Real-world EGFR testing practices for non-small-cell lung cancer by thoracic pathology laboratories across Europe

BACKGROUND

Testing for epidermal growth factor receptor (EGFR) mutations is an essential recommendation in guidelines for metastatic non-squamous non-small-cell lung cancer, and is considered mandatory in European countries. However, in practice, challenges are often faced when carrying out routine biomarker testing, including access to testing, inadequate tissue samples and long turnaround times (TATs).

MATERIALS AND METHODS

To evaluate the real-world EGFR testing practices of European pathology laboratories, an online survey was set up and validated by the Pulmonary Pathology Working Group of the European Society of Pathology and distributed to 64 expert testing laboratories. The retrospective survey focussed on laboratory organisation and daily EGFR testing practice of pathologists and molecular biologists between 2018 and 2021.

RESULTS

TATs varied greatly both between and within countries. These discrepancies may be partly due to reflex testing practices, as 20.8% of laboratories carried out EGFR testing only at the request of the clinician. Many laboratories across Europe still favour single-test sequencing as a primary method of EGFR mutation identification; 32.7% indicated that they only used targeted techniques and 45.1% used single-gene testing followed by next-generation sequencing (NGS), depending on the case. Reported testing rates were consistent over time with no significant decrease in the number of EGFR tests carried out in 2020, despite the increased pressure faced by testing facilities during the COVID-19 pandemic. ISO 15189 accreditation was reported by 42.0% of molecular biology laboratories for single-test sequencing, and by 42.3% for NGS. 92.5% of laboratories indicated they regularly participate in an external quality assessment scheme.

CONCLUSIONS

These results highlight the strong heterogeneity of EGFR testing that still occurs within thoracic pathology and molecular biology laboratories across Europe. Even among expert testing facilities there is variability in testing capabilities, TAT, reflex testing practice and laboratory accreditation, stressing the need to harmonise reimbursement technologies and decision-making algorithms in Europe.

Retrospective study to estimate the prevalence and describe the clinicopathological characteristics, treatments received, and outcomes of HER2-low breast cancer

BACKGROUND

Approximately 80% of all breast cancers (BCs) are currently categorized as human epidermal growth factor receptor 2 (HER2)-negative [immunohistochemistry (IHC) 0, 1+, or 2+/in situ hybridization (ISH) negative]; approximately 60% of BCs traditionally categorized as HER2-negative express low levels of HER2. HER2-low (IHC 1+ or IHC 2+/ISH-) status became clinically actionable with approval of trastuzumab deruxtecan to treat unresectable/metastatic HER2-low BC. Greater understanding of patients with HER2-low disease is urgently needed.

PATIENTS AND METHODS

This global, multicenter, retrospective study (NCT04807595) included tissue samples from patients with confirmed HER2-negative unresectable/metastatic BC [any hormone receptor (HR) status] diagnosed from 2014 to 2017. Pathologists rescored HER2 IHC-stained slides as HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2 IHC 0 after training on low-end expression scoring using Ventana 4B5 and other assays at local laboratories (13 sites; 10 countries) blinded to historical scores. HER2-low prevalence and concordance between historical scores and rescores were assessed. Demographics, clinicopathological characteristics, treatments, and outcomes were examined.

RESULTS

In rescored samples from 789 patients with HER2-negative unresectable/metastatic BC, the overall HER2-low prevalence was 67.2% (HR positive, 71.1%; HR negative, 52.8%). Concordance was moderate between historical and rescored HER2 statuses (81.3%; κ = 0.583); positive agreement was numerically higher for HER2-low (87.5%) than HER2 IHC 0 (69.9%). More than 30% of historical IHC 0 cases were rescored as HER2-low overall (all assays) and using Ventana 4B5. There were no notable differences between HER2-low and HER2 IHC 0 in patient characteristics, treatments received, or clinical outcomes.

CONCLUSIONS

Approximately two-thirds of patients with historically HER2-negative unresectable/metastatic BC may benefit from HER2-low-directed treatments. Our data suggest that HER2 reassessment in patients with historical IHC 0 scores may be considered to help optimize selection of patients for treatment. Further, accurate identification of patients with HER2-low BC may be achieved with standardized pathologist training.

ESMO expert consensus statements (ECS) on the definition, diagnosis, and management of HER2-low breast cancer

Human epidermal growth factor receptor 2 (HER2)-low breast cancer has recently emerged as a targetable subset of breast tumors, based on the evidence from clinical trials of novel anti-HER2 antibody-drug conjugates. This evolution has raised several biological and clinical questions, warranting the establishment of consensus to optimally treat patients with HER2-low breast tumors. Between 2022 and 2023, the European Society for Medical Oncology (ESMO) held a virtual consensus-building process focused on HER2-low breast cancer. The consensus included a multidisciplinary panel of 32 leading experts in the management of breast cancer from nine different countries. The aim of the consensus was to develop statements on topics that are not covered in detail in the current ESMO Clinical Practice Guideline. The main topics identified for discussion were (i) biology of HER2-low breast cancer; (ii) pathologic diagnosis of HER2-low breast cancer; (iii) clinical management of HER2-low metastatic breast cancer; and (iv) clinical trial design for HER2-low breast cancer. The expert panel was divided into four working groups to address questions relating to one of the four topics outlined above. A review of the relevant scientific literature was conducted in advance. Consensus statements were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This article presents the developed statements, including findings from the expert panel discussions, expert opinion, and a summary of evidence supporting each statement.

Refining patient selection for breast cancer immunotherapy: beyond PD-L1

Therapies that modulate immune response to cancer, such as immune checkpoint inhibitors, began an intense development a few years ago; however, in breast cancer (BC), the results have been relatively disappointing so far. Finding biomarkers for better selection of BC patients for various immunotherapies remains a significant unmet medical need. At present, only tumour tissue programmed death-ligand 1 (PD-L1) and mismatch repair deficiency status are approved as theranostic biomarkers for programmed cell death-1 (PD-1)/PD-L1 inhibitors in BC. However, due to the complexity of tumour microenvironment (TME) and cancer response to immunomodulators, none of them is a perfect selector. Therefore, an intense quest is ongoing for complementary tumour- or host-related predictive biomarkers in breast immuno-oncology. Among the upcoming biomarkers, quantity, immunophenotype and spatial distribution of tumour-infiltrating lymphocytes and other TME cells as well as immune gene signatures emerge as most promising and are being increasingly tested in clinical trials. Biomarkers or strategies allowing dynamic assessment of BC response to immunotherapy, such as circulating/exosomal PD-L1, quantity of white/immune blood cell subpopulations and molecular imaging are particularly suitable for immunotreatment monitoring. Finally, host-related factors, such as microbiome and lifestyle, should also be taken into account when planning integration of immunomodulating therapies into BC management. As none of the biomarkers taken separately is accurate enough, the solution could come from composite biomarkers, which would combine clinical, molecular and immunological features of the disease, possibly powered by artificial intelligence.

