Resistance Mutations: Next in ER+ Metastatic Breast Cancer?

“Estrogen receptor (ER) mutations can be easily detected in the plasma of patients with metastatic breast cancer and may hold the key to targeted treatments for women with endocrine-resistant disease, according to new analysis of patients in the BOLERO-2 trial.

” ‘Patients who had mutations had a shorter median survival than those who did not…and patients with different mutations might have different responses to therapies,’ Sarat Chandarlapaty, MD, PhD, a breast medical oncologist from Memorial Sloan Kettering Cancer Center in New York reported at the San Antonio Breast Cancer Symposium.

“BOLERO-2 enrolled postmenopausal women with metastatic, endocrine-resistant, ER-positive breast cancer and changed the standard of care in this setting, as reported by Medscape Medical News.”


Palbociclib's Role in Endocrine-Resistant Breast Cancer

“Palbociclib (Ibrance, Pfizer), the first CDK4/6 inhibitor to be approved for the treatment of breast cancer, has been welcomed by experts for its role in improving outcomes in patients with endocrine-resistant breast cancer.

“The drug should a significant improvement in progression-free survival (PFS) when it was added to fulvestrant (Faslodex, AstraZeneca) in the phase 3 PALOMA 3 trial, as reported recently by Medscape Medical News. The addition of palbociclib to fulvestrant increased median PFS to 9.2 months in patients with estrogen receptor (ER)–positive/HER2-negative endocrine-resistant breast cancer compared with 3.8 months in the placebo-fulvestrant group (P < .001).

“The overall survival data are still immature.

“The full results have now been published in print in the July 16 issue of the New England Journal of Medicine.