Immunotherapy combined with estogen-blockade (aromatase inhibitor+ GnRH agonist) lead to good partial response rate and turned the tumor microenvironment into immuno-active status in ER+/HER2- breast cancer patients.
There was no immunotherapy approved for ER+/HER2- metastatic breast cancer (MBC). In ER+/HER2- MBC patients, when they failed 2-lines of hormone therapy, the overall response rate to the next hormone therapy or to immunotherapy alone was around 5-10%.
We hypothesize that estrogen blocking treatment can enhance the efficacy of immunotherapy in ER+/HER2- MBC. We thus enrolled 15 premenopausal ER+/HER2- MBC patients into the study. estrogen-blockade and immunotherapy.
Our primary endpoint, 8-month progression free survival rate (8M PFS%) was 64.3%. The partial response (PR) rate was 35.7% and the 8-month progression-free survival rate was 64.3%. In our biomarker analysis, we discovered that the immune related signatures were upregulated after the treatment. Increased CD45+ cells, increased CD56dim NK cells, and increased TH1 cells were also noted from NanoString IO360 biomarker analysis.
“This study confirmed that combining estrogen blocking treatment and immunotherapy is an effective strategy for ER+/HER2- MBC. This is the first study to optimize immunotherapy through hormone therapy in ER+/HER2- MBC patients. This strategy also turned an immune cold into an immune hot tumor microenvironment, “says Prof. Yen-Shen Lu.
Prof. Yen-Shen Lu’s email address: [email protected]
