2021 Breast Cancer Year in Review Introduction

Colleagues,

The COVID-19 pandemic continues to impact healthcare across the globe. We are yet to see the full effect of the COVID-19 pandemic on patients with cancer, including patients with breast cancer. With the recent emergence of the COVID-19 Omicron variant, we expect this impact on healthcare and cancer care to continue. This Year in Review series is an important tool to reach audiences and provide timely and relevant information on advancements in oncology.

This Year in Review is focused on breast cancer. Breast cancer is one of the leading causes of cancer deaths in women worldwide. Two new antibody–drug conjugates with a topoisomerase I inhibitor payload have recently been added to the therapy options for breast cancer. Sacituzumab govitecan-hziy is an antitrophoblast cell-surface antigen-2 antibody–drug conjugate that is the first of its kind. It has been approved for the treatment of patients with pretreated metastatic triple-negative breast cancer (TNBC). Trastuzumab deruxtecan (T-DXd) has been approved for patients with HER2-positive breast cancer.

Sacituzumab govitecan is an effective, well-tolerated, new medication for patients with metastatic TNBC. TNBC is a highly metastasized, heterogenous disease that represents approximately 10% to 15% of all breast cancers. It has a poor prognosis and high relapse rate compared with non-TNBCs. New therapies for TNBC have been desperately needed. In April 2020, the US Food and Drug Administration granted accelerated approval to sacituzumab govitecan for the treatment of metastatic TNBC in patients who have received ≥2 previous therapies for metastatic disease.

SASCIA is a phase 3 trial evaluating sacituzumab govitecan for the treatment of patients with metastatic TNBC who have received ≥2 previous therapies for metastatic disease. The primary objective of the SASCIA trial will be to compare invasive disease-free survival between patients treated with sacituzumab govitecan versus a treatment of the physician’s choice. Recruitment started in December 2020 and will take an estimated 36 months (42 patients per month). As of April 21, 2021, 27 of 1200 patients have been randomized in Germany, with other international groups to follow.

Olaparib (Lynparza) monotherapy has shown promising clinical results in patients with treatment-naïve TNBC with germline or somatic homologous repair deficiency. Patients with germline BRCA mutation are increasingly receiving poly (ADP-ribose) polymerase (PARP) inhibitors, such as olaparib, and clinical phase 3 findings show that these patients may benefit from the slowing of disease progression.

Dalpiciclib (SHR6390) plus fulvestrant has been clinically demonstrated to significantly improve progression-free survival and reduce the risk for disease progression or death in patients with hormone receptor–positive, HER2-negative advanced breast cancer whose disease had relapsed or progressed on previous endocrine therapy. Improved knowledge of the biologic pathways, along with a number of new targeted therapies, has resulted in better outcomes for patients with hormone receptor–positive and HER2-negative breast cancer. These new therapies have been used in combination with older treatments to optimize patient outcomes.

A number of other important and interesting results were observed across the studies discussed in this Year in Review. These results will benefit patients with breast cancer and improve their outcomes in years to come.

We are pleased to present these key topics in breast cancer in this Year in Review.

Adam M. Brufsky, MD, PhD
Professor of Medicine
University of Pittsburgh School of Medicine