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At present, immune checkpoint inhibitors (ICIs) are the only approved immunotherapy drugs in BC.

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Tumour PD-L1 and microsatellite status are current companion biomarkers for ICIs in BC; however, these need improvement.

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Evaluation of tumour immune contexture and the dynamics of circulating immune cell counts are promising novel approaches.

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Development of noninvasive monitoring and composite biomarkers will facilitate cancer immunotherapy, including in BC.

Delayed care for patients with newly diagnosed cancer due to COVID-19 and estimated impact on cancer mortality in France

BACKGROUND

The impact of the first coronavirus disease 2019 (COVID-19) wave on cancer patient management was measured within the nationwide network of the Unicancer comprehensive cancer centers in France.

PATIENTS AND METHODS

The number of patients diagnosed and treated within 17 of the 18 Unicancer centers was collected in 2020 and compared with that during the same periods between 2016 and 2019. Unicancer centers treat close to 20% of cancer patients in France yearly. The reduction in the number of patients attending the Unicancer centers was analyzed per regions and cancer types. The impact of delayed care on cancer-related deaths was calculated based on different hypotheses.

RESULTS

A 6.8% decrease in patients managed within Unicancer in the first 7 months of 2020 versus 2019 was observed. This reduction reached 21% during April and May, and was not compensated in June and July, nor later until November 2020. This reduction was observed only for newly diagnosed patients, while the clinical activity for previously diagnosed patients increased by 4% similar to previous years. The reduction was more pronounced in women, in breast and prostate cancers, and for patients without metastasis. Using an estimated hazard ratio of 1.06 per month of delay in diagnosis and treatment of new patients, we calculated that the delays observed in the 5-month period from March to July 2020 may result in an excess mortality due to cancer of 1000-6000 patients in coming years.

CONCLUSIONS

In this study, the delays in cancer patient management were observed only for newly diagnosed patients, more frequently in women, for breast cancer, prostate cancer, and nonmetastatic cancers. These delays may result is an excess risk of cancer-related deaths in the coming years.

ESMO recommendations on the standard methods to detect RET fusions and mutations in daily practice and clinical research

Aberrant activation of RET is a critical driver of growth and proliferation in diverse solid tumours. Multikinase inhibitors (MKIs) showing anti-RET activities have been tested in RET-altered tumours with variable results. The low target specificity with consequent increase in side-effects and off-target toxicities resulting in dose reduction and drug discontinuation are some of the major issues with MKIs. To overcome these issues, new selective RET inhibitors such as pralsetinib (BLU-667) and selpercatinib (LOXO-292) have been developed in clinical trials, with selpercatinib recently approved by the Food and Drug Administration (FDA). The results of these trials showed marked and durable antitumour activity and manageable toxicity profiles in patients with RET-altered tumours. The European Society for Medical Oncology (ESMO) Translational Research and Precision Medicine Working Group (TR and PM WG) launched a collaborative project to review the available methods for the detection of RET gene alterations, their potential applications and strategies for the implementation of a rational approach for the detection of RET fusion genes and mutations in human malignancies. We present here recommendations for the routine clinical detection of targetable RET rearrangements and mutations.

Clinical and molecular practice of European thoracic pathology laboratories during the COVID-19 pandemic. The past and the near future

Background

This study evaluated the consequences in Europe of the COVID-19 outbreak on pathology laboratories orientated toward the diagnosis of thoracic diseases.

Materials and methods

A survey was sent to 71 pathology laboratories from 21 European countries. The questionnaire requested information concerning the organization of biosafety, the clinical and molecular pathology, the biobanking, the workload, the associated research into COVID-19, and the organization of education and training during the COVID-19 crisis, from 15 March to 31 May 2020, compared with the same period in 2019.

Results

Questionnaires were returned from 53/71 (75%) laboratories from 18 European countries. The biosafety procedures were heterogeneous. The workload in clinical and molecular pathology decreased dramatically by 31% (range, 3%-55%) and 26% (range, 7%-62%), respectively. According to the professional category, between 28% and 41% of the staff members were not present in the laboratories but did teleworking. A total of 70% of the laboratories developed virtual meetings for the training of residents and junior pathologists. During the period of study, none of the staff members with confirmed COVID-19 became infected as a result of handling samples.

Conclusions

The COVID-19 pandemic has had a strong impact on most of the European pathology laboratories included in this study. Urgent implementation of several changes to the organization of most of these laboratories, notably to better harmonize biosafety procedures, was noted at the onset of the pandemic and maintained in the event of a new wave of infection occurring in Europe.

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Biosafety measures used in the first wave of the COVID-19 crisis were heterogeneous in 53 European pathology laboratories.

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A dramatic decrease of the workload in pathology laboratories was noted.

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No case of healthcare workers contaminated with SARS-CoV-2 associated with samples handling was identified.

Diagnosis and management of tropomyosin receptor kinase (TRK) fusion sarcomas: expert recommendations from the World Sarcoma Network

Sarcomas are a heterogeneous group of malignancies with mesenchymal lineage differentiation. The discovery of neurotrophic tyrosine receptor kinase (NTRK) gene fusions as tissue-agnostic oncogenic drivers has led to new personalized therapies for a subset of patients with sarcoma in the form of tropomyosin receptor kinase (TRK) inhibitors. NTRK gene rearrangements and fusion transcripts can be detected with different molecular pathology techniques, while TRK protein expression can be demonstrated with immunohistochemistry. The rarity and diagnostic complexity of NTRK gene fusions raise a number of questions and challenges for clinicians. To address these challenges, the World Sarcoma Network convened two meetings of expert adult oncologists and pathologists and subsequently developed this article to provide practical guidance on the management of patients with sarcoma harboring NTRK gene fusions. We propose a diagnostic strategy that considers disease stage and histologic and molecular subtypes to facilitate routine testing for TRK expression and subsequent testing for NTRK gene fusions.

Abstract P3-11-10: Prosigna prognostic signature in pN1mi, estrogen receptor-positive breast cancer:the pN categorization impacts the BC risk stratification

Background

Several validated molecular subtyping tests for breast cancer based on gene expression profiling are now routinely used in clinical practice.The Prosigna® breast cancer (BC) prognostic gene signature assay identifies a gene-expression profile that permits the classification of tumors into subtypes and gives a score for the risk of recurrence (ROR) at 10 years. The assay uses the 50-gene expression profile, weighted together with clinical variables, to generate a risk category and numerical score. The score is reported on a 0-100 scale, for hormone receptor positive BC. Prosigna test results classified tumors according to intrinsic subtypes (Lum A, Lum B, HER2-enriched, basal-like) and ROR risk groups (low risk, 0-40; intermediate risk, 41-60; and high risk, 61-100).

