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--(BUSINESS WIRE)-- 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.

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