Pathologic and molecular responses to neoadjuvant trastuzumab and/or lapatinib from a phase II randomized trial in HER2-positive breast cancer (TRIO-US B07)

Abstract

In this multicenter, open-label, randomized phase II investigator-sponsored neoadjuvant trial with funding provided by Sanofi and GlaxoSmithKline (TRIO-US B07, Clinical Trials NCT00769470), participants with early-stage HER2-positive breast cancer (N = 128) were recruited from 13 United States oncology centers throughout the Translational Research in Oncology network. Participants were randomized to receive trastuzumab (T; N = 34), lapatinib (L; N = 36), or both (TL; N = 58) as HER2-targeted therapy, with each participant given one cycle of this designated anti-HER2 therapy alone followed by six cycles of standard combination chemotherapy with the same anti-HER2 therapy. The primary objective was to estimate the rate of pathologic complete response (pCR) at the time of surgery in each of the three arms. In the intent-to-treat population, we observed similar pCR rates between T (47%, 95% confidence interval [CI] 30-65%) and TL (52%, 95% CI 38-65%), and a lower pCR rate with L (25%, 95% CI 13-43%). In the T arm, 100% of participants completed all protocol-specified treatment prior to surgery, as compared to 69% in the L arm and 74% in the TL arm. Tumor or tumor bed tissue was collected whenever possible pre-treatment (N = 110), after one cycle of HER2-targeted therapy alone (N = 89), and at time of surgery (N = 59). Higher-level amplification of HER2 and hormone receptor (HR)-negative status were associated with a higher pCR rate. Large shifts in the tumor, immune, and stromal gene expression occurred after one cycle of HER2-targeted therapy. In contrast to pCR rates, the L-containing arms exhibited greater proliferation reduction than T at this timepoint. Immune expression signatures increased in all arms after one cycle of HER2-targeted therapy, decreasing again by the time of surgery. Our results inform approaches to early assessment of sensitivity to anti-HER2 therapy and shed light on the role of the immune microenvironment in response to HER2-targeted agents.

Conflict of interest statement

S.H. received contracted research and medical writing assistance from Ambrx, Amgen, Arvinas, Bayer, Daiichi-Sankyo, Genentech/Roche, GSK, Immunomedics, Lilly, Macrogenics, Novartis, Pfizer, OBI Pharma, Pieris, Puma, Radius, Sanofi, Seattle Genetics, and Dignitana. A.P. received institutional research support from Genentech, AstraZeneca, Immunomedics, Nektar, and Macrogenics. L.B. received honoraria from and/or was on the speaker bureau for AstraZeneca, Pfizer, Merck, Puma, Novartis, GlaxoSmithKline, Amgen, Johnson & Johnson, Genentech/Roche, Sandoz, Dendreon, and Genomic Health, and performed consulting work for Integra Connect and Anthem Blue Cross. A.M. is employed by Genentech/Roche and owns stock in Roche. M.P. received research support from Cepheid, was on the Scientific Advisory Board and received research support from Eli Lilly, Zymeworks, and Novartis, was a consultant for and received research support from Puma, and was on the Scientific Advisory Board for Biocartis. C.C. is a scientific advisor to GRAIL and reports stock options as well as consulting for GRAIL and Genentech. D.S. received research funding from Pfizer, Novartis, Syndax, Millenium Pharmaceuticals, Aileron Therapeutics, Bayer, and Genentech, owned stock in Biomarin, Amgen, Seattle Genetics, and Pfizer, served on the Board of Directors for BioMarin, and performed consulting/advisory board work for Eli Lilly, Novartis, Bayer, and Pfizer. The remaining authors declare no competing interests.

Figures

Fig. 1. TRIO-US B07 clinical trial participants.