For node-positive patients, the weight given to the node status is similar when considering pN1mi ([0.2-2mm]) or pN1 (>2mm, 1-3 positive lymph nodes). Our aim was to characterize the Prosigna test classification of the pN1mi subgroup in the French national registry for molecular signatures in ER+ BC.

Methods

Since 2018, four French laboratories using Prosigna test in clinical practice retrospectively implement a national registry for molecular prognostic signatures in ER+ BC. We analyzed the pN1mi subgroup with regards to their clinico-pathological characteristics, Prosigna test results and ROR risk score. Using the definition formula of the prosigna algorithm, we could calculate a hypothetical score if the pN1mi has been considered as pN0 and redefine risk categories for pN1mi breast cancers.

Results

The database included 886 tests performed in routine practice, including 91 (10.3%) pN1mi. The pN1mi BC were ER+ HER2- (88/91, 96.7%), invasive carcinoma of no special type in 81/91 (89%), with a median tumor size of 23 mm (range 12-60). Among these, the median ROR score was 44, and 51/91 tumors (56%) were classified as LumA tumors, 34/91 (41%) as LumB, two asHER2-enriched and one as basal-like. Interestingly, the probability of distant recurrence was 26% if pN1mi BC were considered as N+ but lowered to 10% if considered as pN0. Among the different molecular subtypes, the change from pN1 top N0 has different weight: in Lum A tumors, the switch in the probability of distant recurrences was 13 to 6% according to pN categorization of the pN1mi BC, and the median ROR score moved from 27 to 6 with 15/51(29%) of Lum A tumors considered as high risk if pN1 but only 1/51 if pN0; 31/51 (61%) versus 14/51 (27.5%) were in the intermediate risk group, and only 5/51 (10%) versus 34 (67%) in the low risk group. For LumB tumors, the switch in the probability of distant recurrences was 29% to 17% according to pN categorization and and the median ROR score moved from 60 to 15 with 36/37(97.3%) of Lum B tumors considered as high risk if pN1but only 13/37(35%) ifp N0; 1/37 versus 20/37 (54%) were in the intermediate risk group, and none of the 37 LumB versus 1 in the low risk group.

Conclusion

With regards to Prosigna test in pN1mi BC - and the persistent debate as to whether they should bear the same weight as pN1 pN0 tumors - categorization in ROR risk group is likely to be impacted by the node factor weight, and more importantly among Lum B tumors.

Citation Format: Charafe-Jauffret E, Duprez-Paumier R, Berghian A, Penault-Llorca F, Dauplat MM, Boucraut A, Cohen M, Houvenaeghel G, Maroc C, Pradines A, Cayre A, Etancelin P, Lacroix-triki M. Prosigna prognostic signature in pN1mi, estrogen receptor-positive breast cancer:the pN categorization impacts the BC risk stratification [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-11-10.

Abstract P5-12-09: The ≥5% cut-off reveals tumor PD-L1 positivity as potential selection biomarker for patient enrollment into the trials evaluating anti-PD-1 or anti-PD-L1 agents in neoadjuvant treatment of triple negative breast cancer

Background: Durable responses of triple negative breast cancer (TNBC) to pembrolizumab (anti-PD-1) or atezolizumab (anti-PD-L1) have been reported in the metastatic setting. Moreover, it is currently being hypothesized that immune checkpoint inhibitors might be more effective in the neoadjuvant setting, due to better preserved anti-tumor immunity in early TN disease. However, biomarkers predictive of response to anti-PD-1 or anti-PD-L1 agents, as well as biomarker-based strategies for testing those drugs in the neoadjuvant setting are still lacking. We evaluated PD-L1 protein expression and the composition of tumor-infiltrating lymphocytes (TILs) in untreated TNBC, in order to get a better insight into the TNBC sub-population(s) which would be suitable for neoadjuvant anti-PD-1 or anti-PD-L1 therapy evaluation. Methods: TNBC patients consecutively treated at the Jean Perrin Comprehensive Cancer Centre (Clermont-Ferrand, France), from 01/01/2010 to 12/31/2014, were included. FFPE tumor tissues were assessed for PD-L1 expression by immunohistochemical (IHC) laboratory-developed test (clone 28-8, Abcam), in tumor cells (tPD-L1) and in TILs. Positivity cut-offs evaluated were ≥1%, ≥5% and ≥10%. The amount CD8+, CD4+, FoxP3+ or PD-1+ TILs was determined by counting those cells, detected by IHC methods, within 5 consecutive HPFs (x400), from tumor invasive front toward tumor center. Clinical disease stage was determined using the TNM system. Results: One hundred and two TNBCs were assessed. There were 28.4%, 23.5% or 16.7% tPD-L1-positive cases (cs), for cut-offs ≥1%, ≥5% or ≥10%, respectively. Similarly, 32.4%, 15.7% or 5.9% of cs were positive for PD-L1 in TILs, using the same cut-offs. With ≥5% as cut-off, positivity for tPD-L1 significantly correlated with the amount of CD8+ (p=0.023), FoxP3+ (p=0.0036) or PD-1+ TILs (p=0.043). The same cut-off, applied to TILs, revealed significant correlations between PD-L1 positivity and the amount of each CD8+, CD4+ or PD-1+ TILs (p=0.025, 0.039 and 0.0042, respectively). Interestingly, when the ≥5% cut-off was used, tumors of T2 size were most frequently tPD-L1+ (11/41 cs, 26.8%), compared with the T1 (3/35 cs, 8.6%) and T3+T4 (3/18 cases, 16.7%) (p=0.04). With regards to TILs, with the ≥5% cut-off, the PD-L1+ cases belonged exclusively to the T1+T2 group (15/76), whereas the T3+T4 group was PD-L1-negative (0/18 cs). Other two cut-offs revealed only occasional correlations. Conclusion: This single-center, real-world TNBC cohort contained a high number of smaller tumors (T1-T2). The IHC-based PD-L1 assessment, with ≥5% as the positivity cut-off, revealed that approximately 1/4 of TNBC could be candidates for neoadjuvant anti-PD-1/anti-PD-L1 approaches. Combined with the amount of CD8+ and PD-1+ TILs, tumor PD-L1 positivity might make an easy-to-use composite biomarker for the 1st-level patient selection for PD-1 or PD-L1 inhibitors in neoadjuvant TNBC treatment. The 2nd level could exploit, for example, the assessment of mutation burden in tumors with low tPD-L1 or amount of CD8+ or PD-1+ TILs. Such tumors might be more frequent among larger TNBC (T3-T4).

Citation Format: Finck W, Passildas J, Poirier C, Kwiatkowski F, Abrial C, Durando X, Penault-Llorca F, Radosevic-Robin N. The ≥5% cut-off reveals tumor PD-L1 positivity as potential selection biomarker for patient enrollment into the trials evaluating anti-PD-1 or anti-PD-L1 agents in neoadjuvant treatment of triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-09.

