ARX788 for Treating Patients With HER2-low Locally Advanced Unresectable or Metastatic Breast Cancer

This phase II trial tests how well ARX788 works in treating patients diagnosed with HER2-low, locally advanced unresectable or metastatic breast cancer. ARX788 is an antibody-drug conjugate (ADC) that is given by infusion (diluted and injected slowly into veins). Antibodies are proteins which are naturally produced by the body's immune system to help fight infections. ARX788 consists of antibodies that have been attached to a toxin that has the potential to kill cancer cells. ARX788 sticks to a protein called human epidermal growth factor receptor (HER2), which is found on some breast cancer cells. Giving ARX788 may be safe and effective in treating patients with HER2-low locally advanced unresectable metastatic breast cancer.