Racura Oncology has dosed the first patient in the HARNESS-1 Phase 1a/b trial of RC220 in combination with osimertinib for EGFR-mutant non-small cell lung cancer. The study will assess safety, pharmacokinetics, ctDNA dynamics and early clinical activity of RC220 as a strategy to address therapeutic TKI resistance.
SYDNEY, June 25, 2026 /PRNewswire/ -- Racura Oncology Limited (ASX: RAC), a clinical-stage biopharmaceutical company developing new small molecule based approaches to cancer treatment, today announced that the first patient has been dosed with RC220 in HARNESS-1, a Phase 1a/b clinical trial evaluating RC220 in combination with osimertinib in patients with epidermal growth factor receptor-mutant (EGFR-mutant) non-small cell lung cancer (NSCLC). The first patient received RC220 at 50 mg/m2 by intravenous infusion. No adverse events were observed.
HARNESS-1 is designed to test whether RC220, Racura's proprietary formulation of (E,E)-bisantrene, can be safely combined with osimertinib (Tagrisso®; AstraZeneca), a third-generation EGFR tyrosine kinase inhibitor (TKI) and standard-of-care therapy for EGFR-mutant NSCLC to delay or prevent TKI treatment resistance. Although EGFR TKIs have transformed outcomes for many patients with EGFR-driven lung cancer, acquired treatment resistance remains a central therapeutic challenge.
Daniel Tillett, Ph.D., Chief Executive Officer of Racura Oncology, said: "Dosing the first patient in HARNESS-1 is an important milestone for Racura and for the clinical development of RC220. The scientific rationale for this trial is grounded in the urgent need to address TKI therapeutic resistance in EGFR-mutant NSCLC. RC220 gives us the opportunity to explore whether targeting G4-DNA and RNA structures, including MYC-associated growth pathways, can delay EGFR TKI resistance arising and support a new therapeutic combination for patients treated with osimertinib. We are grateful to Associate Professor Surein Arulananda and the Monash Health team for enrolling and treating the first participant, and to the patients and families who make this research possible."
Scientific Rationale
EGFR-mutant NSCLC is a molecularly stratified lung adenocarcinoma subtype driven by constitutive EGFR kinase signaling and initial sensitivity to EGFR inhibition. However, responses to EGFR tyrosine kinase inhibitors, including osimertinib, are typically limited by acquired resistance, arising through heterogeneous mechanisms such as secondary EGFR alterations, bypass receptor tyrosine kinase activation, MAPK/PI3K pathway reactivation, oncogenic fusions, lineage plasticity, epithelial-to-mesenchymal transition and histologic transformation.