Neoadjuvant chemotherapy using nanoparticle albumin-bound paclitaxel plus trastuzumab and pertuzumab followed by epirubicin and cyclophosphamide for operable HER2-positive primary breast cancer: a multicenter phase II clinical trial (PerSeUS-BC04)

Background Nanoparticle albumin-bound paclitaxel (nab-PTX) is a promising antibody partner for anti-human epidermal growth factor receptor 2 (HER2). We performed neoadjuvant chemotherapy (NAC) for HER2-positive breast cancer (BC) using nab-PTX plus trastuzumab (T-mab) and pertuzumab (P-mab), followed by epirubicin and cyclophosphamide (EC). Methods In this multicenter phase II clinical trial (January 2019-July 2020), patients with stage I (T1c)-IIIB HER2-positive primary BC were treated with four cycles of nab-PTX plus T-mab and P-mab, followed by four cycles of EC. The primary endpoint was the pathological complete response (pCR) rate. Secondary endpoints were clinical response rate (RR), adverse events (AE), and tumor-infiltrating lymphocytes (TILs) in biopsy samples. Results In total, 43 patients were enrolled (mean age, 54 years). Twenty-two patients had HER2, and 21 patients had luminal/ HER2-subtypes. The overall pCR rate was 53.5% (23/43, 95% CI: 42.6-64.1%, p=0.184), whilst the pCR for HER2 was 68.2% (15/22, 95% CI: 45.1-86.1) and 38.1% for luminal/HER2 (8/21, 95% CI: 18.1-61.6%). The RR was 100% [clinical (c) CR:25, partial response (PR): 18]. AEs (>= G3) included neutropenia (23.3%), leukopenia (7.0%), liver dysfunction (7.0%), and peripheral neuropathy (4.7%) when nab-PTX was administered. EC administration resulted in leukopenia (34.2%), neutropenia (31.6%), and febrile neutropenia (15.8%). The TILs in preoperative biopsy samples were significantly higher in pCR compared to non-pCR samples. Conclusion Nab-PTX plus T-mab and P-mab induced a high pCR rate in HER2-positive BC, particularly in the HER2-subtype. Given that AEs are acceptable, this regimen is safe and acceptable as NAC for HER2-positive BC.

Automated summary

In this study, nab-PTX plus trastuzumab and pertuzumab showed a high pCR rate in HER2-positive breast cancer, especially in the HER2 subtype. Although there were some adverse events, they were generally acceptable, indicating that this regimen is safe and effective as neoadjuvant chemotherapy for HER2-positive breast cancer.