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Background: Patients with pathologic complete response (pCR) to neoadjuvant chemotherapy for invasive breast cancer (BC) have better outcomes, potentially warranting less extensive surgical and systemic treatments. Early prediction of treatment response could aid in adapting therapies., Methods: On-treatment biopsies from 297 patients with invasive BC in three randomized, prospective neoadjuvant trials were assessed (GeparQuattro, GeparQuinto, GeparSixto). BC quantity, tumor-infiltrating lymphocytes (TILs), and the proliferation marker Ki-67 were compared to pre-treatment samples. The study investigated the correlation between residual cancer, changes in Ki-67 and TILs, and their impact on pathologic complete response (pCR) and disease-free survival (DFS)., Results: Among the 297 samples, 138 (46%) were hormone receptor-positive (HR+)/human epidermal growth factor 2-negative (HER2-), 87 (29%) were triple-negative (TNBC), and 72 (24%) were HER2+. Invasive tumor cells were found in 70% of on-treatment biopsies, with varying rates across subtypes (HR+/HER2-: 84%, TNBC: 62%, HER2+: 51%; p < 0.001). Patients with residual tumor on-treatment had an 8% pCR rate post-treatment (HR+/HER2-: 3%, TNBC: 19%, HER2+: 11%), while those without any invasive tumor had a 50% pCR rate (HR+/HER2-: 27%; TNBC: 48%, HER2+: 66%). Sensitivity for predicting residual disease was 0.81, with positive and negative predictive values of 0.92 and 0.50, respectively. Increasing TILs from baseline to on-treatment biopsy (if residual tumor was present) were linked to higher pCR likelihood in the overall cohort (OR 1.034, 95% CI 1.013-1.056 per % increase; p = 0.001) and with a longer DFS in TNBC (HR 0.980, 95% CI 0.963-0.997 per % increase; p = 0.026). Persisting or increased Ki-67 was associated with with lower pCR probability in the overall cohort (OR 0.957, 95% CI 0.928-0.986; p = 0.004) and shorter DFS in TNBC (HR 1.023, 95% CI 1.001-1.047; p = 0.04)., Conclusion: On-treatment biopsies can predict patients unlikely to achieve pCR post-therapy. This could facilitate therapy adjustments for TNBC or HER2 + BC. They also might offer insights into therapy resistance mechanisms. Future research should explore whether standardized or expanded sampling enhances the accuracy of on-treatment biopsy procedures. Trial registration GeparQuattro (EudraCT 2005-001546-17), GeparQuinto (EudraCT 2006-005834-19) and GeparSixto (EudraCT 2011-000553-23)., (© 2024. The Author(s).)

Purpose: The PI3K signaling pathway is frequently dysregulated in breast cancer, and mutations in PIK3CA are relevant for therapy resistance in HER2-positive (HER2pos) breast cancer. Mutations in exons 9 or 20 may have different impacts on response to neoadjuvant chemotherapy-based treatment regimens., Experimental Design: We investigated PIK3CA mutations in 1,691 patients with early breast cancer who were randomized into four neoadjuvant multicenter trials: GeparQuattro (NCT00288002), GeparQuinto (NCT00567554), GeparSixto (NCT01426880), and GeparSepto (NCT01583426). The role of different PIK3CA exons and hotspots for pathologic complete response (pCR) following neoadjuvant chemotherapy (NACT) and patient survival were evaluated for distinct molecular subgroups and anti-HER2 treatment procedures., Results: A total of 302 patients (17.9%) of the full cohort of 1,691 patients had a tumor with a PIK3CA mutation, with a different prevalence in molecular subgroups: luminal/HER2-negative (HER2neg) 95 of 404 (23.5%), HER2pos 170 of 819 (20.8%), and triple-negative breast cancer 37 of 468 patients (7.9%). We identified the mutations in PIK3CA exon 20 to be linked with worse response to anti-HER2 treatment (OR = 0.507; 95% confidence interval, 0.320-0.802; P = 0.004), especially in hormone receptor-positive HER2-positive breast cancer (OR = 0.445; 95% confidence interval, 0.237-0.837; P = 0.012). In contrast, exon 9 hotspot mutations p.E452K and p.E545K revealed no noteworthy differences in response therapy. Luminal/HER2neg patients show a trend to have worse treatment response when PIK3CA was mutated. Interestingly, patients with residual disease following neoadjuvant treatment had better survival rates when PIK3CA was mutated., Conclusions: The PIK3CA hotspot mutation p.H1047R is associated with worse pCR rates following NACT in HER2pos breast cancer, whereas hotspot mutations in exon 9 seem to have less impact., (©2024 American Association for Cancer Research.)

Background: The PENELOPE-B study demonstrated that the addition of 1-year post-neoadjuvant palbociclib to endocrine therapy (ET) in patients with high-risk early breast cancer (BC) did not improve invasive disease-free survival (iDFS) compared to placebo. Here, we report results for premenopausal women., Patients and Methods: Patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative BC at high risk of relapse [defined as no pathological complete response after neoadjuvant chemotherapy and a clinical, pathological stage, estrogen receptor, grading (CPS-EG) score ≥3 or 2/ypN+] were randomized to receive 13 cycles of palbociclib or placebo + standard ET. Ovarian function (OF) was evaluated by centrally assessed estradiol, follicle-stimulating hormone and anti-Müllerian hormone serum levels., Results: Overall, 616 of 1250 randomized patients were premenopausal; of these, 30.0% were <40 years of age, 47.4% had four or more metastatic lymph nodes, and 58.2% had a CPS-EG score ≥3. 66.1% of patients were treated with tamoxifen alone, and 32.9% received ovarian function suppression (OFS) in addition to either tamoxifen or aromatase inhibitor (AI). After a median follow-up of 42.8 months (97.2% completeness) no difference in iDFS between palbociclib and placebo was observed [hazard ratio = 0.95, 95% confidence interval (CI) 0.69-1.30, P = 0.737]. The estimated 3-year iDFS rate was marginally higher in the palbociclib arm (80.6% versus 78.3%). Three year iDFS was higher in patients receiving AI than tamoxifen plus OFS or tamoxifen alone (86.0% versus 78.6% versus 78.0%). Patients receiving tamoxifen plus OFS showed a favorable iDFS with palbociclib (83.0% versus 74.1%, hazard ratio = 0.52, 95% CI 0.27-1.02, P = 0.057). Hematologic adverse events were more frequent with palbociclib (76.1% versus 1.9% grade 3-4, P < 0.001). Palbociclib seems not to negatively impact the OF throughout the treatment period., Conclusions: In premenopausal women, who received tamoxifen plus OFS as ET, the addition of palbociclib to ET results in a favorable iDFS. The safety profile seems favorable and in contrast to chemotherapy palbociclib does not impact OF throughout the treatment period., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Current clinical guidelines suggest that breast cancers with low hormone receptor expression (LowHR) in 1-10% of tumor cells should be regarded as hormone receptor positive. However, clinical data show that these patients have worse outcome compared to patients with hormone receptor expression above 10%. We performed DNA methylation profiling on 23 LowHR breast cancer specimens, including 13 samples with HER2 amplification and compared our results with a reference breast cancer cohort from The Cancer Genome Atlas to clarify the status for this infrequent but important patient subgroup., Results: In unsupervised clustering and dimensionality reduction, breast cancers with low hormone receptor expression that lacked HER2 amplification usually clustered with triple negative breast cancer (TNBC) reference samples (8/10; "LowHR TNBC-like"). In contrast, most specimens with low hormone receptor expression and HER2 amplification grouped with hormone receptor positive cancers (11/13; "LowHR HRpos-like"). We observed highly similar DNA methylation patterns of LowHR TNBC-like samples and true TNBCs. Furthermore, the Ki67 proliferation index of LowHR TNBC-like samples and clinical outcome parameters were more similar to TNBCs and differed from LowHR HRpos-like cases., Conclusions: We here demonstrate that LowHR breast cancer comprises two epigenetically distinct groups. Our data strongly suggest that LowHR TNBC-like samples are molecularly, histologically and clinically closely related to TNBC, while LowHR HRpos-like specimens are closely related to hormone receptor positive tumors., (© 2021. The Author(s).)

