Breakthrough in Treatment for Aggressive Breast Cancer

Overview of Metastatic Triple-Negative Breast Cancer

A recent article in the New England Journal of Medicine (NEJM) has reported a significant advancement in extending survival for patients with aggressive breast cancer. Metastatic triple-negative breast cancer is characterized by its spread to distant organs and the absence of vital growth receptors that can be targeted through pharmacological means. This lack of an “Achilles heel” makes treatment particularly challenging.

Challenges in Treating Aggressive Breast Cancers

Typically, breast cancers rely on hormones produced by the body to grow and thrive. However, triple-negative breast cancers do not possess these hormone receptors and have adapted to proliferate without hormonal support. Consequently, patients with this type of cancer often face a grim prognosis, with a median survival rate of only 12 to 15 months. The standard treatment method is chemotherapy, but many patients develop resistance to this approach.

Promising New Research Findings

Researchers at St. Bartholomew’s Breast Cancer Centre in London presented compelling findings at the European Society for Medical Oncology’s 2018 Congress. Their study indicates that a novel therapeutic combination could extend survival by up to 10 months. The research, published in the NEJM, details results from a phase-3 clinical trial involving patients treated with atezolizumab combined with nab-paclitaxel.

Details of the Study and Treatment Combination

The combination therapy includes nab-paclitaxel, a chemotherapy agent used for breast cancer, and atezolizumab, an immunotherapy that targets programmed cell death-ligand 1 (PD-L1). In some cases, tumors overexpress PD-L1, which interacts with the PD-1 protein on T cells, leading to T cell inactivation and allowing tumor growth. Atezolizumab disrupts this interaction, reactivating T cells to combat the tumor.

The study encompassed 900 patients across 246 sites in 41 countries. Participants were divided into two groups: one receiving only nab-paclitaxel and the other receiving the combination of chemotherapy and immunotherapy. Results showed that those undergoing the combined treatment had an average progression-free survival of approximately seven months.

Encouraging Results and Future Implications

Progression-free survival serves as a valuable metric for assessing treatment effectiveness, as it indicates the duration during which the disease remains stable without worsening. Patients receiving the combination therapy experienced an overall survival rate of 21.3 months, offering hope for those with this aggressive breast cancer type. Notably, patients with PD-L1 expression on their tumors had even better outcomes, with an overall survival of 25 months.

Adverse events were reported in 15.9% of patients, indicating that while side effects were present, they were not overwhelmingly prohibitive. This study underscores the potential of combining chemotherapy and immunotherapy as a viable strategy to enhance treatment options for individuals battling aggressive breast cancers.

Author and Reference

Written by Vinayak Khattar, Ph.D., M.B.A.
Reference: Schmid, P., Adams, S., Rugo, H. S., Schneeweiss, A., Barrios, C. H., Iwata, H., . . . Investigators, I. M. T. (2018). Atezolizumab and Nab-Paclitaxel in Advanced Triple-Negative Breast Cancer. N Engl J Med. doi:10.1056/NEJMoa1809615