De-escalated neoadjuvant pertuzumab plus trastuzumab therapy with or without weekly paclitaxel in HER2-positive, hormone receptor-negative, early breast cancer (WSG-ADAPT-HER2+/HR-): survival outcomes from a multicentre, open-label, randomised, phase 2 trial.

BACKGROUND: Several de-escalation neoadjuvant strategies have been investigated to reduce the use of chemotherapy in HER2-positive early breast cancer using pathological complete response as a surrogate endpoint; there are few survival data from these trials. Here, we report 5-year survival data in the WSG-ADAPT-HER2+/HR- trial and address the effect of pathological complete response, early therapy response, and molecular subtype. METHODS: WSG-ASAPT-HER2+/HR-, a part of the ADAPT umbrella trial performed in patients with different subtypes of early breast cancer, was an investigator-initiated, multicentre, open-label, randomised, phase 2 trial done at 40 Breast Cancer Centres in Germany. Eligible patients were aged 18 years or older with histologically confirmed, unilateral, primary invasive, non-inflammatory early breast cancer, hormone receptor-negative and HER2-positive status, and an Eastern Cooperative Oncology Group performance status of 0 or 1 or a Karnofsky performance status of at least 80%. Patients were randomly assigned (5:2, block size 21, stratified by centre and clinical nodal status) to 12 weeks of either trastuzumab (8 mg/kg loading dose, then 6 mg/kg every 3 weeks) plus pertuzumab (840 mg loading dose, then 420 mg every 3 weeks) or trastuzumab plus pertuzumab plus paclitaxel (80 mg/m2 weekly); all drugs were administered intravenously. The primary objective of the trial was to compare the number of patients with a pathological complete response at surgery (ie, no invasive tumour cells in breast and lymph nodes [ypT0/is ypN0], the primary endpoint) in early responders (ie, low cellularity or Ki67 decrease ≥30% after 3 weeks) in the trastuzumab plus pertuzumab group versus all patients (irrespective of an early response) in the trastuzumab plus pertuzumab plus paclitaxel group. Non-inferiority was defined as a pathological complete response no worse than 23% lower in the early-responder proportion of patients in the trastuzumab plus pertuzumab group than in the entire trastuzumab plus pertuzumab plus paclitaxel group. The primary endpoint has been reported previously. Additionally, the primary objective of the ADAPT umbrella trial was the evaluation of the effect of pathological complete response on invasive disease-free survival. At investigator's discretion, further chemotherapy could be omitted in patients with a pathological complete response. Secondary survival endpoints were 5-year invasive disease-free survival, relapse-free survival, locoregional relapse-free survival, distant disease-free survival, and overall survival. The effect of pathological complete response on survival was estimated by Cox regression analysis. All analyses are reported in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01817452, and is closed to recruitment. FINDINGS: Between March 3, 2014, and Oct 6, 2015, 134 patients were recruited and randomly assigned to treatment, 92 to trastuzumab plus pertuzumab and 42 to trastuzumab plus pertuzumab plus paclitaxel. Median follow-up in survivors was 59·9 months (IQR 53·4-61·4). There were no significant differences between the treatment groups in invasive disease-free survival, relapse-free survival, locoregional relapse-free survival, distant disease-free survival, and overall survival. In the trastuzumab plus pertuzumab plus paclitaxel group and in the trastuzumab plus pertuzumab group, the proportions of patients achieving 5-year survival respectively were 98% (95% CI 84-100) and 87% (78-93) for invasive disease-free survival (hazard ratio [HR] 0·32, 95% CI 0·07-1·49; p=0·15); 98% (95% CI 84-100) and 89% (79-94) for relapse-free survival (HR 0·41, 95% CI 0·09-1·91; p=0·25); 100% (95% CI not estimable) and 95% (88-98) for locoregional relapse-free survival (HR 0·41, 95% CI 0·05-3·75; p=0·43); 98% (95% CI 84-100) and 92% (83-96) for distant disease-free survival (HR 0·35, 95% CI 0·04-3·12; p=0·36), and 98% (95% CI 84-100) and 94% (86-97) for overall survival (HR 0·41, 95% CI 0·05-3·63; p=0·43). Pathological complete response was associated with improved invasive disease-free survival (HR 0·14, 95% CI 0·03-0·64; p=0·011). Two invasive disease-free survival events occurred after a pathological complete response (one in each treatment group). INTERPRETATION: The WSG-ADAPT-HER2+/HR- trial showed good survival rates in patients with a pathological complete response after de-escalated 12-week trastuzumab plus pertuzumab with or without weekly paclitaxel. Omission of further chemotherapy did not affect invasive disease-free survival in patients with a pathological complete response. 12 weeks of weekly paclitaxel plus dual HER2 blockade could be an efficacious de-escalated neoadjuvant regimen in patients with hormone receptor-negative, HER2-positive early breast cancer with high pathological complete response rates and good 5-year outcomes. Further trials of this approach are ongoing. FUNDING: Roche, Bayer. TRANSLATION: For the German translation of the abstract see Supplementary Materials section.