Purpose: Assessment of HER2 overexpression using immunohistochemistry (IHC) and/or in situ hybridisation (ISH) for the detection of HER2 amplifications is standard to identify patients for established HER2-directed treatments. Patients with lower HER2 expression levels have recently also become candidates for novel therapies targeting HER2. This study aimed to assess tumour and patient characteristics and prognosis in patients with advanced breast cancer (aBC), relative to low HER2 expression levels., Methods: PRAEGNANT is a prospective aBC registry (NCT02338167), focusing on molecular biomarkers. Patients in all therapy lines receiving any kind of treatment are eligible. This analysis includes patients with conventionally HER2-negative aBC. Clinical outcome was compared in the groups with no (IHC score 0) or with low HER2 expression (IHC 1+, or IHC 2+/ISH negative)., Results: Low HER2 expression levels in triple-negative aBC patients did not influence progression-free survival. Overall survival appeared poorer in patients with IHC 2+ compared with patients with no HER2 expression in the unadjusted analysis (hazard ratio 2.24, 95% confidence interval 0.1.12-4.47). However, this effect was not maintained in the adjusted analysis. In HER2-negative, hormone receptor-positive patients, low HER2 expression appeared to have no effect on prognosis, neither progression-free survival nor overall survival., Conclusions: We could not demonstrate that HER2 expression at a low level and assessed in clinical routine can differentiate patients into prognostic groups. However, the prevalence of patients with a low expression makes this population interesting for clinical trials with potentially active treatments using HER2 as a target., Competing Interests: Conflict of interest statement The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: A.D.H. has received honoraria from Teva, GenomicHealth, Celgene, AstraZeneca, Novartis, Pfizer and Roche; J.E. has received honoraria from AstraZeneca, Daiichi-Sankyo, Eisai, Lilly, Novartis, Pierre Fabre, Roche and Pfizer; M.P.L. has received honoraria from Pfizer, Lilly, Roche, MSD, Hexal, Novartis, AstraZeneca, Eisai, medac and Exact Sciences for advisory boards, lectures and travel support; B.V. has received honoraria from Novartis; F.A.T. has received honoraria from Hexal, Novartis, Tesaro and travel expenses from GSK; F.O. received speaker and consultancy honoraria from Amgen, AstraZeneca, Bayer, BMS, Boehringer, Celgene, Cellex, Chugai, Gilead, Hexal, Ipsen, Janssen-Cilag, Merck, MSD, Novartis, Riemser, Roche, Tesaro and Teva; P.H. received honoraria, unrestricted educational grants and research funding from Amgen, AstraZeneca, Eli Lilly, MSD, Novartis, Pfizer and Roche; H.T. has received honoraria from Novartis, Roche, Celgene, TEVA and Pfizer, and travel support from Roche, Celgene and Pfizer; J.E. has received honoraria from AstraZeneca, Daiichi-Sankyo, Eisai, Lilly, Novartis, Pierre Fabre, Roche and Pfizer; D.L. has received honoraria from Amgen, Eli Lilly, Pfizer, Roche, MSD, Hexal, Novartis, AstraZeneca, TEVA, Celgene, Eisai, and Loreal. M.W. has received speaker honoraria from AstraZeneca, Celgene and Novartis; V.M. has received speaker honoraria from Amgen, AstraZeneca, Daiichi-Sankyo, Eisai, Pfizer, MSD, Novartis, Roche, Teva, Seattle Genetics and consultancy honoraria from Genomic Health, Hexal, Roche, Pierre Fabre, Amgen, ClinSol, Novartis, MSD, Daiichi-Sankyo, Eisai, Lilly, Tesaro and Nektar; E.B. has received honoraria from Novartis, Pfizer, Amgen, Daiichi-Sankyo and onkowissen.de; C.H. has received honoraria from Roche Pharma, Pfizer, AstraZeneca, Novartis and Onkovis; C.M.K. received honoraria from Amgen, Axios, Roche, Teva, Novartis, MSD Sharp & Dohme, Mundipharma, NewCo, Pfizer, Riemser and ZytoService, research grants from Amgen, Axios, Novartis, MSD Sharp & Dohme, NewCo, Pfizer and ZytoService, and travel support from Amgen, Paxman Inc., PharmaMar and Pfizer; R.W. has received honoraria from Amgen, AstraZeneca, Celgene, Daiichi-Sankyo, Esai, Exact Science, Nanostring, GSK, Hexal, Lilly, MSD, Mundipharma, Novartis, Odonate, Pfizer, Pierre Fabre, Riemser, Roche, Sandoz, Seattle Genetics, Tesaro Bio, Teva and Viatris; C.T. has received honoraria from Roche, Daiichi-Sankyo and AstraZeneca; M.U. has received honoraria from Abbvie, Amgen, AstraZeneca, BMS, Celgene, Daiichi-Sankyo, Eisai, Lilly Deutschland, Lilly Int., MSD Merck, Mundipharma, Myriad Genetics, Odonate, Pfizer, PUMA Biotechnology, Roche Pharma, Sanofi Aventis Deutschland, TEVA Pharmaceuticals Ind Ltd, Novartis, Pierre Fabre, Clovis Oncology and Seattle Genetics; P.A.F. received honoraria from Novartis, Pfizer, Roche, Amgen, Celgene, Daiichi-Sankyo, AstraZeneca, Merck-Sharp & Dohme, Eisai, Puma and Teva, his institution conducts research with funding from Novartis and Biontech; W.J. has received honoraria and research grants from Sanofi-Aventis, Novartis, Lilly, Pfizer, Roche, Chugai, AstraZeneca, MSD and Daiichi-Sankyo; T.N.F. has received honoraria from Novartis, Roche, Pfizer, TEVA, Diachii Sankyo, AstraZeneca and MSD; S.Y.B. has received honoraria from Roche Pharma, Novartis, Pfizer, MSD, Teva and AstraZeneca. A.S. has received honoraria from Roche, AstraZeneca, Aurikamed GmbH, Celgene, ClinSol Research GmbH, Connectmedica Sp.Z o.o., Deutsche Gesellschaft für Senologie GmbH, if-kongress management gmbh, I-MED Institute GmbH, Lilly Deutschland GmbH, Medicultus GmbH, med publico GmbH, MSD Sharp & Dohme GmbH, onkowissen.de GmbH, Pfizer GmbH, Schattauer Verlag GmbH, Promedicis GmbH, Tesaro Bio Germany GmbH and W. Zuckschwerdt Verlag GmbH; H.-C.K. has received honoraria from Carl Zeiss Meditec, Theraclion, Novartis, Amgen, AstraZeneca, Pfizer, GSK, SurgVision, Onkowissen and Genomic Health/Exact Sciences, travel support from Tesaro and Daiichi-Sankyo and holds stock of Theraclion and Phaon scientific. All remaining others (A.H., L.H., L.A.W., M.W.B., P.W., D.W.) have declared that they do not have any conflicts of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Treatment of HER2-positive early breast cancer (EBC) continues to evolve with neoadjuvant (pre-operative) and adjuvant (post-operative) HER2-targeted therapies as standard of care. There are two important decision points. The first involves deciding between neoadjuvant therapy or proceeding directly to surgery. Neoadjuvant chemotherapy (NACT) plus pertuzumab-trastuzumab is appropriate for patients with high-risk HER2-positive EBC (tumour diameter ≥2 cm, and/or node-positive disease). Patients with node-negative disease and tumour diameter <2 cm are candidates for upfront surgery followed by paclitaxel for 12 weeks plus 18 cycles of trastuzumab, with the option to add pertuzumab (if pN+). The second decision point involves the pathohistological result at surgery after neoadjuvant therapy. Total pathological complete response (tpCR: ypT0/is, ypN0) is associated with improved survival endpoints. Patients with tumours ≥2 cm and/or node-positive disease at diagnosis who have a tpCR after dual blockade should continue pertuzumab-trastuzumab in the adjuvant setting to complete 1 year (18cycles) of treatment. For patients with invasive residual disease, 14cycles of post-neoadjuvant trastuzumab emtansine (T-DM1) therapy significantly increases invasive-DFS compared with trastuzumab. Extended adjuvant therapy with neratinib is an option in selected patients (HER2-positive and oestrogen receptor [ER]-positive) who have completed adjuvant trastuzumab-based therapy. Less aggressive chemotherapy regimens are recommended in populations with a lower risk of recurrence (patients with small tumours without axillary involvement; patients unlikely to tolerate anthracycline-taxane or taxane-carboplatin regimens). Ultimately, treatment recommendations should be consistent with local and international guidelines. Further studies will guide optimisation of treatment for patients with HER2-positive EBC according to the risk of disease recurrence., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The development of anti-HER2 antibody-drug conjugates opens new therapeutic options for patients with breast cancer, including patients with low expression of HER2. To characterise this new breast cancer subtype, we have compared the clinical and molecular characteristics of HER2-low-positive and HER2-zero breast cancer, including response to neoadjuvant chemotherapy and prognosis., Methods: In this pooled analysis of individual patient data, we evaluated a cohort of 2310 patients with HER2-non-amplified primary breast cancer that were treated with neoadjuvant combination chemotherapy in four prospective neoadjuvant clinical trials (GeparSepto, NCT01583426; GeparOcto, NCT02125344; GeparX, NCT02682693; Gain-2 neoadjuvant, NCT01690702) between July 30, 2012, and March 20, 2019. Central HER2 testing was done prospectively before random assignment of participants in all trials. HER2-low-positive status was defined as immunohistochemistry (IHC) 1+ or IHC2+/in-situ hybridisation negative and HER2-zero was defined as IHC0, based on the American Society of Clinical Oncology/College of American Pathologists guidelines. Disease-free survival and overall survival data were available for 1694 patients (from all trials except GeparX) with a median follow-up of 46·6 months (IQR 35·0-52·3). Bivariable and multivariable logistic regression models and Cox-proportional hazards models were performed based on a predefined statistical analysis plan for analysis of the endpoints pathological complete response, disease-free survival, and overall survival., Findings: A total of 1098 (47·5%) of 2310 tumours were HER2-low-positive and 1212 (52·5%) were HER2-zero. 703 (64·0%) of 1098 patients with HER2-low-positive tumours were hormone receptor positive, compared with 445 (36·7%) of 1212 patients with HER2-zero tumours (p<0.0001). HER2-low-positive tumours had a significantly lower pathological complete response rate than HER2-zero tumours (321 [29·2%] of 1098 vs 473 [39·0%] of 1212, p=0·0002). Pathological complete response was also significantly lower in HER2-low-positive tumours versus HER2-zero tumours in the hormone receptor-positive subgroup (123 [17·5%] of 703 vs 105 [23·6%] of 445, p=0·024), but not in the hormone receptor-negative subgroup (198 [50·1%] of 395 vs 368 [48·0%] of 767, p=0·21). Patients with HER2-low-positive tumours had significantly longer survival than did patients with HER2-zero tumours (3-year disease-free survival: 83·4% [95% CI 80·5-85·9] vs 76·1% [72·9-79·0]; stratified log-rank test p=0·0084; 3-year overall survival: 91·6% [84·9-93·4] vs 85·8% [83·0-88·1]; stratified log-rank test p=0·0016). Survival differences were also seen in patients with hormone receptor-negative tumours (3-year disease-free survival: 84·5% [95% CI 79·5-88·3] vs 74·4% [70·2-78.0]; stratified log-rank test p=0·0076; 3-year overall survival: 90·2% [86·0-93·2] vs 84·3% [80·7-87·3], stratified log-rank test p=0·016), but not in patients with hormone receptor-positive tumours (3-year disease-free survival 82·8% [79·1-85·9] vs 79·3% [73·9-83·7]; stratified log-rank test p=0·39; 3-year overall survival 92·3% [89·6-94·4] vs 88·4% [83·8-91·8]; stratified log-rank test p=0·13)., Interpretation: Our results show that HER2-low-positive tumours can be identified as new subgroup of breast cancer by standardised IHC, distinct from HER2-zero tumours. HER2-low-positive tumours have a specific biology and show differences in response to therapy and prognosis, which is particularly relevant in therapy-resistant, hormone receptor-negative tumours. Our results provide a basis for a better understanding of the biology of breast cancer subtypes and the refinement of future diagnostic and therapeutic strategies., Funding: German Cancer Aid (Deutsche Krebshilfe)., Competing Interests: Declaration of interests CD reports grants from European Commission H2020, German Cancer Aid Translational Oncology, German Breast Group, during the conduct of the study; personal fees from Novartis, Roche, MSD Oncology, Daiichi Sankyo, AstraZeneca, Molecular Health, and Merck, and grants from Myriad, outside the submitted work. CD is the cofounder of Sividon diagnostics. CD has a patent VMScope digital pathology software with royalties paid, a patent WO2020109570A1-cancer immunotherapy pending, and a patent WO2015114146A1 and WO2010076322A1-therapy response issued. AS reports grants from Celgene, Roche, and AbbVie; personal fees from Roche, AstraZeneca, Celgene, Novartis, MSD, Tesaro, Lilly, and Roche, outside the submitted work. TL receives payment or honoraria from Tesaro, MSD, Roche, Novartis, Pfizer, Amgen, Clovis, and Lilly; receives support for travel costs from Roche, Pfizer, MSD, Celgene, and Clovis; reports participation on an Advisory Board from Roche, Tesaro, Amgen, MSD, Pfizer, Lilly, Myriad, Esai, and GSK, outside the submitted work. J-UB reports personal fees from AstraZeneca, Exact Sciences, Amgen, MSD Oncology, Lilly, Novartis, Sysmex, Roche, and Sonoscape, outside the submitted work. PW reports personal fees from Amgen, AstraZeneca, MSD, Novartis, Pfizer, PharmaMar, Roche, Teva, Eisai, Clovis, and Tesaro, outside the submitted work. HT reports consulting fees and travel costs from Pierre Fabre, Pfizer Pharma, Mundipharma, ClinSol, Novartis, Lilly, Grünenthal, Vifor, AstraZeneca, Mylan, and AMGEN; payment or honoraria from Vifor, Novartis, AstraZeneca, ClinSol, Mundipharma, Lilly, and Amgen; participation on an Advisory Board from Novartis, Bristol Myers Squibb, AstraZeneca, Molecular Health, Pfizer, Roche, Grünenthal, and Mylan; and is part of a leadership or fiduciary role in Arbeitskreis klinische Studien. ASCO, BNHO, DGHO, DKG, ESMO, Deutsche Gesellschaft für Senelogie. CJ receives payment or honoraria from Roche, AstraZeneca, Novartis, Lilly, Exact Sciences, and Pierre Fabre; recieves support for travel costs from Roche and AstraZeneca, reports participation on an Advisory Board from Roche, Lilly, and AstraZeneca. MR reports consulting fees from Roche, Novartis, Lilly, and Somatex; receives payment or honoraria from Novartis, Roche, Lilly, Somatex, and AstraZeneca; recieves support for travel costs from Novartis, Pfizer, and Celgene. EFS receives payment or honoraria from AstraZeneca, Pfizer, Celgene, Roche, and Amgen; support for travel costs from Amgen, AstraZeneca, Celgene, Clovis Oncology, Eisai, Erbe, Gedeon, Richter, Genomic Health, Jenapharm, Johnson Johnson, KLS Martin, Matramed, Medac, Mentor, Novartis, Pfizer, Pharma Mar, MSD, Roche, Samsung, Storz, Tewa, Vifor, Medconcept, and Thieme; is part of a leadership or fiduciary role of University of Saarland, Germany, society for German Gynecological Endoscopy. CH reports personal fees from Pfizer, Roche, Novartis, Lilly, AstraZeneca, Celgene, outside the submitted work. PAF reports personal fees from Novartis, Pfizer, Daiichi-Sankyo, AstraZeneca, Eisai, Merck Sharp & Dohme, Lilly, Pierre Fabre, Seattle Genetics, Roche, and Hexal, and grants from Biontech and Cepheid, during the conduct of the study. KL receives payment from Roche, Pfizer, MSD, Novartis, Lilly, and Genomic Health, support for travel costs from Roche, and reports participation on an Advisory Board from Roche, MSD, and Esai. JH reports research grants to institution from Celgene, Novartis, and Hexal; consulting fees from Lilly, Novartis, Roche, Pfizer, Hexal, AstraZeneca, MSD, Celgene, and Abbvie; receives payment from Lilly, Novartis, Roche, Pfizer, AstraZeneca, MSD, Celgene, Eisai, and Abbvie; recieves support for travel costs from Roche, Pfizer, Novartis, Celgene, and Daiichi. TR reports consulting fees from Pfizer, honoraria for presentations from AstraZeneca and receives payment from Pfizer, Roche, and Novartis. MS reports grants from AstraZeneca, BioNtech, Eisai, German Breast Group, Genentech, Novartis, Pantarhei Bioscience, Pfizer, Pierre Fabre, and Roche; consulting fees from AstraZeneca, Eisai, Lilly, Novartis, Pantarhei Bioscience, Pfizer, Pierre Fabre, Roche, and SeaGen; receives payment or honoraria from AstraZeneca, Novartis, Pfizer, Roche, and SeaGen; support for travel costs from Pfizer and Roche; has planned patents, issued or pending from EP 2951317 B1 and EP 2390370 B1; reports participation on an Advisory Board from AstraZeneca, Eisai, Lilly, Novartis, Pantarhei Bioscience, Pfizer, Pierre Fabre, Roche, and SeaGen; medical writing support from Roche. WJ reports grants and personal fees from Sanofi-Aventis, Novartis, Lilly, Pfizer, Roche, Chugai, AstraZeneca, MSD, and Daiichi Sankyo, during the conduct of the study. ES reports consulting fees from Roche and AstraZeneca; receives payment or honoraria from Roche, Pfizer, Novartis, and Astra Zeneca; support for travel costs from Roche, Pfizer, and Daiko. SSe reports reimbursement of travel costs from Novartis and personal fees from Roche, Mundipharma, and Amgen, outside the submitted work. MU reports personal fees and non-financial support from Abbvie, Amgen, AstraZeneca, Celgene, Daiichi Sankyo, Eisai, Lilly Int, MSD Merck, Mundipharma, Myriad Genetics, Odonate, Pfizer, Roche Pharma, Sanofi Aventis Deutschland, TEVA Pharmaceuticals, Novartis, and Clovis Oncology; personal fees from Bristol Myers Squibb, Lilly Deutschland, PUMA Biotechnology, Pierre Fabre, Seattle Genetics, outside the submitted work. SL reports grants or fundings from Amgen, AstraZeneca, Celgene, Novartis, Immunomedics, Pfizer, Roche, DSI Trevor, Vifor, Abbvie, Cepheid, Seagen, and VM Scope; receives payment or honoraria from AstraZeneca, Roche, Novartis, Pfizer, Prime/Medscape, Puma, and Samsung; has planned patents, issued or pending from EP14153692.0; reports participation on an Advisory Board from Amgen, AstraZeneca, DSI, Roche, Merck, Pfizer, BMS, SeaGen, Eirgenix, Celgene, Abbvie, Lilly, GlaxoSmithKline, and Pierre Fabre; is part of a leadership or fiduciary role from BIG. All other authors report no conflicts of interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Purpose: About one third of patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer who have residual invasive disease after neoadjuvant chemotherapy (NACT) will relapse. Thus, additional therapy is needed. Palbociclib is a cyclin-dependent kinase 4 and 6 inhibitor demonstrating efficacy in the metastatic setting., Patients and Methods: PENELOPE-B (NCT01864746) is a double-blind, placebo-controlled, phase III study in women with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary breast cancer without a pathological complete response after taxane-containing NACT and at high risk of relapse (clinical pathological staging-estrogen receptor grading score ≥ 3 or 2 and ypN+). Patients were randomly assigned (1:1) to receive 13 cycles of palbociclib 125 mg once daily or placebo on days 1-21 in a 28-day cycle in addition to endocrine therapy (ET). Primary end point is invasive disease-free survival (iDFS). Final analysis was planned after 290 iDFS events with a two-sided efficacy boundary P < .0463 because of two interim analyses., Results: One thousand two hundred fifty patients were randomly assigned. The median age was 49.0 years (range, 19-79), and the majority were ypN+ with Ki-67 ≤ 15%; 59.4% of patients had a clinical pathological staging-estrogen receptor grading score ≥ 3. 50.1% received aromatase inhibitor, and 33% of premenopausal women received a luteinizing hormone releasing hormone analog in addition to either tamoxifen or an aromatase inhibitor. After a median follow-up of 42.8 months (92% complete), 308 events were confirmed. Palbociclib did not improve iDFS versus placebo added to ET-stratified hazard ratio, 0.93 (95% repeated CI, 0.74 to 1.17) and two-sided weighted log-rank test (Cui, Hung, and Wang) P = .525. There was no difference among the subgroups. Most common related serious adverse events were infections and vascular disorders in 113 (9.1%) patients with no difference between the treatment arms. Eight fatal serious adverse events (two palbociclib and six placebo) were reported., Conclusion: Palbociclib for 1 year in addition to ET did not improve iDFS in women with residual invasive disease after NACT., Competing Interests: Sibylle LoiblHonoraria: Chugai PharmaConsulting or Advisory Role: Pfizer, Roche, Novartis, Seattle Genetics, Celgene, Lilly, AstraZeneca/MedImmune, Bristol-Myers Squibb, Merck KGaA, Abbvie, Amgen, Prime/Medscape, Daiichi Sankyo, Samsung, Puma Biotechnology, Pierre Fabre, Immunomedics, GlaxoSmithKline, EirGenix, BayerResearch Funding: Abbvie, AstraZeneca, Vifor Pharma, Amgen, Celgene, Novartis, Pfizer, Roche, Myriad Genetics, Immunomedics, Seattle Genetics, Daiichi Sankyo, Pierre FabrePatents, Royalties, Other Intellectual Property: Patent Pending EP14153692.0 Frederik MarméHonoraria: Roche/Genentech, Novartis, Pfizer, AstraZeneca, Tesaro, Clovis Oncology, Clovis Oncology, Eisai, Celgene, Genomic Health, PharmaMar, Amgen, CureVac, MSD Oncology, Janssen-Cilag, Immunomedics, Seagen, Myriad GeneticsConsulting or Advisory Role: AstraZeneca, Tesaro, Pfizer, Roche, Novartis, Genomic Health, CureVac, Amgen, Vaccibody, Immunomedics, Celgene, Eisai, Janssen-Cilag, Immunomedics, ImmunomedicsResearch Funding: Roche/Genentech, Novartis, AstraZeneca, Eisai, Tesaro, Tesaro, Tesaro, Clovis Oncology, MSD Oncology, VaccibodyTravel, Accommodations, Expenses: Roche, Roche, Pfizer, Novartis, PharmaMar, AstraZeneca Miguel MartinHonoraria: Roche/Genentech, Lilly, Pfizer, Novartis, Pierre FabreConsulting or Advisory Role: Roche/Genentech, Novartis, Pfizer, Lilly, AstraZeneca, Taiho Pharmaceutical, PharmaMarSpeakers' Bureau: Lilly/ImClone, Lilly/ImClone, Roche/Genentech, Pierre FabreResearch Funding: Novartis, Roche, Puma Biotechnology Michael UntchHonoraria: AstraZeneca, Art tempi, Bristol-Myers Squibb, Celgene, Daiji Sankyo, Roche Pharma AG, Pfizer, Mundipharma, MSD Oncology, Pierre Fabre, Sanofi, Seattle Genetics, AgendiaConsulting or Advisory Role: Amgen, Abbvie, Celgene, Lilly, Mundipharma, Novartis, MSD Oncology, Pfizer, Roche Pharma AG, Agendia, Pierre Fabre, Seattle Genetics Hervé BonnefoiHonoraria: RocheResearch Funding: BayerTravel, Accommodations, Expenses: Roche, Pfizer Sung-Bae KimHonoraria: DAEHWA Pharmaceutical, ISU ABXISConsulting or Advisory Role: Lilly, AstraZeneca, DAEHWA Pharmaceutical, ISU AbxisResearch Funding: Novartis, Dongkook Pharma, Genzyme Harry BearStock and Other Ownership Interests: Abbvie, Pfizer, ViatrisHonoraria: Genomic Health, MerckConsulting or Advisory Role: Merck, RNADxSpeakers' Bureau: Genomic HealthResearch Funding: MerckTravel, Accommodations, Expenses: MerckOpen Payments Link: https://openpaymentsdata.cms.gov/physician/691364 Nicole McCarthyConsulting or Advisory Role: Roche, Pfizer, Novartis, LillyTravel, Accommodations, Expenses: Novartis Karen GelmonHonoraria: AstraZeneca, Merck Sharp & DohmeConsulting or Advisory Role: Pfizer, Novartis, Astrazeneca, Merck, Lilly, Bristol-Myers Squibb, NanoString Technologies, Genomic Health, Janssen Oncology, Roche, MylanResearch Funding: Pfizer, Bristol-Myers Squibb, AstraZeneca, RocheExpert Testimony: Genentech José Angel García-SáenzConsulting or Advisory Role: Novartis, AstraZeneca, Lilly, Seagen, Daiichi Sankyo, Eisai, MSDResearch Funding: AstraZenecaTravel, Accommodations, Expenses: Roche, Novartis Catherine M. KellyHonoraria: Roche, Pfizer, Novartis, MSD Oncology, Exact Sciences, Daiichi Sankyo Europe GmbHTravel, Accommodations, Expenses: Roche, pfizer Toralf ReimerConsulting or Advisory Role: PfizerResearch Funding: Else Kröner-Fresenius-Stiftung, German Cancer AidOther Relationship: Pfizer Masakazu ToiHonoraria: Novartis, TAKEDA, AstraZeneca, Eisai, Chugai Pharma, Taiho Pharmaceutical, Daiichi Sankyo, Yakult Pharmaceutical, Shimadzu, Pfizer, Konica Minolta, Lilly, Kyowa Kirin, Devicore medical Japan, Exact Sciences, Nippon KayakuConsulting or Advisory Role: Daiichi Sankyo, Kyowa Kirin, Bertis, Athenex, Bristol-Myers Squibb, Kansai Medical Net, Terumo, Luxonus, Luxonus, AstraZeneca, LillySpeakers' Bureau: Pfizer, AstraZeneca, Lilly, Daiichi SankyoResearch Funding: Taiho Pharmaceutical, Chugai Pharma, Shimadzu, Astellas Pharma, AFI technology, Japan Breast Cancer Research Group, Pfizer, Eisai, Daiichi Sankyo, AstraZeneca, Ono Pharmaceutical, Nippon Kayaku, Kyoto Breast cancer Research NetworkPatents, Royalties, Other Intellectual Property: JP 2017-143763 WO2017/131162A1, PCT/JP2016/004374Travel, Accommodations, Expenses: Eisai, TakedaOther Relationship: Japan Breast Cancer Research Group, Kyoto Breast Cancer Research Network, Organization for Oncology and Translational Research Hope S. RugoConsulting or Advisory Role: Samsung, Celltrion, Puma BiotechnologyResearch Funding: Macrogenics, OBI Pharma, Eisai, Pfizer, Novartis, Lilly, Genentech, Merck, Immunomedics, Odonate Therapeutics, Daiichi Sankyo, Seattle GeneticsTravel, Accommodations, Expenses: Pfizer, Novartis, Macrogenics, Mylan, Daiichi Sankyo, AstraZeneca SpainOpen Payments Link: https://openpaymentsdata.cms.gov/summary Carsten DenkertStock and Other Ownership Interests: Sividon Diagnostics (now Myriad)Honoraria: Novartis, RocheConsulting or Advisory Role: MSD Oncology, Daiichi Sankyo, Molecular HealthResearch Funding: Myriad GeneticsPatents, Royalties, Other Intellectual Property: VMScope digital pathology software, Patent application: EP18209672—cancer immunotherapy, Patent application EP20150702464—therapy response, Patent application EP20150702464—therapy responseTravel, Accommodations, Expenses: Roche Michael GnantEmployment: SandozHonoraria: Celgene, Roche, Novartis, AstraZeneca, Amgen, NanoString Technologies, Lilly, Medison, PfizerConsulting or Advisory Role: AstraZeneca, LillyTravel, Accommodations, Expenses: AstraZeneca, Pfizer, Amgen, Ipsen, Lilly, Medtronic, Roche/Genentech Andreas MakrisHonoraria: NanoString Technologies, Lilly, Roche, PfizerConsulting or Advisory Role: Roche, Lilly, PfizerSpeakers' Bureau: NanoString Technologies, Pfizer, Lilly, RocheTravel, Accommodations, Expenses: Roche Maria KoehlerEmployment: Bicycle Therapeutics, Repare TherapeuticsStock and Other Ownership Interests: Pfizer, Agios, Amgen, Merck, Gilead SciencesHonoraria: GLG, AtheneumConsulting or Advisory Role: ERVAXX, Lilly Asia Ventures Cynthia Huang-BartelettEmployment: Pfizer, Merck, AstraZenecaStock and Other Ownership Interests: Pfizer, AstraZeneca Maria Jose Lechuga FreanEmployment: PfizerStock and Other Ownership Interests: Pfizer Sabine SeilerStock and Other Ownership Interests: RocheConsulting or Advisory Role: Mundipharma, AmgenTravel, Accommodations, Expenses: Novartis Gunter von MinckwitzStock and Other Ownership Interests: CARA GmbHNo other potential conflicts of interest were reported.

