Sequential neoadjuvant chemotherapy using pegylated liposomal doxorubicin and cyclophosphamide followed by taxanes with complete trastuzumab and pertuzumab treatment for HER2-positive breast cancer: A phase Ⅱ single-arm study

Objective: Despite cardiotoxicity overlap, the trastuzumab/pertuzumab and anthracycline combination remains crucial due to significant benefits. Pegylated liposomal doxorubicin(PLD), a less cardiotoxic anthracycline, was evaluated for efficacy and cardiac safety when combined with cyclophosphamide and followed by taxanes with trastuzumab/pertuzumab in human epidermal growth factor receptor-2(HER2)-positive early breast cancer(BC).Methods: In this multicenter, phase II study, patients with confirmed HER2-positive early BC received four cycles of PLD(30-35 mg/m^(2)) and cyclophosphamide(600 mg/m^(2)), followed by four cycles of taxanes(docetaxel,90-100 mg/m^(2) or nab-paclitaxel, 260 mg/m^(2)), concomitant with eight cycles of trastuzumab(8 mg/kg loading dose,then 6 mg/kg) and pertuzumab(840 mg loading dose, then 420 mg) every 3 weeks. The primary endpoint was total pathological complete response(tp CR, yp T0/is yp N0). Secondary endpoints included breast p CR(bp CR),objective response rate(ORR), disease control rate, rate of breast-conserving surgery(BCS), and safety(with a focus on cardiotoxicity).Results: Between May 27, 2020 and May 11, 2022, 78 patients were treated with surgery, 42(53.8%) of whom had BCS. After neoadjuvant therapy, 47 [60.3%, 95% confidence interval(95% CI), 48.5%-71.2%] patients achieved tp CR, and 49(62.8%) achieved bp CR. ORRs were 76.9%(95% CI, 66.0%-85.7%) and 93.6%(95% CI,85.7%-97.9%) after 4-cycle and 8-cycle neoadjuvant therapy, respectively. Nine(11.5%) patients experienced asymptomatic left ventricular ejection fraction(LVEF) reductions of ≥10% from baseline, all with a minimum value of >55%. No treatment-related abnormal cardiac function changes were observed in mean N-terminal pro-BNP(NT-pro BNP), troponin I, or high-sensitivity troponin.Conclusions: This dual HER2-blockade with sequential polychemotherapy showed promising activity with rapid tumor regression in HER2-positive BC. Importantly, this regimen showed an acceptable safety profile,especially a low risk of cardiac events, suggesting it as an attractive treatment approach with a favorable risk-benefit balance.