ANTI-HER2 ANTIBODIES IN COMBINATION WITH CHEMOTHERAPY OR CHEMOTHERAPY-FREE REGIMENS TARGETING HER2-POSITIVE BREAST CANCER: A SYSTEMATIC REVIEW

Abstract

Breast cancer is the leading cause of cancer-related death in female worldwide. Human epidermal growth factor receptor 2 (HER2) amplification is observed in approximately 20% of breast cancer cases and is associated with poor clinical outcomes. Dual HER2 blockade without chemotherapy represents an attractive therapeutic approach, and it remains unresolved if anti-HER2 therapeutic antibodies are sufficient to replace chemotherapy regimens. In this review, we discuss the approved therapeutic monoclonal antibodies (pertuzumab and trastuzumab) and antibody-drug conjugate (trastuzumab emtansine or T-DM1) for the treatment of HER2-positive breast cancer patients. In summary, phase II and III clinical trials have demonstrated that dual HER2 blockade (pertuzumab and trastuzumab) plus chemotherapy regimens confer better efficacy compared with dual HER2 blockade alone, or anti-HER2 antibody monotherapy, in HER2-positive breast cancer patients. Dual HER2 blockade (pertuzumab and trastuzumab) combined with chemotherapies (5-fluorouracil, epirubicin, cyclophosphamide and docetaxel) yield superior response. Moreover, dual HER2 blockade (T-DM1 and pertuzumab) in combination with docetaxel represents a promising treatment regimen containing T-DM1. Ongoing clinical trials are assessing the optimal chemotherapy of choice with anti-HER2 antibodies combinations. In conclusion, improved outcomes are attributable to selection for the optimal chemotherapy regimen in combination with anti-HER2 antibodies instead of replacing chemotherapy altogether with the current line of anti-HER2 therapeutic antibodies.