Report Back from SABCS 2021: What’s the Latest in MBC Research?
According to Dr Stephanie Graff, a wonderful science translator and a past guest of this podcast,
“At every large oncology conference, a theme begins to emerge. This is typically driven by factors such as technological advances that shift research interests or the “me too” phenomenon in which drug and biotech companies start making drugs similar to ones that early studies suggest appear promising.”
With Dr Graff’s assistance we came up with three main themes at the latest San Antonio Breast Cancer Symposium
Theme 1 We know what we know.
A number of presented trial updates confirmed that data shown earlier was true and the drugs that had been expected to work really work. These trial updates provided long-term data on patient experience, drug safety, and outcomes. The follow-up analyses also allowed researchers to look at smaller subsets of the . For example, researchers reported that in the MONALEESA02 trial, which studied letrozole with or without ribociclib in metastatic breast cancer, every subset benefitted from ribociclib.
In the KEYNOTE-355 study that looked at adding pembrolizumab (or Keytruda) to other treatments used for metastatic triple negative breast cancer, the longer-term follow-up data showed that the drug continued to work for those who had benefitted initially. This means that checkpoint inhibitors (and we will talk about them later) will continue to be a good option for many people with triple negative breast cancer. An update on the Destiny Breast 03 trial showed that a subset of patients with brain metastasis had a very good response rate to Trastuzumab deruxtecan (T-Dxd), which was expected.
Theme 2 New things are always on the horizon.
Neratinib shows promise in Her2 mutant breast cancer (which is surprisingly different from Her2 positive breast cancer). Datopotamab deruxtecan (Dato-DxD), the TROP2-directed antibody-drug conjugate (ADC), displayed strong and durable efficacy results in the form of overall response rates (ORRs) when treating patients with metastatic triple-negative breast cancer, according to cohort data from the phase 1 TROPION-PanTumor01 trial. IT created a lot of buzz and will be moving forward in many subsequent trials. Elacestrant, the first of many oral selective estrogen receptor degraders (SERDs) to hit the big stage, showed only a modest improvement in survival. Whether it'll get to the finish line first remains to be seen. This is an exciting dimension because we really haven't had new endocrine agents for almost 20 years.
Theme 3 how do we individualize our treatment to the specific patient and the specific time during their therapy?
A novel trial design used circulating tumor DNA to determine when to change therapy as a way to potentially outsmart chemotherapy resistance or early cancer growth was interesting, but the concept needs to be tweaked before it is ready for primetime. A liquid biopsy-based approach to treatment selection improved outcomes among patients with hormone receptor-positive, HER2-negative metastatic breast cancer. Patients treated with an aromatase inhibitor plus ibrance who displayed a rising ESR1 mutation in their blood prior to disease progression doubled their median PFS if they switched to fulvestrant plus ibrasnce rather than remaining on the same regimen, results of the randomized phase 3 PADA-1 trial showed.
“PADA-1 is the first trial to demonstrate that, in most patients, resistance-associated mutations in the estrogen receptor gene can be detected and targeted before tumor progression, The trial suggests a statistically and clinically significant benefit when fulvestrant is used during this very new window of opportunity.”
Use of genomics to guide treatment selection improved outcomes for certain patients with metastatic breast cancer, according to the randomized phase 2 SAFIR02-BREAST results Multigene genomic sequencing has been widely adopted. However, it had not been established whether multigene sequencing improved outcomes for patients with metastatic breast cancer. The general implication of this study is that precision medicine can improve patient outcome if it is interpreted with the right tools”
Transcript
This transcript has been edited and condensed for clarity.
Want more?
Check out our past Road to a Cure episodes to learn about the latest MBC research from our guests, renowned clinicians and researchers, featured in this episode.
Over the last 20 years, advances in HER2 targeting treatments, antibody-drug conjugates (ADCs), immune checkpoint inhibitors (ICIs), and cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is) have prolonged survival and changed the breast cancer treatment landscape. Success leads to more questions about optimal drug sequencing, mechanisms of resistance, and how to overcome that resistance. Let’s ask Dr. Stephanie Graff to help us tackle these topics and more.