The breast cancer programme at the ESMO Congress 2026 brings together studies designed to clarify active questions in contemporary breast oncology, featuring late-breaking phase III trials, mature overall survival analyses, post-CDK4/6 strategies, biomarker studies, and an expanding focus on antibody–drug conjugate sequencing, according to OncoDaily. OncLive reported that LBA50 will highlight findings from PANKU-Breast01, a phase 3 trial evaluating izalontamab brengitecan in patients with previously treated, unresectable locally advanced or metastatic HR-positive, HER2-negative breast cancer.
Evaluating Izalontamab Brengitecan in PANKU-Breast01
PANKU-Breast01 (NCT06343948) tests izalontamab brengitecan, a bispecific antibody-drug conjugate targeting both HER2 and EGFR and conjugated to the novel topoisomerase I inhibitor payload Ed-04. Bo Lan is listed as the first author for the study, according to OncoDaily. Following the 2026 ASCO Annual Meeting—where the phase 3 PANKU-Breast02 trial (NCT06382142) demonstrated that izalontamab brengitecan significantly improved progression-free survival compared with physician’s choice of chemotherapy in metastatic triple-negative breast cancer patients who had experienced disease progression following one or two prior lines of therapy—enthusiasm for this agent remains strong, as reported by OncLive.
Assessing Patient-Reported Outcomes in the LidERA Breast Cancer Trial
Abstract 538RO will present patient-reported outcomes from the phase 3 lidERA Breast Cancer trial (NCT04961996) comparing giredestrant versus standard-of-care endocrine therapy in patients with estrogen receptor-positive, HER2-negative early breast cancer. Data revealed at the 2025 San Antonio Breast Cancer Symposium indicated that giredestrant achieved a significant enhancement in disease-free survival while maintaining comparable frequencies of hot flashes and arthralgias and leading to a reduction in treatment discontinuations relative to standard endocrine therapy, according to OncLive. These patient-reported outcomes clarify how patients feel while receiving a drug that may alter the standard of care for early-stage disease.
Investigating Atirmociclib Plus Fulvestrant in FOURLIGHT-1
Abstract 1842O will feature results from the randomized phase 2 FOURLIGHT-1 study (NCT06105632) evaluating atirmociclib combined with fulvestrant in patients with HR-positive, HER2-negative advanced or metastatic breast cancer who have progressed on a prior CDK4/6 inhibitor, OncLive reported. Patients in the trial were randomly assigned to receive atirmociclib plus fulvestrant, or fulvestrant alone, or everolimus plus exemestane. A March 17, 2026, news release from Pfizer indicated that the trial was positive, providing data that may help answer whether CDK4 inhibition can improve upon the efficacy and tolerability of CDK4/6 inhibitors.
ESMO Congress Programme Features Late Breaking Breast Cancer Trials
The ESMO Congress 2026 programme includes additional late-breaking investigations across early and advanced settings. OncoDaily reported that LBA23, titled TALENT, will present final results of a neoadjuvant study evaluating trastuzumab deruxtecan with or without anastrozole, or in sequence with chemotherapy, in HER2-low, HR-positive early-stage breast cancer, with Sara Hurvitz listed as presenting first author. LBA25 from the NATALEE trial will share six-year efficacy and overall survival data for adjuvant ribociclib combined with a nonsteroidal aromatase inhibitor in patients diagnosed with HR-positive/HER2-negative early breast cancer, with Dennis Slamon designated as the first author.
KEYNOTE B49 Study Evaluates Pembrolizumab Versus Placebo with Chemotherapy
OncoDaily noted that LBA51 will cover the randomized, double-blind phase III KEYNOTE-B49 study evaluating pembrolizumab versus placebo in combination with chemotherapy in HR-positive/HER2-negative advanced breast cancer, with Hope Rugo listed as first author. Beyond these abstracts, ESMO 2026 will feature exploratory analyses in patients with baseline brain metastases, including data from the phase 3 TROPION-Breast02 trial of first-line datopotamab deruxtecan-lnk in PD-L1-negative metastatic TNBC, and the phase 3 DESTINY-Breast09 trial of fam-trastuzumab deruxtecan-nxki with or without pertuzumab in HER2-positive disease, according to OncLive.
Questions About the ESMO Congress 2026 Breast Cancer Programme
What does the PANKU-Breast01 trial evaluate?
PANKU-Breast01 evaluates izalontamab brengitecan in patients with previously treated, unresectable locally advanced or metastatic HR-positive, HER2-negative breast cancer.
What did the NATALEE trial prepare for its six-year update?
The NATALEE trial will present six-year overall survival and efficacy outcomes with adjuvant ribociclib plus a nonsteroidal aromatase inhibitor in patients with HR-positive/HER2-negative early breast cancer, with Dennis Slamon listed as the first author.
Which trial investigates atirmociclib for advanced breast cancer?
Assessment of atirmociclib paired with fulvestrant for individuals suffering from HR-positive, HER2-negative advanced or metastatic breast cancer following disease progression on a prior CDK4/6 inhibitor is the focus of the randomized phase 2 FOURLIGHT-1 study.
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