Promising Intracranial Anti-Tumor Activity and Safety Data for Ivonescimab in NSCLC Patients with Brain Metastases Featured at ELCC 2024

On March 22, 2024 Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") reported promising data for its novel, potential first-in-class investigational bispecific antibody, ivonescimab, that is being presented today at the 2024 European Lung Cancer Congress (ELCC 2024) in Prague, Czech Republic (Press release, Summit Therapeutics, MAR 22, 2024, View Source [SID1234641394]). Two posters featuring updated ivonescimab data will be displayed from 12:00 to 12:45pm Central European Time. The posters will also be made available on our website after the presentation period.

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The first poster, "Intracranial Activity of Ivonescimab Alone or in Combination with Platinum Doublet Chemotherapy in Patients with Advanced Non-Small Cell Lung Cancer (NSCLC) and Brain Metastases" includes data from patients with asymptomatic brain metastases at baseline. These patients were enrolled in either AK112-202 (NCT04900363), in which ivonescimab is delivered as monotherapy, or AK112-201 (NCT04736823), in which ivonescimab is delivered in combination with platinum doublet chemotherapy, both of which are Phase II clinical trials for patients with advanced or metastatic NSCLC. This analysis consisted of the 35 patients with advanced or metastatic NSCLC who had asymptomatic brain metastases at baseline; 28 patients were treated with ivonescimab plus chemotherapy in AK112-201, and seven patients were treated with monotherapy ivonescimab in AK112-202.

Notably, median intracranial progression-free survival was 19.3 months across all patients analyzed. Patients across both cohorts experienced an intracranial response rate of 34%, and eight patients (23%) experienced a complete response by RANO criteria. All patients who did not achieve a response demonstrated stable disease or non-progression; no patients experienced intracranial disease progression at the time of the initial follow-up scan. No cases of intracranial bleeding complications were observed in these patients.

"We are pleased to see ivonescimab’s favorable intracranial response rates and median intracranial progression-free survival as well as promising anti-tumor activity and safety profile in the subgroup of patients with brain metastases from NSCLC," said Dr. H. Jack West, Vice President of Clinical Development at Summit. "We are grateful for the patients and clinical investigators supporting these trials, and our ongoing collaboration with our partners at Akeso."

The second poster titled, "Phase 2 Results of Ivonescimab a Novel PD-1/VEGF Bispecific in Combination with Chemotherapy for First Line Treatment of Patients with Advanced / Metastatic Non-Small Cell Lung Cancer" includes updated data from the Phase II trial AK112-201 centered around the cohort of patients in which ivonescimab is combined with chemotherapy for first-line treatment of squamous and non-squamous advanced or metastatic NSCLC in patients without actionable genomic alterations (e.g., positive for endothelial growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK)). Summarized updates in NSCLC patients with EGFR mutations after a tyrosine kinase inhibitor (TKI) and NSCLC patients who have received prior PD-(L)1 plus doublet chemotherapy treatment are included as well.

Of significance, first-line advanced or metastatic squamous NSCLC patients experienced a median PFS of 11.1 months (95% CI: 9.5 – 16.3 months). In addition, first-line patients with advanced or metastatic non-squamous tumors experienced a median PFS of 13.3 months (95% CI: 8.3 – 16.4 months). Median overall survival was not reached in either subset of patients after a median follow-up time of 22.1 months. The frequency of treatment-emergent adverse events (TEAEs) leading to the discontinuation of ivonescimab was 11.1% and 2.8%, respectively, in patients with squamous and non-squamous tumors. The most frequent TEAEs were anemia and decreased neutrophil counts in squamous patients and anemia and constipation in non-squamous patients.

The posters will be presented by, amongst others, Dr. Li Zhang, Sun Yat-Sen University Cancer Center, and Dr. West, with data generated and analyzed by our collaboration and licensing partner, Akeso Inc. (HKEX Code: 9926.HK) with contribution by Summit staff.

Summit continues its clinical development of ivonescimab in order to establish its efficacy and safety in two NSCLC indications:

HARMONi Phase III trial: ivonescimab combined with chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with a third-generation EGFR TKI (NCT05184712)
HARMONi-3 Phase III trial: ivonescimab combined with chemotherapy in first-line metastatic squamous NSCLC patients (NCT05899608)
About the ELCC 2024 Posters

Poster Title: Phase 2 Results of Ivonescimab a Novel PD-1/VEGF Bispecific in Combination with Chemotherapy for First Line Treatment of Patients with Advanced / Metastatic Squamous Non-Small Cell Lung Cancer
ELCC Presentation No.: 68P
Session Date & Time: Friday, March 22, 2024, 12:00 to 12:45pm CET

Poster Title: Intracranial Activity of Ivonescimab Alone or in Combination with Platinum Doublet Chemotherapy in Patients with Advanced Non-Small Cell Lung Cancer and Brain Metastases
ELCC Presentation No.: 174P
Session Date & Time: Friday, March 22, 2024, 12:00 to 12:45pm CET

About Ivonescimab

Ivonescimab, known as SMT112 in Summit’s license territories, the United States, Canada, Europe, and Japan, and as AK112 in China and Australia, is an investigational, novel, potential 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. Ivonescimab displays cooperative binding with each of its intended targets with higher affinity when in the presence of both PD-1 and 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 tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the tumor microenvironment with over 18-fold increased binding affinity to PD-1 in the presence of VEGF in vitro, and over 4-times increased binding affinity to VEGF in the presence of PD-1 in vitro (Zhong, et al, SITC (Free SITC Whitepaper), 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 is to improve upon previously established efficacy thresholds, in addition to side effects and safety profiles associated with these targets.

Ivonescimab was discovered by Akeso Inc. (HKEX Code: 9926.HK) and is currently engaged in multiple Phase III clinical trials. Over 1,600 patients have been treated with ivonescimab in clinical studies globally. Summit has begun its clinical development of ivonescimab in non-small cell lung cancer (NSCLC), commencing enrollment in 2023 in two Phase III clinical trials.

Ivonescimab is an investigational therapy that is not approved by any regulatory authority.