Clinical trial shows new therapy holds promise for patients with subtype carrying high risk for metastasis
Results from a clinical study co-led by a researcher at UT Southwestern show promise in using immunotherapy and chemotherapy before surgery among breast cancer patients. (Photo credit: Getty Images)
A phase three clinical trial co-led by a researcher at UT Southwestern Harold C. Simmons Comprehensive Cancer Center showcases the promise of administering immunotherapy along with chemotherapy before surgery in patients with breast cancer at high risk of spreading. The findings, published in Nature Medicine, suggest preoperative immunotherapy is more effective for some breast cancer patients, the study authors say.
“We hope that these results inform treatment decisions and, in turn, improve outcomes for patients with breast cancer, ultimately improving cure rates,” said Heather McArthur, M.D., M.P.H., Professor of Internal Medicine in the Division of Hematology and Oncology at UT Southwestern. Dr. McArthur is Clinical Director of the Breast Cancer Program at the Simmons Cancer Center. She co-led the study with international colleagues.
Heather McArthur, M.D., M.P.H., is Professor of Internal Medicine in the Division of Hematology and Oncology at UT Southwestern. Dr. McArthur is Clinical Director of the Breast Cancer Program at the Simmons Cancer Center. She holds the Komen Distinguished Chair in Clinical Breast Cancer Research.
The study focused on patients with early-stage, operable estrogen receptor positive (ER+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer. This subtype, which comprises about 70% of the more than 3 million breast cancer cases diagnosed annually, can respond unpredictably to treatments, Dr. McArthur explained, posing substantial challenges for effective management.
Although administering chemotherapy before patients have surgery to remove tumors is often a standard treatment approach, she added, researchers have suspected that immunotherapy – which harnesses the power of patients’ own immune system to fight their cancer – might improve outcomes. Giving patients immunotherapy while their tumors are still in place allows the immune system to “see” the tumors, a necessary step to train the patient’s fighting cells to recognize them, react, and attack them.
The researchers worked with 510 patients with this breast cancer subtype at 221 sites in 31 countries. About half of these patients received a standard regimen of chemotherapy along with nivolumab, an anticancer immunotherapy agent; the other half received chemotherapy along with a placebo before surgery. After surgery, all patients received endocrine therapy, a type of cancer therapy that targets the estrogen receptor.
Nearly 14% of patients who received the placebo with chemotherapy before surgery had a pathological complete response, meaning that no evidence of cancer remained at the time of surgery. In contrast, about 25% of those who received nivolumab with chemotherapy before surgery had a pathological complete response. Patients were more likely to benefit from nivolumab if they produced more PDL-1, the protein targeted by the drug. These results suggest that adding immunotherapy early in the course of treatment for operable ER+/HER2- breast cancer could improve cure rates, Dr. McArthur said. To that end, follow-up from the study is planned to determine whether the improvement in surgical outcomes translates into improvements in long-term cure rates.
The study was funded by Bristol Myers Squibb. UT Southwestern is also supported by the National Cancer Institute (NCI) Cancer Center Support Grant (P30CA142543).
Dr. McArthur holds the Komen Distinguished Chair in Clinical Breast Cancer Research. She has received consulting fees and research funding from Bristol Myers Squibb.