Recent Trial Data in HER2+ Metastatic Breast Cancer


Before moving on to the patient profiles, expert panelists review recent clinical trial data that have impacted treatment selection and sequencing in HER2+ metastatic breast cancer.


Neil Iyengar, MD:Before we get to the cases, I want to briefly touch on some of the recent data that came out of the San Antonio [Breast Cancer Symposium] this past December. I will mention that I was particularly struck by long-term data from the HER2CLIMB trial. We also saw some subgroup analysis from the DESTINY-Breast03 study. I’ll point out that in the longer-term follow-up of HER2CLIMB that was presented at San Antonio, we continue to see the overall survival benefit and we continue to see prolonged overall survival benefits. So we certainly know that tucatinib is indeed an active agent.

In the DESTINY-Breast-03 subgroup analysis that we saw at San Antonio, we got a signal that trastuzumab-deruxtecan may also have CNS [central nervous system] activity in the patients within that trial who had stable brain metastasis. Now we have data from a large prospective randomized controlled trial, HER2CLIMB, showing the activity of tucatinib-based therapy in patients with stable and active brain metastases, as well as subgroup data from DESTINY-Breast-03 showing that trastuzumab-deruxtecan might have activity in patients with stable brain metastasis.

Of course, we also have data from the TUXEDO trial and the DEBRA study, both suggesting that trastuzumab-deruxtecan has activity in stable brain metastasis, and possibly in active brain metastasis as well, although, additional data are needed. As you mentioned, Milana, this is a major area of need for our patients with HER2-positive breast cancer. You mentioned that in HER2CLIMB, almost 50% of patients who had a baseline MRI had brain metastasis. This is higher than some of the prior observational cohort data, which suggested 30% to 40% of patients. I think that if we start screening our asymptomatic patients, we’ll find that the rates of CNS involvement are actually even higher.

Transcript edited for clarity.

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