifically engineered tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, iScience, 2025). 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 ivonescimab’s design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, iScience, 2025) increasing to approximately 10 days at steady state dosing, is to improve upon
2 previously established efficacy thresholds, side effects, and safety profiles associated with prior approved drugs to these targets. Ivonescimab was engineered by Akeso Inc. (HKEX Code: 9926.HK) and is currently utilized in multiple Phase III clinical trials. Over 4,000 patients have been treated with ivonescimab in clinical studies globally and over 70,000 patients when considering those treated in a commercial setting in China, as noted by Akeso. There are currently 16 Phase III clinical studies that are either announced, ongoing, or have been completed studying ivonescimab, five of which are Summit-sponsored global studies, one of which is a multiregional study sponsored by a cooperative group, and 10 of which are being or have been conducted in China 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 2025, Summit began enrolling patients in HARMONi-7. Summit expanded its Phase III clinical development program into colorectal cancer (CRC) in the fourth quarter of 2025 by initiating enrollment in HARMONi-GI3. In 2026, Summit announced initiation of HARMONi-GU1, a Phase II/III study in urothelial carcinoma (bladder cancer) with global clinical trial site activations planned to begin by the fourth quarter of 2026. HARMONi is a Phase III clinical trial evaluating 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 third-generation EGFR TKI (e.g., osimertinib). Detailed results of the study were provided in September 2025, and a Biologics License Application (BLA) was submitted to the United States Food and Drug Administration (FDA) for marketing authorization, which the FDA accepted for filing in January 2026; the goal Prescription Drug User Fee Act (PDUFA) date is November 14, 2026. HARMONi-3 is a Phase III clinical trial evaluating 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. The clinical trial is evaluating the two histologies as individual, separately powered cohorts with independent statistical powering. HARMONi-7 is a Phase III clinical trial evaluating ivonescimab monotherapy compared to pembrolizumab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression. HARMONi-GI3 is a Phase III clinical trial evaluating ivonescimab in combination with chemotherapy compared with bevacizumab plus chemotherapy in patients with first-line unresectable metastatic CRC. HARMONi-GU1 is a Phase II/III clinical trial evaluating ivonescimab plus the antibody drug conjugate (ADC) enfortumab vedotin (EV) compared to pembrolizumab plus EV as first-line therapy in patients with previously untreated locally advanced or metastatic urothelial carcinoma (la/mUC). ILLUMINE is a Phase III study being conducted by GORTEC, a cooperative group dedicated to Head and Neck Oncology, in recurrent / metastatic head and neck squamous cell carcinoma (r/m HNSCC). ILLUMINE is a three- arm Phase III clinical trial designed to evaluate ivonescimab monotherapy, as well as ivonescimab in combination with ligufalimab, Akeso’s proprietary anti-CD47 monoclonal antibody, compared to monotherapy pembrolizumab in patients with PD-L1 positive r/m HNSCC.
3 Five Phase III ivonescimab clinical trials have read out to date, all five with positive data. Four of these five studies are in NSCLC, and one is in biliary tract cancer (BTC). In addition to Summit’s positive HARMONi study, Akeso has had positive read-outs in three single-region (China), randomized Phase III clinical trials, HARMONi-A, HARMONi-2, and HARMONi-6, for ivonescimab in NSCLC, including a statistically significant overall survival benefit in all three studies from China. Akeso has also reported a statistically significant OS benefit in the single- region (China), randomized Phase III HARMONi-GI1 trial in advanced BTC. 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. HARMONi-GI1 is a Phase III clinical trial evaluating ivonescimab in combination with chemotherapy compared with durvalumab plus chemotherapy as a first-line treatment for patients with advanced BTC. Akeso is actively conducting additional Phase III clinical studies in settings outside of NSCLC and biliary-tract cancer, including triple-negative breast cancer, head and neck squamous cell carcinoma, small cell lung cancer, colorectal cancer, and pancreatic 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. About Summit Therapeutics Inc. 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 the company’s shares are listed on the Nasdaq Global Market (symbol "SMMT"). Summit is headquartered in Miami, Florida, with additional offices in Palo Alto, California, Princeton, New Jersey, Dublin, Ireland, and Oxford, UK. For more information, please visit https://www.smmttx.com and follow Summit on X @SMMT_TX. 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. and other collaborations, the intended use of the net proceeds from the private placements, 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
4 submission of applications for marketing approvals, the expected timing of BLA submissions or FDA decisions, 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. Summit defines a “positive study” as a clinical study with one or more prespecified primary endpoints in which one of those endpoints achieves a statistically significant benefit according to the protocol or statistical analysis plan. 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. References: 1. Xiong A, Wang L, Chen J, Wu L, Liu B, Yao J, et al. Ivonescimab versus pembrolizumab for PD-L1-positive non- small cell lung cancer (HARMONi-2): a randomised, double-blind, phase 3 study in China. Lancet. 2025;405(10481):839-849. doi:10.1016/S0140-6736(24)02722-3. Summit Therapeutics’ Media & Investor Contacts: Nathan LiaBraaten Senior Director, Investor Relations Tracy Jones Director, Media & Public Relations investors@smmttx.com
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