Benmelstobart plus antiangiogenic therapy vs chemotherapy for metastatic triple-negative breast cancer: phase III trial

This open-label phase III trial assessed a chemotherapy-free regimen for recurrent/metastatic triple-negative breast cancer (TNBC). Patients were 1:1 randomized to benmelstobart plus anlotinib or nab-paclitaxel monotherapy, stratified by prior taxane exposure, liver and brain metastases. Planned enrollment was 322, yet recruitment was prematurely stopped by COVID-19, leaving only 147 randomized participants (75 experimental, 72 control). All efficacy analyses are exploratory and require cautious interpretation. The primary endpoint, IRC-assessed progression-free survival (PFS), was not met. Investigator-assessed median PFS reached 7.85 months for the combination vs. 5.55 months for nab-paclitaxel (HR = 0.70, 95%CI 0.46–1.06, P = 0.1687). Median overall survival (OS) was 35.81 vs. 21.03 months (HR = 0.78, 95%CI 0.49–1.24, P = 0.2625). Grade ≥3 treatment-related adverse events affected 58.7% of combination patients and 36.6% of monotherapy patients. This regimen failed to deliver statistically superior clinical benefits over nab-paclitaxel, only showing a non-significant favorable trend. Further trials are warranted to validate this observation. Trial ID: NCT04405505, registered May 24, 2020 on ClinicalTrials.gov.