Background: The phase 3 KATHERINE trial demonstrated significantly improved invasive disease-free survival with adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab in patients with HER2-positive early breast cancer and residual invasive disease after neoadjuvant chemotherapy plus HER2-targeted therapy., Methods: Patients who received taxane- and trastuzumab-containing neoadjuvant therapy (with/without anthracyclines) and had residual invasive disease (breast and/or axillary nodes) at surgery were randomly assigned to 14 cycles of adjuvant T-DM1 (3.6 mg/kg intravenously every 3 weeks) or trastuzumab (6 mg/kg intravenously every 3 weeks). The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (QLQ-C30) and breast cancer module (QLQ-BR23) were completed at screening, at day 1 of cycles 5 and 11, within 30 days after study drug completion, and at 6- and 12-month follow-up visits., Results: Of patients who were randomly assigned to T-DM1 (n = 743) and trastuzumab (n = 743), 612 (82%) and 640 (86%), respectively, had valid baseline and ≥1 postbaseline assessments. No clinically meaningful changes (≥10 points) from baseline in mean QLQ-C30 and QLQ-BR23 scores occurred in either arm. More patients receiving T-DM1 reported clinically meaningful deterioration at any assessment point in role functioning (49% vs 41%), appetite loss (38% vs 28%), constipation (47% vs 38%), fatigue (66% vs 60%), nausea/vomiting (39% vs 30%), and systemic therapy side effects (49% vs 36%). These differences were no longer apparent at the 6-month follow-up assessment, except for role functioning (23% vs 16%)., Conclusion: These data suggest that health-related quality of life was generally maintained in both study arms over the course of treatment., (© 2020 The Authors. Cancer published by Wiley Periodicals LLC on behalf of American Cancer Society.)

Background: Dose-dense (DD) adjuvant chemotherapy improves outcomes in early breast cancer (BC). However, there are no phase 3 randomized data to inform on its combination with trastuzumab for patients with human epidermal growth factor receptor 2 (HER2)-positive disease., Methods: This was a protocol-predefined secondary analysis of the randomized phase 3 Pan-European Tailored Chemotherapy (PANTHER) trial. Women 65 years old or younger with node-positive or high-risk, node-negative BC were randomized 1:1 to either tailored (according to hematologic nadirs) and DD epirubicin and cyclophosphamide followed by docetaxel or standard 5-fluorouracil, epirubicin, and cyclophosphamide plus docetaxel every 3 weeks. Patients with HER2-positive disease received 1 year of adjuvant trastuzumab. The primary endpoint was BC relapse-free survival. In addition, HER2-positive patients and an equal number of HER2-negative patients matched for age, treatment group, and institution who were enrolled at Swedish sites were asked to participate in a predefined study of cardiac safety and underwent echocardiography or multigated acquisition scanning and electrocardiography at the baseline and at 4 and 6 years of follow-up., Results: There were 342 HER2-positive patients; 335 received at least 1 dose of trastuzumab, and 29 patients discontinued trastuzumab prematurely. Relapse-free survival was not statistically significantly in favor of the tailored and DD group (hazard ratio, 0.68; 95% confidence interval, 0.37-1.27; P = .231). Cardiac outcomes after 4 and 6 years of follow-up did not differ significantly between HER2-positive and HER2-negative patients or between the 2 treatment groups., Conclusions: The combination of DD chemotherapy and trastuzumab decreased the relative risk for relapse by 32% in comparison with standard treatment, a statistically nonsignificant difference. Its efficacy and safety merit further evaluation as part of both escalation and de-escalation strategies., (© 2019 American Cancer Society.)

Circulating microRNA (ct-miRNAs) are able to identify patients with differential response to HER2-targeted therapy. However, their dynamics are largely unknown. We assessed 752 miRNAs from 52 NeoALTTO patients with plasma pairs prior and two weeks after trastuzumab. Increased levels of ct-miR-148a-3p and ct-miR-374a-5p were significantly associated with pathological complete response (pCR) ( p = 0.008 and 0.048, respectively). At a threshold ≥ the upper limit of the 95%CI of the mean difference, pCR resulted 45% (95%CI 24%-68%), and 44% (95%CI 22%-69%) for ct-miR-148a-3p and ct-miR-374a-5p, respectively. Notably, ct-miR-148a-3p retained its predictive value (OR 3.42, 95%CI 1.23-9.46, p = 0.018) in bivariate analysis along with estrogen receptor status. Combined information from ct-miR-148a-3p and ct-miR140-5p, which we previously reported to identify trastuzumab-responsive patients, resulted in greater predictive capability over each other, with pCR of 54% (95%CI 25%-81%) and 0% (95%CI 0%-31%) in ct-miR-148a/ct-miR-140-5p high/present and low/absent, respectively. GO and KEGG analyses showed common enriched terms between the targets of these ct-miRNAs, including cell metabolism regulation, AMPK and MAPK signaling, and HCC progression. In conclusion, early modulated ct-miR-148-3p may inform on the functional processes underlying treatment response, integrate the information from already available predictive biomarkers, and identify patients likely to respond to single agent trastuzumab-based neoadjuvant therapy.

