Event: SABCS 2021

Giuseppe Curigliano, MD, PhD, University of Milan and European Institute of Oncology, Milan, Italy, provides the rational for exploring the role of immunotherapy in HER-positive and hormone receptor (HR)-positive breast cancer and outlines key clinical trials. The Phase Ib/II trial PANACEA (NCT02129556) investigated the combination of trastuzumab and pembrolizumab in patients with HER2-positive metastatic breast cancer who had been heavily pretreated, demonstrating significant rates of progression-free survival (PFS). Phase III KATE3 (NCT04740918) explored the combination of trastuzumab emtansine plus atezolizumab in HER2-positive and PDL1-positive locally advanced or metastatic breast cancer, also showing significant PFS rates compared to the active comparator. The Phase III trial Astefania (NCT04873362) examined trastuzumab emtansine in combination with atezolizumab in patients with invasive breast cancer who are HER2- and PDL-1- positive. Prof. Curigliano additionally describes clinical trials investigating HR-positive breast cancer. Preliminary signs of activity were observed in the Phase II GELATO (NCT03147040) trial evaluating the combination of carboplatin plus atezolizumab specifically in patients with metastatic invasive lobular breast cancer. Further, a trial was reported evaluating treatment for patients with HR-positive, HER2-negative breast cancer with AC chemotherapy for three cycles followed by immune and endocrine therapy in the neoadjuvant setting. This trial was designed in regards to PAM50 molecular subtypes and it was noted that only patients with the basal-like subtype achieved pathologic complete response (pCR). Lastly, HER2 vaccines are discussed for patients with both HER2-positive and HER2-low breast cancer. This interview took place at the San Antonio Breast Cancer Symposium 2021 in San Antonio.