What are your treatment options for HER2 over-expressing metastatic breast cancer in a patient whose LVEF decreased to <50% from normal baseline on HER2-directed therapy and EF fails to improve after holding therapy for 2 months?

The decision for stopping HER2 therapy for cardiomyopathy should be weighed against the risk of their metastatic disease progressing on suboptimal therapy. With closer monitoring and help from a cardiologist to optimize medical management, I have been able to continue effective anti-HER2 therapy in mild to moderate cardiomyopathy cases. The SAFE-HEaRt study backs up this approach. The cardiac risk is low with new agents like TDXd and tucatinib, but the trials restricted entry to normal EF patients. However, following this same approach, I have been able to use TDXd and tucatinib as well in mild to moderate cardiomyopathy cases.