In vivo growth inhibition study evaluated the sensitivity of DB-1310 to Her3-positive breast cancer and lung cancer xenograft models….It also showed dose-dependent antitumor killing activity in a HER3-positive breast cancer HCC1569 xenograft model and a lung cancer NCI-H441 xenograft model. Tumor regression was observed in a NSCLC patient-derived xenograft model with EGFR mutation under DB-1310 treatment....DB-1310 exhibited its efficacy in tumor models both in vitro and in vivo. These studies suggest that DB-1310 as a novel HER3-targeting ADC showed antitumor efficacy for HER3 positive tumors with good safety profile.