Skip to Navigation Skip to Search Skip to Content
Search All Centers

How are Breast Cancer Patients Responding to New Therapies?

Read Transcript
View next

Published on July 23, 2020

How are Breast Cancer Patients Responding to New Therapies?

Recently, the Food and Drug Administration (FDA) granted the approval of two new treatment options for HER2-positive breast cancer; trastuzumab deruxtecan (Enhertu) and tucatinib (Tukysa). What do the approvals mean for patients? Where do these therapies fit in to breast cancer care?
 
Dr. Erika Hamilton, from Sarah Cannon Research Institute, shares highlights from the clinical trials that led to the approval of both the antibody-drug conjugate and HER2 tyrosine kinase inhibitor. Dr. Hamilton explains how the treatments work to target cancer cells and what settings they're approved for. She also describes patient response and response duration in those with HER2 metastatic disease and brain metastases.

Featuring

Transcript | How are Breast Cancer Patients Responding to New Therapies?

Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

Dr. Hamilton:

It's been really a busy past couple of years, which is what we work towards, but we love seeing. We've had a variety of new agents over the past little bit. I think probably the most recent are two new drugs for HER2-amplified breast cancer. That's a less common type of breast cancer that's about 15% of the breast cancers we see. And those are trastuzumab deruxtecan (Enhertu), are really long name, but it's a HER2 antibody-drug conjugate, and that was approved for patients that had seen at least two regimens in a metastatic setting. And then we also saw the approval of tucatinib (Tukysa), which is a new tyrosine kinase inhibitor, a pill that you take that blocks HER2. And that trial was really designed in the same arena, in that third line space, but it got an approval for second line and beyond HER2-positive disease. And there are some few nuances about those trials that we can get into, but I think that was really exciting, because over the past few years, we've seen a situation where we're taking a lot of our great metastatic HER2-positive therapies and moving those up into the earlier settings so we were left with a situation where we really needed more therapies for metastatic disease.

So to get into a little bit of the details, trastuzumab deruxtecan, we first saw some data a couple of years ago at ASCO, at the presentation there. And this was a large trial. It was a single-arm trial, enrolled a lot of patients, and the response rate... Not only the response rate, but the clinical benefit rate and the duration of response, how long those patients remained on trastuzumab deruxtecan if they were receiving it, was really impressive. So response rates over 90%, really. Duration of response almost in that year and a half range, much longer than we typically see with pretreated disease. And so based on that, we actually saw the FDA approve trastuzumab deruxtecan. It's interesting. It's approved for third line and beyond. In the trial, some of these patients were really quite heavily pretreated, with a median of six prior lines of therapy, so to see activity like that was extremely encouraging.

It's an antibody-drug conjugate, which I explain to my patients. It's interesting. It's not chemo. It is chemo. It's a little bit of both. It's where you take the chemotherapy and you kind of join it with the HER2 antibody. So when you infuse that into somebody's bloodstream, it circulates around not really doing anything until it finds that target, and then it drops its chemotherapy right on the target. And so in the news, back when we had T-DM1 approved, et cetera, it was coined the smart bomb. It's a way to deliver our therapy directly to our cancer cells.

On the other end, in a different mechanism of action, we also saw the approval of tucatanib, which is a HER2 tyrosine kinase inhibitor. It's similar to drugs like lapatinib (Tykerb) or neratinib (Nerylnx) that are already approved in this space, but what's special about tucatinib is it only blocks HER2. It doesn't block HER1, or another name is EGFR. And a lot of our side effects of lapatinib and neratinib come from the fact that we blocked EGFR. That's rash and diarrhea. And so tucatinib was really a great opportunity to get in there, be active against HER2, and maybe have a little bit less side effects. It's approved in combination with capecitabine (Xeloda), which is a common oral chemotherapy we give for breast cancer, and trastuzumab, our oldie but goodie HER2 antibody. And so that was improved in the third line space trial-wise, but second line and beyond with our approval.

What's really special about this drug is it crosses into the blood-brain barrier well. And so in the trial, instead of including only those patients that had brain metastases that were treated and stable, they also include two other groups of patients with brain metastases that are a little bit atypical from what we're used to seeing in trials. They included patients that had asymptomatic, untreated brain metastases, or patients that had had local treatment for their brain metastases but subsequently had those brain metastases grow. So it really was a very high-risk population, and they showed benefit across the board, progression-free survival, response rate, progression-free survival in brain mets, as well as overall survival for those patients receiving the combination of all three drugs compared to capecitabine and trastuzumab alone.

Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

Recommended for You

View next