KN026 is an anti-HER2 bispecific antibody that can simultaneously bind two non-overlapping epitopes of HER2, leading to a dual HER2 signal blockade.
This is an open-label, multicenter, dose-escalation and parallel-group expansion Phase II clinical trial to evaluate the efficacy, safety and tolerability of KN026 in combination with palbociclib and fulvestrant in women or male with HER2-positive metastatic breast cancer .The subjects will receive 20 mg/kg IV Q2W+ palbociclib 100/125 mg/day orally+/-Fulvestrant 500 mg IM until progressive disease, unacceptable toxicity or death.