Results from the phase 3 PANKU-Breast02 trial showed that izalontamab brengitecan (iza-bren), a bispecific antibody-drug conjugate targeting EGFR and HER3, significantly improved outcomes in patients with previously treated advanced or metastatic triple-negative breast cancer (TNBC).
Among 418 patients, iza-bren reduced the risk of disease progression or death by 71%, achieving a median progression-free survival of 8.5 months compared with 3.1 months for standard chemotherapy. The drug also reduced the risk of death by 40%, improving median overall survival to 15.9 months versus 12.5 months. The objective response rate was 51.7%, more than double the 20.5% seen with chemotherapy.
Benefits were consistent across all patient subgroups, including HER2-zero and HER2-low tumors. Although severe side effects were more frequent with iza-bren, they were generally manageable, and few patients discontinued treatment. Investigators said the findings support iza-bren as a potential new standard of care for TNBC.