ERBB2 and neoplasm: One example of overcoming ADC resistance was illustrated in the previously described study by Takegawa et al., who found that T-DXd was able to overcome T-DM1 resistance in HER2-positive gastric cancer cells, and that the novel DNA topoisomerase I inhibitor incorporated into the ADC, with aberrant expression of ABC transporters, may be responsible for this enhanced anti-tumor activity [65].