Race Oncology (ASX:RAC) received human ethics approval from the St. Vincents Hospital, Melbourne human research ethics committee to begin a phase 1a/b clinical trial assessing the safety, tolerability and pharmacokinetics of its RC220 therapy candidate, in combination with osimertinib, in patients with non-small cell lung cancer that have activating epidermal growth factor receptor mutations, according to a Wednesday Australian bourse filing.

Phase 1a will begin with a circulating tumor DNA screening stage, followed by dose escalation, where between 12 and 40 patients will receive intravenous infusion of RC220 on the first day of a 21-day cycle in combination with standard-of-care osimertinib. The study will start with three single-patient cohorts before transitioning to a larger number of patient cohorts to identify the maximum tolerated dose of RC220.

In the Phase 1b stage, 40 patients will be randomized to one of two treatment dose levels.

Monash Health in Victoria will start enrolling patients for the trial with the support of Beyond Drug Development, subject to final institutional approval and site activation, expected by the late December quarter to the early March quarter of 2026.

Its shares fell 8% in recent trading on Wednesday.