130 participants were enrolled across three treatment arms. All participants received docetaxel plus carboplatin (TC) every 3 weeks. In addition, participants in Arm 1 received trastuzumab (TCH), Arm 2 received lapatinib (TCL), and Arm 3 received both trastuzumab and lapatinib (TCHL). Two participants withdrew from the study prior to starting any treatment, leaving 128 participants remaining in the intent to treat (ITT) population. Of 128 participants, 25 came off study treatment prior to surgery (10 in Arm 2, 15 Arm 3), leaving 103 participants included in the evaluable analysis.

Fig. 2. Characteristics of the cohort prior to treatment.

a Selected clinical and expression characteristics and tumor subtypes across the cohort. White squares reflect missing data. b Expression values of selected genes within the HER2 amplicon. c Pearson correlation coefficient matrix of key gene expression signatures. *P = 0.010 and **P = 0.012 for correlation with pCR (two-sided Wald test). d Distribution of ESR1 pathway gene expression scores (from ref. ) by HR subtype (top) and their correlation with immune scores (from ref. ) (bottom). FISH: fluorescent in situ hybridization; IHC: immunohistochemistry; TILs: tumor-infiltrating lymphocytes; HR: hormone receptor; pCR: pathologic complete response; IC; integrative subtype/integrative cluster.

Fig. 3. Tumor and microenvironmental changes on short-term HER2-targeted therapy.

a Subtype classifications (intrinsic and integrative) pre-treatment and after 14–21 days of HER2-targeted therapy. b Normalized enrichment scores from gene set enrichment analysis (GSEA) representing the degree of change of each gene set after 14–21 days of HER2-targeted therapy. Dotted lines separate those with FDR < 0.1. Black gene sets are Hallmark Molecular Signatures and blue gene sets were curated. c Pearson correlation coefficient matrix of single-sample GSEA (ssGSEA) scores. Ordering of gene sets is based on hierarchical clustering. Gene sets without labeled source in parentheses are Hallmark Molecular Signatures. d ER IHC H-score pre-treatment and after 14–21 days of HER2-targeted therapy correlate (r = 0.83) (left), and few tumors shift their ER H-score substantially (right) with treatment. e Change in proliferation ssGSEA scores after 14–21 days of HER2-targeted therapy by treatment arm. The mean drop in proliferation was highest with combination therapy, followed by lapatinib therapy (two-sided t test p = 0.28 compared to combination therapy), followed by trastuzumab therapy (p = 0.0087 compared to combination therapy; p = 0.13 compared to lapatinib). Centerline is median, box limits are upper and lower quartiles, whiskers are 1.5x the interquartile range, and empty points are outliers. f Change in percentage of cells positive for Ki67 by immunohistochemistry, pre-treatment to after 14–21 days of HER2-targeted therapy, stratified by treatment arm. P-values are from two-sided paired t-tests of the log-transformed Ki67 values. HR: hormone receptor; ER: estrogen receptor; H-score: histochemical score.

Fig. 4. Microenvironment changes across HER2-targeted therapy and chemotherapy.

a Normalized enrichment scores from gene set enrichment analysis (GSEA) representing the degree of change of each gene set at the time of surgery compared to pre-treatment. Dotted lines separate those with FDR < 0.1. b Normalized enrichment scores at surgery compared to pre-treatment (y-axis) vs after 14–21 days of HER2-targeted therapy compared to pre-treatment (x-axis). Dotted lines separate those with FDR < 0.1. Immune and some stromal sets increase after 14–21 days of HER2-targeted therapy but are reduced at the time of surgery. c Change in stromal TILs and inflammatory cell percentage across treatment. P-values are from two-sided paired t-tests, comparing on-treatment to pre-treatment (N = 55 for stromal TIL and N = 94 for inflammatory cells) and surgery to pre-treatment (N = 14 for stromal TIL and N = 78 for inflammatory cells). d Proportion of immune infiltrate represented by each immune cell subtype, according to CIBERSORT (top) and immunoStates (bottom). Pre-treatment (N = 89) is matched to on-treatment (N = 89); surgery (N = 59) is a subset. TIL: tumor-infiltrating lymphocytes.