Molecular Subtyping of Invasive Breast Cancer Using a PAM50-Based Multigene Expression Test-Comparison with Molecular-Like Subtyping by Tumor Grade/Immunohistochemistry and Influence on Oncologist's Decision on Systemic Therapy in a Real-World Setting.

In intermediate risk hormone receptor (HR) positive, HER2 negative breast cancer (BC), the decision regarding adjuvant chemotherapy might be facilitated by multigene expression tests. In all, 142 intermediate risk BCs were investigated using the PAM50-based multigene expression test Prosigna® in a prospective multicentric study. In 119/142 cases, Prosigna® molecular subtyping was compared with local and two central (C1 and C6) molecular-like subtypes relying on both immunohistochemistry (IHC; HRs, HER2, Ki-67) and IHC + tumor grade (IHC+G) subtyping. According to local IHC, 35.4% were Luminal A-like and 64.6% Luminal B-like subtypes (local IHC+G subtype: 31.9% Luminal A-like; 68.1% Luminal B-like). In contrast to local and C1 subtyping, C6 classified >2/3 of cases as Luminal A-like. Pairwise agreement between Prosigna® subtyping and molecular-like subtypes was fair to moderate depending on molecular-like subtyping method and center. The best agreement was observed between Prosigna® (53.8% Luminal A; 44.5% Luminal B) and C1 surrogate subtyping (Cohen's kappa = 0.455). Adjuvant chemotherapy was suggested to 44.2% and 88.6% of Prosigna® Luminal A and Luminal B cases, respectively. Out of all Luminal A-like cases (locally IHC/IHC+G subtyping), adjuvant chemotherapy was recommended if Prosigna® testing classified as Prosigna® Luminal A at high / intermediate risk or upgraded to Prosigna® Luminal B.

Efficacy of deescalated chemotherapy according to PAM50 subtypes, immune and proliferation genes in triple-negative early breast cancer: Primary translational analysis of the WSG-ADAPT-TN trial.

In the neoadjuvant WSG-ADAPT-TN trial, 12-week nab-paclitaxel + carboplatin (nab-pac/carbo) was highly effective and superior to nab-paclitaxel + gemcitabine (nab-pac/gem) in triple-negative breast cancer regarding pathological complete response (pCR). Predictive markers for deescalated taxane/carbo use in TNBC need to be identified. Patients received 4 × nab-pac 125 mg/m2 (plus carbo AUC2 or gem 1,000 mg/m2 d1,8 q21). Expression of 119 genes and PAM50 scores by nCounter were available in 306/336 pretherapeutic samples. Interim survival analysis was planned after 36 months median follow-up. Basal-like (83.3%) compared to other subtypes was positively associated with pCR (38% vs. 20%, p = 0.015), as was lower HER2 score (p < 0.001). Proliferation biomarkers were positively associated with pCR, that is, PAM50 proliferation, ROR scores (all p < 0.004), higher Ki-67 (IHC; p < 0.001). For nab-pac/carbo, expression of immunological (CD8, PD1 and PFDL1) genes and proliferation markers (proliferation and ROR scores, MKI67, CDC20, NUF2, KIF2C, CENPF, EMP3 and TYMS) were positively associated with pCR (p < 0.05 for all). For nab-pac/gem, angiogenesis genes were negatively associated with pCR (ANGPTL4: p = 0.05; FGFR4: p = 0.02; VEGFA: p = 0.03). pCR after 12 weeks was strongly associated with favorable outcome (3y event-free survival: 92% vs. 71%, p < 0.001). In early TNBC, basal-like subtype, higher Ki-67 (IHC) and lower HER2 score were, associated with chemosensitivity. Chemoresistance pathways differed between the two taxane based combinations. Combination of proliferation/immune markers and PAM50 subtype could allow patient selection for further deescalated chemotherapy and/or immune treatment approaches.

