Study of KN026 in Combination With Palbociclib and Fulvestrant in Patients With Advanced Breast Cancer

A Phase II Study to Evaluate Efficacy, Safety and Tolerability of KN026 in Combination With Palbociclib and Fulvestrant in Patients With Locally Advanced HER2-positive Breast Cancer

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.

KN026 is an anti-HER2 bispecific antibody that can simultaneously bind two non-overlapping epitopes of HER2, leading to a dual HER2 signal blockade.

Inclusion Criteria:

• Male or female subject >= 18 years;
• Histologically or cytologically confirmed, metastatic or locally advanced unresectable HER2-positive;
• Adequate organ function assessed within 7 days prior to first trial treatment
• ECOG score 0 or 1;
• Left ventricular ejection fraction (LVEF) ≥ 50% at baseline;
• Life expectancy >3 months

Exclusion Criteria:

• Untreated active CNS metastasis or leptomeningeal metastasis;
• Uncontrolled tumor-related pain;
• Has received other anti-tumor treatment or an investigational drug within 28 days or within 5 times of half-life (whichever is shorter, and no less than 2 weeks) prior to the first trial treatment;
• Major surgery for any reason within 28 days;
• Curative radiation within 3 months of the first dose of trial treatment;
• History of uncontrolled intercurrent illness;
• Other medical conditions that at the discretion of investigator interfere with the requirements of the trial in terms of safety or efficacy evaluation, or treatment compliance