Abstract P5-12-05: Phenotypic discordance between primary and metastatic breast cancer (MBC) in a large scale real-life multicentre French cohort

Background: Therapeutic options at diagnosis for metastatic breast cancers (MBC) differ largely according to cancer phenotype (namely, hormone receptor (HR) and HER2 status). Reported discordance rates between primary tumor and metastasis vary widely in literature, with a median of 18% for estrogen receptor, 31% for progesterone receptor and 10% for HER2. The present study aimed to compare phenotypic profiles between primary and MBC in the real-life setting.

Patients (pts) and methods:

Epidemio-Strategy and Medical Economics (ESME)MBC data platform (NCT03275311) is a French national, multicenter, observational cohort using clinical trials' methodology for data capture, monitoring and quality controls. At the time of analysis, it comprised data of 16703 consecutive newly diagnosed MBC pts (1/01/08-31/12/14) treated in 18 French comprehensive cancer centres. The primary endpoint was the discordance rate of HR and HER2 status between primary tumor and MBC (biopsy of metastatic site done within 6 months of MBC diagnosis). Only patients with both histological reports available were considered. Potential factors associated with phenotype discordance were assessed in a multivariate logistic regression.

Results: 2933 out of 16703 (17.6%) had a biopsy in the first 6 months of metastatic disease. HR and/or HER2 status was available in 1677 pts. The discordance rate between primary and matched MBC was 14.2% (222/1566) for HR: loss of expression in 72.5%, gain in 27.5%. For HER2, the discordance rate was 7.8% (84/1076): 45.2% of losses and 54.8% of gains of expression. The primary HR+/HER2+ subgroup had the highest rate of changes: 53% (49/92) with either a loss of HR (43%), loss of HER2 (43%) or a loss of both (14%). 18% (33/181) of primary triple-negative breast cancer (TNBC) had a phenotypic change with a majority of HR gain (79%). In multivariate analysis, administration of adjuvant chemotherapy +/- targeted therapy was the sole independent predictor of HR status modification (OR: 1.73, 95%CI 1.27-2.36, p=0.001). The presence of a mixed histology was the only predictor of HER2 discordance (OR =2.57, 95%CI 1.19-5.55, p=0.016).

Patient characteristics Total population (n=16703)Pts with primary and MBC phenotype available (n=1677)Age at metastatic diagnosis Median (range)61 (19-99)60 (24-93)De novo MBC4507 (27.1%)221 (13.2%)Number of metastatic sites Median (range)1 (1-9)2 (1-7)MBC sites  Brain1200 (7.2%)138 (8.2%)Visceral7755 (46.4%)928 (55.3%)Non-visceral7748 (46.4%)611 (36.4%)Phenotypic profileN = 2933N=1677TNBC356 (18.5%)272 (19.3%)HR+/HER2-1251 (65.0%)917 (65.2%)HR-/HER2+150 (7.8%)105 (7.5%)HR+/HER2+168 (8.7%)112 (8%)Missing1008271Metastatic site samplingN=2933N=1677Bone692 (24.2%)419 (25.5%)Liver514 (18.0%)355 (21.6%)Skin379 (13.3%)203 (12.4%)Node306 (10.7%)169 (10.3%)Lung258 (9.0%)168 (10.2%)Pleura283 (9.9%)121 (7.4%)CNS/CSF*132 (4.6%)42 (2.6%)Other or multiple296 (10.3%)165 (10.0%)Missing7335* CNS= central nervous system, CSF=cerebro-spinal fluid

Conclusion: Biopsy and phenotype re-evaluation of MBC early in the disease course has a confirmed potential significant therapeutic impact in this large scale real life setting and should be proposed as often as possible.

Citation Format: Lefevre S, Lusque A, Joyon N, Arnould L, Penault-Llorca F, MacGrogan G, Treilleux I, Vincent-Salomon A, Haudebourg J, Maran-Gonzalez A, Charafe-Jauffret E, Courtinard C, Franchet C, Verriele V, Brain E, Tas P, Delaloge S, Filleron T, LaCroix-Triki M. Phenotypic discordance between primary and metastatic breast cancer (MBC) in a large scale real-life multicentre French cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-05.

Abstract P4-15-02: TILs variations, proliferative response and PEPI scores in patients with luminal breast cancer receiving neoadjuvant letrozole-palbociclib or chemotherapy: An extended analysis of the NEOPAL trial

Background

The role of chemotherapy in early luminal breast cancer remains challenged. The NEOPAL trial (NCT 02400567; Cottu et al, ESMO 2017 LBA09) compared sequential chemotherapy (CT) and letrozole-palbociclib (LP) as neoadjuvant treatment in PAM50 defined high-risk luminal breast cancer patients, showing that LP might be as efficient as CT with regard to breast conserving surgery and pathological response. We report here extended exploratory pathological results, focusing on tumor infiltrating lymphocytes (TILs), proliferative response and preoperative endocrine prognostic index (PEPI) scores.

Material and Methods

Tumor blocks from baseline biopsy and surgical specimens were available for centralized review from the 106 randomized patients (53 in each arm). TILs quantification, KI67 staining and counting, and ER quantification were performed according to standard methods. Residual proliferative cancer burden (RPCB) and PEPI scores were computed according to published algorithms. Wilcoxon rank sum test and Mann Whitney test were used to compare paired and unpaired data. The chi-square and Fisher exact tests were used for categorical variables.

Results

Overall, median TILs count did not differ between LP and CT patients, both at baseline (p=0.37) and at the end of treatment (p=0.42). Median TILs count climbed from 5% (0-60) to 10% (1-60) in the LP arm (p=0.0026) and from 2% (0-30) to 10% (0-60) in the CT arm (p=0.0023). Median Ki67 dropped sharply in both arms, from 30% (1-80) to 1% (0-30) in the LP arm (p=1.10e-8) and from 30% (2-80) to 5% (0-30) in the CT arm (p=3.10e-9). Decrease in the Ki67 geometric mean was as sharp. Of note, while baseline Ki67 was similar in both arms (p=0.315), decrease in the LP arm was significantly more profound than in the CT arm (p=0.00075). Pathological response according to RPCB were as follows, in the LP and CT arm, respectively: class 0: 9.6%/10.2%; class I: 84.6%/73.5%; class II: 5.8%/16.3%. The relapse free survival PEPI scores were as follow in the LP and CT arm, respectively: class I: 13.5%/16.3%; class II: 59.6%/46.9%; class III: 28.9%/36.8% (p=0.504). Breast cancer specific survival PEPI scores were as follow in the LP and CT arm, respectively: class I: 18.9%/8.2%; class II: 54.7%/40.8%; class III: 26.4%/51%. These results were significantly better in the LP arm (p=0.027). There was no correlation between final TILs quantification and the RPCB or PEPI scores.

