Triple-negative breast cancer is an aggressive type of breast cancer that often grows fast and metastasizes more quickly than other types of breast cancer. Approximately 2,000 to 3,000 women in the Netherlands are diagnosed with this type of cancer every year. The current standard treatment consists of four types of chemotherapy in combination with immunotherapy. It is not currently clear, however, which patients benefit from this combination treatment, and which patients are subject to over-treatment: when patients are unnecessarily exposed to more therapies than they need, which can lead to unnecessary side effects.
Medical oncologist and researcher Marleen Kok: “Previous international research has shown that adding immunotherapy to standard chemotherapy treatment improves the survival in early-stage triple-negative breast cancer. The BELLINI trial may offer an alternative for these patients.” In the trial, the researchers show that immunotherapy with nivolumab and ipilimumab can be an effective treatment for triple-negative breast cancer. These drugs boost the immune system, which can help to prevent over-treatment and side effects associated with chemotherapy. The results of the trial were presented on the 16th of September by PhD candidate and pathology resident Iris Nederlof at the European Society for Medical Oncology (ESMO) Congress in Barcelona, and have been published in Nature Medicine.
In the first part of the study, patients were treated with nivolumab or a combination of nivolumab and ipilimumab four weeks before receiving chemotherapy. Some patients showed a clear activation of the immune system while others displayed a reduction in tumor size. This effect was particularly evident in patients with a high number of immune cells, also known as tumor-infiltrating lymphocytes (TILs). This group seems to respond well to immunotherapy.
In the second part of the study, patients with a high immune cell count were treated with combined immunotherapy six weeks before chemotherapy. In a third of these patients, no cancer cells were found during surgery. These patients did not receive any chemotherapy following immunotherapy.
“The fact that one third of this patient group achieved a complete response after only 6 weeks of immunotherapy without chemotherapy, is a potential first step toward a more personalized treatment for triple-negative breast cancer.”
Another promising result is that the treatment led to a significant decrease in circulating tumor DNA (ctDNA), an indicator of the presence of cancer cells in the body. In more than 20% of the patients, no detectable ctDNA was found after treatment, suggesting that treatment with immunotherapy has been effective in clearing cancer cells even without chemotherapy.
This study shows that short-term immunotherapy without chemotherapy might be a promising option for a select group of patients with triple-negative breast cancer, particularly for those with a high immune cell count. While these results are encouraging, the researchers emphasize that we need further research into immunotherapy treatment for triple-negative breast cancer. Larger trials are required, in which patients receiving immunotherapy can be followed over longer periods.
“A similar trial looking into just immunotherapy has already been initiated in France, and two major initiatives are underway in America to reduce chemotherapy if immunotherapy proves effective. As treatment improves and more people live longer with and after cancer, personalized treatment is increasingly important to ensure quality of life.”
This scientific publication has been made possible in part by the American Association for Cancer Research (AACR).