Triple HER2 Blockade With Trastuzumab, Pertuzumab, and Pyrotinib Versus Dual HER2 Blockade in the Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Randomized, Phase II Study

Abstract

This study aimed to evaluate the efficacy and safety of triple human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab, pertuzumab, and pyrotinib (TPPy) versus dual HER2 blockade with trastuzumab and pertuzumab (TP) in the neoadjuvant treatment of HER2-positive breast cancer. Patients with stage II–III HER2-positive breast cancer were randomized (1:1) to receive TPPy or TP alongside weekly nab-paclitaxel for 12 weeks. The primary endpoint was total pathological complete response (tpCR; ypT0/isN0). Exploratory biomarker and pathway analysis was done to identify patients benefiting from pyrotinib. A total of 109 patients were enrolled, and 108 received treatment: 55 in the TPPy group and 53 in the TP group. The tpCR rate was 65.5% (95% confidence interval [CI]: 51.4%–77.8%) in the TPPy group, and 60.4% (95% CI: 46.0%–73.5%) in the TP group (p = 0.585). In the TPPy group, 52 (94.5%) and 23 (41.8%) patients experienced dose interruption and discontinuation, respectively. The most common grade ≥3 adverse events in the TPPy and TP groups were diarrhea (58.1% vs. 0%) and neutropenia (23.6% vs. 15.1%). In conclusion, triple HER2 blockade did not improve tpCR rates compared with dual blockade but was associated with greater toxicity, particularly diarrhea.

Keywords

breast cancer / neoadjuvant therapy / HER2 blockade / pathological complete response / pyrotinib

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