Case Overview
A 52-year-old postmenopausal woman with a history of T2N0M0 estrogen receptor-positive/progesterone receptor-negative, HER2 immunohistochemistry (IHC) 0 breast cancer underwent lumpectomy and sentinel lymph node biopsy. Despite completing adjuvant therapy, she experienced disease progression, leading to the initiation of sacituzumab govitecan, which resulted in a partial response and symptomatic improvement.
Clinical Trial Insights
The TROPiCS-02 clinical trial (NCT03901339) evaluated sacituzumab govitecan in patients with metastatic or locally recurrent, inoperable HR-positive, HER2-negative breast cancer who had received at least one line of endocrine therapy, taxane, and CDK4/6 inhibitor. The trial demonstrated a median progression-free survival (PFS) improvement of 1.5 months (HR, 0.65; 95% CI, 0.53-0.81; P = .0001) and a 3-month overall survival (OS) benefit (HR, 0.79; 95% CI, 0.65-0.96; P = .020) compared to treatment of physician's choice (TPC).
Efficacy and Safety
At a median follow-up of 12.8 months, sacituzumab govitecan showed a 12-month PFS rate of 21.7% versus 8.4% for TPC, and an 18-month PFS rate of 14.4% versus 4.7% for TPC. The treatment was effective regardless of TROP2 expression levels or HER2 IHC status. Safety analysis revealed no new safety signals, with neutropenia and diarrhea being the most common adverse events. Grade 3 or greater events occurred in 74% of patients on sacituzumab versus 60% on TPC.
Conclusion
Sacituzumab govitecan represents a significant advancement in the treatment of heavily pretreated HR+/HER2- breast cancer, offering hope for improved outcomes in this challenging patient population. The TROPiCS-02 trial's findings underscore the potential of antibody-drug conjugates in expanding the therapeutic landscape for breast cancer.
