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.

Pembrolizumab in combination with gemcitabine for patients with HER2-negative advanced breast cancer: GEICAM/2015-04 (PANGEA-Breast) study

BACKGROUND

We evaluated a new chemoimmunotherapy combination based on the anti-PD1 monoclonal antibody pembrolizumab and the pyrimidine antimetabolite gemcitabine in HER2- advanced breast cancer (ABC) patients previously treated in the advanced setting, in order to explore a potential synergism that could eventually obtain long term benefit in these patients.

METHODS

HER2-negative ABC patients received 21-day cycles of pembrolizumab 200 mg (day 1) and gemcitabine (days 1 and 8). A run-in-phase (6 + 6 design) was planned with two dose levels (DL) of gemcitabine (1,250 mg/m² [DL0]; 1,000 mg/m² [DL1]) to determine the recommended phase II dose (RP2D). The primary objective was objective response rate (ORR). Tumor infiltrating lymphocytes (TILs) density and PD-L1 expression in tumors and myeloid-derived suppressor cells (MDSCs) levels in peripheral blood were analyzed.

RESULTS

Fourteen patients were treated with DL0, resulting in RP2D. Thirty-six patients were evaluated during the first stage of Simon's design. Recruitment was stopped as statistical assumptions were not met. The median age was 52; 21 (58%) patients had triple-negative disease, 28 (78%) visceral involvement, and 27 (75%) ≥ 2 metastatic locations. Progression disease was observed in 29 patients. ORR was 15% (95% CI, 5-32). Eight patients were treated ≥ 6 months before progression. Fourteen patients reported grade ≥ 3 treatment-related adverse events. Due to the small sample size, we did not find any clear association between immune tumor biomarkers and treatment efficacy that could identify a subgroup with higher probability of response or better survival. However, patients that experienced a clinical benefit showed decreased MDSCs levels in peripheral blood along the treatment.

CONCLUSION

Pembrolizumab 200 mg and gemcitabine 1,250 mg/m² were considered as RP2D. The objective of ORR was not met; however, 22% patients were on treatment for ≥ 6 months. ABC patients that could benefit of chemoimmunotherapy strategies must be carefully selected by robust and validated biomarkers. In our heavily pretreated population, TILs, PD-L1 expression and MDSCs levels could not identify a subgroup of patients for whom the combination of gemcitabine and pembrolizumab would induce long term benefit.

TRIAL REGISTRATION

ClinicalTrials.gov and EudraCT (NCT03025880 and 2016-001,779-54, respectively). Registration dates: 20/01/2017 and 18/11/2016, respectively.

Multidisciplinary consensus on optimising the detection of NTRK gene alterations in tumours

The recent identification of rearrangements of neurotrophic tyrosine receptor kinase (NTRK) genes and the development of specific fusion protein inhibitors, such as larotrectinib and entrectinib, have revolutionised the diagnostic and clinical management of patients presenting with tumours with these alterations. Tumours that harbour NTRK fusions are found in both adults and children; and they are either rare tumours with common NTRK fusions that may be diagnostic, or more prevalent tumours with rare NTRK fusions. To assess currently available evidence on this matter, three key Spanish medical societies (the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Pathological Anatomy (SEAP), and the Spanish Society of Paediatric Haematology and Oncology (SEHOP) have brought together a group of experts to develop a consensus document that includes guidelines on the diagnostic, clinical, and therapeutic aspects of NTRK-fusion tumours. This document also discusses the challenges related to the routine detection of these genetic alterations in a mostly public Health Care System.

Correction to: Liquid biopsy in oncology: a consensus statement of the Spanish Society of Pathology and the Spanish Society of Medical Oncology

The article Liquid biopsy in oncology.

Mutational Screening of BRCA1/2 Genes as a Predictive Factor for Therapeutic Response in Epithelial Ovarian Cancer: A Consensus Guide from the Spanish Society of Pathology (SEAP-IAP) and the Spanish Society of Human Genetics (AEGH)

Germline/somatic BRCA-mutated ovarian carcinomas (OC) are associated to have better response with platinum-based chemotherapy and long-term prognosis than non-BRCA-associated OCs. In addition, these mutations are predictive factors to response to Poly(ADP-ribose) polymerase (PARP) inhibitors. Different positioning papers have addressed the clinical recommendations for BRCA testing in OC. This consensus guide represents a collection of technical recommendations to address the detection of BRCA1/2 mutations in the molecular diagnostic testing strategy for OC. Under the coordination of Spanish Society of Pathology (SEAP-IAP) and the Spanish Society of Human Genetics (AEGH), these recommendations have been developed by pathologists and geneticists taking into account previously published recommendations and their experience in the molecular characterization of these genes. Since the implementation of BRCA testing as a predictive factor can initiate the workflow by testing germline mutations in the blood or by testing both germline and somatic mutations in tumor tissue, distinctive features of both strategies are discussed. Additionally, the recommendations included in this paper provide some references, quality parameters, and genomic tools aimed to standardize and facilitate the clinical genomic diagnosis of OC.

