Breast cancer survival could be extended with two new drug combinations

By Dr. Ananya Mandal, MDOct 21 2018

Study 1

A new study has shown that a combination of drugs palbociclib, along with hormone therapy can significantly increase the survival among women with advanced breast cancer.

The new study titled, “Overall Survival with Palbociclib and Fulvestrant in Advanced Breast Cancer,” was published in the latest issue of the New England Journal of Medicine and the results of the PALOMA-3 trial were also presented at the European Society of Medical Oncology congress in Munich, Germany. The researchers from Institute of Cancer Research and Royal Marsden NHS Foundation Trust, found that women with advanced breast cancer treated with this combination lived for seven months longer than those who were treated with hormonal therapy alone. Among women who had earlier responded favourably to hormone therapy, the average survival when palbociclib and hormone therapy was administered together was around 10 months.

Dividing breast cancer cell. Image Credit: royaltystockphoto.com / Shutterstock

Study leader, Professor Nick Turner of the Institute of Cancer Research said, “These results indicate that we can now offer women with incurable breast cancer some precious extra survival time before their condition worsens. It is very encouraging.” The study involved a total of 521 women with advanced, hormone-sensitive breast cancer. The researchers attempted to see if the combination therapy worked better than conventional chemotherapy.

Results of the study funded by palbociclib’s manufacturer Pfizer, showed that women who were given a combination therapy survived for an average of 34.9 months. This is an average of 6.9 months longer than women treated only with hormonal therapy. Three years after the study enrolment 49.6 percent of the participants who had received the combination therapy were still alive compared to 40.8 percent of the participants who had received only hormone therapy.

Authors concluded in their study, “Among patients with hormone-receptor–positive, HER2-negative advanced breast cancer who had sensitivity to previous endocrine therapy, treatment with palbociclib–fulvestrant resulted in longer overall survival than treatment with placebo–fulvestrant. The differences in overall survival in the entire trial group were not significant.”

Study 2

Yet another combination of an immunotherapy drug atezolizumab with standard chemotherapy was found to prolong life of patients with advanced triple-negative breast cancers.

This study titled, “Atezolizumab and Nab-Paclitaxel in Advanced Triple-Negative Breast Cancer,” was led by Professor Peter Schmid, clinical director of breast cancer at St Bartholomew's Hospital and professor of cancer medicine at Queen Mary University of London and the results of the study were published in the New England Journal of Medicine. According to Schmid this study is a “massive step forward” and could soon “lead to a cure in some patients and may apply in the treatment of other forms of breast cancers in the future.”

The researchers explained that the chemotherapy made the tumour vulnerable and the immunotherapy then targeted the breast cancer cells. In this trial 451 patients were included in two groups – one to receive atezolizumab plus nab-paclitaxel or placebo plus nab-paclitaxel. The patients all had untreated metastatic triple-negative breast cancer. The patients were all followed up for an average 12.9 months.

Results showed that progression-free survival was 7.2 months with atezolizumab plus nab-paclitaxel and it was 5.5 months with placebo plus nab-paclitaxel. Median overall survival was 21.3 months with the combination therapy and it was 17.6 months with paclitaxel along with placebo. Side effects were seen among 15.9 percent patients on the combination and 8.2 percent on paclitaxel alone. At 25 months after the study 60 percent of the combination group were still alive. The combination treatment was found to reduce the risk of the cancer progress by up to 40 percent.

According to Professor Schmid, “Triple-negative breast cancer is an aggressive form of breast cancer. It is particularly tragic that those affected are often young. I'm thrilled that by using a combination of immunotherapy and chemotherapy we are able to significantly extend lives compared to the standard treatment of chemotherapy alone.”