Debra Patt, MD, PhD, MBA, Texas Oncology, US Oncology Network, discusses practice changing results from the DESTINY-Breast04 trial, which showed a 50% reduction in the risk of disease progression or death with trastuzumab deruxtecan vs standard chemotherapy for patients with HER2-low metastatic breast cancer.

These findings were presented at the 2022 ASCO Annual Meeting.

Transcript:

My name is Dr. Debra Patt and I'm an Executive Vice President of Texas Oncology part of the US Oncology Network. I'm so excited today to see the plenary session of the DESTINY-Breast04 data presented. The DESTINY-Breast04 data evaluated 557 patients with advanced breast cancer that had been previously treated that express HER2 in a low way. What this means is that they are 1+ or 2+ on their immunohistochemistry. This is important because historically these patients have been categorized only as positive or negative indicated by ASCO cap guidelines and there wasn't really an appreciation of treatment differentiation by HER2-low as opposed to positive or negative.

So as the DESTINY-Breast04 data evaluated this HER2-low patient population, what we found is that patients who were treated Enhertu, or trastuzumab deruxtecan, in comparison to physician's choice of chemotherapy, that they actually had a survival benefit from being treated within Enhertu in comparison to physician's choice chemotherapy. The medication trastuzumab deruxtecan conveyed a favorable overall survival advantage.

When you take the patients that are ER+ and HER2-low, that survival advantage was 24 months in comparison to 17.5 months. This is in a patient population that was already pretreated and in comparison to chemotherapy that we use today.

I think this is an incredibly important advancement for patients with advanced breast cancer is about 55% of advanced breast cancer patients express HER2 that is low. And this is a novel therapeutic opportunity that allows us on Monday morning to make treatment enhancements to this very important patient population. Not only does this convey a survival advantage, but also the toxicity profile was more favorable of patients that received trastuzumab deruxtecan in comparison to chemotherapy in this study, DESTINY-Breast04.

Thank you so much for your attention today. I'm excited about this novel treatment paradigm that we can introduce to patients in the clinic.

Source:

Modi S, Jacot W, Yamashita T, et al. Trastuzumab deruxtecan (T-DXd) versus treatment of physician’s choice (TPC) in patients (pts) with HER2-low unresectable and/or metastatic breast cancer (mBC): Results of DESTINY-Breast04, a randomized, phase 3 study. Presented at: ASCO Annual Meeting; June 3-7, 2022. Chicago, IL, and virtual. Abstract LBA3.