Combining electrokinetic transport and bioremediation for enhanced removal of crude oil from contaminated marine sediments: Results of a long-term, mesocosm-scale experiment

Marine sediments represent an important sink of harmful petroleum hydrocarbons after an accidental oil spill. Electrobioremediation techniques, which combine electrokinetic transport and biodegradation processes, represent an emerging technological platform for a sustainable remediation of contaminated sediments. Here, we describe the results of a long-term mesocosm-scale electrobioremediation experiment for the treatment of marine sediments contaminated by crude oil. A dimensionally stable anode and a stainless-steel mesh cathode were employed to drive seawater electrolysis at a fixed current density of 11 A/m². This approach allowed establishing conditions conducive to contaminants biodegradation, as confirmed by the enrichment of Alcanivorax borkumensis cells harboring the alkB-gene and other aerobic hydrocarbonoclastic bacteria. Oil chemistry analyses indicated that aromatic hydrocarbons were primarily removed from the sediment via electroosmosis and low molecular weight alkanes (nC₆ to nC₁₀) via biodegradation.

Combination of KIR2DS4 and FcγRIIa polymorphisms predicts the response to cetuximab in KRAS mutant metastatic colorectal cancer

Cetuximab is a standard-of-care treatment for RAS wild-type metastatic colorectal cancer (mCRC) but not for those harbor a KRAS mutation since MAPK pathway is constitutively activated. Nevertheless, cetuximab also exerts its effect by its immunomodulatory activity despite the presence of RAS mutation. The aim of this study was to determine the impact of polymorphism FcγRIIIa V158F and killer immunoglobulin-like receptor (KIR) genes on the outcome of mCRC patients with KRAS mutations treated with cetuximab. This multicenter Phase II clinical trial included 70 mCRC patients with KRAS mutated. We found KIR2DS4 gene was significantly associated with OS (HR 2.27; 95% CI, 1.08–4.77; P = 0.03). In non-functional receptor homozygotes the median OS was 2.6 months longer than in carriers of one copy of full receptor. Multivariate analysis confirmed KIR2DS4 as a favorable prognostic marker for OS (HR 6.71) in mCRC patients with KRAS mutation treated with cetuximab. These data support the potential therapeutic of cetuximab in KRAS mutated mCRC carrying non-functional receptor KIR2DS4 since these patients significantly prolong their OS even after heavily treatment. KIR2DS4 typing could be used as predictive marker for identifying RAS mutated patients that could benefit from combination approaches of anti-EGFR monoclonal antibodies and other immunotherapies to overcome the resistance mediated by mutation in RAS.

Abstract PD9-04: FGFR4 as a key regulator of HER2E subtype in the primary and metastatic setting

Background: Therapeutic targets in TNBC remain a challenge. We have observed that some Luminal A primary breast tumors give rise to HER2-enriched (HER2E) subtype metastases but remain clinically HER2 negative (HER2E/cHER2-). Molecular features that drive these HER2E/cHER2- tumors may represent key targets of metastatic progression.

Methods: A comparative genetic and transcriptomic analysis in TCGA (1100 patients) related to the FGFR family was performed. We focused on FGFR4, in part, due to its unique association with the HER2E expression subtype and we developed a robust FGFR4-signature based upon a supervised analysis of a HER2E/cHER2- PDX (WHIM11) treated with a FGFR4 inhibitor (BLU9931). We also constructed a new Luminal Tumor Score (LTS) to identify the optimal axis of separation between Luminal A versus HER2E tumors (higher scores represent greater Luminal A phenotype). Univariate and multivariate analyses were performed using TCGA and METABRIC (1971 samples). Finally, we performed RNA-seq on a cohort of 77 matched primary breast cancer and metastatic tissues pairs from the GEICAM/2009-03 and Hospital Clinic of Barcelona study, and did multiple analyses on these cohorts using our FGFR4-signatures.

