Racura Oncology Ltd Doses First Lung Cancer Patient in RC220 Trial
First patient dosed in HARNESS-1 — Racura’s lung cancer milestone
Racura Oncology (ASX: RAC) has treated the first patient in its Phase 1 HARNESS-1 clinical trial of RC220 for EGFR-mutant non-small cell lung cancer (NSCLC), marking the start of patient dosing in the program.
Critically, no adverse events were observed during or after the RC220 infusion.
The patient was treated at 50mg/m² by Principal Investigator Associate Professor Surein Arulananda and his team at Monash Health in Clayton, Victoria.
The milestone, announced on 25 June 2026, begins active dosing in a program targeting a patient group where resistance to current targeted therapies remains a significant clinical challenge.
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Why HARNESS-1 targets a major unmet need
Patients with EGFR-mutant NSCLC can benefit from targeted tyrosine kinase inhibitor (TKI) therapy. However, resistance to TKI treatments, such as osimertinib, remains a significant clinical challenge.
HARNESS-1 is evaluating whether RC220 (E,E-bisantrene) can be safely combined with the standard-of-care TKI osimertinib (Tagrisso®; AstraZeneca) in this patient population.
The Emory University collaboration provided independent preclinical validation of RC220’s synergy with osimertinib, with preliminary data showing statistically significant results (p < 0.01) in osimertinib-resistant mouse models, helping to underpin the scientific rationale that HARNESS-1 is now testing in patients.
For investors, the trial positions RC220 as a potential combination therapy addressing a clearly defined gap in patient care.
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The clinical problem: EGFR-mutant NSCLC patients respond to TKI therapy, but resistance to treatments like osimertinib is a major ongoing challenge.
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RC220’s proposed role: Assessed in combination with osimertinib to determine whether the two can be safely combined to support patients facing this resistance.
How the HARNESS-1 trial is structured
HARNESS-1 is a multi-centre Phase 1a/b study designed with a careful, staged approach. The trial begins with an observational (screening) stage that uses circulating tumour DNA (ctDNA), a blood-based marker of cancer activity, to help identify and enrol eligible patients.
The first treatment stage uses single-patient cohorts for the first three dose escalations (50mg/m², 100mg/m² and 150mg/m²) before progressing to larger cohorts to identify the maximum tolerated dose (MTD).
RC220 is administered by intravenous infusion on Day 1 of each 21-day cycle, in combination with standard-of-care maintenance osimertinib. Between 12 and 40 patients are expected to participate in the dose-escalation stage.
Once a recommended dose has been established and reviewed against available safety and pharmacokinetic (PK) data, the study moves into a double-blind, randomised Phase 1b expansion stage, where 40 patients will receive one of two RC220 dose levels alongside osimertinib.
| Stage | Design | Dose Levels | Patient Numbers | Key Endpoints |
|---|---|---|---|---|
| Dose escalation | Single-patient cohorts, then larger cohorts | 50 / 100 / 150mg/m² | 12–40 patients | Safety, PK, MTD |
| Phase 1b expansion | Double-blind, randomised | Two RC220 dose levels | 40 patients | PFS, overall survival, ctDNA changes, cancer-specific mutation changes |
What “first patient dosed” means for investors
The treatment of the first patient marks the start of patient dosing in this important clinical program.
No adverse events were observed during or after the RC220 infusion.
ctDNA plays a supporting role here. As a blood-based marker of cancer activity, it helps identify eligible patients and monitor disease, supporting precision enrolment into the study.
Clinical progress of this kind reflects the progress being made across Racura’s oncology pipeline.
CEO commentary
Dr Daniel Tillett, CEO/MD, Racura Oncology
“Treating the first patient in HARNESS-1 is an important step in the clinical development of RC220 and reflects the progress being made across Racura’s oncology pipeline. This trial is focused on a patient group where resistance to current targeted therapies remains a significant challenge. We are grateful to A/Prof Surein Arulananda and his team at Monash Health for their work in recruiting and treating the study’s first participant, and we thank the patients and families supporting this clinical research.”
RC220 and Racura’s broader pipeline
Racura’s lead asset, (E,E)-bisantrene, is a small molecule anticancer agent designed to silence cancer growth pathways through G4-DNA and RNA binding, including the cancer growth regulator MYC. According to the company, the compound has demonstrated therapeutic activity in cancer patients and has a well-characterised safety profile.
Recent discoveries have enabled composition of matter IP filings that provide for 20 years of patent protection over (E,E)-bisantrene.
RC220, a proprietary formulation of (E,E)-bisantrene, is being advanced across multiple oncology indications:
RC220’s parallel clinical activity extends beyond HARNESS-1: the CPACS Phase 1 trial in solid tumour patients has already cleared its first cohort with zero dose-limiting toxicities and advanced to the 80mg/m2 dose level, providing investors with an additional data point on the compound’s emerging safety profile.
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Phase 3 program in acute myeloid leukaemia (AML)
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Phase 1a/b program in EGFR-mutant NSCLC (HARNESS-1)
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Phase 1a/b program in combination with doxorubicin for solid tumour patients
Racura is also exploring partnerships, licence agreements, and other commercial opportunities to support the development of RC220.
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What comes next for HARNESS-1
Additional clinical trial sites are expected to open in the coming months, supporting increased patient recruitment and study progress. Dose escalation will continue toward identifying the maximum tolerated dose before the trial advances into its Phase 1b expansion stage.
Investors seeking trial details, including open and recruiting sites, can refer to the Australian and New Zealand public clinical trial registry under the trial code ACTRN12626000325303.
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