A Case Report on Prolonged Response with Trastuzumab Emtansine (T-DM1) in Recurrent Advance Breast Cancer Setting

Breast cancer holds the dubious distinction of being the most prevalent malignant tumor among women worldwide the 5 year survival rate for patients with advanced or metastatic forms of the disease is estimated at a mere 23%, with approximately 20% of cases exhibiting an amplification of the human epidermal growth factor receptor 2 (HER2). HER2 overexpression was linked to a dismal prognosis prior to the advent of targeted HER2 therapies. The introduction of ado-trastuzumab emtansine (T-DM1) has emerged as one of the standard treatment options for HER2-positive breast cancer patients who experience a recurrence or progression of the disease. This case concerns a patient with recurrent metastatic breast cancer who achieved an unusually extended period of time without the disease progressing while on T-DM1 treatment. After experiencing disease progression on multiple treatment lines involving trastuzumab, the patient achieved a nearly complete clinical remission (cCR) with T-DM1 therapy. The availability of cost-effective biosimilars has expanded access to advanced biologic therapies, which were previously limited to a small segment of the population due to the cost barrier.