Conclusions

In this prospective multicenter study with centralized pathological review, neoadjuvant letrozole-palbociclib combination generates impressive proliferative and endocrine specific response features. It compared well with chemotherapy. The LP combination also significantly increased lymphocytic infiltration. Its clinical significance and utility remain to be elucidated, but it potentially adds new prognostic and theranostic information.

Citation Format: Vincent-Salomon A, Mathieu M-C, Bataillon G, Arnould L, Verrièle V, Ghnassia J-P, Haudebourg J, Penault-Llorca F, Lefebvre C, Maran-Gonzalez A, Guinebretière J-M, Duprez R, Berghian A, Blanc-Fournier C, Calès V, Galant C, Delrée P, Lemonnier J, Delaloge S, Cottu PH. TILs variations, proliferative response and PEPI scores in patients with luminal breast cancer receiving neoadjuvant letrozole-palbociclib or chemotherapy: An extended analysis of the NEOPAL trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-15-02.

Targeting the human epidermal growth factor receptor 2 (HER2) oncogene in colorectal cancer

Human epidermal growth factor receptor 2 (HER2) is an oncogenic driver, and a well-established therapeutic target in breast and gastric cancers. Using functional and genomic analyses of patient-derived xenografts, we previously showed that a subset (approximately 5%) of metastatic colorectal cancer (CRC) tumors is driven by amplification or mutation of HER2. This paper reviews the role of HER2 amplification as an oncogenic driver, a prognostic and predictive biomarker, and a clinically actionable target in CRC, considering the specifics of HER2 testing in this tumor type. While the role of HER2 as a biomarker for prognosis in CRC remains uncertain, its relevance as a therapeutic target has been established. Indeed, independent studies documented substantial clinical benefit in patients treated with biomarker-driven HER2-targeted therapies, with an impact on response rates and duration of response that compared favorably with immunotherapy and other examples of precision oncology. HER2-targeted therapeutic strategies have the potential to change the treatment paradigm for a clinically relevant subgroup of metastatic CRC patients.

Abstract P4-15-03: Tumor-infiltrating lymphocytes in breast ductal carcinoma in situ: Correlations with tumor pathobiology in a French cohort of 495 cases (BONBIS)

Background: Numerous studies have shown important impact of tumor-infiltrating lymphocytes (TILs) on natural or therapeutically-modified evolution of invasive breast cancer (IBC), however knowledge about TIL role in breast ductal carcinoma in situ (DCIS) is still limited. Because of the lack of reliable prognostic parameters, DCIS treatment is much less personalized than IBC therapy. BONBIS is a phase 3 French multicenter randomized trial designed to compare 2 schemes of adjuvant radiotherapy (adjRT) for DCIS (Azria et al, ASCO meeting 2011, TPS 131). It is accompanied by a translational study of DCIS pathobiology, aimed to discover predictive or prognostic biomarkers. Here we present results of TIL density (TIL-d) assessment, its correlation with pathobiology of the lesions and preliminary clues for further biomarker search in this DCIS cohort. Methods: Formalin-fixed, paraffin-embedded DCIS surgical specimens, obtained before adjRT, were prospectively collected and centrally reviewed for histology (architectural pattern, nuclear grade, proliferation, presence of necrosis), receptor status (ER, PR, HER2) and TIL-d. TIL-d was assessed on H&E-stained DCIS sections and reported as percentage of the DCIS specialized stroma area occupied by lymphocytes, lympho-plasmocytes and plasmocytes. Tumors were classified using the St Gallen 2011 criteria for IBC (PMID 21709140). For purpose of this study, the HER2+ category included all cases with HER2 protein expression scored 2+ and 3+, irrespective of the ERBB2 amplification status. Results: TIL-d was assessed in 495 cases, with distribution as follows: 0-4% TILs (D1): 85.5% (n=423); 5-9% TILs (D2): 9.3% (n=46); ≥10% TILs (D3): 5.2% (n=26). Molecular subclasses of those cases were: luminal A (LumA): 39% (n=192); luminal B (LumB): 25.5% (n=126), HER2+: 28.5% (n=141) and triple-negative (TN): 7% (n=33). TIL-d significantly correlated with molecular subclass: ≥5% TILs (D2) were found in 39.4% (13/33) TN, 22.7% (32/141) HER2+, 18.2% (23/126) LumB and only in 1% (2/192) LumA cases (p<10-7). TIL-d of ≥10% (D3) was found only in 26/495 cases (5.2%) and of ≥50% only in one. Similarly to D2, D3 was most frequent in TN, and then in HER2+, LumB and LumA lesions (15%, 9.2%, 7.1%, 0.5%, resp., p<10-7). TIL-d significantly correlated with 2 architectural patterns: positively with solid (38.8%, 52.2% and 60% of D1, D2 and D3 within the solid lesions, resp., p=0.03) but negatively with cribriform (53%, 32.6% and 28% of D1, D2 and D3 within the cribriform lesions, resp., p=0.0027). Finally, the presence of necrosis was significantly associated with TIL-d of ≥5% (65.7% vs 84.5%, D1 vs D2+D3, p=0.071). Due to still short follow-up, the analysis of predictive factors for survival or adjRT benefit was not performed. Conclusion: This DCIS cohort is characterized by low density of TILs. Richer infiltration by TILs (≥10%) was found, as reported in IBC, in TN and HER2+ lesions, however ≥50% TILs was an extremely rare finding. Interestingly, the LumB cases had TIL-d comparable to the HER2+ cases. The associations between ≥10% TILs and molecular subclass or with DCIS architecture will be evaluated in the future as biomarkers of adjRT impact on survival in this cohort.

Citation Format: Bayol B, Tixier-Deves L, Dauplat M, Kwiatkowski F, Cayre A, Abrial C, Azria D, Penault-Llorca F, Radosevic-Robin N. Tumor-infiltrating lymphocytes in breast ductal carcinoma in situ: Correlations with tumor pathobiology in a French cohort of 495 cases (BONBIS) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-03.

Abstract P5-22-18: Withdrawn

This abstract was withdrawn by the authors.

Abstract P1-09-11: A phase Ib study of oral administration of lucitanib in combination with fulvestrant in patients with HR+ metastatic breast cancer (mBC)

FGFR1 amplification could mediate resistance to endocrine therapy and FGFR1 inhibition reverses this resistance. This phase Ib seeks to evaluate whether the combination of lucitanib, a potent FGFR/VEGFR/PDFGR inhibitor, in combination with fulvestrant, an endocrine agent, reverses resistance to fulvestrant.

Eligible patients for this study were postmenopausal with ER+/HER2- mBC and have relapsed during or after treatment with fulvestrant. There were 2 parts in the study: a dose allocation to assess the tolerability of the combination in terms of DLTs and MTD using a modified Continual Reassessment Method (mCRM) [part I] and a dose expansion, with patients assigned to 2 different cohorts based on FGFR amplification, to further evaluate the tolerability of the combination and to identify the recommended phase II dose (RP2D) [part II]. Surrogate target hitting biomarkers were also dosed at baseline and on-treatment. The sponsor decided to halt the clinical development in mBC indication and the study was prematurely terminated after 18 patients (15 in part I and 3 in part II). The presentation will focus on these 18 patients.

