Neoadjuvant pyrotinib plus nab-paclitaxel, doxorubicin, and cyclophosphamide for HER2-positive locally advanced breast cancer: a retrospective case-series study

Abstract

Background: The anti-tumor activity of pyrotinib has been confirmed in human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. This study investigated the effect of pyrotinib plus nab-paclitaxel, doxorubicin, and cyclophosphamide as neoadjuvant therapy in patients with HER2-positive locally advanced breast cancer. Methods: In this single-center retrospective study, female patients with HER2-positive locally advanced breast cancer received pyrotinib 320 mg orally once a day and the TAC regimen (nab-paclitaxel 260 mg/m2, liposomal doxorubicin 20 mg/m2, and cyclophosphamide 600 mg/m2) on day 1 of each 21-day cycle. Surgery was performed after 4-6 cycles of neoadjuvant therapy. The outcomes included total pathological complete response (tpCR, ypT0/Tis ypN0) rate, objective response rate (ORR) after neoadjuvant therapy, progressionfree survival, overall survival, and the incidence of adverse events (AEs). Results: Between March 2019 and January 2020, a total of 22 patients were included. The median age was 48 years (range, 32-60). The ORR was 100% after the completion of neoadjuvant therapy. Ten (45.5%) patients achieved tpCR, including four of ten (40.0%) patients with positive hormone receptor, and six of 12 (50.0%) patients with negative hormone receptor. As at December 2020, no disease recurrence, progression, or death occurred. All patients suffered AEs after neoadjuvant therapy, most of which were grade 1-2. Grade >3 AEs included diarrhea [4 (18.2%)], rash [2 (9.1%)], and hand-foot syndrome [1 (4.5%)]. Conclusions: Neoadjuvant pyrotinib combined with the TAC regimen showed promising clinical benefit in patients with HER2-positive locally advanced breast cancer, with an acceptable safety profile.