The recently approved antibody-drug conjugate trastuzumab deruxtecan (T-DXd; Enhertu) was clearly more effective in treating metastatic HER2-positive breast cancer than standard-of-care trastuzumab emtansine (T-DM1; Kadcyla), researchers reported at the virtual European Society for Medical Oncology (ESMO) virtual meeting.
In this exclusive video, , of Mount Sinai Hospital in New York City, offers her takeaways from the DESTINY-Breast03 trial.
Following is a transcript of her remarks:
The abstract that I'm most excited about is a phase III trial comparing two antibody-drug conjugates in HER2-positive metastatic breast cancer in the second-line setting. Prior to this study, an antibody-drug conjugate, T-DM1, was considered standard of care in the second-line setting, but this phase III randomized trial compared two antibody-drug conjugates in the second-line setting, T-DM1 and T-DXd, and showed a massive improvement in progression-free survival with the T-DXd molecule as compared to T-DM1.
The median progression-free survival was 25 months for T-DXd versus 7 months for T-DM1, which is a massive improvement that is one of the biggest differences I've ever seen in progression-free survival in any randomized trial.
What's also interesting is that there was less interstitial lung disease seen in this clinical trial, probably because it's a less heavily pretreated group of patients, because that was a major concern that had come out of the earlier T-DXd trials.
Certainly this will change my practice, and I will be using T-DXd in the second-line setting. I'm actually not so surprised about these results, because I have had such dramatic responses in my own patients and using T-DXd, but it's really nice to see this important head-to-head comparison.