ESMO 2026 乳腺癌多项研究读出：Sac-TMT、Keytruda 与 Kisqali 数据更新

At ESMO 2026, there were several significant breast cancer readouts for all variants of the disease, with immune-targeted therapies continuing to shine.

Breast cancer is the most common cancer among women globally, accounting for roughly 25% of all female cancer diagnoses; however, it does impact people of both sexes.

At the European Society for Medical Oncology (ESMO) Annual Meeting 2026, held in Madrid, Spain, from 23 to 27 October, there were a significant number of readouts in breast cancer, with novel mechanisms of action starting to show their potential.

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Breast cancer management is no longer just about prolonging survival for patients but is now about refining target precision, reducing toxicity, and offering smarter, chemo-free therapeutic pathways in both early-stage and metastatic disease.

Here is a deep dive into the pivotal updates from Madrid that could redefine the clinical standard of care (SoC).

Sac-TMT reduces risk of death by 40%

Sacituzumab tirumotecan (Sac-TMT) is a TROP2 antibody-drug conjugate (ADC) which is owned by Chinese biotech Kelun-Biotech. MSD agreed to a deal worth up to $1.4bn with Kelun in 2022 to develop, manufacture, and commercialise the drug in all territories outside of Greater China.

The drug is being investigated in a variety of indications, including breast cancer, non-small cell lung cancer (NSCLC) and endometrial cancer, among others.

Data from a variety of the programmes for this drug were presented during ESMO 2026, including the Phase III OptiTROP-Breast-01 study (NCT05347134), which is being managed by Kelun and enrolled 263 patients with triple-negative breast cancer (TNBC) in China.

At a median follow-up of 29.4 months, the risk of death was reduced by 40%, with an overall survival (OS) hazard ratio (HR) of 0.60 for sac-TMT versus chemotherapy. Median OS was 14.7 months and 9.9 months in the two groups, respectively.

The 30-month OS rate was 26.8% in the sac-TMT group versus 13.2% in the chemotherapy group, and the adjusted risk of death was reduced by 45%.

Professor Man Li, oncologist at the Second Hospital of Dalian Medical University, said: “For patients with advanced TNBC who have received multiple lines of therapy and have limited treatment options, sac-TMT monotherapy demonstrated a significant survival benefit compared with chemotherapy. In addition, based on its favourable safety profile and efficacy results, sac-TMT can achieve the dual clinical benefit of prolonging survival and improving quality of life, and help address an unmet need for patients with later-line TNBC.”

MSD is also running several studies of the drug in breast cancer, including TroFuse-010 (NCT06312176) in patients with metastatic HR+/HER2- breast cancer and the TroFuse-011 study (NCT06841354) in TNBC.

While it was not one of MSD’s breast cancer studies that showed positive data at ESMO 2026, the positive data from Kelun’s breast cancer trial, as well as MSD’s success with the drug in endometrial cancer, which was selected as one of the late-breaking abstracts (LBAs) for the third Presidential Symposium, suggests that benefit can be seen in both breast cancer patients and a more diverse patient population.

MSD’s Keytruda data less positive

Less positive for MSD, data from the Phase III KEYNOTE-B49 trial (NCT04895358) was presented by Dr Hope Rugo, division chief of breast medical oncology at the City of Hope Comprehensive Cancer Centre. Patients in the trial received Keytruda (pembrolizumab) plus chemotherapy or placebo and chemotherapy.

While the study met its primary endpoint, with an improvement in progression-free survival (PFS), the difference was quite small, with median PFS in the investigational cohort at 6.7 months compared to 6.0 months in the control group, representing an HR of 0.74.

The study, in which approximately 800 patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2−) locally recurrent inoperable or metastatic breast cancer, also showed no corresponding advantage in OS, with the control group actually seeing a higher OS of 22.2 months compared to 21 months in the Keytruda cohort.

Data from a subgroup with high PD-L1 expression, with a CPS ≥10, did see a more pronounced benefit in PFS of 7.5 months in the combination arm compared with 4.4 months in the placebo cohort, equating to a 0.59 HR. Again in this subgroup, which represented approximately 21% of patients, no significant OS benefit was seen.

