De-escalating treatment in the adjuvant setting in HER2-positive breast cancer

Cardiac outcomes of subjects on adjuvant trastuzumab emtansine vs paclitaxel in combination with trastuzumab for stage I HER2-positive breast cancer (ATEMPT) study (TBCRC033): a randomized controlled trial

The excellent outcomes seen in patients treated with adjuvant trastuzumab emtansine (T-DM1) in the ATEMPT trial and the favorable toxicity profile associated with this agent make T-DM1 a potential therapeutic option for select patients with stage I HER2-positive breast cancer. Moreover, T-DM1 is an established adjuvant treatment for patients with HER2-positive breast cancer with the residual invasive disease after neoadjuvant therapy. Given that cardiotoxicity is the most significant adverse event of trastuzumab, which is a main molecular component of T-DM1, we conducted a sub-analysis of the ATEMPT trial to determine the cardiac safety of adjuvant T-DM1. In this analysis, the incidence of grade 3–4 left ventricular systolic dysfunction (LVSD) in T-DM1 or trastuzumab plus paclitaxel arms were respectively 0.8 and 1.8%. In addition, three (0.8%) patients in the T-DM1 arm and six (5.3%) patients in the adjuvant paclitaxel with trastuzumab (TH) arm experienced a significant asymptomatic left ventricular ejection fraction (LVEF) decline that per-protocol required holding T-DM1 or trastuzumab. All patients with available follow-up data experienced full resolution of cardiac symptoms and LVEF normalization. Furthermore, we performed an exploratory analysis to assess the relationship between age, baseline LVEF, and body mass index with cardiac outcomes. No significant association between these baseline characteristics and the incidence of significant asymptomatic LVEF decline or symptomatic LVSD was identified. The low incidence of significant cardiac adverse events in this population during therapy with adjuvant T-DM1 suggests that studies on the cost-effectiveness of cardiac monitoring during adjuvant therapy using anthracycline-free regimens are needed.

Clinical Trial Registration: ClinicalTrials.gov, NCT01853748

Optimum duration of adjuvant trastuzumab in treatment of human epidermal growth factor receptor-2 positive early breast cancer: protocol for a network meta-analysis of randomised controlled trials

INTRODUCTION

Controversy regarding optimum duration of trastuzumab treatment remains in patients with human epidermal growth factor receptor-2 (HER2) positive early breast cancer. The objective of applying network meta-analysis (NMA) is to integrate existing evidence based on direct and indirect comparisons of efficacy and safety, and then to determine the duration of trastuzumab treatments with the greatest impact on therapeutic outcomes in HER2-positive early breast cancers.

METHODS AND ANALYSIS

Electronic searching of trastuzumab treatments for early breast cancer by titles and abstracts will be conducted for the period from inception to 16 June 2019 in PubMed, Cochrane Library, Embase and ClinicalTrils.gov, as well as the annual meetings of San Antonio Breast Cancer Symposium (SABCS), European Society of Medical Oncology (ESMO) and American Society of Clinical Oncology (ASCO) online archives. The outcomes of interest are overall survival, disease-free survival, acceptability, cardiotoxicities and grade 3 to 4 non-haematological toxicities. Two independent reviewers will screen and extract eligible data based on the inclusion and exclusion criteria, and then assess the risk of bias and evidence quality of individual studies using Cochrane Collaboration's tool and Grades of Recommendation, Assessment, Development and Evaluation (GRADE). The heterogeneity, transitivity and inconsistency of NMA will be evaluated. In addition, we will perform subgroup and sensitivity analyses to assess the robustness and reliability of findings in our NMA.

ETHICS AND DISSEMINATION

Ethics approval is not required for our NMA. Findings from our NMA will be submitted as peer-reviewed journal manuscripts and international conference reports.

TRIAL REGISTRATION NUMBER

CRD42019139109.

Advances in EGFR/HER2-directed clinical research on breast cancer

The discovery of the HER2 molecules has embarked a series of investigations on the efficacy and safety of different types of anti-HER2 therapies for treating breast cancer, with the clinical pathway requiring a more detailed, more precise, and more dynamics therapeutic approaches due to the heterogeneity of the disease. As the "do more" and "do less" approaches are becoming more important to personalize treatment for early HER2-positive breast cancer, recent advances aim at tackling the advanced stage of the disease by using novel therapeutic agents and combination strategies. There are also important points of consideration on prognosis and choice of therapies, including HER2 gene copy number, HER2 heterogeneity, tissue biomarkers, blood-based biomarkers, and HER2 mutation and its treatment. Altogether, these could potentially play a vital role in the journey of HER2-positive breast cancer patient to achieve greater survival benefit and potentially a cure for the disease.

GRB7 dependent proliferation of basal-like, HER-2 positive human breast cancer cell lines is mediated in part by HER-1 signaling

GRB7 gene encodes a multi-domain signal transduction molecule and is part of the core of the HER-2 amplicon. GRB7 is commonly co-amplified and overexpressed with HER-2 in human breast cancer. This study addresses the role of GRB7 in HER-2 positive human breast cancers resistant to HER-2 targeted therapy. HCC1954, 21MT1, and JIMT1 are basal like HER-2 positive breast cancer cell lines based on expression profiling. These three cell lines are resistant to trastuzumab and lapatinib treatment. Knockdown of GRB7 protein expression with siRNA transfection as well as lentiviral vector mediated shRNA over-expression decreased the growth of HCC1954, 21MT1, and JIMT1 cells in vitro and the growth of tumor xenografts these cells formed in animal models. When assayed by ki-67 staining and TUNEL assay, the mechanism of reduced tumor xenograft growth appeared to be distinct. Reduced proliferation and increased apoptosis were seen in 21MT1 cells, while reduced proliferation was seen in HCC1954 cells and increased apoptosis in JIMT1 cells. Phospho-proteome profiling found HER-1 tyrosine phosphorylation was reduced with GRB7 knock down in JIMT1 cells. Immuno-blotting and immuno-precipitation experiments found HER-1 phosphorylation was reduced with GRB7 knock down in all three cell lines. HER-1 knock down via siRNA transient transfection as well as blocking HER-1 function with panitumumab decreased proliferation of all three cell lines in vitro. Our study finds that GRB7 has an essential growth promoting function which is mediated in part by HER-1 activation. The potential of HER-1 targeting in therapy resistant HER-2 positive breast cancer merits further study.