Immune Effects of Sacituzumab Govitecan with or without Pembrolizumab in Metastatic Hormone Receptor-Positive (HR+) Breast Cancer

Breast Cancer
Sara Tolaney, MD, MPH
Dana-Farber Cancer Institute


Worldwide, breast cancer is the most common non-skin cancer and the leading cause of cancer death in women. In the United States, breast cancer accounts for nearly one-third of all new cancer diagnoses among women with over 250,000 new cases per year. Metastatic breast cancer remains incurable and is a major cause of mortality in the United States with over 40,000 women succumbing to the disease each year. Hormone receptor positive (HR+) breast cancer accounts for approximately 70% of breast cancer cases and although patients with metastatic disease are initially responsive to treatment, it eventually develops resistance. After resistance develops, patients are treated with chemotherapy and typically develop progressive disease after 4 to 5 months and have a median overall survival of 18 months. Therefore, novel therapies are urgently needed for patients with endocrine resistant HR+ metastatic breast cancer. Sacituzumab govitecan is a novel antibody-drug conjugate (ADC). ADCs work by combining an antibody and chemotherapy agent to target and kill cancer cells. This phase II study will assess if sacituzumab govitecan in combination pembrolizumab, an immune checkpoint inhibitor targeting PD-1, can increase the length of time before the cancer spreads or grows in patients with HR+ and PD-L1+ metastatic breast cancer.

Trial Registration: Identifier: NCT04448886