Results: FGFR4 was significantly higher in HER2E subtype (P<0.0001), independent of HER2 clinical status. FGFR4 amplification/deletions and mutations were rare and did not correlate with FGFR4 high expression. In vivo, BLU9931 treatment of WHIM11 showed a significant tumor growth inhibition (P=0.01), prolonged survival, and a significant higher LTS (P=0.016). We also identified 745 up-regulated genes called FGFR4-repressed (FGFR4-rep) and 427 down regulated genes called FGFR4-induced (FGFR4-ind), after BLU9931 treatment. Gene set enrichment analysis revealed that FGFR4-ind genes were enriched for STAT3, PI3K/AKT/mTOR pathway and KRAS activation, proliferation, hypoxia, glycolysis and metastasis. FGFR4-rep genes were involved with KRAS inhibition, cell polarity, p53 pathway and upregulation of IFNγ response. In the METABRIC cohort, FGFR4-ind and FGFR4-rep each predicted OS (HR=6.30, P<0.0001; HR=0.33; P<0.0001, respectively). Multivariate analysis showed FGFR4-ind (HR=2.34, P=0.014) as a significant independent prognostic factor beyond subtype for OS. Supervised analysis of the 77 primary-met cohort revealed that the FGFR4-ind was significantly higher in luminal metastases compared with their primaries counterparts (P<0.001), along with proliferation, angiogenesis, and a M2 macrophage signature (with most other immune features being unchanged). Finally, univariate and multivariate analysis demonstrated that the FGFR4-related signatures predicted site-specific metastasis for lung, liver and brain, but not for bone and lymph nodes.

Conclusion: FGFR4 is one of the drivers of HER2-enriched subtype tumors, including those that are clinically HER2-. The FGFR4-ind signature was predictive of worse survival, progression in the metastatic setting, and site-specific metastasis. Treatment options in HER2-enriched TNBC, and for HER2E/cHER2+ patients, may benefit from targeting FGFR4, whose high expression is not based upon genomic or genetic features.

Citation Format: Garcia Recio S, Parker JS, Fan C, Mott K, He X, Cejalvo JM, Brasó Maristany F, Galván P, Lluch A, Albanell J, Rojo F, Martinez de Dueñas E, Prat A, Perou CM. FGFR4 as a key regulator of HER2E subtype in the primary and metastatic setting [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 PD9-04.

Abstract P5-12-03: Genome copy number entropy as predictor of response for neoadjuvant therapy in early breast cancer

Background

Copy Number Alterations (CNAs) represent changes in the copy number of genomic segments of somatic cells due to chromosomal instability. CNAs include gene amplifications or deletions and can be involved in tumorigenesis. We analyzed CNAs data in pre- and post-treatment (ttm) tumors from patients (pts) with early breast cancer (BC) in the neoadjuvant trials GEICAM/2006-03 and GEICAM/2006-14, with the aim to identify CNAs in particular genomic regions (genetic entropy) associated with treatment response.

Methods

GEICAM/2006-03 (NCT00432172) HER2-negative pts were selectively treated according to clinical subtypes: triple negative (TN) pts were treated with standard anthracycline/taxane -based chemotherapy (AT-CT) +/- carboplatin, while luminal patients were randomized to AT-CT vs. hormonotherapy; GEICAM/2006-14 (NCT00841828) HER2+ pts received AT-CT plus anti-HER2 therapy.Shallow-whole genome Illumina sequencing DNA data from 204 paraffin-embedded tumors (100 pre- and 104 post-ttm) were segmented to obtain CNAs and recurrent altered genomic regions were defined. We used Wilcoxon test to analyze the frequency of altered regions and logistic regression analyses to explore their association with tumor response, in terms of pathological complete response (pCR) in breast and axilla. Validation of altered genes associated with therapy response was performed in the microarray gene expression-based Hatzis dataset (GSE25066) from pts receiving neoadjuvant AT-CT (1).

