e-Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2021

Quantifying the benefit of the addition of pertuzumab to standard neoadjuvant chemotherapy plus trastuzumab for HER 2 positive breast cancer – the experience of a single oncology unit (#233)

Jun Beng Kong 1 , Jacqui Thomson 1
  1. Medical Oncology, Frankston Hospital, Peninsula Health, Frankston, Victoria, Australia

AIMS

Pathologic complete response (pCR) in HER 2 positive breast cancer is associated with improved long term overall survival and event free survival (1). The addition of pertuzumab to standard treatment (including trastuzumab and chemotherapy) of HER 2 breast cancer in the neoadjuvant setting is associated with increased pCR rates (2,3). Currently, pertuzumab is not PBS funded in Australia for use in the neoadjuvant context and needs to be funded through a single payment access program at a cost to the patient of around $6000. The aim of this study is to assess the pathological response rate of the addition of pertuzumab to standard treatment of HER 2 positive breast cancer within our unit.

 

METHODS

A retrospective case series of all patients (between May 2019 until April 2021) treated in the neoadjuvant context with curative surgery were conducted. Demographic, menopausal status, hormone status, clinical stage, grade, Ki-67, chemotherapy agent, comorbid status, type of surgery, final histopathology, pCR rates, documented relapse were collected and analysed.

 

RESULTS
26 patients were included in the study of which 13 patients received the addition of pertuzumab. All patients received trastuzumab and chemotherapy. In the pertuzumab group 11/13 (84.6%) had at least stage IIB disease compared to 4/13 (30.7%) in the non-pertuzumab group. Among patients who had pertuzumab, 9/13 (69.2%) achieved pCR compared to 6/13 (46.1%) of patients without the addition of pertuzumab. The addition of pertuzumab to standard therapy is well tolerated in the majority of patients.

 

CONCLUSION

This  study provides a comparison of pCR rates between addition of pertuzumab to standard treatment versus standard treatment alone in the neoadjuvant treatment of early HER 2 breast cancer in a real world setting. The addition of pertuzumab to standard treatment of HER2 positive breast cancer was associated with a clinically meaningful benefit in obtaining pCR.

  1. Broglio K, Quintana M, Foster M, Olinger M, McGlothlin A, Berry S, et al. Association of pathologic complete response to neoadjuvant therapy in HER2-positive breast cancer with long-term outcomes. JAMA Oncol. 2016 Jun 1;2(6):751-60.
  2. Gianni L, Pienkowski T, Im Y, Roman L, Tseng L, Liu M, et al. Efficacy and safety of neoadjuvant pertuzumab and trastuzumab in women with locally advanced, inflammatory, or early HER2-positive breast cancer (NeoSphere): a randomised multicentre, open-label, phase 2 trial. Lancet Oncol. 2012 Jan;13(1):25-32.
  3. Shao Z, Pang D, Yang H, Li W, Wang S, Cui S, et al. Efficacy, safety, and tolerability of pertuzumab, trastuzumab, and docetaxel for patients with early or locally advanced ERBB2-positive breast cancer in Asia: The PEONY phase 3 randomized clinical trial. JAMA Oncol. 2020 Mar 12 [cited 2021 Aug 11];6(3):e193692. Available from: https://pubmed.ncbi.nlm.nih.gov/31647503/ DOI: 10.1001/jamaoncol.2019.3692