Cardiotoxicity monitoring of pyrotinib in combination with nab-paclitaxel, doxorubicin, and cyclophosphamide in HER2-positive breast cancer: a single-armed clinical trial.

Background: Human epidermal growth factor receptor 2 (HER2) inhibitors play a vital role in the treatment of HER2-positive breast cancer. Numerous studies have shown that traditional HER2 inhibitors and chemotherapeutics such as albumin-paclitaxel, liposomal doxorubicin, and cyclophosphamide (TAC regimen) have different degrees of cardiotoxicity. Pyrotinib is a novel small-molecule HER2 inhibitor and has no cardiotoxicity. Here, the purpose of this study was to investigate the cardiac safety of pyrotinib with TAC regimen for HER2-positive breast cancer.

Methods: In this study, 22 patients with stage I-IIIA HER2-positive breast cancer were screened, enrolled, and assigned to receive either neoadjuvant or postoperative adjuvant treatment with pyrotinib (320-400 mg, once daily) combined with TAC (albumin-paclitaxel 260 mg/m, liposomal doxorubicin 20 mg/m, cyclophosphamide 600 mg/m) from December 2019 to May 2021. Patients' heart function was monitored using electrocardiogram, echocardiogram, and serological indicators. ST segment and T wave change, left ventricular ejection fraction (LVEF, %), N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), creatine kinase (CK), creatine kinase myoglobin band (CK-MB), together with patients' weight, white blood cells (WBC), red blood cells (RBC), platelets, plasma lipid, and glucose were recorded.

Results: Before and after the 2nd, 4th, and 6th cycles of treatment, the incidence of abnormal electrocardiogram of patients enrolled in the neoadjuvant treatment group was 36.4%, 27.3%, 27.3%, and 27.3%, respectively, while in the postoperative adjuvant treatment, the incidence was 45.5%, 36.4%, 36.4%, and 36.4%, respectively. LVEF before and after treatment in the neoadjuvant chemotherapy group was 65.36%±2.25% and 65.00%±2.15% (t=1.305, P=0.221), while in the postoperative adjuvant treatment group, LVEF was 66.27%±2.69% and 65.18%±1.89% (t=1.359, P=0.204). Pyrotinib combined with a TAC regimen may have induced a decrease in RBC. No obvious abnormality was found in the level of NT-pro-BNP, CK, CK-MB, patients' weight, WBC, platelets, plasma lipid, or glucose in all enrolled patients during the entire treatment process.

Conclusions: Our findings indicated that neither neoadjuvant nor postoperative adjuvant treatment using pyrotinib combined with a TAC regimen to treat patients with HER2-positive breast cancer increased cardiotoxicity. However, the treatment may have induced a decrease in RBC and further research is needed.