Neoadjuvant Taxane/Carboplatin/Trastuzumab/Pertuzumab in Patients with HER2-Positive Early or Locally-Advanced Breast Cancer: A Retrospective, Single-Center, Observational Study

Abstract Pertuzumab + trastuzumab combined with neoadjuvant chemotherapy is a standard approach for treating locally-advanced HER2-positive breast cancer. To evaluate pathologic complete response (pCR) rates, safety, and tolerability of the taxane (docetaxel/paclitaxel) +carboplatin + trastuzumab + pertuzumab regimen in a North Indian cohort. In this retrospective, single-center, observational study, patients with early-stage or locally advanced HER2-positive breast cancer were enrolled. All patients were treated with neoadjuvant taxane + carboplatin + trastuzumab + pertuzumab from April 2018 to September 2024. pCR (ypT0 ypN0) was assessed after surgery. Safety outcomes were recorded based on a number of events and toxicity. Data were summarized using descriptive statistics. Univariate analysis was conducted to identify the predictors of pCR, where a two-sided p < 0.05 was considered statistically significant. Analyses were performed in RStudio. Forty-one patients (median age: 55 years), with 61% postmenopausal at presentation, were enrolled. The overall pCR rate was 56.1% (23/41), with higher pCR rates in hormone receptor-negative (63.6% vs. 47.4%), T2/T3 (65.4%/60%), and node-negative (100%) tumors. Docetaxel-based regimens showed significantly higher pCR rates than nondocetaxel regimens (74.1% vs. 21.4%, p = 0.002). Although docetaxel-based therapy showed superior efficacy, weekly paclitaxel/carboplatin (AUC2: weekly regimen) demonstrated better tolerability (14.3% dose reductions vs. 29.6% with docetaxel). Grade ≥ 3 adverse events included febrile neutropenia (19.5%), cytopenia (19.5%), and diarrhea (4.9%). Breast-conserving surgery (BCS) was feasible in 61% of patients (n = 25), with 84% (n = 21) among those undergoing BCS achieving pCR. The taxane (docetaxel/paclitaxel) + carboplatin + trastuzumab + pertuzumab regimen achieved high pCR rates in this cohort, consistent with global data. Weekly paclitaxel-based regimens may improve tolerability, particularly in elderly or comorbidity-burdened populations.