Patients had ECOG PS 0 or 1 and median number of previous treatments in metastatic setting was 3. Two doses of lucitanib (10mg daily n=9 and 12.5mg daily n=6) in combination with 500 mg/month of fulvestrant were tested in part I. At the 10mg dose level, one patient experienced a DLT (grade 3 hypertension). Based on global lucitanib development program data, it was decided to start Part II with lucitanib 10mg daily. The most common related grade ≥3 toxicities occurring in more than 10% of patients were hypertension (78%) and asthenia (22%). All patients required at least one dose interruption mainly for toxicities, while 13 patients (72%) required at least a dose reduction for toxicities. Thirteen patients (72%) withdrew from the study for disease progression, 3 (17%) for adverse events (at 10mg) and 2 (11%) for non-medical reasons. Three patients achieved a confirmed partial response (as per RECIST v1.1), one at 10mg and two at 12.5mg. About 55% of the patients experienced clinical benefit with a median duration of the benefit of 39.6 weeks and a maximun duration of the benefit of 79.1 weeks for 1 patient (PR at Cycle 4). Biomarker modulations were consistent with lucitanib mode of action; targeting VEGFRs (significant increase of VEGFA, IL8, PlGF) and FGFR1 (significant increase of FGF23).

The combination is feasible but requires close patient monitoring and intensive management of adverse events. Those are in line with the anti-angiogenic activity of lucitanib.

  10mg (N=12)12.5mg (N=6)All (N=18)Objective Response Rate (ORR)n(%) 11 (8.3)2 (33.3)3 (16.7) 95% CI 3[1.5;35.4][9.7;70.0][5.8;39.2]Clinical Benefit Rate (CBR)n(%) 24 (33.3)6 (100.0)10 (55.6) 95% CI 3[13.8;61.0][61.0;100.0][33.7;75.4]Duration of Clinical Benefitmedian (weeks)28.171.339.6 95% CI 3[27.9; 32.7][29.1; 79.1][27.9; 79.1]1: CR or PR 2: CR or PR or stabilization (SD or NonCR/NonPD) >24 weeks or at end of cycle 6 3: 95% Wilson method of Confidence interval of the estimate

Citation Format: Campone M, Bachelot T, Penault-Llorca F, Pallis A, Agrapart V, Pierrat M-J, Poirot C, Paux G, Dubois F, Xuereb L, Robert R, Andre F. A phase Ib study of oral administration of lucitanib in combination with fulvestrant in patients with HR+ metastatic breast cancer (mBC) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-09-11.

Abstract P2-03-01: Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration

Aims: (i) Determine whether between-observer reproducibility for Ki67 when assessed on whole sections according to a standardized scoring protocol is adequate for clinical application. (ii) Compare between-observer reproducibility of Ki67 scores assessed on hot-spots to scores using a global method that averages across a tissue section.

Background: The nuclear proliferation biomarker Ki67 has multiple potential roles in breast cancer, including aiding decisions based on prognosis, but unacceptable levels of between-laboratory variability have been observed. The International Ki67 in Breast Cancer Working Group has undertaken a systematic program to determine whether Ki67 measurement can be analytically validated and standardized across labs. In phase 1, variability in visual interpretation was identified as an important source of variability. Phases 2 and 3a showed that adherence to defined scoring methods substantially improved reproducibility in scoring tissue microarrays and core-cut biopsies. We now assess whether acceptable reproducibility can be achieved on whole sections.

Methods: Adjacent sections from 30 primary ER+ breast cancers were centrally stained for Ki67 to assemble 4 sets of 30 stained tumor sections, circulated around 23 labs in 12 countries. Ki67 was scored by 2 methods by all labs: (a) global: 4 fields of 100 tumor cells each were selected to reflect observed heterogeneity in nuclear staining (b) hot-spot: the field with highest Ki67 percentage of tumor cells with nuclear staining was selected and up to 500 cells scored. Ki67 scores were log2-transformed for statistical analyses and back-transformed for presentation. The primary objective was to assess whether either method could achieve an intraclass correlation coefficient (ICC) significantly greater than 0.8, considered substantial to almost-perfect reproducibility. Secondary objectives were to assess which method had highest observed ICC and to assess whether observers identified the same “hot-spots”.

Results: ICC for the global method was 0.87 (95%CI: 0.799-0.93), marginally meeting the prespecified success criterion. The ICC for the hot-spot method was 0.83 (95%CI: 0.74-0.90) and had a CI extending below the success criterion. Across the 23 labs, geometric mean value of the 30 scores ranged from 8.5 to 19.6 for the global method and from 12.8 to 30.3 for the hot-spot method. The overall mean (95% CI) of these values was 12.9 (11.9-14.0) and 20.9 (19.1-22.8), respectively. Visually, between-laboratory agreement in location of selected hot-spot varies between cases. The median times for scoring were 9 and 6 minutes for global and hot-spot methods respectively.

Conclusions: The global method marginally met the prespecified criterion of success; it should now be evaluated for clinical validity in appropriate cohorts of cases. The hot-spot method was observed to have slightly less reproducibility between labs. The time taken for scoring by either method is practical using counting software we are making publicly available. Establishment of external quality assessment schemes is likely to improve the reproducibility between labs further.

(Supported by a grant from the Breast Cancer Research Foundation)

Citation Format: Nielsen TO, Leung SCY, Zabaglo LA, Arun I, Badve SS, Bane AL, Bartlet JMS, Borgquist S, Chang MC, Dodson A, Ehinger A, Fineberg S, Focke CM, Gao D, Gown AM, Gutierrez C, Hugh JC, Kos Z, Lænkholm A-V, Mastropasqua MG, Moriya T, Nofech-Mozes S, Osborne CK, Penault-Llorca FM, Piper T, Sakatani T, Salgado R, Starczynski J, Sugie T, van der Vegt B, Viale G, Hayes DF, McShane LM, Dowsett M. Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-01.

