Optimizing Outcomes in Estrogen-Receptor–Positive and HER2-Positive Metastatic Breast Cancer

For patients with estrogen-receptor–positive, human epidermal growth factor receptor 2–positive metastatic breast cancer (ER+/HER2+ MBC), the treatment approach is challenging due to potential additive toxicity if chemotherapy or an antibody–drug conjugate is combined with a cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitor. In such a patient, when the disease responds to induction therapy with a taxane plus antibody therapy (trastuzumab and pertuzumab), the current approach is to discontinue chemotherapy after about six cycles and continue antibody therapy either alone or with endocrine therapy. Now, investigators report the results of the international, open-label, randomized, phase 3 PATINA trial. The 518 participants had advanc…