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EO1001 Phase 1-2a study featured at ASCO 2026; dose escalation successfully completed and Phase 2 expansion cohorts actively enrolling at biologically active dose levels
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EO1001 is specifically designed to target EGFR extracellular domain (ECD) alterations, addressing an emerging class of treatment-resistant tumors with significant unmet need
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Preclinical data presented at AACR 2026 demonstrated up to ~40-fold greater potency than osimertinib in patient-derived EGFR ECD-mutant tumor models, supporting a biomarker-directed development strategy for a patient population with no approved targeted therapies
MENLO PARK, CA / ACCESS Newswire / June 1, 2026 / Edison Oncology Holding Corp. (“Edison Oncology” or the “Company”) today announced the presentation of a Trials-in-Progress poster detailing the ongoing Phase 1-2a study of EO1001, the Company’s oral, brain-penetrant pan-ErbB inhibitor, at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, being held May 29 – June 2, 2026, in Chicago, Illinois.
“Patients whose tumors harbor EGFR extracellular domain mutations represent one of the most underserved populations in oncology today,” “The entire approved armamentarium of EGFR-targeted therapies-from erlotinib to osimertinib-was designed to inhibit the intracellular kinase domain and has limited or no activity against ECD mutations, which drive tumor growth through a fundamentally different mechanism. EO1001 was specifically designed to address this biology, and the data we are presenting at ASCO, together with the preclinical findings we shared at AACR earlier this year, reinforce our conviction that EO1001 represents a differentiated and potentially first-in-class approach for this genetically defined patient population. Our presentation at ASCO 2026 highlight’s Edison Oncology’s continued execution of the EO1001 clinical program and our broader biomarker-driven precision oncology strategy, We look forward to continuing to advance this program and to partnering with organizations that share our commitment to bringing meaningful new options to patients who currently have none.”
EGFR Extracellular Domain Mutations: A Large and Underserved Patient Population
EGFR alterations are among the most common oncogenic drivers in human cancer. A clinically important subset of these-mutations in the extracellular domain (ECD) of the receptor-drive tumor growth through a mechanism that is structurally distinct from the kinase domain mutations targeted by all currently approved EGFR inhibitors, including osimertinib, erlotinib, afatinib, and dacomitinib. As a result, patients whose tumors harbor EGFR ECD mutations have no approved targeted therapy options.
EGFR ECD mutations occur across multiple tumor types representing large patient populations with high unmet need. In glioblastoma-the most common and lethal primary brain tumor, where EGFR alterations are found in approximately 40-50% of cases-ECD mutations including EGFRvIII and recurrent missense variants such as R108 and A289 substitutions collectively account for the majority of EGFR alterations, with ECD missense variants alone representing approximately 10-15% of all GBM cases. In colorectal cancer, acquired EGFR ECD mutations emerge as a clinically important resistance mechanism to anti-EGFR antibody therapy (cetuximab, panitumumab) in approximately 15-30% of patients who progress on these treatments, impairing antibody binding while preserving downstream signaling. ECD-driven EGFR signaling has also been observed in subsets of neuroendocrine tumors and other solid tumor malignancies. Across these settings, available EGFR-targeted therapies-designed to block the intracellular kinase domain-have demonstrated limited activity, leaving patients with few options.
EO1001: Designed to Address ECD Mutations Across Tumor Types
EO1001 is a novel, oral, irreversible pan-ErbB inhibitor designed from the ground up to achieve meaningful CNS exposure and to inhibit the full spectrum of ErbB receptor alterations-including EGFR, HER2, and HER4-with specific activity against ECD mutations that are not addressed by currently approved kinase domain-directed therapies. Its irreversible mechanism of action provides sustained target engagement, and its oral, once-daily formulation is designed for clinical convenience in an outpatient setting.
