Eligible patients will be enrolled to the treatment arm based on breast cancer subtype.~Patients will receive study treatment on Day 1 of a Q3W cycle. Treatment with CX-2009 monotherapy (Arms A and B) or CX-2009 in combination with CX-072 (Arm C) will be given until disease progression or symptomatic deterioration, unacceptable toxicity necessitating treatment discontinuation, or if the patient meets certain study defined criteria for discontinuation. On-treatment tumor assessments, will occur every 6 weeks per RECIST v1.1 for the first 48 weeks, and every 12 weeks thereafter.
A Phase 2, clinical study in advanced, metastatic breast cancer that will evaluate CX-2009 monotherapy in both Hormone Receptor(HR) positive/HER2 negative breast cancer and in TNBC, and evaluate CX-2009+CX-072 in TNBC