HER2-TARGETED THERAPIES

Presentation and Diagnosis

Jane is a 70-year-old postmenopausal woman who was diagnosed with stage III invasive HER2+ breast cancer (ER/PR+). She underwent a lumpectomy and decided that she wanted to be treated within a clinical trial. 

Treatment

Jane was treated on CALGB 40601, a phase III trial in which patients with HER2+ breast cancer were randomly assigned to receive weekly paclitaxel with trastuzumab and lapatinib, weekly paclitaxel with trastuzumab, or weekly paclitaxel with lapatinib. In the clinical trial, she was randomly assigned to receive weekly paclitaxel/trastuzumab/lapatinib. Prior to starting treatment, Jane received an echocardiogram, which indicated a left ventricular ejection fraction (LVEF) of 60%. She tolerated the paclitaxel/trastuzumab/lapatinib therapy well and continued to undergo routine follow-up as indicated by the clinical trial, receiving echocardiograms every 3 months. 

Cardiovascular Toxicity Mitigation and Management

Three months after starting her clinical trial therapy, Jane had an echocardiogram that indicated that her LVEF had decreased to 55%. After 6 months on treatment, her next echocardiogram reported a further decreased LVEF of 45%. She reported no symptoms (i.e., no shortness of breath, extremity edema, or chest pain) at that time. Jane’s oncologist and advanced practitioner decided to hold her paclitaxel/trastuzumab/lapatinib therapy. Jane was then followed for the next 2 years, at which time she reported having headaches. She was noted to have a brain lesion, with biopsy indicating metastatic breast cancer. She received stereotactic brain irradiation and was started on pertuzumab/trastuzumab/docetaxel after an echocardiogram revealed an LVEF of 60%.