In the past year, the U.S. Food and Drug Administration (FDA) approved four treatment options for patients with breast cancer, which are summarized herein.
T-DXd for HER2-Low Breast Cancer
On August 5, 2022, the FDA approved fam-trastuzumab deruxtecan-nxki (Enhertu; T-DXd) for adult patients with unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH‑) breast cancer who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy. Approval was based on the results of the phase III DESTINY-Breast04 trial (see page 12).
T-DXd for Unresectable or Metastatic HER2-Positive Breast Cancer
On May 4, 2022, the FDA granted regular approval to T-DXd for patients with unresectable or metastatic HER2-positive breast cancer who have received a prior anti–HER2-based regimen either in the metastatic setting, or in the neoadjuvant or adjuvant setting and have developed disease recurrence during or within 6 months of completing therapy. Approval was based on the results of the phase III DESTINY-Breast03 trial (see page 18).
Adjuvant Olaparib for High-Risk Early Breast Cancer
On March 11, 2022, the FDA approved olaparib (Lynparza) for the adjuvant treatment of adult patients with deleterious or suspected deleterious germline BRCA-mutated HER2-negative high-risk early breast cancer who have been treated with neoadjuvant or adjuvant chemotherapy. Patients must be selected for therapy based on an FDA-approved companion diagnostic for olaparib. Approval was based on the results of the phase III OlympiA trial (see page 41).
Abemaciclib Plus Endocrine Therapy for Early Breast Cancer
On October 12, 2021, the FDA approved abemaciclib (Verzenio) with endocrine therapy (tamoxifen or an aromatase inhibitor) for adjuvant treatment of adult patients with hormone receptor–positive, HER2-negative, node-positive, early breast cancer at high risk of recurrence and a Ki-67 score ≥ 20%, as determined by an FDA-approved test. This is the first CDK 4/6 inhibitor approved for adjuvant treatment of breast cancer. Approval was based on the results of the phase III monarchE trial (see here).