Abstract P2-09-29: Potential recurrence markers of locally advanced triple negative breast cancer treated by combined neoadjuvant EGFR targeting and chemotherapy, revealed by genomic analyses and assessment of tumor-infiltrating lymphocytes

Background: Epidermal growth factor receptor (EGFR) is expressed in ˜50% of triple negative breast cancer (TNBC) and has been proposed as a therapeutic target in this disease. However, trials testing EGFR blockade in TNBC failed to show significant clinical benefit. Probable reasons for such results were patient selection based on EGFR expression and the enrollment of heavily pretreated metastatic patients. Our team has conducted two neoadjuvant trials testing the activity of the anti-EGFR antibodies panitumumab (PTB) and cetuximab (CTX) combined with chemotherapy in locally advanced TNBC. Biomarkers predictive of pathological complete response (pCR) were the level of tumor cell EGFR protein expression and tumor-infiltrating lymphocytes' (TILs) profile (PMIDs 24827135, 26649807). The PTB-treated pts had a higher pCR rate (47%) than the CTX-treated pts (24%), but also a twice higher relapse rate, after 5 years of follow-up. Here we report results of genomic and TILs studies, performed in order to reveal possible determinants of recurrences in those trials. Methods: Tumor tissues sampled before and after neoadjuvant therapy (NAT) have been analyzed by next generation sequencing (NGS) using a targeted exome panel (MSK-IMPACT) of 410 cancer-related genes. Gene expression was evaluated by Affymetrix arrays. TIL density was assessed on pre-NAT samples according to Salgado et al, 2014 (PMID 25214542). The correlation between response, recurrences, genomic and TIL findings was analyzed in a case-by-case fashion. Results: Sixteen tumors that achieved pCR (PTB: 11, CTX: 5) and 23 non-pCR tumors (PTB: 11, CTX: 12) have been analyzed. For 14 non-pCR tumors (PTB: 6, CTX: 8) data have been obtained both from the pre-NAT and the post-NAT sample. Among those tumors, 6 recurred within 2 years after surgery (PTMB: 3, CTX: 3) and assays are on-going on several others that relapsed. Several genomic aberrations that potentially played a causative role in opposing to therapy were identified. We observed multiple mutations in the PI3K pathway in several non-pCR or relapsing pts. Interestingly, in a residual tumor (RT) of a non-pCR patient we found 3 different activating mutations in PIK3CA and one in PTEN. Another example of genomic selection induced by pharmacological pressure is the emergence of a HRAS G12S mutation in a RT after CTX. Additional novel findings include in-frame mutations and deletions in ARID1B and PARP1 amplification in non-pCR pts. Most of the tumors which recurred had ≤10% TILs (9/13) and only 4/13 had ≥30%. Among the tumors with a post-NAT RT but without recurrence, 17/33 had ≤10% TILs and 16/33 ≥30%. No particular link between TIL density and mutation pattern was observed. Conclusions: This is an example of a case-by-case approach where we captured the intrinsic inter-tumor heterogeneity, which is likely responsible for the different responses to EGFR-targeting in TNBC. Genes/pathways candidate of resistance to therapy are currently being validated.

Citation Format: Radosevic-Robin N, Cocco E, Privat M, Abrial C, Penault-Llorca F, Scaltriti M. Potential recurrence markers of locally advanced triple negative breast cancer treated by combined neoadjuvant EGFR targeting and chemotherapy, revealed by genomic analyses and assessment of tumor-infiltrating lymphocytes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-29.

Abstract P1-07-02: Chemotherapy (CT) decision in patients (pts) with node-positive (N+), ER+, early breast cancer (EBC) in the wake of new ASCO guideline – A different take on the evidence for the 21-gene recurrence score (RS) assay

Background: The use of molecular tools for prognosis and prediction of CT benefit in EBC has increased the complexity of decision making. The 21-gene RS (Oncotype DX) is included in the ASCO (2007) and NCCN guidelines (2006) for prognosis (risk of distant recurrence [DR]) and prediction of CT benefit in N0, ER+ EBC. In 2015, the NCCN added that the RS assay could be considered for select patients with 1-3 N+, ER+ EBC. Recently the ASCO BC biomarker/guideline group (J Clin Oncol 2016) advised that the “clinician should not use the 21-gene RS to guide decisions” and called the evidence quality “intermediate” and the recommendation “moderate” based on review of 2 N+ studies. It also advised no change in N+ clinical practice until the prospective SWOG S1007 study (RxPONDER) matures in several years. These discordant recommendations have led to major confusion among physicians, pts and payers. To address this controversy we herein report a comprehensive analysis of the body of evidence regarding the clinical utility of the RS in N+, ER+ EBC.

Methods: All published studies involving N+, ER+ EBC with RS data were analyzed by type of study design and category of trial (validation, supportive, decision impact, cost-effectiveness, and prospective outcomes).

Results: 30 studies provided clinical evidence supporting the value and utility of the RS in N+, ER+ pts. 7 studies employed a prospective-retrospective design or were prospective outcomes with clinical utility in >8000 N+ pts (Table). 23 additional studies assessed the impact of RS on CT decisions or cost-effectiveness.

Study in N+/ER+Type of studyNEndpoints/resultsSWOG S8814 (Lancet Oncol 2010)Pro-retro36710-year DFS and BCSS: RS predicts risk of DFS event, BC death, and CT benefit (none to slightly worse if very low risk RS and 1-3 N+)TransATAC (JCO 2010)Pro-retro3069-year DR: RS predicts risk of DR in pts treated with ET without CTECOG E2197 (JCO 2008)Pro-retro2325-year DR: RS predicts DR risk in CT+ET treated ptsNSABP B-28 (ASCO-BCS 2012)Pro-retro106510-year DRFI: RS predicts DR risk in CT+ET treated ptsPACS-01 (ASCO 2014)Pro-retro5305-year DRFI/DFS: RS predicts DR risk in CT+ET treated ptsSEER (npj BC 2016)Prospective outcomes46915-year BCSM: RS predicts BCSM; pts with RS <18 (Nmi, 1-3 N+) had 1.0% BCSMWSG PlanB (JCO 2016)Prospective outcomes1198 (1088 N1-3/110 N0)3-year DFS: 98.4% in high risk N0/N+ ER+, RS <12 group and 97.5% in RS 12-25 group (5-year DFS 94.0% in both RS groups)BCSM: BC-specific mortality; BCSS: BC-specific survival; DFS: disease free survival; DR: distant recurrence; DRFI: distant recurrence free interval; ET: endocrine therapy; Nmi: micrometastases; pro-retro: prospective-retrospective.

Conclusions: The 21-gene RS has now been studied in >10,000 N+, ER+ EBC pts across 30 studies worldwide, including 2 prospective outcomes studies in >5000 pts, confirming that the RS consistently identifies low risk 1-3 N+ pts in whom CT can effectively and safely be avoided. This evidence suggests that ER+ pts with few N+ and low RS should have a discussion of the pros and cons of adjuvant CT until the results of RxPONDER provide a definitive answer in several years.

Citation Format: Mamounas E, Goldstein L, Penault-Llorca F, Roche H, Gluz O, Harbeck N, Nitz U, O'Shaughnessy J, Albain K. Chemotherapy (CT) decision in patients (pts) with node-positive (N+), ER+, early breast cancer (EBC) in the wake of new ASCO guideline – A different take on the evidence for the 21-gene recurrence score (RS) assay [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-07-02.

