Expert perspectives on novel management of HER2+ metastatic breast cancer in the context of recent clinical trials and FDA approvals.
Cynthia Lynch, MD: My name is Dr Cynthia Lynch, and I’m a medical oncologist specializing in breast cancer with Cancer Treatment Centers of America, which is now a part of City of Hope. I'm going to talk a little bit about HER2+ metastatic breast cancer, and some of the treatments that are currently available.
For the current standard for individuals who have metastatic HER2+ breast cancer in the frontline setting, we would typically think of HER2-directed therapies in combination with a taxane. That would entail the use of trastuzumab and pertuzumab along with either docetaxel or paclitaxel. There is some data out there that supports the use of using HER2 targeted agents in combination with an endocrine therapy in patients who have hormone receptor-positive disease. However, in general I would typically favor the use of combining the antibodies along with a taxane, then subsequently if a patient is doing well on their taxane therapy, once they have completed several  cycles and they're doing well, then we would typically drop off the taxane, the cytotoxic agent, and continue the antibodies. At that point if someone is hormone receptor-positive, then we would add back in an endocrine therapy.
For many years now, for second-line metastatic HER2+ breast cancer trastuzumab emtansine [T-DM1] was considered the standard of care. That was based on a prior trial called the AMELIA trial that showed progression-free arrival of around 6-7 months. That was the basis of that becoming the standard of care after an individual has progressed on trastuzumab containing regimen and taxane, from there we would then we would be stepping to T-DM1. There are other drugs that are also can be utilized; the landscape has changed quite a bit over the past 2 years for HER2+ breast cancer. We do now have data looking at use of tucatinib in combination with trastuzumab and the oral chemotherapy capecitabine. One of the drugs I'll be talking a little bit more about today would be trastuzumab deruxtecan, or T-DXd, as well. I will say that prior to these drugs coming on the scene, previously we would be looking at doing combinations of trastuzumab with various chemotherapies, and there was also data for capecitabine and lapatinib.
Transcript edited for clarity.