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2021 ESMO Conference recap on breast cancer

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image of male researcher looking into a microscope

Are you interested in learning about cutting edge research? This past weekend the world’s top oncologists and cancer researchers virtually attended Europe’s prestigious oncology conference, the European Society for Medical Oncology (ESMO) Congress. Leaders in oncology come to ESMO to learn and present the most promising developments in cancer care. The research studies shared at conferences like ESMO often become the basis of clinical guideline updates. We summarized a few of the major breast cancer advances presented at the Congress.

Improved treatment options for HER2+ metastatic breast cancer

Many of the breast cancer clinical trials presented at ESMO focused on HER2+ breast cancer in the metastatic setting. One trial did a head-to-head comparison of the benefits of two approved therapies. Another shared data on a novel treatment. 

The Phase III DESTINY-Breast03 directly compared Trastuzumab deruxtecan (Enhertu) to Trastuzumab emtansine (Kadcyla) and found that Trastuzumab deruxtecan demonstrated a 72% reduction in the risk of disease progression or death compared to Trastuzumab emtansine1. The median time to disease progression assessed by researchers was 25.1 months on Trastuzumab deruxtecan as compared to 7.2 months on Trastuzumab emtansine. Based on these promising results, the study authors said this could lead to a “potential paradigm shift in the treatment of HER2+ metastatic breast cancer”. 

Researchers also presented preliminary data on the novel antibody-drug conjugate, Trastuzumab duocarmazine, in the Phase III Tulip study. Trastuzumab duocarmazine showed improved progression-free survival compared to standard chemotherapy in HER2+ metastatic breast cancer patients who had progressed on prior therapy. Patients on Trastuzumab duocarmazine had a median progression free survival of 7 months compared to 4.9 months in patients in the chemotherapy group. These results will be validated through further analysis and overall survival data will be presented when it has matured.

First-line CDK 4/6 inhibition shows improved overall survival for HR+/HER2- metastatic breast cancer

In previous research, CDK4/6 inhibitors have been shown to prolong the time to disease progression in HR+/HER2- metastatic breast cancer. The MONALEESA-2 trial presented at ESMOis the first clinical trial to show that adding a CDK4/6 inhibitor to first-line hormonal treatment improves overall survival in patients as well. In this trial, adding CDK4/6 inhibitor, Ribociclib (Kisqali), not only improved progression free survival, but patients taking Ribociclib with Letrozole had a median overall survival of 63.9 months compared to 51.4 months in patients taking Letrozole alone. The survival benefit of adding Ribociclib to first-line hormone therapy is statistically and clinically significant.

Have questions?

In addition to making up to date research available, our medical team is here to help you understand the latest insights about breast cancer topics. If you have any questions or comments about this research–how it relates to your medical care, or wish to better understand the overall research on a particular topic–, you can reach out to us via the “Ask” section in the Outcomes4Me App.


  1. Cortes J, Kim S, Chung W, et al. Trastuzumab deruxtecan (T-DXd) vs Trastuzumab emtansine (T-DM1) in patients (Pts) with HER2+ metastatic breast cancer (mBC): Results of the randomized phase III DESTINY-Breast03 study. Presented at: European Society for Medical Oncology (ESMO) Congress 2021; September 16-21, 2021. Abstract LBA1.
  2. “Enhertu Reduced the Risk of Disease Progression or Death By 72% Vs. Trastuzumab Emtansine (T-DM1) in Patients with Her2-Positive Metastatic Breast Cancer.” AstraZeneca, 18 Sept. 2021, www.astrazeneca.com/content/astraz/media-centre/press-releases/2021/enhertu-reduced-the-risk-of-disease-progression-or-death-by-72-vs-Trastuzumab-emtansine-t-dm1-in-patients-with-her2-positive-metastatic-breast-cancer.html. 
  3. Manich CS, O’Shaughnessy J, Aftimos PG, et al. Primary outcome of the phase III SYD995.002/TULIP trial comparing [vic] Trastuzumab duocarmazine to physician’s choice treatment in patients with pre-treated HER2-positive locally advanced or metastatic breast cancer. Presented at: European Society for Medical Oncology (ESMO) Congress 2021; September 16-21, 2021. Abstract LBA15.
  4. Hortobagyi GN, Stemmer SM, Burris HA, et al. Overall survival (OS) results from the phase III MONALEESA-2 (ML-2) trial of postmenopausal patients (pts) with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2−) advanced breast cancer (ABC) treated with endocrine therapy (ET) ± Ribociclib (RIB). Presented at: European Society for Medical Oncology (ESMO) Congress 2021; September 16-21, 2021. Abstract LBA17_PR.

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