Abstract 225P
Background
Phase I and phase II trials have proved the antitumor activity and acceptable tolerability of pyrotinib plus chemotherapy in HER2-positive metastatic breast cancer (BC). We assessed the efficacy and safety of neoadjuvant pyrotinib plus albumin-bound paclitaxel and trastuzumab in women with HER2-positive early or locally advanced BC in an open-label phase II study.
Methods
Chinese patients with previously untreated non-metastatic HER2-positive BC (clinical stage IIA∼IIIC) were assigned to receive the following neoadjuvant regimen: pyrotinib 400 mg orally/qd/D1-21 q3wk; albumin-bound paclitaxel 125mg/m2/wk D1/8/15 q3wk);trastuzumab 8mg/kg loading dose D1 cycle 1; 6mg/kg D1 q3wk, for a total of 4 cycles (1 cycle = 3 weeks). After surgery, patients received adjuvant epirubicin + cyclophosphamide for 4 cycles (1 cycle = 3 weeks), then HER2-targeted therapy of physician’s choice. The primary end point was pCR defined as ypT0/Tis ypN0. Secondary endpoints were pCR defined as ypT0/Tis, investigator-assessed overall response rate (ORR) per RECIST, version 1.1 and adverse event (AE) profiles per NCI-CTC AE, version 4.0.
Results
There was a total of 21 patients enrolled between May 17, 2019 and Nov 26, 2019. The pCR (ypT0/Tis ypN0) rate was 57.1% (12/21), while the pCR (ypT0/Tis) rate was 61.9% (13/21). ORR reached 100% (21/21) by the clinical response assessment at the end of neoadjuvant treatment. Grade≥3 treatment-related AEs were observed in 42.9% (9/21) of patients. Among them, the most frequent events were diarrhea in 6 patients (28.6%), decreased white blood cell count in 5 patients (23.8%), and vomiting in 2 patients (9.5%). Dose modification and interruption of pyrotinib due to AEs occurred in 6 (28.6%) and 11 (52.4%) patients, respectively.
Conclusions
In women with HER2-positive early or locally advanced BC, the neoadjuvant regimen pyrotinib plus albumin-bound paclitaxel and trastuzumab effectively promoted pCR of tumor and presented an acceptable tolerability. This study provides a preliminary and first proof for the application of pyrotinib in the neoadjuvant settings.
Clinical trial identification
NCT04152057.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.