A phase 3 clinical trial, EVER-132-002, has demonstrated that sacituzumab govitecan (SG) significantly improves progression-free survival (PFS) in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer who have received two to four prior chemotherapy regimens. The study, conducted across multiple sites in mainland China, Republic of Korea and Taiwan, highlights the potential of SG as a valuable treatment option for this patient population.
The EVER-132-002 trial enrolled patients with histologically confirmed HR+/HER2- metastatic or locally recurrent inoperable breast cancer. HR+ was defined as ≥1% of cells expressing hormonal receptors, and HER2- was defined as IHC0, IHC1+ or IHC2+ and in situ hybridization negative. Patients were required to have received two to four prior systemic chemotherapy regimens for metastatic breast cancer and to be eligible for one of the chemotherapy options chosen by the investigator. The primary endpoint was PFS per Blinded Independent Central Review (BICR) using Response Evaluation Criteria in Solid Tumors v1.1.
Efficacy Results
The trial met its primary endpoint, demonstrating a statistically significant improvement in PFS for patients treated with SG compared to those treated with chemotherapy. The hazard ratio (HR) was 0.70, indicating a reduced risk of disease progression or death in the SG arm. Secondary endpoints, including overall survival (OS), objective response rate (ORR), and duration of response (DoR), were also analyzed.
Safety Profile
Safety was assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events v5.0. The safety profile of SG was found to be manageable, with adverse events consistent with those previously reported for this agent. Researchers monitored treatment-emergent adverse events (TEAEs) and serious adverse events to ensure patient safety throughout the trial.
Study Design and Patient Population
Patients were randomized 1:1 to receive SG (10 mg/kg intravenously on days 1 and 8 of every 3-week cycle) or chemotherapy of physician’s choice (eribulin, capecitabine, gemcitabine, or vinorelbine). Randomization was stratified according to the presence of visceral metastases, the number of prior chemotherapy regimens, and prior CDK4/6 inhibitor treatment. The study was compliant with the Declaration of Helsinki and International Council for Harmonisation Good Clinical Practice guidelines.
Implications for Clinical Practice
The findings from the EVER-132-002 trial suggest that sacituzumab govitecan could offer a meaningful benefit for patients with HR+/HER2- metastatic breast cancer who have limited treatment options. The study supports the use of SG in heavily pre-treated patients, providing a potential new standard of care in this setting.
