Palbociclib. efficacious but predictive biomarkers still needed

Several therapeutic options are available for management of premenopausal patients with metastatic hormonereceptor- positive breast cancer, including single-agent endocrine therapy or combination regimens. Single agent treatment with an aromatase inhibitor or tamoxifen has resulted in major improvements in the adjuvant setting but has shown little clinical benefi t in metastatic disease.1,2 Endocrine therapy is the standard of care for hormone-receptor-positive luminal, HER2-negative metastatic breast cancer. However, resistance to endocrine treatment remains a major clinical problem, especially for patients with metastatic disease. Therefore management of resistance to endocrine therapy is an active area of research.3