BRCA1-like profile predicts benefit of tandem high dose epirubicin-cyclophospamide-thiotepa in high risk breast cancer patients randomized in the WSG-AM01 trial.

BRCA1 is an important protein in the repair of DNA double strand breaks (DSBs), which are induced by alkylating chemotherapy. A BRCA1-like DNA copy number signature derived from tumors with a BRCA1 mutation is indicative for impaired BRCA1 function and associated with good outcome after high dose (HD) and tandem HD DSB inducing chemotherapy. We investigated whether BRCA1-like status was a predictive biomarker in the WSG AM 01 trial. WSG AM 01 randomized high-risk breast cancer patients to induction (2× epirubicin-cyclophosphamide) followed by tandem HD chemotherapy with epirubicin, cyclophosphamide and thiotepa versus dose dense chemotherapy (4× epirubicin-cyclophospamide followed by 3× cyclophosphamide-methotrexate-5-fluorouracil). We generated copy number profiles for 143 tumors and classified them as being BRCA1-like or non-BRCA1-like. Twenty-six out of 143 patients were BRCA1-like. BRCA1-like status was associated with high grade and triple negative tumors. With regard to event-free-survival, the primary endpoint of the trial, patients with a BRCA1-like tumor had a hazard rate of 0.2, 95% confidence interval (CI): 0.07-0.63, p = 0.006. In the interaction analysis, the combination of BRCA1-like status and HD chemotherapy had a hazard rate of 0.19, 95% CI: 0.067-0.54, p = 0.003. Similar results were observed for overall survival. These findings suggest that BRCA1-like status is a predictor for benefit of tandem HD chemotherapy with epirubicin-thiotepa-cyclophosphamide.

Predictive role of HER2/neu, topoisomerase-II-alpha, and tissue inhibitor of metalloproteinases (TIMP-1) for response to adjuvant taxane-based chemotherapy in patients with intermediate-risk breast cancer: results from the WSG-AGO EC-Doc trial.

Taxane-anthracycline-based adjuvant chemotherapy is standard of care in patients with node-positive breast cancer (BC) but is also associated with severe side effects and significant costs. It is yet unclear, which biomarkers would predict benefit from taxanes and/or general chemoresistance. In this study, we investigate a large cohort of patients with intermediate-risk BC treated within the WSG EC-DOC Trial for the predictive impact of topoisomerase-II-alpha, HER2/neu, and TIMP-1. Tumor tissue was available in a representative cohort of 772 cases of the WSG EC-DOC Trial collective which compared 4xEC-4xDoc versus 6xCEF/CMF. In addition to hormone receptor status and Ki-67, HER2/neu+ and topoisomerase-II-alpha status using fluorescence in situ hybridisation (FISH) and immunohistochemistry, TIMP-1 using immunohistochemistry, and aneuploidy of chromosome 17 using FISH were evaluated and correlated with outcome and taxane benefit. There was significant superiority of EC-Doc over CEF regarding 5-year DFS (90 vs. 80 %, respectively, p = 0.006) particularly in patient subgroups defined by HR+, HER2/neu+, high proliferation (i.e., Ki-67 ≥ 20 %), patient age >50 years old and normal chromosome 17 status, high TIMP-1 and low topoisomerase-II-alpha protein expression. Significant prognostic factors in multivariate analysis were EC-Doc therapy (HR = 0.61; 95 %CI 0.38-0.986), age <50 years old (HR = 1.682; 95 %CI 1.025-2.579), centrally assessed grade 3 (HR = 4.657; 95 %CI 1.809-11.989), and high Ki-67 (HR = 2.232; 95 %CI 1.209-4.121). Interestingly, we observed a significant interaction between treatment arm (EC-Doc vs. CEF) and high topoisomerase-II-alpha protein expression (HR = 0.427; 95 %CI 0.203-0.900) in multivariate interaction analysis. Despite of univariate predictive effect of HER2/neu status among other factors only topoisomerase-II-alpha protein expression was associated with significant benefit from EC-Doc compared to CEF by multivariate interaction analysis.

