This study is preliminary, but it holds promise for the treatment of some patients with metastatic ERpositive breast cancer. Further study is needed to determine what percentage of patients with ER-resistant metastatic breast cancer acquire HER2 mutations, as well as to establish whether the combination of neratinib and fulvestrant (Faslodex) is effective or whether a different strategy is needed.
A new study presented at the 2018 American Association for Cancer Research meeting suggests that HER2 mutations can be acquired during metastatic cancer and their development represents a previously unreported mechanism of resistance to treatment.
Breast cancer is one of the most common cancer diagnoses in the United States. The National Cancer Institute estimates that 252,710 American women will be diagnosed with breast cancer and 40,610 will die from the disease in 2017. For the majority (62%) of women with breast cancer, the disease is confined to the breast, and the 5-year survival approaches 100%. However, for women with metastatic disease, the likelihood of survival at 5 years drops to 27%.
Breast cancer affects more women than any other type of cancer, and represents 15% of all new cancer cases in the United States. A total of 252,710 new breast cancer cases were estimated to be diagnosed in 2017, and more than 40,600 deaths. The prognosis worsens for patients with locally advanced breast cancer and even more so for those with metastatic disease.
For the first time, a randomized clinical trial has shown significant tumor shrinkage with a phosphoinositide-3-kinase inhibitor in patients with estrogen receptor–positive, HER2-negative early breast cancer, according to results presented at the 2017 ESMO Congress.
Treatment with a regimen of pembrolizumab plus trastuzumab in patients with trastuzumab-resistant advanced HER2-positive breast cancer was well-tolerated and had clinical benefit in those whose tumors were positive for a biomarker for pembrolizumab.