Background: The German NIU HER2 model was developed based on five variables found to have statistically significant influences on HER2-positivity, to allow exploration of deviations between model-predicted and actual HER2-positivity rates as a measure of testing quality. The prospective, non-interventional EPI HER2 BC study (NCT02666261) compared NIU and EPI data, aiming to validate the NIU model., Methods: HER2 status and patient-/tumour-related information were collected from eligible patients with invasive breast cancer. The influence of variables on HER2-positivity was compared between studies and the NIU model validated using EPI data with cut-off and variable coefficients from the NIU study. The influences of additional variables, centre effects and laboratory-specific parameters were also explored., Results: The study included 14,729 EPI and 15,281 NIU samples; HER2-positivity rates were comparable (13.5% versus 14.2%). The five covariates from NIU were shown to significantly affect HER2-positivity using EPI data. The Youden Index for the NIU model refitted to EPI data (0.3632) and the NIU model for prediction of HER2-positivity in EPI (0.3552) was close to that for the NIU model fitted to NIU data (0.3888), validating the NIU model. Replacing hormone receptor status with progesterone and oestrogen receptor expression, and adding method of sample extraction as a variable improved the model's predictive strength (ROC AUC 0.7402; Youden Index 0.3935)., Conclusions: Reliable, high-quality HER2-testing methods are essential for selection of patients with HER2-positive breast cancer for HER2-tageted treatment. Integration of our model into a locally used software or website may improve its viability for use in clinical practice., Competing Interests: Declaration of competing interest All authors received support for third-party writing assistance for this manuscript, provided by Roche Pharma AG, Grenzach-Wyhlen, Germany. J.R. received a grant and non-financial support from Roche Pharma AG during the conduct of this study. A.L. received a grant from Roche Pharma AG during the conduct of this study, and received travel fees from Roche, Novartis and BioNTech Diagnostics, and grants from BioNTech Diagnostics, outside the submitted work. P.S. received a grant and personal fees from Roche Pharma AG during the conduct of this study, and received grants and personal fees from Roche and Genomic Health, and personal fees from Novartis, outside the submitted work. H.-U.S. is an employee of Targos Molecular Pathology (Kassel, Germany) and received personal fees for consulting from Roche during the conduct of this study and from BMS, MSD, Novartis Oncology, Pfizer and Abbott Molecular outside the submitted work. T.D. received travel and consulting fees from Leica Biosystems, Inc. J.A. and C.K. are employees of Roche and have stock ownership in Roche. W.K. is an employee of BDS Koch, which receives fees from Roche and other clients for statistical services. M.U. has received personal fees and non-financial support from AbbVie, Amgen GmbH, AstraZeneca, Celgene GmbH, Daiichi Sankyo, Eisai GmbH, Janssen Cilag, Johnson & Johnson, Lilly Int., MSD Merck, Mundipharma, Myriad Genetics, Odonate, Pfizer GmbH, Riemser, Roche Pharma AG, Sanofi Aventis Deutschland GmbH, Sividon Diagnostics and TEVA Pharmaceuticals Industries Ltd, and personal fees from BMS, Lilly Deutschland and PUMA Biotechnology, outside the submitted work., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Lapatinib (L) plus trastuzumab (T) with weekly paclitaxel significantly increased the pathologic complete response (pCR) rate compared with the anti-human epidermal growth factor receptor 2 (HER2) agent alone plus paclitaxel. The event-free survival (EFS) and overall survival (OS) by the treatment arms L + T vs. T and L vs. T and the relationship between pCR and EFS/OS both in the whole study population and according to hormone receptor-negative and hormone receptor-positive cohorts after a median follow-up of 6.7 years were assessed., Patients and Methods: Four hundred fifty-five patients with HER2-positive early breast cancer randomly received L 1500 mg/day (n = 154), T (common dose, n = 149) or L 1000 mg/day plus T (n = 152) for 6 weeks, followed by the assigned anti-HER2 treatment combined with paclitaxel weekly × 12. After surgery, patients received 3 cycles of fluorouracil, epirubicin and cyclophosphamide. The primary end-point was pCR (ypT0/is; for current analysis, it is ypT0/is ypN0), and the secondary end-points were EFS and OS., Results: Six-year EFS rates were 67%, 67% and 74% with L, T and L + T, respectively (L vs T: hazard ratio [HR], 0.98 [95% confidence interval {CI}, 0.64-1.51; P = .93]; L + T vs T: HR, 0.81 [95% CI, 0.52-1.26; P = .35]). Six-Year OS rates were 82%, 79% and 85% for L, T and L + T, respectively (L vs T: HR, 0.85 [95% CI, 0.49-1.46; P = .56]; L + T vs T: HR, 0.72 [95% CI, 0.41-1.27; P = .26]). In landmark analyses, patients with a pCR had a significantly higher 6-year EFS (77% and 65%) and OS (89% and 77%) compared with those without a pCR for both overall and the hormone receptor-negative cohort., Conclusion: Achieving a pCR is important in HER2-positive disease and translates into better long-term outcome with regard to EFS and OS., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: In premenopausal patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer, the gonadotoxicity of trastuzumab and lapatinib remains largely uncertain, and the prognostic effect of treatment-related amenorrhea (TRA) is unknown., Methods: In the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization (BIG 2-06) phase III trial, HER2-positive early breast cancer patients were randomized (1:1:1:1) to receive one year of trastuzumab, lapatinib, their sequence, or their combination. As per study protocol, menopausal status was collected in all patients at random assignment and at week 37 visit. We investigated TRA rates and whether TRA in patients with hormone receptor-positive and -negative tumors would impact disease-free survival (DFS) and overall survival (OS). Landmark and time-dependent modeling were used to account for guarantee-time bias. All statistical tests were two-sided., Results: A total of 2862 premenopausal women were included, of whom 1679 (58.7%) had hormone receptor-positive disease. Median age was 43 (interquartile range = 38-47) years. Similar TRA rates were observed in the trastuzumab (72.6%), lapatinib (74.0%), trastuzumab→lapatinib (72.1%), and trastuzumab+lapatinib (74.8%) arms (P = .64). The association between TRA and survival outcomes differed according to hormone-receptor status (Pinteraction for DFS = .007; Pinteraction for OS = .003). For hormone receptor-positive patients, the TRA cohort had statistically significantly better DFS (adjusted hazard ratio [aHR] = 0.58, 95% confidence interval [CI] = 0.45 to 0.76) and OS (aHR = 0.63, 95% CI = 0.40 to 0.99) than the no TRA cohort. No difference was observed in hormone receptor-negative patients., Conclusions: In this unplanned analysis, no association between TRA rate and type of anti-HER2 treatment was observed. TRA was associated with statistically significant survival benefits in premenopausal hormone receptor-positive/HER2-positive early breast cancer patients.

Background: The focus of this study is to identify particular microRNA (miRNA) signatures in exosomes derived from plasma of 435 human epidermal growth factor receptor 2 (HER2)-positive and triple-negative (TN) subtypes of breast cancer (BC)., Methods: First, miRNA expression profiles were determined in exosomes derived from the plasma of 15 TNBC patients before neoadjuvant therapy using a quantitative TaqMan real-time PCR-based microRNA array card containing 384 different miRNAs. Forty-five miRNAs associated with different clinical parameters were then selected and mounted on microRNA array cards that served for the quantification of exosomal miRNAs in 435 BC patients before therapy and 20 healthy women. Confocal microscopy, Western blot, and ELISA were used for exosome characterization., Results: Quantification of 45 exosomal miRNAs showed that compared with healthy women, 10 miRNAs in the entire cohort of BC patients, 13 in the subgroup of 211 HER2-positive BC, and 17 in the subgroup of 224 TNBC were significantly deregulated. Plasma levels of 18 exosomal miRNAs differed between HER2-positive and TNBC subtypes, and 9 miRNAs of them also differed from healthy women. Exosomal miRNAs were significantly associated with the clinicopathological and risk factors. In uni- and multivariate models, miR-155 (p = 0.002, p = 0.003, respectively) and miR-301 (p = 0.002, p = 0.001, respectively) best predicted pathological complete response (pCR)., Conclusion: Our findings show a network of deregulated exosomal miRNAs with specific expression patterns in exosomes of HER2-positive and TNBC patients that are also associated with clinicopathological parameters and pCR within each BC subtype.

Background: Tumour-infiltrating lymphocytes (TILs) are predictive for response to neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) and HER2-positive breast cancer, but their role in luminal breast cancer and the effect of TILs on prognosis in all subtypes is less clear. Here, we assessed the relevance of TILs for chemotherapy response and prognosis in patients with TNBC, HER2-positive breast cancer, and luminal-HER2-negative breast cancer., Methods: Patients with primary breast cancer who were treated with neoadjuvant combination chemotherapy were included from six randomised trials done by the German Breast Cancer Group. Pretherapeutic core biopsies from 3771 patients included in these studies were assessed for the number of stromal TILs by standardised methods according to the guidelines of the International TIL working group. TILs were analysed both as a continuous parameter and in three predefined groups of low (0-10% immune cells in stromal tissue within the tumour), intermediate (11-59%), and high TILs (≥60%). We used these data in univariable and multivariable statistical models to assess the association between TIL concentration and pathological complete response in all patients, and between the amount of TILs and disease-free survival and overall survival in 2560 patients from five of the six clinical trial cohorts., Findings: In the luminal-HER2-negative breast cancer subtype, a pathological complete response (pCR) was achieved in 45 (6%) of 759 patients with low TILs, 48 (11%) of 435 with intermediate TILs, and 49 (28%) of 172 with high TILs. In the HER2-positive subtype, pCR was observed in 194 (32%) of 605 patients with low TILs, 198 (39%) of 512 with intermediate TILs, and 127 (48%) of 262 with high TILs. Finally, in the TNBC subtype, pCR was achieved in 80 (31%) of 260 patients with low TILs, 117 (31%) of 373 with intermediate TILs, and 136 (50%) of 273 with high TILs (p<0·0001 for each subtype, χ 2 test for trend). In the univariable analysis, a 10% increase in TILs was associated with longer disease-free survival in TNBC (hazard ratio [HR] 0·93 [95% CI 0·87-0·98], p=0·011) and HER2-positive breast cancer (0·94 [0·89-0·99], p=0·017), but not in luminal-HER2-negative tumours (1·02 [0·96-1·09], p=0·46). The increase in TILs was also associated with longer overall survival in TNBC (0·92 [0·86-0·99], p=0·032), but had no association in HER2-positive breast cancer (0·94 [0·86-1·02], p=0·11), and was associated with shorter overall survival in luminal-HER2-negative tumours (1·10 [1·02-1·19], p=0·011)., Interpretation: Increased TIL concentration predicted response to neoadjuvant chemotherapy in all molecular subtypes assessed, and was also associated with a survival benefit in HER2-positive breast cancer and TNBC. By contrast, increased TILs were an adverse prognostic factor for survival in luminal-HER2-negative breast cancer, suggesting a different biology of the immunological infiltrate in this subtype. Our data support the hypothesis that breast cancer is immunogenic and might be targetable by immune-modulating therapies. In light of the results in luminal breast cancer, further research investigating the interaction of the immune system with different types of endocrine therapy is warranted., Funding: Deutsche Krebshilfe and European Commission., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Aim: The Neoadjuvant PI3K inhibition in HER2 OverExpressing Breast cancEr (NeoPHOEBE) trial evaluated the efficacy and safety of buparlisib, a pan-phosphatidylinositol 3-kinase (PI3K) inhibitor, plus trastuzumab and paclitaxel as neoadjuvant treatment for human epidermal growth factor receptor-2 positive (HER2+) breast cancer., Methods: NeoPHOEBE was a neoadjuvant, phase II, randomised, double-blind study. Women with HER2+ breast cancer were randomised within two independent cohorts by PIK3CA mutation status and, in each cohort stratified by oestrogen receptor (ER) status to receive buparlisib or placebo plus trastuzumab (first 6 weeks) followed by buparlisib or placebo with trastuzumab and paclitaxel. Primary end-point was pathological complete response (pCR) rate; key secondary end-point was objective response rate (ORR) at 6 weeks. Exploratory end-points were evaluation of Ki67 levels and change in tumour infiltrating lymphocytes (TILs) in intermediate biopsies at day 15., Results: Recruitment was suspended mainly due to liver toxicity after enrolment of 50 of the planned 256 patients. In each arm (buparlisib n = 25; placebo n = 25) 21 patients (84%) had wild type PIK3CA and 4 patients (16%) had mutant PIK3CA. Overall, pCR rate was similar between buparlisib and placebo arms (32.0% versus 40%; one-sided P = 0.811). A trend towards higher ORR (68.8% versus 33.3%; P = 0.053) and a significant decrease in Ki67 (75% versus 26.7%; P = 0.021) was observed in buparlisib versus placebo arm in the ER+ subgroup (P interaction  = 0.03)., Conclusions: Addition of the pan-PI3K inhibitor buparlisib to taxane-trastuzumab-based therapy in HER2+ early breast cancer was not feasible. However, the higher ORR and Ki67 reduction in the ER+, HER2+ subgroup indicates a potential role for PI3K-targeted therapy in this setting and may warrant further investigation with better-tolerated second-generation PI3K inhibitors., Trial Registration Identifier: NCT01816594., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: The GENEVIEVE study compared the pathological complete response (pCR) rate (ypT0/is ypN0/+) in patients with operable human epidermal growth factor receptor 2 (HER2)-negative breast cancer (BC) treated with either cabazitaxel or paclitaxel., Methods: GENEVIEVE was a prospective, multicentre, randomised, open-label, phase II study comparing the efficacy and the safety of four 3-weekly cycles cabazitaxel versus 12 weeks of paclitaxel given as neoadjuvant treatment. Primary end-point was the pCR rate defined as the complete absence of invasive carcinoma on histological examination of the breast irrespective of lymph node involvement (ypT0/is, ypN0/+) after the taxane treatment. Patients could receive an anthracycline-based therapy thereafter., Results: Overall, 333 patients were randomised and started treatment with 74.7% and 83.2% of patients completing treatment in the cabazitaxel and paclitaxel arms, respectively. Patients in cabazitaxel arm had a significantly lower pCR rate compared to the paclitaxel arm (1.2% versus 10.8%; p = 0.001). A total of 42 (25.3%) patients in the cabazitaxel arm and 17 (10.2%) in the paclitaxel arm had at least one serious adverse event (p < 0.001). Dose reductions were observed in 9.6% patients in the cabazitaxel arm compared to 11.4% in the paclitaxel arm (p = 0.721). Main reason for dose reductions was non-haematological toxicities in 3.0% versus 7.8% (p = 0.087), respectively., Conclusions: The GENEVIEVE study showed no short-term effect of cabazitaxel in triple-negative or luminal B/HER2-negative primary BC, while there seemed to be no differences in drug exposure and patient compliance between the two arms., Clinical Trials Registration: ClinicalTrials.gov NCT01779479., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Clinical trials have shown that trastuzumab, a recombinant monoclonal antibody against HER2 receptor, significantly improves overall survival and disease-free survival in women with HER2-positive early breast cancer, but long-term follow-up data are needed. We report the results of comparing observation with two durations of trastuzumab treatment at a median follow-up of 11 years, for patients enrolled in the HERA (HERceptin Adjuvant) trial., Methods: HERA (BIG 1-01) is an international, multicentre, open-label, phase 3 randomised trial of 5102 women with HER2-positive early breast cancer, who were enrolled from hospitals in 39 countries between Dec 7, 2001, and June 20, 2005. After completion of all primary therapy (including, surgery, chemotherapy, and radiotherapy as indicated), patients were randomly assigned (1:1:1) to receive trastuzumab for 1 year (once at 8 mg/kg of bodyweight intravenously, then 6 mg/kg once every 3 weeks) or for 2 years (with the same dose schedule), or to the observation group. Primary endpoint is disease-free survival, and analyses are in the intention-to-treat population. Hazard ratios (HRs) were estimated from Cox models, and survival curves were estimated by the Kaplan-Meier method. Comparison of 2 years versus 1 year of trastuzumab is based on 366-day landmark analyses. This study is registered with ClinicalTrials.gov (NCT00045032)., Findings: Of the 5102 women randomly assigned in the HERA trial, three patients had no evidence of having provided written informed consent to participate. We followed up the intention-to-treat population of 5099 patients (1697 in observation, 1702 in 1-year trastuzumab, and 1700 in 2-years trastuzumab groups). After a median follow-up of 11 years (IQR 10·09-11·53), random assignment to 1 year of trastuzumab significantly reduced the risk of a disease-free survival event (HR 0·76, 95% CI 0·68-0·86) and death (0·74, 0·64-0·86) compared with observation. 2 years of adjuvant trastuzumab did not improve disease free-survival outcomes compared with 1 year of this drug (HR 1·02, 95% CI 0·89-1·17). Estimates of 10-year disease-free survival were 63% for observation, 69% for 1 year of trastuzumab, and 69% for 2 years of trastuzumab. 884 (52%) patients assigned to the observation group selectively crossed over to receive trastuzumab. Cardiac toxicity remained low in all groups and occurred mostly during the treatment phase. The incidence of secondary cardiac endpoints was 122 (7·3%) in the 2-years trastuzumab group, 74 (4·4%) in the 1-year trastuzumab group, and 15 (0·9%) in the observation group., Interpretation: 1 year of adjuvant trastuzumab after chemotherapy for patients with HER2-positive early breast cancer significantly improves long-term disease-free survival, compared with observation. 2 years of trastuzumab had no additional benefit., Funding: F Hoffmann-La Roche (Roche)., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: The neoadjuvant phase III GeparSepto study showed that substituting nab-paclitaxel for standard solvent-based paclitaxel significantly improved the pathologic complete response (pCR) rate achieved with a sequential neoadjuvant chemotherapy regimen of paclitaxel, epirubicin, and cyclophosphamide for high-risk primary breast cancer. Recent trials demonstrated that in HER2+ breast cancer pCR can be increased by using pertuzumab in addition to trastuzumab and chemotherapy. The present analysis focuses on efficacy and safety data from the subset of patients with HER2+ tumors from the GeparSepto trial (n = 396) in comparison to the HER2- cohort., Patients and Methods: Patients with histologically confirmed breast cancer (n = 1206) received four cycles of weekly paclitaxel [either solvent-based (Pac) or nab-paclitaxel (nab-Pac), according to randomization] followed by 4 cycles of epirubicin 90 mg/m2 plus cyclophosphamide 600 mg/m2 q3w, with concurrent trastuzumab and pertuzumab q3w for those with HER2+ tumors. The primary endpoint was pCR defined as ypT0 ypN0., Results: Higher rates of pCR were achieved in HER2+ than in HER2- tumors (57.8% versus 22.0%, P < 0.0001), with the highest rate in the HER2+/HR- cohort (71.0%; 66.7% Pac, 74.6% nab-Pac). In HER2+/HR+ tumors, the pCR rate was 52.9% (49.7% Pac, 56.4% nab-Pac). Grade ≥3 toxic effects were significantly more common in HER2+ than in HER2- patients, with grade 3-4 diarrhea in 7.6% versus 0.9% (P < 0.001) and febrile neutropenia in 6.3% versus 3.3% (P = 0.023) of patients. Left ventricular ejection fraction decreases from baseline were uncommon, with 2.0% versus 0.4% of patients showing decreases to <50% along with a ≥10% decrease from baseline., Conclusion: In HER2+ early breast cancer, a dual HER2-targeted combination of pertuzumab and trastuzumab, together with taxane-epirubicin-cyclophosphamide neoadjuvant chemotherapy, achieved high rates of pCR., (© The Author 2016. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Despite >10 years of routine human epidermal growth factor receptor 2 (HER2) testing in breast cancer, testing quality is still an issue. Guidelines recommend assessing HER2 positivity rates as a quality indicator; however, the extent to which patient- or tumor-related factors influence HER2 positivity is still unknown. The present study analyzed these influences to identify pathology centers with HER2 positivity rates unexplained by patient- or tumor-related factors. This observational, prospective study monitored routine HER2 testing at 57 institutes of pathology in Germany (January 2013-August 2014). Data collected included HER2 test result, patient- and tumor-related factors, sample source, and method of sample retrieval. Factors influencing HER2 positivity rates were identified by multiple logistic regression. Individual center effects were assessed in an extended multiple logistic regression model by their statistical significance after adjusting for the combined effect of patient- or tumor-related covariates and multiple testing. Analyses included 15 332 invasive breast cancer samples. Histologic grade showed the strongest influence on HER2 positivity, followed by hormone receptor status, histologic subtype, age, and nodal status (all P<0.0001). The overall HER2 positivity rate across centers was 14.4% (range 7.1-27.3%). A statistically significant center effect on the HER2 positivity rate was identified for three centers (P<0.05), with a trend toward a center effect for a further three (P<0.2). This study, the first of its kind, highlights that assessing HER2 testing quality with HER2 positivity rates should include standardized assessment of patient- or tumor-related characteristics to identify centers with HER2 testing quality issues more effectively. As treatment options for HER2-positive breast cancer continue to evolve, identifying the right patients is key.

