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Early Change in Breast Cancer Tx Based on Genomic Testing Boosts PFS

— HR-positive breast cancer patients with ER mutations doubled their median PFS

by Greg Laub, Director, Video, ľֱ

MedpageToday

Among patients with hormone receptor (HR)-positive breast cancer treated with an aromatase inhibitor plus palbociclib (Ibrance), those who displayed rising ESR1 mutation levels in circulating tumor DNA before disease progression doubled their median progression-free survival following a switch to fulvestrant plus palbociclib, according to results from the phase III presented at the virtual San Antonio Breast Cancer Symposium.

In this exclusive ľֱ video, , of Icahn School of Medicine at Mount Sinai in New York City, discusses the results of the study.

Following is a transcript of her remarks:

Good morning, this is Dr. Amy Tiersten from Mount Sinai Hospital in New York City. There were a lot of exciting breast cancer abstracts presented at the San Antonio meeting this month.

One of the studies that I found most interesting is the PADA-1 trial. And this is a tremendously exciting study as it really is the first study in breast cancer which shows that switching therapy based on genomic findings prior to clinical progression improves outcome in metastatic breast cancer patients.

So in this trial, patients with metastatic breast cancer with hormone receptor-positive, HER2-negative, who were found to have emerging acquired ESR1 mutations, which can confer resistance to aromatase inhibitors, found on circulating tumor DNA, who were switched from an aromatase inhibitor plus a CDK4/6 inhibitor to fulvestrant with continuation of the CDK4/6 inhibitor, had more than a doubling of progression free survival for around around 6 months to around 12 months.

However, patients who are switched to fulvestrant based on standard clinical progression had only a PFS of three and a half months.

The implication here is that early detection of resistant disease based on genomic testing, and that switching therapy based on this finding, actually may make a difference -- something that has never been shown before.

There are a lot of other ongoing trials investigating this finding, which hopefully will lend support to this approach.

  • author['full_name']

    Greg Laub is the Senior Director of Video and currently leads the video and podcast production teams.