Abstract P6-09-05: Prognostic and predictive values of high endothelial venules (HEV) and tumor infiltrating CD8+ lymphocytes (CD8) in tumors of patients included in the adjuvant PACS04 trial: HEV is predictive of outcome for HER2+ tumors exposed to trastuzumab

Background: HEV are specialized blood vessels that function as portals of entry for lymphocytes into lymphoid organs and tumor tissues (Moussion and Girard, Nature 2011, 479:542-546; Girard et al, Nature Rev Immunol 2012, 12:762-773). We retrospectively considered HEV and CD8 as potential prognostic and/or predictive factors in a large randomized adjuvant trial of node positive breast cancer patients (PACS04). This trial included 3010 node positive patients randomized between anthracyclins alone or anthracyclins and docetaxel chemotherapy. Patients with HER2+ expressing tumors had a second randomization with or without trastuzumab given sequentially for one year. With 59.5 median follow-up, metastatic free interval (MFI), the first end-point, was 84.5% at 5 years for the whole population.

Methods: 1660 tumor samples (9.7% triple negative, 67.5% HR+/HER2- and 22.8% HER2+) were collected and analyzed by immunostaining on full sections for HEV (MECA-79 mAb, BD Biosciences) and CD8 (C8/144B mAb, Dako). HEV densities were determined as previously described (Martinet et al., Cancer Res 2011, 71:5678-5687). CD8+ cells and tumor-infiltrating lymphocytes (TIL) were scored according to recently published guidelines. Univariate analyses were performed using cox proportional hazard model for continuous variable. Independent analyses for the predictive evaluation of trastuzumab outcome were performed in the HER2+ subgroup.

Results: MFI and overall survival at 5 years for this series are respectively of 84.9% (TN: 77.4%, HR+/HER2-: 89%, HER2+:75.8%) and 91% not different with the total group. The table shows expression of the different markers according to the subgroup of tumors.

Marker values according to sub molecular classification TNRH+/HER2-HER2+/RH-Number1601119378Metastatic events3411990HEV/mm2(median,range)0.51 (0, 7.73)0.13 (0, 10.23)0.38 (0, 13.63)CD8score (median, range)2 (0, 3)1 (0, 3)2 (0, 3)Table 1

No difference in univariate analysis was observed in TN and HR+/HER2- subgroups in terms of relationship between marker expression and outcomes. For the HER2+ group, HEV and CD8 were correlated to better outcome (HEV: HR=0.73, p =0.011; CD8: HR=0.64; p=0.006). For HER2+ patients not receiving trastuzumab (222 pts, 55 events), CD8 was predictive of metastasis risk (HR: 0.65, p=0.032), but not HEV (HR:0.82, p=0.09). Conversely, in the trastuzumab treated group (156 pts, 35 events), HEV was significantly correlated with a lower risk of relapse (HR: 0.45, p=0.02), but CD8 was not (HR:0.63, p=0.07). TIL counts are still ongoing and will be reported at time of presentation.

Conclusions: HEV and CD8 are associated with better prognosis in the HER2+ tumor group. Interestingly, HEV presence in the tumor seems to be a significant predictive factor of trastuzumab efficacy.

Citation Format: Roché HH, Lafouresse FF, Filleron T, Laffont R, Maisongrosse V, Pichery M, Le Guellec S, Penault-Llorca F, Lemonnier J, Lacroix-Triki M, Girard J-P. Prognostic and predictive values of high endothelial venules (HEV) and tumor infiltrating CD8+ lymphocytes (CD8) in tumors of patients included in the adjuvant PACS04 trial: HEV is predictive of outcome for HER2+ tumors exposed to trastuzumab [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-05.

Abstract P2-05-04: Evaluation of intra-tumor heterogeneity, test reproducibility and their impact in breast cancer samples assessed by Prosigna™: Results from a decision impact prospective study and a matched case-control study

Background: Recent molecular biology technologies reveals insight into tumor heterogeneity but quantification and impact on reproducibility of tests is not well known. The objective of this study was to assess the extent to which tumor heterogeneity may affect the prognosis of patients assessed by Prosigna™ (PAM50) gene signature assay compared to test reproducibility.

Methods: Reproducibility was measured by testing replicate tissue sections from 186 FFPE breast tumor blocks across 2 sites (Institut Curie, Centre Jean Perrin) following independent pathology review at each site. Consecutive slides came from blocks of patients included in the Decision Impact prospective study which examined whether the Prosigna™ test influences adjuvant treatment decision (Clinical trial information: NCT02395575). To evaluate heterogeneity and its impact in terms of outcome, we selected among T1N0 patients treated in Institut Curie between 2003 and 2008, 32 patients who did recur and 28 matched control group who did not (2 'controls' recurred during the study). Analyses were performed on two parts of each tumor. NanoString's Prosigna™ outputs (risk of recurrence (ROR) score, 10 year probability of distant recurrence, risk category, and intrinsic subtype (Luminal A/B, HER2-enriched, Basal-like)) were measured and compared to evaluate heterogeneity (defined as difference in terms of subtype and/or risk category between the two parts) and reproducibility. Correlation between heterogeneity and outcome was performed. Impact was assessed by tumor board analysis.

Results: Pearson correlation coefficients for ROR score and probability of distant recurrence predicted were .95 and .97, respectively in the reproducibility study and .82 and .86, in the tumor heterogeneity study. The measured standard deviation (SD) was 5.4 and 8.1 ROR units corresponding to 1.6% and 2.8% in terms of risk of distant metastasis free survival within the reproducibility study and the tumor heterogeneity study, respectively. Kappa coefficients for intrinsic subtype and risk category agreement were 0.88 and 0.87 in the reproducibility study, and 0.67 and 0.58 in the tumor heterogeneity study. Tumor board analysis of discordant cases showed that the impact, in terms of decision of chemotherapy administration, concerns 3% of patients because of reproducibility and 8% because of tumor heterogeneity, comparing favorably with the discordance between Prosigna™ and immunohistochemistry (27%). Probability of distant recurrence was higher in the cases (15%) compared to control (9%) (p=.001) in the tumor heterogeneity study confirming the performance of the Prosigna™ test.

Conclusion: We validated in the prospective Decision Impact study the analytical performance of NanoString's Prosigna™ assay across multiple clinical testing laboratories. We showed in these two studies that tumor heterogeneity has more impact than reproducibility performance. The clinical impact on the decision making based on tumor heterogeneity is however limited, since it does not correlate to outcomes, whereas the Prosigna™ ROR score has been shown to correlate very well to outcomes.

Citation Format: Rouzier R, Bonneau C, Cayre A, Hequet D, Gentien D, Bonhomme A, Mouret-Reynier M-A, Dubot C, Cottu P, Roulot A, Morel P, Salomon A, Callens C, Guinebretiere J-M, Penault-Llorca F. Evaluation of intra-tumor heterogeneity, test reproducibility and their impact in breast cancer samples assessed by Prosigna™: Results from a decision impact prospective study and a matched case-control study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-04.