Introduction: Targeted intraoperative radiotherapy (TARGIT - IORT) as a tumour bed boost after breast conserving surgery is well established for women with early breast cancer. A previous study from our group shows a beneficial effect of TARGIT-IORT on overall survival (OS) but not disease-free survival (DFS) after neoadjuvant chemotherapy compared to an external boost suggesting a potential non-inferiority of TARGIT-IORT. In this study, we present results regarding the high-risk subset of patients (i.e. with triple negative (TN) and HER2 positive tumours) from this cohort., Method: In this non-randomized cohort study involving patients with HER2 positive (n= 28) and triple negative (n=42) tumours after NACT we compared outcomes of 40 patients with tumour bed boost applied with TARGIT IORT during lumpectomy versus 30 patients treated in the previous 13 months with external (EBRT) boost. All patients received whole breast radiotherapy. Rates of DFS and OS were compared., Results: Median follow up was 49 months. In comparison of TARGIT-IORT vs. EBRT 5-year Kaplan- Meier estimates of OS showed no significant difference among patients with HER2 positive tumours (100% vs. 91.7%, log rank p = 0.22). The same was seen for DFS (83.3% vs. 77.0%, log rank p=0.38). The results for TN cases were similar (OS : 87.5% vs. 74.1%, log rank p=0.488; DFS 87.5% vs. 60%, log rank p=0.22)., Conclusion: Although survival estimates trended towards favouring TARGIT-IORT, no significant differences could be observed and the significantly positive result for OS favoring TARGIT-IORT in the whole cohort of 116 patients could not be reproduced in this subset analysis of patients with TN and HER2 positive tumours. This may be contributable to the limited number of patients but may also indicate that effects seen in the whole cohort were mainly driven by ER and/or PR positive and HER2 negative tumours. Most importantly, non-inferiority of TARGIT-IORT as an intraoperative boost could be reproduced in these high-risk patients., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Purpose: We elucidated the value of tumor-infiltrating lymphocytes (TIL) as an independent predictor for pathologic complete response (pCR) rate and as a prognostic marker for disease-free survival (DFS) in patients with HER2-positive breast cancer in the neoadjuvant setting., Experimental Design: We evaluated stromal TILs in 498 HER2-positive breast cancer samples of the neoadjuvant GeparQuattro (G4) and GeparQuinto (G5) trials. Levels of TILs were determined as a continuous parameter per 10% increase and as lymphocyte-predominant breast cancer (LPBC; ≥ 60% TILs), and correlated with pCR rate and DFS., Results: In the complete cohort, HER2-positive LPBC cases had a significantly increased pCR rates compared with non-LPBC types. They were significant predictors for pCR in univariate (10% TILs: OR 1.12, P = 0.002; LPBC: OR 2.02, P = 0.002) and multivariate analyses (10% TILs: OR 1.1, P = 0.014; LPBC: OR 1.87, P = 0.009). This effect was also detectable in the trastuzumab-treated (10% TILs: OR 1.12, P = 0.018; LPBC: OR 2.08, P = 0.013) but not in the lapatinib-treated subgroup. We identified a low-risk (pCR/LPBC) and a high-risk group (no pCR/no LPBC) regarding DFS. In triple-positive breast cancer, TILs are of more prognostic relevance than pCR., Conclusions: We could demonstrate the predictive and prognostic impact of TILs in HER2-positive breast cancer in the neoadjuvant setting. In combination with pCR rate, TILs may help to stratify prognostic subgroups, thereby guiding future therapy decisions. Clin Cancer Res; 22(23); 5747-54. ©2016 AACR., (©2016 American Association for Cancer Research.)

Background: TP53 mutations are frequent in breast cancer, however their clinical relevance in terms of response to chemotherapy is controversial., Methods: 450 pre-therapeutic, formalin-fixed, paraffin-embedded core biopsies from the phase II neoadjuvant GeparSixto trial that included HER2-positive and triple negative breast cancer (TNBC) were subjected to Sanger sequencing of exons 5-8 of the TP53 gene. TP53 status was correlated to response to neoadjuvant anthracycline/taxane-based chemotherapy with or without carboplatin and trastuzumab/lapatinib in HER2-positive and bevacizumab in TNBC. p53 protein expression was evaluated by immunohistochemistry in the TNBC subgroup., Results: Of 450 breast cancer samples 297 (66.0%) were TP53 mutant. Mutations were significantly more frequent in TNBC (74.8%) compared to HER2-positive cancers (55.4%, P < 0.0001). Neither mutations nor different mutation types and effects were associated with pCR neither in the whole study group nor in molecular subtypes (P > 0.05 each). Missense mutations tended to be associated with a better survival compared to all other types of mutations in TNBC (P = 0.093) and in HER2-positive cancers (P = 0.071). In TNBC, missense mutations were also linked to higher numbers of tumor-infiltrating lymphocytes (TILs, P = 0.028). p53 protein overexpression was also linked with imporved survival (P = 0.019)., Conclusions: Our study confirms high TP53 mutation rates in TNBC and HER2-positive breast cancer. Mutations did not predict the response to an intense neoadjuvant chemotherapy in these two molecular breast cancer subtypes.

Background: The predictive value of PIK3CA mutations in HER2 positive (HER2+) breast cancer treated with neoadjuvant anti-HER2 and chemotherapy has been reported, but the power for subgroup analyses was lacking., Patients and Methods: We combined individual patient data from five clinical trials evaluating PIK3CA mutations and associations with pathological complete response (pCR), disease-free survival (DFS) and overall survival (OS). Patients received either trastuzumab (T), lapatinib (L) or the combination T/L in addition to a taxane-based chemotherapy. PIK3CA was genotyped in tumour biopsies taken before therapy., Results: A total of 967 patients were included in this analysis; the median follow-up is 47 months. Overall, the pCR rate was significantly lower in the PIK3CA mutant compared with the wild-type group (16.2% versus 29.6%; P < 0.001). Within the hormone-receptor positive (HR+) subgroup, the PIK3CA mutant group had a pCR rate of only 7.6% compared with 24.2% in the wild-type group (P < 0.001). In contrast, in the HER2+/HR- group, there was no difference in pCR (27.2% versus 36.4%; P = 0.125) according to PIK3CA mutation status (interaction test P = 0.036). According to treatment arm, the pCR rate for mutant versus wild-type was 20.3% versus 27.1% for T (P = 0.343), 11.3% versus 16.9% for L (P = 0.369) and 16.7% versus 39.1% for T/L (P < 0.001). In the HR+ T/L group, the pCR rate was 5.5% versus 33.9% (interaction between HR and PIK3CA genotype P = 0.008). DFS and OS were not significantly different by mutation status, though the incidence rate of events was low. However, HR+/PIK3CA mutant patients seemed to have significantly worse DFS {hazard ratio (HR) 1.56 [95% confidence interval (CI) 1.00-2.45], P = 0.050; Pinteraction = 0.021}. T/L tended to improve DFS compared with T in the wild-type cohort, especially in the HR- group [HR 0.72, 95% CI (0.41-1.25), P = 0.242]., Conclusion: Overall PIK3CA mutant/HER2+ tumours had significantly lower pCR rates compared with wild-type tumours, however mainly confined to the HR+/PIK3CA mutant population. No definite conclusions can be drawn regarding survival., (© The Author 2016. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: The PI3K/AKT pathway and phosphatase and tensin homolog (PTEN) aberrations are common in breast cancer. We investigated the correlation between phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), PTEN, p4EBP1 (phosphorylated E4 binding protein 1), and pathologic complete response (pCR) in patients receiving neoadjuvant therapy., Experimental Design: We retrospectively evaluated PIK3CA, PTEN, and p4EBP1 protein expression in centrally HER2-positive patients (n = 181) who received epirubicin cyclophosphamide/trastuzumab followed by docetaxel/trastuzumab alone or concomitant/followed by capecitabine within the GeparQuattro study. PTEN was assessed using the automated quantitative immunofluorescence analysis and was analyzed as a dichotomic variable. p4EBP1 was assessed by immunohistochemistry and used as a continuous and dichotomic variable., Results: p4EBP1 was available from 137, PTEN from 108, and PIK3CA genotype from 83 patients. Overall, the pCR rate in PTEN-low tumors was 27.6%, and in PTEN-high tumors, it was 57.1% (P = 0.010). pCR rates were not statistically different between PIK3CA wild-type and mutant (35% vs. 22%) or p4EBP1 IRS ≤ 4 and IRS > 4 (39% vs. 33%). pCR rate was 57.1% (8/14) in PTEN-high/PIK3CA wild-type and decreased to 15.4% in PTEN-low/PIK3CA-mutant tumors (P = 0.023). In multivariable analysis adjusted for baseline parameters, PTEN independently predicted pCR in the following cohorts: overall [OR, 7.54; 95% confidence interval (CI), 2.03-28.06; P = 0.003], PIK3CA wild-type (OR, 23.81; 95% CI, 1.75-324.05; P = 0.017), p4EBP1 IRS > 4 (OR, 11.53; 95% CI, 1.84-72.24; P = 0.009), and hormone receptor-positive (OR, 40.91; 95% CI, 2.93-570.44; P = 0.006). p4EBP1 was independently predictive for pCR in PIK3CA wild-type tumors (OR, 0.14; 95% CI, 0.03-0.78; P = 0.025)., Conclusions: The study showed the potential role of PIK3CA genotype, PTEN, and p4EBP in predicting pCR after anthracycline-taxane-based chemotherapy and anti-HER2 treatment. Clin Cancer Res; 22(11); 2675-83. ©2016 AACR., (©2016 American Association for Cancer Research.)

