Poll Results Highlight Breast Cancer Abstracts of Interest at ESMO 2026

As the 2026 ESMO Congress approaches, we’re preparing to see several potentially practice-informing breast cancer presentations spanning early-stage and metastatic hormone receptor (HR)–positive disease, triple-negative breast cancer (TNBC), HER2-positive disease, and breast cancer brain metastases. Several abstracts will explore key questions surrounding long-term survival with adjuvant CDK4/6 inhibition, novel antibody-drug conjugates (ADCs), and next-generation CDK4 inhibition.

We polled our followers on social media about their opinions on some of the most talked-about breast cancer abstracts they’re looking forward to seeing at this year’s meeting.

To read more about these studies and additional abstracts of interest ahead of ESMO 2026, read our in-depth preview.

Poll: Which breast cancer abstract are you most excited to see presented at the 2026 ESMO Congress?

• LBA25: 6-year NATALEE data
• LBA50: PANKU-Breast01
• 538RO: PROs from lidERA
• 1842O: FOURLIGHT-1

Among the most anticipated presentations is LBA25, which will feature 6-year overall survival (OS) and efficacy outcomes from the phase 3 NATALEE trial (NCT03701334) of adjuvant ribociclib (Kisqali) plus a nonsteroidal aromatase inhibitor in patients with HR-positive, HER2-negative early breast cancer. The update follows data presented at the 2025 ESMO Congress showing that adjuvant abemaciclib (Verzenio) plus endocrine therapy improved OS vs endocrine therapy alone in patients with high-risk disease in the phase 3 monarchE trial (NCT03155997).¹ Since then, experts have been awaiting updated data after 3 years of ribociclib treatment.

LBA50 will highlight findings from PANKU-Breast01 (NCT06343948), a phase 3 trial evaluating izalontamab brengitecan (iza-bren) in patients with previously treated, unresectable locally advanced or metastatic HR-positive, HER2-negative breast cancer. Iza-bren is a bispecific ADC that targets both HER2 and EGFR and is conjugated to the novel topoisomerase I inhibitor payload Ed-04. Interest is high following the 2026 ASCO Annual Meeting, where the phase 3 PANKU-Breast02 trial (NCT06382142) showed a significant improvement in progression-free survival with iza-bren vs physician’s choice of chemotherapy in patients with metastatic TNBC who had progressed after 1 or 2 prior lines of therapy.²

Abstract 538RO will report patient-reported outcomes (PROs) from the phase 3 lidERA Breast Cancer trial (NCT04961996) of giredestrant vs standard-of-care (SOC) endocrine therapy in patients with estrogen receptor–positive, HER2-negative early breast cancer. Findings presented at the 2025 San Antonio Breast Cancer Symposium showed that giredestrant significantly improved disease-free survival, with similar rates of arthralgias and hot flashes and fewer treatment discontinuations vs standard endocrine therapy.³ The PRO data will help clarify how patients feel while receiving a drug that may change the SOC for early-stage disease.

Abstract 1842O will present results from the randomized phase 2 FOURLIGHT-1 study (NCT06105632) of atirmociclib (PF-07220060) plus fulvestrant (Faslodex) in patients with HR-positive, HER2-negative advanced or metastatic breast cancer who have progressed on a prior CDK4/6 inhibitor. Patients were randomly assigned to receive atirmociclib plus fulvestrant, or fulvestrant or everolimus (Afinitor) plus exemestane, and a March 2026 news release indicated that the trial was positive.⁴ The data may help answer the question of whether CDK4 inhibition can improve upon the efficacy and tolerability of CDK4/6 inhibitors, an emerging area that will require careful evaluation.

On LinkedIn, respondents (n = 10) favored LBA25 (50%), followed by LBA50 and 1842O (20% each) and 538RO (10%). Results were similar on X, with respondents (n = 3) favoring LBA25 (66.7%), followed by 1842O (33.3%).

Poll: What breast cancer subtype or area are you most excited to learn more about at the 2026 ESMO Congress?

• HR-positive breast cancer
• TNBC
• HER2-positive breast cancer
• Breast cancer brain metastases

On LinkedIn, respondents (n = 47) favored TNBC (38%), followed by HR-positive breast cancer (30%), HER2-positive breast cancer (17%), and breast cancer brain metastases (15%). Results were more varied on X, with respondents (n = 11) favoring HR-positive breast cancer and HER2-positive breast cancer (36.4%), followed by TNBC (18.2%) and breast cancer brain metastases (9.1%).

Beyond these abstracts, ESMO 2026 will include exploratory analyses in patients with baseline brain metastases. These include data from the phase 3 TROPION-Breast02 trial (NCT05374512) of first-line datopotamab deruxtecan-dlnk (Datroway) in patients with PD-L1–negative metastatic TNBC, and from the phase 3 DESTINY-Breast09 trial (NCT04784715) of fam-trastuzumab deruxtecan-nxki (Enhertu) with or without pertuzumab (Perjeta) in patients with HER2-positive disease.

Collectively, these presentations underscore the rapid pace of therapeutic evolution across breast cancer subtypes.

References

1. Johnston S, Martin M, O’Shaughnessy J, et al. Overall survival with abemaciclib in early breast cancer. Ann Oncol. 2026;37(2):155-165. doi:10.1016/j.annonc.2025.10.005
2. Wu J, Zhang J, Ouyang Q, et al. Izalontamab brengitecan (iza-bren) versus physician’s choice of chemotherapy in patients with unresectable locally advanced or metastatic triple-negative breast cancer (TNBC): a randomized phase III study. J Clin Oncol. 2026;44(suppl 17):LBA1003. doi:10.1200/JCO.2026.44.17_suppl.LBA1003
3. Bardia A, Schmid P, Martín M, et al. Giredestrant vs standard-of-care endocrine therapy as adjuvant treatment for patients with estrogen receptor-positive, HER2-negative early breast cancer: results from the global phase III lidERA breast cancer trial. Presented at: 2025 San Antonio Breast Cancer Symposium; December 9-12, 2025; San Antonio, TX. Abstract GS1-10.
4. Pfizer announces positive topline phase 2 results for next-generation CDK4 inhibitor, atirmociclib, in second-line metastatic breast cancer. News release. Pfizer. March 17, 2026. Accessed October 12, 2026. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-announces-positive-topline-phase-2-results-next