GLP toxicity studies using cynomolgus monkeys showed that YL202 is well tolerated with calculated therapeutic index (TI, HNSTD/MED) of ~100 for repeat dosing. No lung or platelet toxicity findings were observed at doses up to the maximum tolerated dose (MTD).Based on these preclinical results, it demonstrates that YL202’s advanced ADC design results in an increased therapeutic margin, and YL201 could be further developed in HER3 positive cancer patients.