Impact of RNA Signatures on pCR and Survival after 12-Week Neoadjuvant Pertuzumab plus Trastuzumab with or without Paclitaxel in the WSG-ADAPT HER2+/HR- Trial.

PURPOSE: To identify associations of biological signatures and stromal tumor-infiltrating lymphocytes (sTIL) with pathological complete response (pCR; ypT0 ypN0) and survival in the Phase II WSG-ADAPT HER2+/HR- trial (NCT01817452). EXPERIMENTAL DESIGN: Patients with cT1-cT4c, cN0-3 HER2+/HR- early breast cancer (EBC) were randomized to pertuzumab+trastuzumab (P+T, n = 92) or P+T+paclitaxel (n = 42). Gene expression signatures were analyzed in baseline biopsies using NanoString Breast Cancer 360 panel (n = 117); baseline and on-treatment (week 3) sTIL levels were available in 119 and 76 patients, respectively. Impacts of standardized gene expression signatures on pCR and invasive disease-free survival (iDFS) were estimated by logistic and Cox regression. RESULTS: In all patients, ERBB2 [OR, 1.70; 95% confidence interval (CI), 1.08-2.67] and estrogen receptor (ER) signaling (OR, 1.72; 95% CI, 1.13-2.61) were favorable, whereas PTEN (OR, 0.57; 95% CI, 0.38-0.87) was unfavorable for pCR. After 60 months median follow-up, 13 invasive events occurred (P+T: n = 11, P+T+paclitaxel: n = 2), none following pCR. Gene signatures related to immune response (IR) and ER signaling were favorable for iDFS, all with similar HR about 0.43-0.55. These patterns were even more prominent in the neoadjuvant chemotherapy-free group, where additionally BRCAness signature was unfavorable (HR, 2.00; 95% CI, 1.04-3.84). IR signatures were strongly intercorrelated. sTILs (baseline/week 3/change) were not associated with pCR or iDFS, though baseline sTILs correlated positively with IR signatures. CONCLUSIONS: Distinct gene signatures were associated with pCR versus iDFS in HER2+/HR- EBC. The potential role of IR in preventing recurrence suggests that patients with upregulated IR signatures could be candidates for de-escalation concepts in HER2+ EBC.

De-escalated Neoadjuvant Chemotherapy in Early Triple-Negative Breast Cancer (TNBC): Impact of Molecular Markers and Final Survival Analysis of the WSG-ADAPT-TN Trial.

