Supplementary Figure S1. Study design and tissue availability for biomarker analysis.

Supplementary Figure S4. Decision tree algorithm to construct the multiparameter classifier of response in TBCRC023.

Association between week 4 CM and disease status at first restaging after adjusting for CTC

Overall and within batch Coefficient of Variation for CM and each Gene.

Supplementary Figure S6. Distribution of HER2 gene ratio in relation to PIK3CA mutation status and HER2-enriched subtype.

Association between week 4 CM and disease status at first restaging after adjusting for CEA.

Supplementary Figure 2 displays the relationship between the week 8 CM level and the change in CM level (Week 8 – baseline). Figure S4B and C use box plots to display the relationship between disease status at first restaging and week 8 CM level or change in CM level (Week 8 – baseline).

Supplementary figure 4 displays time updates ROC curves for week 4 CM level using two additional methods (A) binary thresholding and (B) random forest.

Association between week8 CM and change in CM and disease status at first restaging.

Association between week 4 CM and PFS and OS

Supplementary Figure S2. Distribution of HER2 gene ratio and protein in the two neoadjuvant cohorts.

Supplementary figure 5 displays time updated ROC curves for (A) CM level at week 8, (B) Change in CM level (Week8 – Week4) and (C) the Combination of week 8 CM level and Change in CM level (Week 8-Week 4) using linear discriminant analysis.

Supplementary Figure 3 displays baseline CM level by disease status at first restaging.

Association between week 4 CM and disease status at first restaging after adjusting for CA27-29.

PURPOSELong-term outcomes of patients with stage I human epidermal growth factor receptor 2 (HER2)-positive breast cancer receiving adjuvant trastuzumab emtansine (T-DM1) remain undefined, and prognostic predictors represent an unmet need.METHODSIn the ATEMPT phase II trial, patients with stage I centrally confirmed HER2-positive breast cancer were randomly assigned 3:1 to adjuvant T-DM1 for 1 year or paclitaxel plus trastuzumab (TH). Coprimary objectives were to compare the incidence of clinically relevant toxicities between arms and to evaluate invasive disease-free survival (iDFS) with T-DM1. Correlative analyses included the HER2DX genomic tool, multiomic evaluations of HER2 heterogeneity, and predictors of thrombocytopenia.RESULTSAfter a median follow-up of 5.8 years, 11 iDFS events were observed in the T-DM1 arm, consistent with a 5-year iDFS of 97.0% (95% CI, 95.2 to 98.7). At 5 years, the recurrence-free interval (RFI) was 98.3% (95% CI, 97.0 to 99.7), the overall survival was 97.8% (95% CI, 96.3 to 99.3), and the breast cancer-specific survival was 99.4% (95% CI, 98.6 to 100). Comparable iDFS was observed with T-DM1 irrespective of tumor size, hormone receptor status, centrally determined HER2 immunohistochemical score, and receipt of T-DM1 for more or less than 6 months. Although ATEMPT was not powered for this end point, the 5-year iDFS in the TH arm was 91.1%. Among patients with sufficient tissue for HER2DX testing (n = 187), 5-year outcomes significantly differed according to HER2DX risk score, with better RFI (98.1% v 81.8%, hazard ratio [HR], 0.10, P = .01) and iDFS (96.3% v 81.8%, HR, 0.20, P = .047) among patients with HER2DX low-risk versus high-risk tumors, respectively.CONCLUSIONAdjuvant T-DM1 for 1 year leads to outstanding long-term outcomes for patients with stage I HER2-positive breast cancer. A high HER2DX risk score predicted a higher risk of recurrence in ATEMPT.

AbstractPurpose: The neutralizing peptibody trebananib prevents angiopoietin-1 and angiopoietin-2 from binding with Tie2 receptors, inhibiting angiogenesis and proliferation. Trebananib was combined with paclitaxel±trastuzumab in the I-SPY2 breast cancer trial. Patients and Methods: I-SPY2, a phase II neoadjuvant trial, adaptively randomizes patients with high-risk, early-stage breast cancer to one of several experimental therapies or control based on receptor subtypes as defined by hormone receptor (HR) and HER2 status and MammaPrint risk (MP1, MP2). The primary endpoint is pathologic complete response (pCR). A therapy “graduates” if/when it achieves 85% Bayesian probability of success in a phase III trial within a given subtype. Patients received weekly paclitaxel (plus trastuzumab if HER2-positive) without (control) or with weekly intravenous trebananib, followed by doxorubicin/cyclophosphamide and surgery. Pathway-specific biomarkers were assessed for response prediction. Results: There were 134 participants randomized to trebananib and 133 to control. Although trebananib did not graduate in any signature [phase III probabilities: Hazard ratio (HR)-negative (78%), HR-negative/HER2-positive (74%), HR-negative/HER2-negative (77%), and MP2 (79%)], it demonstrated high probability of superior pCR rates over control (92%–99%) among these subtypes. Trebananib improved 3-year event-free survival (HR 0.67), with no significant increase in adverse events. Activation levels of the Tie2 receptor and downstream signaling partners predicted trebananib response in HER2-positive disease; high expression of a CD8 T-cell gene signature predicted response in HR-negative/HER2-negative disease. Conclusions: The angiopoietin (Ang)/Tie2 axis inhibitor trebananib combined with standard neoadjuvant therapy increased estimated pCR rates across HR-negative and MP2 subtypes, with probabilities of superiority >90%. Further study of Ang/Tie2 receptor axis inhibitors in validated, biomarker-predicted sensitive subtypes is warranted.

Kaplan-Meier survival plot of pCR vs. non-pCR in both trebananib and control arms

RPPA endpoints and genes/signatures involved in TIE2 signaling that were studied

Trebananib vs Control pCR–Biomarker Associations