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Amcenestrant Active in Postmenopausal, ER-Positive Breast Cancer

— Hannah Linden, MD, discusses the encouraging results from the AMEERA-1 trial

MedpageToday

Treatment with amcenestrant demonstrated antitumor activity in postmenopausal women with heavily pretreated advanced or metastatic estrogen receptor (ER)-positive breast cancer, according to findings from the , presented during the virtual 2020 San Antonio Breast Cancer Symposium.

In this exclusive ֱ video, , of the Seattle Cancer Care Alliance and University of Washington School of Medicine, discusses the study findings.

Following is a transcript of her remarks:

At San Antonio I had the pleasure of presenting the results from the AMEERA-1 trial. This is a phase I/II trial, which evaluated oral amcenestrant, which is a selective estrogen receptor downregulator, or SERD, compound -- one of many in this class that are emerging really as an oral option outside of fulvestrant [Faslodex].

Fulvestrant is an active, great drug, but its IM [intramuscular] delivery makes it uncomfortable for patients, and potentially the oral SERDs are a way to improve upon the activity in this class. There are down-modulators and degraders out there, and this compound is moving along into actually second-line studies in phase II and in first-line phase III randomized trials. This data is the data that got to the starting dose for the single-agent monotherapy.

We enrolled patients in a couple of different arms -- one had more heavily treated patients, and one had less heavily treated patients -- for a total of 62 women who received single-agent therapy at a range of doses from 150 mg to 600 mg. And the final dose that emerged from the trial was 400 mg.

The oral SERD is really active in breast cancer in these patients, achieving stable disease in a third of patients in the entire group. But when we reduced that just to the women who have not received prior targeted therapy, the response rate combined with clinical benefit was more like two thirds, 64%.

And interestingly, the drug amcenestrant showed a clinical benefit with patients who were either ESR1 wild-type or mutant, and some patients actually cleared their ESR1 mutations on the study. But there did not appear to be a relationship between the ESR1 mutation status and the response.

So the plan for this drug, as we described a little bit earlier, is to move it forward in multiple settings. We already have treated many patients in combination with another agent, a molecularly targeted agent, CDK4/6 inhibitor, palbociclib [Ibrance].

And this data is looking promising, and we hope to present that in another 6 months, the Parts C and D combination arms, to share the activity of the agent in that setting, which we all anticipate would be the more common setting that these drugs were given in.

Thanks for your attention.

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