PURPOSE: Although optimal treatment in early triple-negative breast cancer (TNBC) remains unclear, de-escalated chemotherapy appears to be an option in selected patients within this aggressive subtype. Previous studies have identified several pro-immune factors as prognostic markers in TNBC, but their predictive impact regarding different chemotherapy strategies is still controversial. EXPERIMENTAL DESIGN: ADAPT-TN is a randomized neoadjuvant multicenter phase II trial in early patients with TNBC (n = 336) who were randomized to 12 weeks of nab-paclitaxel 125 mg/m2 + gemcitabine or carboplatin d 1,8 q3w. Omission of further (neo-) adjuvant chemotherapy was allowed only in patients with pathological complete response [pCR, primary endpoint (ypT0/is, ypN0)]. Secondary invasive/distant disease-free and overall survival (i/dDFS, OS) and translational research objectives included quantification of a predictive impact of markers regarding selection for chemotherapy de-escalation, measured by gene expression of 119 genes (including PAM50 subtype) by nCounter platform and stromal tumor-infiltrating lymphocytes (sTIL). RESULTS: After 60 months of median follow-up, 12-week-pCR was favorably associated (HR, 0.24; P = 0.001) with 5y-iDFS of 90.6% versus 62.8%. No survival advantage of carboplatin use was observed, despite a higher pCR rate [HR, 1.04; 95% confidence interval (CI), 0.68-1.59]. Additional anthracycline-containing chemotherapy was not associated with a significant iDFS advantage in pCR patients (HR, 1.29; 95% CI, 0.41-4.02). Beyond pCR rate, nodal status and high sTILs were independently associated with better iDFS, dDFS, and OS by multivariable analysis. CONCLUSIONS: Short de-escalated neoadjuvant taxane/platinum-based combination therapy appears to be a promising strategy in early TNBC for using pCR rate as an early decision point for further therapy (de-) escalation together with node-negative status and high sTILs. See related commentary by Sharma, p. 4840.

Inter-observer agreement for the histological diagnosis of invasive lobular breast carcinoma.

Invasive lobular breast carcinoma (ILC) is the second most common breast carcinoma (BC) subtype and is mainly driven by loss of E-cadherin expression. Correct classification of BC as ILC is important for patient treatment. This study assessed the degree of agreement among pathologists for the diagnosis of ILC. Two sets of hormone receptor (HR)-positive/HER2-negative BCs were independently reviewed by participating pathologists. In set A (61 cases), participants were provided with hematoxylin/eosin (HE)-stained sections. In set B (62 cases), participants were provided with HE-stained sections and E-cadherin immunohistochemistry (IHC). Tumor characteristics were balanced. Participants classified specimens as non-lobular BC versus mixed BC versus ILC. Pairwise inter-observer agreement and agreement with a pre-defined reference diagnosis were determined with Cohen's kappa statistics. Subtype calls were correlated with molecular features, including CDH1/E-cadherin mutation status. Thirty-five pathologists completed both sets, providing 4,305 subtype calls. Pairwise inter-observer agreement was moderate in set A (median κ = 0.58, interquartile range [IQR]: 0.48-0.66) and substantial in set B (median κ = 0.75, IQR: 0.56-0.86, p < 0.001). Agreement with the reference diagnosis was substantial in set A (median κ = 0.67, IQR: 0.57-0.75) and almost perfect in set B (median κ = 0.86, IQR: 0.73-0.93, p < 0.001). The median frequency of CDH1/E-cadherin mutations in specimens classified as ILC was 65% in set A (IQR: 56-72%) and 73% in set B (IQR: 65-75%, p < 0.001). Cases with variable subtype calls included E-cadherin-positive ILCs harboring CDH1 missense mutations, and E-cadherin-negative ILCs with tubular elements and focal P-cadherin expression. ILCs with trabecular growth pattern were often misclassified as non-lobular BC in set A but not in set B. In conclusion, subtyping of BC as ILC achieves almost perfect agreement with a pre-defined reference standard, if assessment is supported by E-cadherin IHC. CDH1 missense mutations associated with preserved E-cadherin protein expression, E- to P-cadherin switching in ILC with tubular elements, and trabecular ILC were identified as potential sources of discordant classification.

Phenotype Discordance between Primary Tumor and Metastasis Impacts Metastasis Site and Outcome: Results of WSG-DETECT-PriMet.

