Multicenter phase 2 trial of the combination of KN046 and KN026 for advanced HER2-positive breast cancer

KN046 is a PD-L1/CTLA-4 bispecific antibody, and KN026 can bind two non-overlapping epitopes of HER2 simultaneously, leading to a dual HER2 signal blockade. A multicenter phase 2 trial in China evaluated the combination of KN046 and KN026 in patients with previously treated advanced HER2-positive breast cancer. The objective response rate was 47.2% (95% CI 30.4-64.5) and the median progression-free survival was 5.6 months (4.1-13.8). 94.4% of patients experienced treatment-related adverse events of any grade, and 27.8% experienced grade 3 or 4 TRAEs; there were no grade 5 TRAEs. The authors conclude that the chemotherapy-free regimen of KN046 plus KN026 demonstrated favorable clinical efficacy with acceptable toxicity in pretreated patients with advanced HER2-positive breast cancer.