The latest analysis of the Phase III TROPiCS-02 study (NCT03901339), investigating the use of sacituzumab govitecan in hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancer, has revealed promising results. The study, which focused on patients with pretreated, endocrine-resistant, HR+/HER2- metastatic breast cancer, demonstrated a significant overall survival advantage for sacituzumab govitecan compared to treatment of physician's choice. The research was presented at the 2023 ASCO Annual Meeting (Abstract 1003).
The trial enrolled eligible patients with HR+/HER2- metastatic breast cancer who had previously received taxane, endocrine therapy, CDK4/6 inhibitors, and 2-4 lines of chemotherapy. The participants were randomly assigned to receive either sacituzumab govitecan (10 mg/kg IV on Day 1 and 8, every 21 days) or treatment of physician's choice until disease progression or unacceptable toxicity.
The primary endpoint was progression-free survival, while key secondary endpoints included overall survival and safety. Additionally, an exploratory analysis assessed overall survival based on HER2 immunohistochemistry (IHC).
Study Details
In the study, a cohort of 543 patients was enrolled with 272 individuals assigned to receive sacituzumab govitecan and 271 patients assigned to receive treatment of physician's choice. After a median follow-up of 12.75 months, a total of 437 overall survival events were recorded.
The extended follow-up analysis reaffirmed the superior overall survival outcomes associated with sacituzumab govitecan compared to treatment of physician's choice, with a median overall survival of 14.5 months for sacituzumab govitecan versus 11.2 months for treatment of physician's choice (HR: 0.79; 95% CI: 0.65-0.95; nominal P=0.01).
At the 12-month mark, the overall survival rates for sacituzumab govitecan and treatment of physician's choice were 60.9 percent and 47.1 percent, respectively, providing further evidence of the survival benefits conferred by sacituzumab govitecan in this specific patient population. Remarkably, regardless of HER2 status, the analysis demonstrated that sacituzumab govitecan improved overall survival, with both the HER2 IHC0 and HER2-low groups exhibiting prolonged survival rates when compared to treatment of physician's choice.
In an interview with Oncology Times, study author Sara Tolaney, MD, MPH, revealed the impact of their research on treatment approaches for patients diagnosed with HR+/HER2- metastatic breast cancer. Tolaney is Associate Professor of Medicine at Harvard Medical School and Chief of the Division of Breast Oncology in the Susan F. Smith Center for Women's Cancers at Dana-Farber Cancer Institute.
Oncology Times: How do the results of this trial impact the treatment landscape for HR+/HER2- metastatic breast cancer, and what are the potential implications for clinical practice?
Tolaney: "Data from TROPiCS-02 demonstrate that sacituzumab govitecan results in improved progression-free survival and overall survival compared to standard chemotherapy in patients with metastatic HR+ breast cancer who have progressed on endocrine therapy and prior chemotherapy in the metastatic setting. These data confirm the benefits of sacituzumab govitecan and it is important as it adds an effective treatment option for patients with metastatic HR+ disease."
Oncology Times: What were the most common adverse events observed with sacituzumab govitecan in the TROPiCS-02 trial and how were they managed?
Tolaney: "Common adverse events with sacituzumab govitecan include neutropenia, diarrhea, and fatigue. About half of the patients in the trial used growth factor support to help with the neutropenia, and loperamide, as needed, is very effective for patients with diarrhea."
Oncology Times: What are the next steps for research in this area, and how do you envision future treatment options for patients with HR+/HER2- metastatic breast cancer evolving in light of these findings?
Tolaney: "There is interest in seeing if sacituzumab govitecan could be used in an earlier line setting for metastatic HR+ breast cancer. The ASCENT-07 trial (NCT02574455) is looking at sacituzumab compared to standard chemotherapy in patients who have progressed on endocrine therapy in the metastatic setting, but had not received any chemotherapy for their metastatic disease."
Dibash Kumar Das is a contributing writer.
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