INTRODUCTION: Tumor biological factors of breast cancer (BC) such as hormone receptor (HR) status, HER2 status, and grade can differ in the metastatic cascade from primary to lymph node (LN) metastasis and to distant metastatic tissue. Systematic data regarding therapeutic consequences are yet limited. METHODS: We conducted a prospectively planned, retrospective cohort study comparing BC phenotype in tissue from primary tumors (PTs), locoregional LN metastases, and disease recurrence (DR). HR and HER2 as well as tumor grade in PTs and DR were obtained by a database search. No centralized biomarker testing was performed. The impact of changes in tumor biological factors on post-recurrence survival (PRS) and overall survival was analyzed. RESULTS: PriMet comprises 635 patients (LN tissue in 142 patients). Discrepancies for HR or HER2 status between PT and DR were observed in 18.7 and 21.6% of cases, respectively. For HR status, positivity of PT and negativity of DR was seen more often (13.2%) than vice versa (5.5%). For HER2 status, negativity of the primary and positivity of DR was seen more often (14.9%) than vice versa (6.7%). Discordance was more often observed between PT and LN metastasis compared to LN versus DR. However, numbers were small. Compared to concordant non-triple-negative (TN) disease, concordant TN disease showed significantly inferior PRS. CONCLUSION: We demonstrate receptor discordance to occur relatively frequently between PT, LN metastasis, and DR and to impact patient prognosis. However, clinical consequences of receptor discordance need to be drawn with caution considering clinical aspects as well as tumor biology.

Granulomatous Mastitis: A Therapeutic and Diagnostic Challenge.

Granulomatous mastitis (GM) is a rare benign inflammatory breast disease that affects mostly women of childbearing age with a history of breastfeeding. The etiopathogenesis is still unknown; however, inflammation as the result of a reaction to trauma, metabolic or hormonal processes, autoimmunity, and an infection with Corynebacterium kroppenstedtii have all been implicated. Clinical findings are pain, mass, hyperemia, and inflammation. Because the clinical presentation can mimic infectious mastitis or inflammatory carcinoma, the disease course is often protracted. The diagnosis is made by histopathology. Biopsies show a granulomatous formation in combination with a localized infiltration of multi-nucleated giant cells, epithelioid histiocytes, and plasma cells. Ultrasound, mammography, and magnetic resonance imaging are not specific; however, ultrasound and mammography should be done to exclude other pathologies. Due to the lack of data including randomized controlled studies, the management of GM is controversial. In Western industrialized countries, most authors use a therapy regimen starting with antibiotics and corticosteroids, followed by continuous steroid therapy and surgery in patients with persisting symptoms. More data are needed to define the best therapy. The role of immunotherapy has not yet been ascertained. The implementation of a registry to collect more information on this rare disease is highly recommended.

Subclonal analysis in a lobular breast cancer with classical and solid growth pattern mimicking a solid-papillary carcinoma.

Recently, a new variant of invasive lobular breast cancer (ILBC) with solid-papillary-like growth pattern has been described. We present a case of ILBC with solid-papillary-like growth pattern in the main tumour mass and classical invasive lobular growth pattern in adjacent satellite foci. The two tumour components were subjected to comprehensive molecular analyses. Both components were ER/PR-positive, HER2-negative, and showed a complete loss of E-cadherin and beta-catenin protein expression, as determined by immunohistochemistry. Gene expression profiling classified the main tumour and a satellite focus as luminal-B and luminal-A subtypes, respectively. Whole-genome copy number profiles were highly similar in both tumour components. Shared copy number alterations (CNAs) included gains of chromosome 1q21.1-q43 and losses of chromosome 16q11.2-q24.3, the locus of the CDH1/E-cadherin tumour suppressor gene. CNAs detected only in the main tumour included a gain of chromosome 20q12-q13.33 and a loss of chromosome 1p36.33-p34.3, which has recently been associated with the solid variant of ILBC. Next generation sequencing revealed an identical, truncating CDH1 mutation (p.G169fs*5) in both tumour components confirming a common clonal ancestry. In conclusion, we confirm the recently described variant of ILBC with solid-papillary-like growth pattern and provide evidence that it evolves from classical ILBC by subclonal evolution.