Sydney, Australia, October 12, 2026
Racura Oncology Limited has received clearance to advance its investigational cancer therapy RC220 to the next planned dose level of 100 mg/m² in the Phase 1a/b HARNESS-1 clinical trial for patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC). The decision follows a review by the trial’s Safety Review Committee (SRC), which identified no dose-limiting toxicities or treatment-related safety concerns in either of the two patients treated at the initial dose of 50 mg/m² during the defined safety observation period. RC220 is being evaluated in combination with osimertinib, an established EGFR tyrosine kinase inhibitor, to investigate a potential treatment strategy for patients whose cancer may become resistant to existing targeted therapies. The dose-escalation decision marks an early clinical development milestone for Racura Oncology. However, the announcement reports a safety review and permission to proceed to a higher dose; it does not establish that RC220 is effective against lung cancer.
HARNESS-1 Trial Advances Following Safety Review
The HARNESS-1 study, also designated RAC-020, is a multicenter Phase 1a/b clinical trial designed to evaluate RC220 in combination with osimertinib in patients with EGFR-mutant NSCLC. In the initial cohort, two patients received RC220 at 50 mg/m² by intravenous infusion, alongside osimertinib at 80 mg daily. The second patient received three RC220 doses at 21-day intervals without reported dose-limiting toxicities or treatment-related safety concerns during the relevant observation period. The SRC reviewed the available safety information before recommending progression to the next planned dose level. The company had enrolled a second patient at the starting dose after the first patient experienced Grade 2 colitis outside the trial’s defined safety observation period. Although the cause of the colitis was undetermined, a contribution from RC220 could not be excluded. This distinction is important when interpreting early clinical safety findings. The committee’s clearance supports continued investigation under the study protocol, but the small number of patients means that the treatment’s safety profile remains preliminary.
RC220 Targets Cancer-Related Molecular Pathways
RC220 is a proprietary formulation of (E,E)-bisantrene, a small-molecule anticancer agent being developed to address limitations associated with drug solubility and intravenous administration. Racura is investigating its ability to interact with G-quadruplex DNA and RNA structures, which occur in regulatory regions of genetic material and can influence gene expression. The company’s research focuses particularly on MYC, an important regulator of cancer cell growth and survival. By stabilizing these molecular structures, RC220 is designed to interfere with transcriptional and post-transcriptional processes that support malignant cell proliferation. In EGFR-mutant NSCLC, targeted medicines such as osimertinib can initially control disease, but resistance may emerge through several mechanisms, including secondary genetic alterations, activation of alternative signaling pathways and changes in tumor cell characteristics. The combination of RC220 and osimertinib is intended to investigate whether targeting additional cancer-related molecular processes can provide a useful strategy in this setting. These mechanisms represent the scientific rationale for the study, rather than demonstrated clinical benefits in patients receiving the combination.
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Next Steps in Clinical Development
Following the SRC recommendation, Racura Oncology has begun pre-screening for the next cohort, which is expected to include one patient receiving RC220 at 100 mg/m² alongside osimertinib at 80 mg daily. Under the initial accelerated dose-escalation design, the trial evaluates progressively higher doses, with safety reviews guiding decisions about whether the study can proceed. The planned early dose levels are 50 mg/m², 100 mg/m² and 150 mg/m², followed by a more structured escalation approach intended to help identify a suitable dose for further investigation. The overall dose-escalation stage is expected to involve approximately 12 to 40 patients. Subject to the availability of appropriate safety and pharmacokinetic data, the program is expected to advance to a randomized Phase 1b dose-expansion stage involving 40 patients. Investigators plan to assess safety, tolerability, pharmacokinetics and preliminary clinical activity, including progression-free survival, overall survival and changes in circulating tumor DNA. These future assessments will be essential for determining whether RC220 can offer meaningful benefits beyond the current treatment approach. For now, the move to 100 mg/m² represents a step forward in dose evaluation, not confirmation of therapeutic efficacy.
Source: Racura Oncology press release
