A Randomized Phase III Study Evaluating Izalontamab Brengitecan (Iza-bren) Versus Physician’s Choice of Chemotherapy in Patients with Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer (TNBC)

Jiong Wu, MD, PhD, presented interim phase 3 PANKU-Breast02 data evaluating izalontamab brengitecan (iza-bren), a potentially first-in-class EGFRxHER3 bispecific antibody-drug conjugate, vs physician’s choice of chemotherapy in patients with previously treated unresectable locally advanced or metastatic triple-negative breast cancer. The randomized study met its dual primary end points, demonstrating statistically significant and clinically meaningful improvements in progression-free survival by blinded independent central review and overall survival. Median progression-free survival was 8.5 months with iza-bren vs 3.1 months with chemotherapy, and median overall survival was 15.9 months vs 12.5 months, respectively. Iza-bren also produced a higher confirmed objective response rate than chemotherapy, at 51.7% vs 20.5%. Safety findings were described as manageable, with low rates of treatment discontinuation due to treatment-emergent adverse events and adjudicated interstitial lung disease. These findings support iza-bren as a potential new standard of care for patients with few effective post-taxane treatment options remaining in current practice.