Day 3 Program

Poster Spotlight 5: Optimizing and Expanding the Therapeutic Arsenal in HR+ Metastatic Breast Cancer

Day 3: December 10, 2026

7:00 AM–8:30 AM CST

221 ABC

Session Details

Moderator

Sarah Sammons

PS5-1

Molecular underpinnings of efficacy and resistance to giredestrant: Rationalizing clinical benefit across breast cancer settings

Ciara Metcalfe, Genentech, South San Francisco, CA

PS5-2

Real-world ctDNA profiling of intrinsic resistance and molecular dynamics to oral SERD monotherapy in HR+/HER2- metastatic breast cancer

Sherry Shen, Memorial Sloan Kettering Cancer Center, New York, NY

PS5-3

Long-term survival outcomes according to <sup>18</sup>F-fluoroestradiol PET/CT uptake in ER-positive/HER2-negative metastatic breast cancer (MBC): updated results from the ET-FES trial

Alessandra Gennari, University of Piemonte Orientale, Novara, Italy

PS5-4

Trastuzumab deruxtecan (T-DXd) versus sacituzumab govitecan (SG) in HER2-low/0 metastatic breast cancer (mBC) by HER2 status and Trop-2 expression

Alexis LeVee, UCLA David Geffen School of Medicine, Los Angeles, CA

PS5-5

Emergence of integrin beta 6 expressing breast cancer persisters through endocrine and CDK4/6 inhibitor therapy.

Justin Rendleman, The Rockefeller University, New York, NY

PS5-6

Discussant: Title TBD

Andrew Davis, Washington University in St. Louis, St. Louis, MO

PS5-7

First-in-human phase 1 dose-escalation and expansion study of MEN2312, an oral and selective dual KAT6A/B inhibitor, as monotherapy and in combination with endocrine therapy (ET) in patients (pts) with ER+/HER2- advanced breast cancer (aBC): preliminary results

Seth Wander, Massachusetts General Hospital, Boston, MA

PS5-8

Pi3kα Inhibitor TOS-358 + fulvestrant +/- CDK4/6i : Safe + Effective combination in P1 HR+HER2- mBC

Antonio Giordano, Dana Farber, Boston, MA

PS5-9

Alisertib + endocrine therapy (ET) in patients (pts) with ET-resistant HR+, HER2- metastatic breast cancer (MBC): evidence of enhanced activity in MYC-activated tumors from the phase 2 ALISCA-Breast1 study

Tufia C. Haddad, Mayo Clinic, Rochester, MN

PS5-10

On-treatment circulating tumor DNA dynamics in evERA Breast Cancer: A Phase III trial of giredestrant + everolimus in patients with estrogen receptor-positive, HER2-negative advanced breast cancer in the post-cyclin-dependent kinase 4/6 inhibitor setting

Adam Brufsky, University of Pittsburgh Cancer Institution, Pittsburgh, PA

PS5-11

Gedatolisib triplet versus giredestrant plus everolimus in HR-positive, HER2-negative advanced breast cancer (aBC): a matching-adjusted indirect comparison (MAIC)

Sara M Tolaney, Dana-Farber Cancer Institute, Boston, MA

PS5-12

Discussant: Title TBD

Rena D. Callahan, University of California, Los Angeles, Los Angeles, CA