Background: Lapatinib (L) plus trastuzumab (T) improves outcomes for metastatic human epidermal growth factor 2-positive breast cancer and increases the pathologic complete response in the neoadjuvant setting, but their role as adjuvant therapy remains uncertain., Methods: In the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization trial, patients with centrally confirmed human epidermal growth factor 2-positive early breast cancer were randomly assigned to 1 year of adjuvant therapy with T, L, their sequence (T→L), or their combination (L+T). The primary end point was disease-free survival (DFS), with 850 events required for 80% power to detect a hazard ratio (HR) of 0.8 for L+T versus T., Results: Between June 2007 and July 2011, 8,381 patients were enrolled. In 2011, due to futility to demonstrate noninferiority of L versus T, the L arm was closed, and patients free of disease were offered adjuvant T. A protocol modification required P ≤ .025 for the two remaining pairwise comparisons. At a protocol-specified analysis with a median follow-up of 4.5 years, a 16% reduction in the DFS hazard rate was observed with L+T compared with T (555 DFS events; HR, 0.84; 97.5% CI, 0.70 to 1.02; P = .048), and a 4% reduction was observed with T→L compared with T (HR, 0.96; 97.5% CI, 0.80 to 1.15; P = .61). L-treated patients experienced more diarrhea, cutaneous rash, and hepatic toxicity compared with T-treated patients. The incidence of cardiac toxicity was low in all treatment arms., Conclusion: Adjuvant treatment that includes L did not significantly improve DFS compared with T alone and added toxicity. One year of adjuvant T remains standard of care., (© 2015 by American Society of Clinical Oncology.)

Recently the American Society of Clinical Oncology and the College of American Pathologists have updated their clinical practice guidelines for HER2 testing in breast cancer. In order to evaluate these new recommendations, we have re-assessed the HER2 status of 6018 breast cancer cases of the screening population for the HERceptin adjuvant (HERA) trial that were originally centrally tested by fluorescence in situ hybridization based on the FDA-released test guidelines. According to the most recent 2013 ASCO/CAP recommendations, 3380 (56.2%) cases were classified as HER2 positive compared with 3359 (55.8%) applying the HERA/FDA scheme and 3339 (55.5%) applying the 2007 ASCO/CAP guidelines. Twenty-one cases switched from negative (HERA/FDA scheme) to positive (2013 ASCO/CAP guidelines). This group is characterized by a mean HER2 gene copy number of ≥6.0, polysomy or co-amplification of CEP17 with an average CEP17 count of 5, and with HER2 receptor overexpression in 75% of cases. On the basis of the HER2 gene copy number alone, we observe 494 cases (8.2%) that are in the equivocal range. Most of these cases (>80%) were also nondecisive by immunohistochemistry (score 2+) irrespective of whether ratio was <2.0>. The number of equivocal cases that would require HER2 reflex testing decreases to 113 (1.9%) if in addition to the HER2 gene copy number also the ratio of HER2 and CEP17 copy numbers is considered via dual-color in situ hybridization. The combination of applying the HER2 mean gene copy number as well as the HER2/CEP17 ratio to define equivocal test decisions by fluorescence in situ hybridization as proposed by the current ASCO/CAP guidelines appears to be a more optimum approach to adopt in order to avoid or minimize reporting of false negative results. Using the mean HER2 gene copy number alone for decision making results in a significant increase of equivocal cases.

Purpose: Modulation of immunologic interactions in cancer tissue is a promising therapeutic strategy. To investigate the immunogenicity of human epidermal growth factor receptor 2 (HER2) -positive and triple-negative (TN) breast cancers (BCs), we evaluated tumor-infiltrating lymphocytes (TILs) and immunologically relevant genes in the neoadjuvant GeparSixto trial., Patients and Methods: GeparSixto investigated the effect of adding carboplatin (Cb) to an anthracycline-plus-taxane combination (PM) on pathologic complete response (pCR). A total of 580 tumors were evaluated before random assignment for stromal TILs and lymphocyte-predominant BC (LPBC). mRNA expression of immune-activating (CXCL9, CCL5, CD8A, CD80, CXCL13, IGKC, CD21) as well as immunosuppressive factors (IDO1, PD-1, PD-L1, CTLA4, FOXP3) was measured in 481 tumors., Results: Increased levels of stromal TILs predicted pCR in univariable (P < .001) and multivariable analyses (P < .001). pCR rate was 59.9% in LPBC and 33.8% for non-LPBC (P < .001). pCR rates ≥ 75% were observed in patients with LPBC tumors treated with PMCb, with a significant test for interaction with therapy in the complete (P = .002) and HER2-positive (P = .006), but not the TNBC, cohorts. Hierarchic clustering of mRNA markers revealed three immune subtypes with different pCR rates (P < .001). All 12 immune mRNA markers were predictive for increased pCR. The highest odds ratios (ORs) were observed for PD-L1 (OR, 1.57; 95% CI, 1.34 to 1.86; P < .001) and CCL5 (OR, 1.41; 95% CI, 1.23 to 1.62; P < .001)., Conclusion: Immunologic factors were highly significant predictors of therapy response in the GeparSixto trial, particularly in patients treated with Cb. After further standardization, they could be included in histopathologic assessment of BC., (© 2014 by American Society of Clinical Oncology.)

Purpose: Phosphatidylinositol 3-kinase (PI3K)/AKT pathway aberrations are common in breast cancer, with mutations in PIK3CA being the most common. This study investigated the association between PIK3CA genotype and pathologic complete response (pCR) rates in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with either dual or single anti-HER2 treatment in addition to neoadjuvant chemotherapy., Patients and Methods: PIK3CA mutations in 504 tumor samples from participants in the neoadjuvant GeparQuattro, GeparQuinto, and GeparSixto studies were evaluated. All HER2-positive patients received either trastuzumab or lapatinib or the combination plus anthracycline-taxane chemotherapy. PIK3CA mutations were evaluated in formalin-fixed, paraffin-embedded tissues from core biopsies with a tumor cell content of ≥ 20% by using classical Sanger sequencing of exon 9 and exon 20., Results: Overall, 21.4% of the patients harbored a PIK3CA mutation. Detection of a PIK3CA mutation was significantly associated with a lower pCR rate (19.4% with PIK3CA mutation v 32.8% with PIK3CA wild-type; odds ratio [OR], 0.49; 95% CI, 0.29 to 0.83; P = .008). In the 291 hormone receptor (HR) -positive tumors, pCR rate was 11.3% with a PIK3CA mutation compared with 27.5% with PIK3CA wild-type (OR, 0.34; 95% CI, 0.15 to 0.78; P = .011). In 213 patients with HR-negative tumors, pCR rate was 30.4% with PIK3CA mutation and 40.1% without (OR, 0.65; 95% CI, 0.32 to 1.32; P = .233; interaction test P = .292). In multivariable analysis, HR status and PIK3CA status provided independent predictive information. In patients with PIK3CA mutation, the pCR rates were 16%, 24.3%, and 17.4% with lapatinib, trastuzumab, and the combination, respectively (P = .654) and in the wild-type group, they were 18.2%, 33.%, and 37.1%, respectively (P = .017). Disease-free survival and overall survival were not statistically significantly different between patients with mutant and wild-type PIK3CA., Conclusion: HER2-positive breast carcinomas with a PIK3CA mutation are less likely to achieve a pCR after neoadjuvant anthracycline-taxane-based chemotherapy plus anti-HER2 treatment, even if a dual anti-HER2 treatment is given., (© 2014 by American Society of Clinical Oncology.)

Trastuzumab and lapatinib are established treatments for patients with HER2 (human epidermal growth factor receptor 2)-positive breast cancer with different mechanisms of action. The focus of this study is to investigate, whether altered expression levels of potentially relevant microRNAs (miRs) in serum are associated with response to trastuzumab or lapatinib. Circulating miR-21, miR-210, and miR-373 were quantified with TaqMan MicroRNA assays in serum of 127 HER2-postive breast cancer patients before and after neoadjuvant therapy and in 19 healthy controls. Patients received chemotherapy combined with either trastuzumab or lapatinib within the prospectively randomized Geparquinto trial. The association between miR levels and pathological response (pCR) to therapy and type of therapy was examined. Serum levels of miR-21 (p = 5.04e-08, p = 1.43e-10), miR-210 (p = 0.00151, p = 1.6e-05), and miR-373 (p = 7.87e-06, p = 1.75e-07) were significantly higher in patients before and after chemotherapy than in healthy women. Concentrations of miR-21 (p = 5.73e-08), miR-210 (p = 0.000724), and miR-373 (p = 0.00209) increased further after chemotherapy. A significant association of higher serum levels of miR-373 with advanced clinical tumor stage could be detected (p < 0.002). An association of miR-21 levels before (p = 0.0091) and after (p = 0.037) chemotherapy with overall survival of the patients could be detected, independent of type of anti-HER2 therapy. No association of circulating miRs with pCR was found. Our findings demonstrate a specific influence of neoadjuvant therapy on the serum levels of miR-21, miR-210, and miR-373 in breast cancer patients together with a prognostic value of miR-21.

Purpose: To document the rate and outcome of trastuzumab-associated cardiac dysfunction in patients following 1 or 2 years of adjuvant therapy., Patients and Methods: The Herceptin Adjuvant (HERA) trial is a three-arm, randomized trial comparing 2 years or 1 year of trastuzumab with observation in 5,102 patients with human epidermal growth factor receptor 2 (HER2) -positive early-stage breast cancer. Cardiac function was closely monitored. Eligible patients had left ventricular ejection fraction (LVEF) ≥ 55% at study entry following neoadjuvant chemotherapy with or without radiotherapy. This 8-year median follow-up analysis considered patients randomly assigned to 2 years or 1 year of trastuzumab or observation., Results: The as-treated safety population for 2 years of trastuzumab (n = 1,673), 1 year of trastuzumab (n = 1,682), and observation (n = 1,744) is reported. Cardiac adverse events leading to discontinuation of trastuzumab occurred in 9.4% of patients in the 2-year arm and 5.2% of patients in the 1-year arm. Cardiac death, severe congestive heart failure (CHF), and confirmed significant LVEF decrease remained low in all three arms. The incidence of severe CHF (0.8%, 0.8%, and 0.0%, respectively) and confirmed significant LVEF decrease (7.2%, 4.1%, and 0.9%, respectively) was significantly higher in the 2-year and 1-year trastuzumab arms compared with the observation arm. Severe CHF was the same for 2-year and 1-year trastuzumab. Of patients with confirmed LVEF decrease receiving 2-year trastuzumab, 87.5% reached acute recovery. Of patients with confirmed LVEF decrease receiving 1-year trastuzumab, 81.2% reached acute recovery., Conclusion: Long-term assessment at 8-year median follow-up confirms the low incidence of cardiac events for trastuzumab given sequentially after chemotherapy and radiotherapy, and cardiac events were reversible in the vast majority of patients., (© 2014 by American Society of Clinical Oncology.)

Background: Preclinical data suggest that triple-negative breast cancers are sensitive to interstrand crosslinking agents, and that synergy may exist for the combination of a taxane, trastuzumab, and a platinum salt for HER2-positive breast cancer. We therefore aimed to assess the efficacy of the addition of carboplatin to neoadjuvant therapy for triple-negative and HER2-positive breast cancer., Methods: Patients with previously untreated, non-metastatic, stage II-III, triple-negative breast cancer and HER2-positive breast cancer were enrolled. Patients were treated for 18 weeks with paclitaxel (80 mg/m(2) once a week) and non-pegylated liposomal doxorubicin (20 mg/m(2) once a week). Patients with triple-negative breast cancer received simultaneous bevacizumab (15 mg/kg intravenously every 3 weeks). Patients with HER2-positive disease received simultaneous trastuzumab (8 mg/kg initial dose with subsequent doses of 6 mg/kg intravenously every 3 weeks) and lapatinib (750 mg daily). Patients were randomly assigned in a 1:1 ratio with dynamic allocation and minimisation, stratified by biological subtype and Ki-67 level to receive, at the same time as the backbone regimens, either carboplatin (AUC 1·5 [2·0 for the first 329 patients] once a week) or no carboplatin. The primary endpoint the proportion of patients who achieved a pathological complete response (defined as ypT0 ypN0), analysed for all patients who started treatment; a p value of less than 0·2 was deemed significant for the primary endpoint. This trial is registered with ClinicalTrials.gov, number NCT01426880., Findings: 296 patients were randomly assigned to receive carboplatin and 299 to no additional carboplatin, of whom 295 and 293 started treatment, respectively. In this final analysis, 129 patients (43·7%, 95% CI 38·1-49·4) in the carboplatin group achieved a pathological complete response, compared with 108 patients (36·9%, 31·3-42·4) without carboplatin (odds ratio 1·33, 95% CI 0·96-1·85; p=0·107). Of the patients with triple-negative breast cancer, 84 (53·2%, 54·4-60·9) of 158 patients achieved a pathological complete response with carboplatin, compared with 58 (36·9%, 29·4-44·5) of 157 without (p=0·005). Of the patients with HER2-positive tumours, 45 (32·8%, 25·0-40·7) of 137 patients achieved a pathological complete response with carboplatin compared with 50 (36·8%, 28·7-44·9) of 136 without (p=0·581; test for interaction p=0·015). Haematological and non-haematological toxic effects that were significantly more common in the carboplatin group than in the no-carboplatin group included grade 3 or 4 neutropenia (192 [65%] vs 79 [27%]), grade 3 or 4 anaemia (45 [15%] vs one [<1%]), grade 3 or 4 thrombocytopenia (42 [14%] vs one [<1%]), and grade 3 or 4 diarrhoea (51 [17%] vs 32 [11%]); carboplatin was more often associated with dose discontinuations (141 [48%] with carboplatin and 114 [39%] without carboplatin; p=0·031). The frequency of grade 3 or 4 haematological events decreased from 82% (n=135) to 70% (n=92) and grade 3 or 4 non-haematological events from 78% (n=128) to 59% (n=77) in the carboplatin arm when the dose of carboplatin was reduced from AUC 2·0 to 1·5., Interpretation: The addition of neoadjuvant carboplatin to a regimen of a taxane, an anthracycline, and targeted therapy significantly increases the proportion of patients achieving a pathological complete response. This regimen seems to increase responses in patients with triple-negative breast cancer, but not in those with HER2-positive breast cancer., Funding: GlaxoSmithKline, Roche, and Teva., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Choice of therapy for breast cancer relies on human epidermal growth factor receptor-2 (HER2) and estrogen receptor α (ER) status. Before randomization in the phase III Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation (ALTTO) trial for HER2-positive disease, HER2 and ER were centrally reviewed by Mayo Clinic (Rochester, MN, and Scottsdale, AZ) for North America and by the European Institute of Oncology (IEO; Milan, Italy) for the rest of world (except China). Discordance rates (local vs. central review) differed between Mayo and IEO. Among locally HER2-positive cases, 5.8 % (Mayo) and 14.5 % (IEO) were centrally HER2 negative. Among locally ER-positive cases, 16.2 % (Mayo) and 4.2 % (IEO) were centrally ER-negative. Among locally ER-negative cases, 3.4 % (Mayo) and 21.4 % (IEO) were centrally ER-positive. We, therefore, performed a ring study to identify features contributing to these differing discordance rates. Mayo and IEO exchanged slides for 25 HER2 and 35 ER locally/centrally discordant cases. Both laboratories performed IHC and FISH for HER2 using the HercepTest(®) and PathVysion HER2 DNA probe kit/HER2/centromere 17 probe mixture. IHC for ER was tested centrally using the monoclonal ER 1D5 antibody (Mayo) or the DAKO cocktail of ER 1D5 and 2.123 antibodies (IEO). Mayo and IEO confirmed the central HER2-negative result in 100 % of 25 cases. Mayo and IEO confirmed the central ER result in 29 (85 %) of 34 evaluable cases. The five Mayo-negative/IEO-positive cases were ER-positive when retested at Mayo using the DAKO ER cocktail. In this ring study, ALTTO ineligibility did not change when HER2 testing was performed by either IEO or Mayo central laboratories. However, a dual antibody ER assay had fewer false-negative test results than an assay with a single antibody, and there was more discordance between the two ER reagents than has been previously reported. Using even slightly different assay methods yielded different results, even between experienced central laboratories.

