Racura Oncology (ASX:RAC) said the Safety Review Committee completed its review of safety data from the HARNESS-1 trial single-patient first group who received a dose of its RC220 drug candidate at 50 milligrams per square meter with osimertinib 80 milligrams daily, according to a Wednesday Australian bourse filing.

No dose-limiting toxicities or treatment-related safety concerns were identified during the safety observation period. However, the patient reported moderate symptoms consistent with colitis, an inflammation of the large intestine or colon, after the period ended. The cause of these symptoms has not yet been determined, and clinical investigations are ongoing.

The observed colitis was not considered a dose-limiting toxicity or treatment-related adverse event. However, the committee recommended that one additional patient receive the drug candidate at 50 milligrams per square meter with 80 milligrams of osimertinib before dose escalation to 100 mg/m2 occurs, as a prudent precaution.

The committee is expected to meet again in the next six to eight weeks to evaluate the safety data from the second patient.