Earlier this year at the AACR Annual Meeting (April 2026), Edison Oncology presented preclinical data from patient-derived tumor models harboring clinically relevant EGFR ECD mutations (R108K and A289T), with osimertinib-the current standard-of-care EGFR TKI-as the comparator. In a glioblastoma model harboring the R108K ECD mutation, EO1001 demonstrated approximately 40-fold greater potency than osimertinib at Day 5. In a neuroendocrine tumor model harboring the A289T ECD mutation, EO1001 maintained a consistent potency advantage over osimertinib across both Day 5 and Day 7 time points. These findings demonstrate that the functional gap between EO1001 and kinase domain-directed inhibitors is particularly pronounced in ECD mutant settings-precisely the tumors where currently available therapies fail.
The ASCO 2026 Trials-in-Progress poster also presents complementary preclinical data supporting EO1001’s activity in intracranial glioblastoma models-including EGFR-amplified (GBM12) and EGFRvIII-driven (GBM39, U87) models-where EO1001 demonstrated significant tumor growth inhibition and survival benefit relative to both untreated controls and lapatinib-treated animals. In the HER2-positive N87 gastric flank model, EO1001 demonstrated superior activity to lapatinib. In the H1975 NSCLC model (EGFR T790M), EO1001 showed superior activity to erlotinib and activity equivalent to afatinib. EO1001 also achieved rapid CNS penetration with sustained tumor exposure following oral administration in vivo, with brain-to-plasma concentration ratios supporting its design as a CNS-active agent.
Phase 1-2a Clinical Study
The ongoing first-in-human, multicenter, open-label Phase 1-2a study (ANZCTR:ACTRN12620000583943), conducted in collaboration with Senz Oncology at Monash Health and The Alfred in Melbourne, Australia, is evaluating the safety, pharmacokinetics, and preliminary antitumor activity of EO1001 in patients with advanced ErbB-driven solid tumors, including those with CNS involvement. The study employs an accelerated titration design in Phase 1, transitioning to a standard 3+3 schema following any Grade ≥2 treatment-related toxicity. Dose escalation has been successfully completed across multiple dose levels. The trial has advanced to Phase 2 expansion cohorts enrolling patients at or below the recommended Phase 2 dose, designed to further characterize safety, pharmacokinetics, and antitumor activity-including CNS-directed activity-at biologically active dose levels. Exploratory endpoints include pharmacodynamic and molecular biomarker assessment in available tissue, as well as optional cerebrospinal fluid sampling to further assess CNS drug exposure and pathway modulation.
Edison Oncology holds exclusive worldwide rights to develop and commercialize EO1001 outside of China, Hong Kong, and Taiwan. The Company is actively seeking development partnerships to advance EO1001 into biomarker-selected expansion and registration-directed studies across ErbB-driven tumor types, with a particular focus on the ECD mutation-defined patient population.
ASCO 2026 Presentation Details:
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Title: An ongoing phase 1-2a study of EO1001, an oral brain-penetrant pan-ErbB inhibitor, in patients with advanced ErbB-driven solid tumors including CNS disease.
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Abstract Number: TPS8681
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Session Title: Lung Cancer-Non-Small Cell Metastatic
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Session Type: Poster Session
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Date: Sunday, May 31, 2026
The abstract is currently available on the ASCO meeting website at https://www.asco.org/abstracts-presentations/266706.
About Edison Oncology Holding Corp.
Edison Oncology is a clinical-stage biopharmaceutical company focused on developing small-molecule therapies for genetically defined cancers with significant unmet need. The Company’s approach centers on identifying compounds with established clinical safety profiles and demonstrated anticancer activity, then applying contemporary tools in genomics, biomarker science, and mechanistic biology to define the patient populations most likely to benefit – an approach made possible by advances in precision oncology that were not available when many of these compounds were first studied. The Company advances programs through a capital-efficient model combining internal development with strategic co-development and licensing partnerships, retaining meaningful rights while enabling rapid clinical advancement. Edison Oncology’s pipeline targets patient populations with no currently approved targeted therapy, including patients with EGFR extracellular domain mutations (EO1001), ARID1A-deficient cancers (EO3001), and CDA-high tumors (EO4426). To learn more, please visit https://www.edisononcology.com/ and follow us for updates on LinkedIn.
Contact
Hayden IR
Brett Maas
(646) 536-7331
brett@haydenir.com
or
James Carbonara
(646)-755-7412
james@haydenir.com
SOURCE: Edison Oncology Holding Corp.
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