Introduction: We have recently described an increased lymphocytic infiltration rate in breast carcinoma tissue is a significant response predictor for anthracycline/taxane-based neoadjuvant chemotherapy (NACT). The aim of this study was to prospectively validate the tumor-associated lymphocyte infiltrate as predictive marker for response to anthracycline/taxane-based NACT., Patients and Methods: The immunological infiltrate was prospectively evaluated in a total of 313 core biopsies from HER2 negative patients of the multicenter PREDICT study, a substudy of the neoadjuvant GeparQuinto study. Intratumoral lymphocytes (iTuLy), stromal lymphocytes (strLy) as well as lymphocyte-predominant breast cancer (LPBC) were evaluated by histopathological assessment. Pathological complete response (pCR) rates were analyzed and compared between the defined subgroups using the exact test of Fisher., Results: Patients with lymphocyte-predominant breast cancer (LPBC) had a significantly increased pCR rate of 36.6%, compared to non-LPBC patients (14.3%, p<0.001). LPBC and stromal lymphocytes were significantly independent predictors for pCR in multivariate analysis (LPBC: OR 2.7, p = 0.003, strLy: OR 1.2, p = 0.01). The amount of intratumoral lymphocytes was significantly predictive for pCR in univariate (OR 1.2, p = 0.01) but not in multivariate logistic regression analysis (OR 1.2, p = 0.11)., Conclusion: Confirming previous investigations of our group, we have prospectively validated in an independent cohort that an increased immunological infiltrate in breast tumor tissue is predictive for response to anthracycline/taxane-based NACT. Patients with LPBC and increased stromal lymphocyte infiltration have significantly increased pCR rates. The lymphocytic infiltrate is a promising additional parameter for histopathological evaluation of breast cancer core biopsies.

Background: Trastuzumab has established efficacy against breast cancer with overexpression or amplification of the HER2 oncogene. The standard of care is 1 year of adjuvant trastuzumab, but the optimum duration of treatment is unknown. We compared 2 years of treatment with trastuzumab with 1 year of treatment, and updated the comparison of 1 year of trastuzumab versus observation at a median follow-up of 8 years, for patients enrolled in the HERceptin Adjuvant (HERA) trial., Methods: The HERA trial is an international, multicentre, randomised, open-label, phase 3 trial comparing treatment with trastuzumab for 1 and 2 years with observation after standard neoadjuvant chemotherapy, adjuvant chemotherapy, or both in 5102 patients with HER2-positive early breast cancer. The primary endpoint was disease-free survival. The comparison of 2 years versus 1 year of trastuzumab treatment involved a landmark analysis of 3105 patients who were disease-free 12 months after randomisation to one of the trastuzumab groups, and was planned after observing at least 725 disease-free survival events. The updated intention-to-treat comparison of 1 year trastuzumab treatment versus observation alone in 3399 patients at a median follow-up of 8 years (range 0-10) is also reported. This study is registered with ClinicalTrials.gov, number NCT00045032., Findings: We recorded 367 events of disease-free survival in 1552 patients in the 1 year group and 367 events in 1553 patients in the 2 year group (hazard ratio [HR] 0·99, 95% CI 0·85-1·14, p=0·86). Grade 3-4 adverse events and decreases in left ventricular ejection fraction during treatment were reported more frequently in the 2 year treatment group than in the 1 year group (342 [20·4%] vs 275 [16·3%] grade 3-4 adverse events, and 120 [7·2%] vs 69 [4·1%] decreases in left ventricular ejection fraction, respectively). HRs for a comparison of 1 year of trastuzumab treatment versus observation were 0·76 (95% CI 0·67-0·86, p<0·0001) for disease-free survival and 0·76 (0·65-0·88, p=0·0005) for overall survival, despite crossover of 884 (52%) patients from the observation group to trastuzumab therapy., Interpretation: 2 years of adjuvant trastuzumab is not more effective than is 1 year of treatment for patients with HER2-positive early breast cancer. 1 year of treatment provides a significant disease-free and overall survival benefit compared with observation and remains the standard of care., Funding: F Hoffmann-La Roche (Roche)., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Purpose: To evaluate the benefit of adjuvant trastuzumab in patients diagnosed with human epidermal growth factor receptor 2 (HER2) -positive invasive lobular carcinoma (ILC) enrolled onto the Herceptin Adjuvant (HERA) trial., Patients and Methods: Patients randomly assigned to receive one year of trastuzumab and one year of observation in the HERA trial were included (n = 3,401). Centrally reviewed estrogen receptor (ER), progesterone receptor (PgR), and HER2 copy numbers were used. First site-specific relapse pattern was evaluated for ILC and invasive ductal carcinoma (IDC). The magnitude of trastuzumab benefit was assessed using the Cox proportional hazards model for disease-free survival (DFS) and overall survival (OS)., Results: Median follow-up time was 4 years. A total of 187 ILC and 3,213 IDC patients were included. High Allred scores (6 to 8) were more common in patients with ILC than IDC for both ER (36.9% v 22.7%) and PgR (44.1% v 28.5%). A trend toward decreased HER2 copy number was observed in the ILC group. The ILC and IDC subgroups had similar patterns of first site of disease relapse. DFS hazard ratios (HRs) comparing 1 year of trastuzumab versus observation were 0.63 for ILC (95% CI, 0.34 to 1.15) and 0.77 for IDC (95% CI, 0.67 to 0.89; P for interaction = .49). The OS HRs comparing 1 year of trastuzumab versus observation were 0.60 for ILC (95% CI, 0.27 to 1.31) and 0.86 for IDC (95% CI, 0.71 to 1.06; P for interaction = .29)., Conclusion: In this retrospective analysis, there was no suggestion that patients in the ILC cohort experienced a different magnitude of benefit from adjuvant trastuzumab than those in the IDC cohort.

Background: Hormone and human epidermal growth factor receptor 2 (HER2) receptors are the most important breast cancer biomarkers, and additional objective and quantitative test methods such as messenger RNA (mRNA)-based quantitative analysis are urgently needed. In this study, we investigated the clinical validity of RT-PCR-based evaluation of estrogen receptor (ESR1) and HER2 mRNA expression., Patients and Methods: A total of 1050 core biopsies from two retrospective (GeparTrio, GeparQuattro) and one prospective (PREDICT) neoadjuvant studies were evaluated by quantitative RT-PCR for ESR1 and HER2., Results: ESR1 mRNA was significantly predictive for reduced response to neoadjuvant chemotherapy in univariate and multivariate analysis in all three cohorts. The complete pathologically documented response (pathological complete response, pCR) rate for ESR1+/HER2- tumors was 7.3%, 8.0% and 8.6%; for ESR1-/HER2- tumors it was 34.4%, 33.7% and 37.3% in GeparTrio, GeparQuattro and PREDICT, respectively (P < 0.001 in each cohort). In the Kaplan-Meier analysis in GeparTrio patients with ESR1+/HER2- tumors had the best prognosis, compared with ESR1-/HER2- and ESR1-/HER2+ tumors [disease-free survival (DFS): P < 0.0005, overall survival (OS): P < 0.0005]., Conclusions: Our results suggest that mRNA levels of ESR1 and HER2 predict response to neoadjuvant chemotherapy and are significantly associated with long-term outcome. As an additional option to standard immunohistochemistry and gene-array-based analysis, quantitative RT-PCR analysis might be useful for determination of the receptor status in breast cancer.

Introduction: Recent data suggest that benefit from trastuzumab and chemotherapy might be related to expression of HER2 and estrogen receptor (ESR1). Therefore, we investigated HER2 and ESR1 mRNA levels in core biopsies of HER2-positive breast carcinomas from patients treated within the neoadjuvant GeparQuattro trial., Methods: HER2 levels were centrally analyzed by immunohistochemistry (IHC), silver in situ hybridization (SISH) and qRT-PCR in 217 pretherapeutic formalin-fixed, paraffin-embedded (FFPE) core biopsies. All tumors had been HER2-positive by local pathology and had been treated with neoadjuvant trastuzumab/ chemotherapy in GeparQuattro., Results: Only 73% of the tumors (158 of 217) were centrally HER2-positive (cHER2-positive) by IHC/SISH, with cHER2-positive tumors showing a significantly higher pCR rate (46.8% vs. 20.3%, P <0.0005). HER2 status by qRT-PCR showed a concordance of 88.5% with the central IHC/SISH status, with a low pCR rate in those tumors that were HER2-negative by mRNA analysis (21.1% vs. 49.6%, P <0.0005). The level of HER2 mRNA expression was linked to response rate in ESR1-positive tumors, but not in ESR1-negative tumors. HER2 mRNA expression was significantly associated with pCR in the HER2-positive/ESR1-positive tumors (P = 0.004), but not in HER2-positive/ESR1-negative tumors., Conclusions: Only patients with cHER2-positive tumors - irrespective of the method used - have an increased pCR rate with trastuzumab plus chemotherapy. In patients with cHER2-negative tumors the pCR rate is comparable to the pCR rate in the non-trastuzumab treated HER-negative population. Response to trastuzumab is correlated to HER2 mRNA levels only in ESR1-positive tumors. This study adds further evidence to the different biology of both subsets within the HER2-positive group.

Background: We were able to demonstrate a predictive value of serum HER2 (sHER2) in patients receiving trastuzumab in the neoadjuvant GeparQuattro trial. However, the role of sHER2 in patients receiving neoadjuvant therapy (NT) with lapatinib is still unclear., Methods: The neoadjuvant GeparQuinto trial compared trastuzumab vs lapatinib in addition to chemotherapy in HER2-positive primary breast cancer patients. The sHER2 levels were measured by enzyme-linked immunosorbant assay in 210 patients, of whom 109 (52%) patients received trastuzumab and 101 (48%) lapatinib at three different time points., Results: Twenty-two percent of patients had elevated baseline sHER2 levels (>15 ng ml⁻¹). A decrease of sHER2 levels (>20%) in the trastuzumab and lapatinib-treated group during NT was seen in 44% and 24% of the patients, an increase of sHER2 levels (>20%) was seen in 6% and 41% of patients, respectively. Higher pre-chemotherapy sHER2 levels were associated with higher pathological complete remission (pCR) rates in the entire study cohort (OR 1.8, 95% CI 1.02-3.2, P=0.043). A decline of sHER2 levels (>20%) during NT was a predictor for pCR in the lapatinib-treated patient group (OR: 11.7, 95% CI 1.3-110, P=0.031)., Conclusion: Results of this study demonstrate that sHER2 levels change differently during NT depending on the anti-HER2 treatment strategy. Elevated baseline sHER2 levels (>15 ng ml⁻¹) and a decrease of sHER2 levels (>20%) early after therapy initiation are both relevant criteria to predict response to lapatinib-based treatment., (© 2012 Cancer Research UK)

Adjacent ductal carcinoma in situ (DCIS) is found in approximately 45% of invasive ductal carcinomas (IDC) of the breast. Pure DCIS overexpresses HER2 in approximately 45%. There is uncertainty whether adjacent DCIS impacts on the response to neoadjuvant chemotherapy and trastuzumab as well as whether HER2 expression in IDC component or adjacent DCIS changes throughout treatment. Core biopsies and surgical tissue from participants of the GeparQuattro study with HER2-positive IDC were centrally examined for the area of invasive ductal component and adjacent DCIS before and after receiving neoadjuvant anthracycline-taxane-trastuzumab containing chemotherapy. HER2 overexpression in IDC and adjacent DCIS was quantified separately by immunohistochemistry using the Ventana automated staining system. Pathological complete response (pCR) was defined as no residual invasive or non-invasive tumor tissue. Fifty-nine (37.3%) of 158 IDCs presented with adjacent DCIS at diagnosis. These tumors showed lower regression grades than pure IDC (P = 0.033). The presence of adjacent DCIS was an independent negative predictor of pCR [odds ratio 0.42 (95% CI 0.2-0.9), P = 0.027]. Adjacent DCIS area decreased from pre-treatment to surgery (r = 0.205) with 30 (50.8%) IDCs with adjacent DCIS showing complete eradication of adjacent DCIS. HER2 status of adjacent DCIS was highly correlated with HER2 status of IDC component before (r = 0.892) and after treatment (r = 0.676). Degree of HER2 overexpression of the IDC component decreased in 16 (33.3%) out of 49 patients without a pCR. These 16 IDCs showed lower RGs compared to the 33 IDCs with unchanged HER2 expression (P = 0.055). HER2-positive IDCs with adjacent DCIS is less responsive to neoadjuvant chemotherapy and trastuzumab compared to pure IDC. However, complete eradication of adjacent DCIS is frequently observed. HER2-overexpression of the invasive ductal component decreases in a subset of tumors, which showed less tumor regression.