Benefits with Novartis’ Kisqali continue at six years

Novartis also revealed longer-term follow-up data in the Phase III NATALEE trial (NCT03701334), with clinically meaningful OS continuing at six years for patients with early-stage HR+/HER2- breast cancer at risk of recurrence.

Patients in the study are being treated with Kisqali (ribociclib), a CDK4/6 inhibitor, plus endocrine therapy (ET) compared to ET alone for three years. The data found that the risk of death was reduced by 19.1% in the investigational combination cohort compared to the ET-alone cohort. At the same six-year time point, OS was 91.86% in the Kisqali group versus 89.73% in the control arm, widening the absolute benefit to 2.1 percentage points.

In conversation during ESMO, principal investigator of NATALEE, Dr Dennis Slamon, chief of Haematology and Oncology at UCLA Department of Medicine, said: “That statistic should be viewed in the context that if we just looked at the data one year ago, at the five-year mark, it was a 1.5 percentage point difference, so at the six-year mark it has grown, and the curve looks like it’s continuing to separate, even though the patients have finished all their therapy more than three years ago. This is very encouraging that there’s a long-term effect that is post-therapy.”

The invasive disease-free survival (iDFS) benefit increased from 4.1% at five years to 5.3% at six years, underscoring the long-term value of dual inhibition, with benefit observed years after treatment completion.

Breast-cancer specific survival (BCSS) was also supportive of OS benefit, showing a near 30% reduction in risk of breast cancer-specific deaths compared to ET alone.

The trial enrolled patients in the broadest early breast cancer (eBC) population of patients with stage II and III HR+/HER2- early breast cancer at high risk of recurrence, including those with high-risk node-negative disease and all node-positive patients.

Slamon added that even though six years is the last time point for the study analysis, Roche has confirmed it will continue to monitor patients for another four years to see if this benefit continues to show.

Patients tolerate Roche’s oral SERD

Roche and its oncology arm Genentech presented further data for its oral selective estrogen receptor degrader (SERD), giredestrant, in ER-positive, HER2-negative early and advanced breast cancer.

The rapid oral session included patient-reported outcome (PRO) data from the Phase III lidERA trial (NCT04961996), which assessed continued physical functioning, role functioning, and health-related quality of life (HRQOL) in patients. Of those who filled out PRO questionnaires in the early stages of the study, more than 50% who received the study drug reported low or no adverse events (AEs), confirming they were not significantly impacted by any, as per the Functional Assessment of Cancer Therapy–General (FACT-G) item GP5.

At a later stage of the study, across these time points, around 80% of patients receiving the study drug reported being slightly bothered by AEs versus 76% to 80% of those receiving SoC.

NEC Bio sees signal with personalised oral drug

Another breast cancer readout came from NEC Bio, which presented data from a Phase I/II study of its oral, individualised neoantigen therapy, NECVAX-NEO1, used in combination with immune checkpoint inhibitors (ICIs) and chemotherapy for patients with TNBC.

In the first cohort of the study (NCT06631092), eight patients with TNBC were treated with NECVAX-NEO1 in a neoadjuvant setting.

Five patients achieved pathological complete response (CR) at surgery, accompanied by corresponding biomarker changes. In all patients, immunogenic neoepitopes used in NECVAX-NEO1 were detected, as demonstrated by ELISPOT analysis.

Regarding the results of the clinical study, Dr Heinz Lubenau, CEO of NEC Bio Therapeutics, said: “Our clinical Phase I/II data are demonstrating promising immune responses in the neoadjuvant treatment of early-stage TNBC patients. The additional patients in cohort 2 are being treated with a higher dose of NECVAX-NEO1 on top of Keytruda plus chemotherapy, which is the SoC regimen, which includes pembrolizumab. We look forward to further evaluation of NECVAX-NEO1 as a potential treatment option for cancer patients with high medical need.”

The Tokyo-based company is now enrolling more patients, including at sites in the US following an IND approval from the US Food and Drug Administration (FDA).

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