Key Highlights

  • The Safety Review Committee recommended that planned dose escalation of RC220 to 100 mg/m2 proceed in the Phase 1 HARNESS-1 trial.
  • Neither Cohort 1 patient, dosed at 50 mg/m2 with osimertinib, experienced a dose-limiting toxicity or other treatment-related safety concern.
  • Cohort 2 is a single patient, pre-screening is under way, and the clearance concerns safety only, not efficacy.

Racura Oncology Limited (ASX:RAC) announced on 12 October 2026 that the Safety Review Committee (SRC) has cleared RC220 to move to the next planned dose level of 100 mg/m2 in its Phase 1 HARNESS-1 trial (RAC-020). The trial is evaluating RC220 in combination with osimertinib in patients with EGFR-mutant non-small cell lung cancer (EGFRm NSCLC).

Cohort 1 safety findings

The SRC reviewed all safety data from both Cohort 1 patients, who received RC220 at 50 mg/m2 with osimertinib at 80 mg daily. No dose-limiting toxicities or treatment-related safety concerns were identified in either patient during the safety observation period. The second patient had received three doses of RC220, 21 days apart, without such events. With two patients, the dataset is very small.

Next step: Cohort 2

Pre-screening is under way to enrol the single patient in Cohort 2, who will receive RC220 at 100 mg/m2 alongside osimertinib at 80 mg daily. Racura describes the step as moving the trial from Cohort 1 to Cohort 2 after completing a safety review. The release does not give a date for dosing the Cohort 2 patient.

How escalation works in HARNESS-1

The release explains that the trial raises the RC220 dose in planned steps. At each step a patient is treated at a set dose and monitored, and the safety results are reviewed before moving to the next dose. The SRC, a group of clinicians and trial experts, reviews all available safety information, which can include side effects, laboratory results, clinical observations, dose-limiting toxicities and treatment exposure.

The company states that the SRC does not decide whether the medicine is commercially valuable or effective, and its role is limited to whether the safety data support the next planned dose level.

What could delay escalation

Racura notes that dose escalation may be paused, or the dose reduced, if a dose-limiting toxicity or other safety concern is observed in later cohorts. The trial is being run with Principal Investigator A/Prof Surein Arulananda and the Monash Health team.

Trial structure

HARNESS-1 is a Phase 1 trial evaluating the safety and tolerability of RC220 combined with osimertinib in EGFR-mutant non-small cell lung cancer, with osimertinib at a fixed 80 mg daily. Cohorts enrol single patients at stepped RC220 doses, starting at 50 mg/m2 and moving to 100 mg/m2. A patient in Cohort 1 received three doses 21 days apart. The company says this reinforces the safety profile at that dose level, though the sample is two patients.

What the clearance does and does not mean

Racura explains that clearance means Cohort 2 can begin and that Racura has completed an important safety review step. It does not indicate anti-tumour activity, and the release provides no response or efficacy data. Phase 1 trials aim to understand safety and tolerability as the dose increases, which is why each step is reviewed before the next one begins.