Background: The anti-HER2 monoclonal antibody trastuzumab and the tyrosine kinase inhibitor lapatinib have complementary mechanisms of action and synergistic antitumour activity in models of HER2-overexpressing breast cancer. We argue that the two anti-HER2 agents given together would be better than single-agent therapy., Methods: In this parallel groups, randomised, open-label, phase 3 study undertaken between Jan 5, 2008, and May 27, 2010, women from 23 countries with HER2-positive primary breast cancer with tumours greater than 2 cm in diameter were randomly assigned to oral lapatinib (1500 mg), intravenous trastuzumab (loading dose 4 mg/kg [DOSAGE ERROR CORRECTED], subsequent doses 2 mg/kg), or lapatinib (1000 mg) plus trastuzumab. Treatment allocation was by stratified, permuted blocks randomisation, with four stratification factors. Anti-HER2 therapy alone was given for the first 6 weeks; weekly paclitaxel (80 mg/m(2)) was then added to the regimen for a further 12 weeks, before definitive surgery was undertaken. After surgery, patients received adjuvant chemotherapy followed by the same targeted therapy as in the neoadjuvant phase to 52 weeks. The primary endpoint was the rate of pathological complete response (pCR), analysed by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00553358., Findings: 154 patients received lapatinib, 149 trastuzumab, and 152 the combination. pCR rate was significantly higher in the group given lapatinib and trastuzumab (78 of 152 patients [51·3%; 95% CI 43·1-59·5]) than in the group given trastuzumab alone (44 of 149 patients [29·5%; 22·4-37·5]; difference 21·1%, 9·1-34·2, p=0·0001). We recorded no significant difference in pCR between the lapatinib (38 of 154 patients [24·7%, 18·1-32·3]) and the trastuzumab (difference -4·8%, -17·6 to 8·2, p=0·34) groups. No major cardiac dysfunctions occurred. Frequency of grade 3 diarrhoea was higher with lapatinib (36 patients [23·4%]) and lapatinib plus trastuzumab (32 [21·1%]) than with trastuzumab (three [2·0%]). Similarly, grade 3 liver-enzyme alterations were more frequent with lapatinib (27 [17·5%]) and lapatinib plus trastuzumab (15 [9·9%]) than with trastuzumab (11 [7·4%])., Interpretation: Dual inhibition of HER2 might be a valid approach to treatment of HER2-positive breast cancer in the neoadjuvant setting., Funding: GlaxoSmithKline., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Background: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor A, has shown clinical efficacy in patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer. We evaluated the efficacy, measured according to the rate of pathological complete response (absence of invasive and intraductal disease in the breast and the axillary lymph nodes), and the safety of adding bevacizumab to neoadjuvant chemotherapy in patients with early-stage breast cancer., Methods: We randomly assigned 1948 patients with a median tumor size of 40 mm on palpation to receive neoadjuvant epirubicin and cyclophosphamide followed by docetaxel, with or without concomitant bevacizumab. Patients with untreated HER2-negative breast cancer were eligible if they had large tumors, hormone-receptor-negative disease, or hormone-receptor-positive disease with palpable nodes or positive findings on sentinel-node biopsy, and no increased cardiovascular or bleeding risk., Results: Overall, the rates of pathological complete response were 14.9% with epirubicin and cyclophosphamide followed by docetaxel and 18.4% with epirubicin and cyclophosphamide followed by docetaxel plus bevacizumab (odds ratio with addition of bevacizumab, 1.29; 95% confidence interval, 1.02 to 1.65; P=0.04); the corresponding rates of pathological complete response were 27.9% and 39.3% among 663 patients with triple-negative tumors (P=0.003) and 7.8% and 7.7% among 1262 patients with hormone-receptor-positive tumors (P=1.00). Breast-conserving surgery was possible in 66.6% of the patients in both groups. The addition of bevacizumab, as compared with neoadjuvant therapy alone, was associated with a higher incidence of grade 3 or 4 toxic effects (febrile neutropenia, mucositis, the hand-foot syndrome, infection, and hypertension) but with a similar incidence of surgical complications., Conclusions: The addition of bevacizumab to neoadjuvant chemotherapy significantly increased the rate of pathological complete response among patients with HER2-negative early-stage breast cancer. Efficacy was restricted primarily to patients with triple-negative tumors, in whom the pathological complete response is considered to be a reliable predictor of long-term outcome. (Funded by Sanofi-Aventis and Roche, Germany; ClinicalTrials.gov number, NCT00567554.).

Neoadjuvant treatment with a sequential anthracycline-taxane-based chemotherapy in combination with trastuzumab (Herceptin) is currently a preferred therapy for patients with HER2-positive breast cancer. This approach is based on the higher pathologic complete response (pCR) of 40% seen with the addition of trastuzumab, compared with a 17% pCR with chemotherapy alone. The pCR can be increased to 75% with dual HER2-receptor blockade and chemotherapy. Higher pCR rates are found in hormone-receptor-negative tumors. Patients with a pCR after chemotherapy and trastuzumab showed a significantly better outcome compared with those who did not have a pCR. The need for additional or alternate treatment options is great in patients who do not achieve a pCR. Addition of lapatinib (Tykerb) or pertuzumab (Omnitarg) to trastuzumab is a therapeutic option. Recent findings suggest pCR might not be the appropriate surrogate for long-term outcome in patients with hormone receptor-positive and HER2-positive tumors.

Aims: To review the recent literature on neoadjuvant treatment of breast cancer with respect to insights that might be used for better using systemic treatment in early breast cancer., Results: Much more insight was gained during recent years on how to use information on pathologic complete response (pCR). pCR appears to be a valid surrogate for long-term survival mainly in triple-negative and HER2-positive disease. Patient with breast cancer of these subtypes can be relieved from poor prognosis if they achieve a pCR after neoadjuvant treatment. It can even be speculated that the extent of local and post-surgical systemic treatment can be further reduced. Patients without pCR show a high risk of early recurrence and are at high need for new treatment options. These advantages lead to the recommendation that use of neoadjuvant treatment should not be indicated by tumor size but far more by tumor subtype. As pCR appears to be more sensitive to detect treatment effects than disease-free survival, the neoadjuvant approach identifies easier promising treatments and can even discriminate optimal approaches for biologically defined subgroups. A recent meta-analysis examining pattern of neoadjuvant chemotherapy suggests that luminal-B type tumors require longer duration of treatment, triple-negative tumors require dose-intensified anthracycline-taxane-based treatment of only short duration, and HER2-positive tumors require longer duration (if hormone-receptor positive) and an optimal dose of taxanes. As biomarkers can be easily assessed on tumor tissue before, during, and after treatment, there is increasing data available on markers that e.g. potentially predict resistance to anti-HER2 treatment, predict response to anti-angiogenic drugs as well as efficacy of PARP inhibitors. Validation of these candidate markers remains a challenging task, as patients cohort are usually small and finding studies are compromised by multiple testing., Conclusion: With the acquired new knowledge from neoadjuvant studies will help to individualize treatment based on biological behavior of breast cancer subtypes., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Purpose: To evaluate efficacy and safety of epirubicin and cyclophosphamide followed by paclitaxel and trastuzumab as neoadjuvant treatment in patients with human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer., Patients and Methods: Patients with centrally confirmed HER2-overexpressing breast cancer (≥ 2 cm or inflammatory) received four 3-week cycles epirubicin and cyclophosphamide (90/600 mg/m(2)) followed by four 3-week cycles paclitaxel (175 mg/m(2)) and trastuzumab (6 mg/kg) before surgery. Trastuzumab was continued after surgery to complete 1 year of treatment. Primary end point was pathologic complete response (pCR) defined as no residual invasive tumor in breast and lymphatic tissue., Results: Thirty-nine percent of 217 enrolled patients achieved a pCR. Breast conservation was possible in 64% of patients. Three-year disease-free survival (DFS) was 88% in patients with pCR compared to 73% in patients without pCR (P = .01). Three-year overall survival (OS) was 96% in patients with pCR compared to 86% in patients without pCR (P = .025). pCR was the only significant prognostic factor for DFS (hazard ratio [HR] 2.5; 95% CI, 1.2 to 5.1; P = .013) and OS (HR, 4.9; 95% CI, 1.4 to 17.4; P = .012) in multivariable analysis. Cardiac toxicity was reported in eight patients (3.7%) of whom six presented with an asymptomatic left ventricular ejection fraction decrease and two with symptomatic chronic heart failure., Conclusion: Neoadjuvant combination of trastuzumab and chemotherapy resulted in a high pCR rate in HER2-overexpressing primary breast cancer. Patients with a pCR after neoadjuvant anti-HER2 therapy in combination with chemotherapy followed by maintenance trastuzumab have an improved long-term outcome. Patients without a pCR had an increased risk for relapse and death.

Background: Treatment with adjuvant trastuzumab for 1 year improves disease-free survival and overall survival in patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer. We aimed to assess disease-free survival and overall survival after a median follow-up of 4 years for patients enrolled on the Herceptin Adjuvant (HERA) trial., Methods: The HERA trial is an international, multicentre, randomised, open-label, phase 3 trial comparing treatment with trastuzumab for 1 and 2 years with observation after standard neoadjuvant, adjuvant chemotherapy, or both in patients with HER2-positive early breast cancer. The primary endpoint was disease-free survival. After a positive first interim analysis at a median follow-up of 1 year for the comparison of treatment with trastuzumab for 1 year with observation, event-free patients in the observation group were allowed to cross over to receive trastuzumab. We report trial outcomes for the 1-year trastuzumab and observation groups at a median follow-up of 48·4 months (IQR 42·0-56·5) and assess the effect of the extensive crossover to trastuzumab. Our analysis was by intention-to-treat. The HERA trial is registered with the European Clinical Trials Database, number 2005-002385-11., Findings: The HERA trial population comprised 1698 patients randomly assigned to the observation group and 1703 to the 1-year trastuzumab group. Intention-to-treat analysis of disease-free survival showed a significant benefit in favour of patients in the 1-year trastuzumab group (4-year disease-free survival 78·6%) compared with the observation group (4-year disease-free survival 72·2%; hazard ratio [HR] 0·76; 95% CI 0·66-0·87; p<0·0001). Intention-to-treat analysis of overall survival showed no significant difference in the risk of death (4-year overall survival 89·3%vs 87·7%, respectively; HR 0·85; 95% CI 0·70-1·04; p=0·11). Overall, 885 patients (52%) of the 1698 patients in the observation group crossed over to receive trastuzumab, and began treatment at median 22·8 months (range 4·5-52·7) from randomisation. In a non-randomised comparison, patients in the selective-crossover cohort had fewer disease-free survival events than patients remaining in the observation group (adjusted HR 0·68; 95% CI 0·51-0·90; p=0·0077). Higher incidences of grade 3-4 and fatal adverse events were noted on 1-year trastuzumab than in the observation group. The most common grade 3 or 4 adverse events, each in less than 1% of patients, were congestive cardiac failure, hypertension, arthralgia, back pain, central-line infection, hot flush, headache, and diarrhoea., Interpretation: Treatment with adjuvant trastuzumab for 1 year after chemotherapy is associated with significant clinical benefit at 4-year median follow-up. The substantial selective crossover of patients in the observation group to trastuzumab was associated with improved outcomes for this cohort., Funding: F Hoffmann-La Roche, Michelangelo Foundation., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

In the context of neoadjuvant therapy (NT) for breast cancer patients, different targeted therapy approaches are currently evaluated in clinical trials. Serum markers could help to monitor and optimize such treatment strategies. We investigated human epidermal growth factor receptor 2 serum (sHER2) levels in 175 breast cancer patients participating in the GeparQuattro trial. This study incorporated NT approaches and additional trastuzumab treatment for all patients with HER2-positive tumors. Human epidermal growth factor receptor 2 serum levels were measured by enzyme-linked immunosorbent assay (ELISA) before initiation of NT and after NT (pre-surgery) in a HER2-positive (n = 90) and a HER2-negative patient cohort (n = 85). Median pre-chemotherapy sHER2 levels were higher in patients with positive HER2 status of the primary tumor than in patients with negative HER2 status (14.9 ng/ml vs. 7.7 ng/ml, P < 0.001). A pre-chemotherapy sHER2 cut-off level of 10 ng/ml had the best sensitivity and specificity in discriminating between HER2-positive and HER2-negative primary tumors. In HER2-positive patients, we found a significant positive association between pathological complete remission (pCR) and elevated sHER2 levels (above 15 ng/ml, P = 0.045) and a decrease of sHER2 levels during NT (P = 0.02), which was also significant in multivariate analysis (OR = 3.29, 95% CI 1.001-10.89, P = 0.049). In HER2-negative patients, we observed no association between sHER2 levels and pCR (P > 0.05). Monitoring sHER2 levels in the presence of anti-HER2 treatment might be an adjunct to the clinical evaluation during NT.

Purpose: Core needle biopsies (CNBs) are widely used to determine human epidermal growth factor receptor 2 (HER2) status in breast cancer. Recent publications reported up to 20% false-positive results on CNBs if immunohistochemistry (IHC) is compared with fluorescent in situ hybridization (FISH). To clarify, if confirmation of IHC positivity by FISH is generally required, we analyzed the reliability of IHC positivity on CNBs versus surgical specimens in a multi-institutional study., Patients and Methods: Five pathologic laboratories contributed to this study by performing IHC on 500 CNBs and the corresponding surgical specimens overall. If IHC revealed score 2+ or 3+, HER2 status was confirmed by FISH in a central laboratory. We compared evaluation according to US Food and Drug Administration-approved scoring criteria and recently published American Society of Clinical Oncology (ASCO)-College of American Pathologists (CAP) guidelines., Results: CNBs scored 3+ revealed five false-positive results if scoring followed the US Food and Drug Administration criteria (five of 40; 12.5%) and two false-positives in terms of the ASCO-CAP criteria (two of 33; 6.1%). IHC was false negative in one CNB only. By contrast, IHC on surgical specimens revealed five false-negative results, but only one false-positive result (one of 35; 2.9%) if scored following US Food and Drug Administration-approved criteria. With the aid of the ASCO-CAP criteria, false-positive IHC results were obtained in only one of the five participating institutions., Conclusion: IHC 3+ scores on CNBs proved to be reliable in four of the five participating institutions if scoring followed the ASCO-CAP criteria. Therefore, accurate determination of HER2 status in breast cancer is possible on CNB using the common strategy to screen all cases by IHC and retest only 2+ scores by FISH. Prerequisites are quality assurance and the application of the new ASCO-CAP criteria.

Purpose: This study was aimed at detecting and characterizing circulating tumor cells (CTC) before and after neoadjuvant therapy (NT) in the peripheral blood of patients with breast cancer., Experimental Design: The clinical trial GeparQuattro incorporated NT approaches (epirubicin/cyclophosphamide prior to randomization to docetaxel alone, docetaxel in combination with capecitabine, or docetaxel followed by capecitabine) and additional trastuzumab treatment for patients with HER2-positive tumors. We used the Food and Drug Administration-approved CellSearch system for CTC detection and evaluation of HER2 expression and developed HER2 immunoscoring for CTC., Results: We detected > or =1 CTC/7.5 mL in 46 of 213 patients (21.6%) before NT and in 22 of 207 patients (10.6%) after NT (P = 0.002). Twenty (15.0%) initially CTC-positive cases were CTC-negative after NT, whereas 11 (8.3%) cases were CTC-positive after NT, although no CTC could be found before NT. CTC detection did not correlate with primary tumor characteristics. Furthermore, there was no association between tumor response to NT and CTC detection. HER2-overexpressing CTC were observed in 14 of 58 CTC-positive patients (24.1%), including 8 patients with HER2-negative primary tumors and 3 patients after trastuzumab treatment. CTC scored HER2-negative or weakly HER2-positive before or after NT were present in 11 of 21 patients with HER2-positive primary tumors. HER2 overexpression on CTC was restricted to ductal carcinomas and associated with high tumor stage (P = 0.002)., Conclusion: CTC number was low in patients with primary breast cancer. The decrease in CTC incidence during treatment was not correlated with standard clinical characteristics and primary tumor response. Information on the HER2 status of CTC might be helpful for stratification and monitoring of HER2-directed therapies., (Copyright 2010 AACR.)