Long-time Response with Ado-trastuzumab Emtansine in a Recurrent Metastatic Breast Cancer

Abstract

Case report Breast cancer (BC) is the most common cancer in women worldwide. The 5-year survival of patients with metastatic disease is estimated at 23%. Ado-trastuzumab emtansine (T-DM1) is a HER2-antibody drug conjugate which incorporates the HER2 targeted actions of trastuzumab with the microtubule inhibitor emtansine, resulting in cell cycle arrest and apoptosis. Currently T-DM1 was approved for the treatment of HER2-positive pre-treated metastatic BC. A 52-year-old female was diagnosed with Triple Positive Stage IIIC multifocal invasive ductal carcinoma of left breast. After completing neoadjuvant chemotherapy based on data from the Neo-sphere trial with dual HER2 blockade, she underwent bilateral mastectomy. Final pathology showed partial response. Post operatively, due to poor wound healing adjuvant treatments were delayed. She received 4 cycles of adjuvant chemotherapy with dd adriamycin, cytoxan and adjuvant radiation therapy. She was started on Q21 days trastuzumab following completion of adjuvant chemotherapy, and adjuvant endocrine therapy was initiated after completion of radiation therapy. Imaging done due to incomplete response to neoadjuvant treatment, showed liver lesions and liver biopsy confirmed recurrence. She was started on T-DM1, endocrine therapy with anastrazole was continued. She was initially receiving T-DM1 Q21 days, subsequently due to grade 1 fatigue and thrombocytopenia it was changed to Q28 days cycle. She is currently status post 37 cycles (20 cycles of Q21 days and 17 cycles of Q28 days). T-DM1 was approved for treatment (single-agent) of HER2-positive, metastatic BC based on phase III data from the EMILIA trial which randomized HER2-positive (HER2+), unresectable, locally advanced or metastatic BC patients. T-DM1 had 9.6 months median PFS vs 6.4 months with lapatinib + capecitabine. Another phase III trial, TH3RESA study, compared TDM1 to the treatment of the physician's choice in a patient who progressed on two or more anti-HER2 treatments. Median PFS in the T-DM1 arm was nearly double that of patients in the control arm (6.2 vs 3.3 months). Herein, we present a case of a woman with recurrent triple positive metastatic BC with a lengthy progression-free survival on TDM1 chemotherapy.