ASCO: You’re listening to a podcast from Cancer.Net. This cancer information website is produced by the American Society of Clinical Oncology, known as ASCO, the world’s leading professional organization for doctors who care for people with cancer. The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement. Cancer research discussed in this podcast is ongoing, so the data described here may change as research progresses. In this podcast, Cancer.Net Associate Editor Dr. Norah Lynn Henry discusses several studies presented at the 2019 San Antonio Breast Cancer Symposium, held December tenth through fourteenth in San Antonio, Texas. Dr. Henry is an Associate Professor in the University of Michigan's Division of Hematology/Oncology in the Department of Internal Medicine and is the Breast Oncology Disease Lead at the Rogel Cancer Center. View Dr. Henry’s disclosures at Cancer.Net. ASCO would like to thank Dr. Henry for discussing this research. Dr. Henry: Hello. I'm Dr. Lynn Henry from the Rogel Cancer Center at the University of Michigan. I would like to share with you a few of the research highlights related to breast cancer from the recent 2019 San Antonio Breast Cancer Symposium. I do not have any relationships to disclose related to these studies. Many of the exciting trials that were presented at this conference were for treatment of HER2-positive breast cancer. This is a specific type of breast cancer that accounts for about 1 in 5 breast cancers. Both of the studies I'm going to discuss related to HER2 involve treatment of patients with metastatic HER2-positive breast cancer or cancer that has spread beyond the breast and surrounding lymph nodes. The first trial is called HER2CLIMB. This is a phase III trial examining a new drug called tucatinib that is a pill that is designed to turn off HER2. Because of the type of drug that it is, it is thought to treat cancer both outside and inside of the brain which is important because many patients with this specific type of breast cancer can have the cancer spread to the brain. Patients who enrolled on this trial had previously been treated with multiple different treatments for HER2-positive metastatic breast cancer. In addition, almost half of the patients had metastases or cancer in their brain. In the HER2CLIMB trial, all enrolled patients were treated with the anti-HER2 antibody drug trastuzumab, also called Herceptin, as well as a chemotherapy drug called capecitebine or Xeloda. In addition, two-thirds received the new drug tucatinib and one-third received placebo. Overall, the drug combination was pretty well tolerated by patients with some diarrhea and fatigue. What is exciting about this trial is the patients who were treated with tucatinib had a longer time until their cancer progressed compared to those who took placebo. Those patients who had cancer in their brain got a similar benefit from the drug as those who didn't. In addition, on average, patients were also more likely to live longer if they took the tucatinib drug, an average of 4.5 months longer. This represents a potentially exciting new treatment option for patients with HER2-positive breast cancer. However, it has not yet been approved by the FDA. The second trial called DESTINY-Breast01 tested another new drug also for HER2-positive breast cancer. This drug is called trastuzumab deruxtecan which is a standard HER2 treatment trastuzumab with a chemotherapy drug attached to it. This was actually a phase II trial in which all patients got the same dose of this new drug in the data that they showed at the meeting. Everyone had been previously treated with a number of different drugs