Results

A total of 672 regions covering the whole genome were identified upon analysis of CNAs data. Regions were categorized according to their alteration status as amplified, normal and lost. Comparative analysis of alterations revealed 11 regions significantly different (p<0.05) in pre- vs post-ttm tumors. Logistic regression analysis showed that in pre-ttm tumors specific alterations of 8 regions localized in 3 different genomic loci (11q12, 16q22 and 21q22) were significantly associated with pCR (p<0.05). Independent analyses of CNAs data with “CGH regions” and “GISTIC2.0” tools confirmed the special relevance of 2 of these 8 regions (#653 and #654), amplified in the locus 21q22.12. This locus contains 20 genes whose expression was tested in Hatzis dataset (1) (GSE25066): the analysis showed that overexpression of 5 of these 20 genes (CHAF1B, CBR1, CBR3, RCAN1 and SLC5A3) turned out to be significantly higher in the cohort of pts who reached pCR, in agreement with our findings. Some of these genes have already been described as proliferation markers (CHAF1B) or involved in treatment response (CBR1) in BC. Other genes related to BC in this genomic region are the transcription factor RUNX1 and the Lysine Methyltransferase SETD4.

Conclusions

According to our results, neoadjuvant therapy can modulate genomic aberrations landscape in BC. Our data suggest that amplification of specific genes in the genomic locus (21q22.12) is involved in the neoadjuvant therapy response in early BC.

(1): Hatzis et al., JAMA 2011, 305(18) 1873-81

Citation Format: Alba E, Rueda OM, Lluch A, Albanell J, Chin S-F, Chacón JI, Calvo L, De la Haba-Rodriguez J, Bermejo B, Ribelles N, Sánchez-Rovira P, Plazaola A, Barnadas A, Cirauqul B, Ramos M, Arcusa A, Carrasco E, Herranz J, Chiesa M, Caballero R, Santonja A, Rojo F, Caldas C. Genome copy number entropy as predictor of response for neoadjuvant therapy in early 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 P5-12-03.

Abstract P2-08-04: Prediction of distant recurrence by EndoPredict in patients with estrogen receptor-positive, HER2-negative breast cancer who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET)

Background: EndoPredict (EPclin) is a validated prognostic test combining expression of 12 cancer-related genes for breast cancer patients with estrogen receptor (ER) positive, HER2-negative disease who received 5 years of endocrine therapy (Buus et al., 2017; Dubsky et al. 2012) and for women who received chemotherapy (Martin et al., 2014). Here, we determine the EPclin and 10-year distant recurrence free interval (DRFI) rates for patients who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET) using data from five large clinical trials.

Methods: A total of 3746 women with ER-positive, HER2-negative disease were included in this analysis. 2630 patients received 5 years of ET alone (ABCSG-6/8, TransATAC) and 1116 patients received ET+C (GEICAM 2003-02/9906). EPclin incorporates tumor size and nodal status and accounts for different EPClin scores between ET+C and ET alone cohorts. The primary objective was to evaluate the 10-year DRFI rates as a continuous function of EPclin separately for patients in ET+C and ET. Secondary objectives included assessing the difference in the prognostic ability of EPclin between ET+C and ET overall (years 0-10) and for specific follow-up periods (years 0-5 and years 5-10). The primary endpoint was DRFI and the secondary endpoint was breast cancer free interval (BCFI). Cox proportional hazard models were used to estimate 10-year DRFI rates and to assess the prognostic information provided by EPclin.

Results: All of the women on ET alone and 49% of those on ET+C were postmenopausal. Women who received ET+C had more node positive disease, more poorly differentiated tumours, and higher EPclin scores than those who received ET alone. Women who received ET+C had significantly smaller increases in 10-year DRFI rates with increasing EPclin score than those receiving ET alone (Table). EPclin was highly prognostic for DRFI in all women who received ET alone (HR=2.79 (2.49-3.13), P<0.0001) as well as in those who received ET+C (HR=2.27 (1.99-2.59), P<0.0001), both in the overall cohort and in postmenopausal women only (ET+C: HR=2.64 (2.07-3.37), P<0.0001). We observed a significant interaction between EPclin and treatment for DRFI at 10 years (Pinteraction=0.022). EPclin was highly prognostic in ET alone and ET+C in years 0-5 and in particular in years 5-10. Similar results were observed when BCFI was the endpoint.

Conclusion: In our results from a non-randomized analysis, we observed significantly smaller increases in 10-year DRFI rates with increasing EPclin scores for women who received ET+C compared to those who received ET alone. Our indirect comparisons suggest that a high EPclin score can predict chemotherapy benefit in women with ER-positive, HER2-negative disease.

10-year DRFI risks (%) (95% CI) according to EPclin score for patients who received ET+C versus ET alone. ET+CETEPclin10-year DR risk (%)10-year DR risk (%)11.1% (0.5-1.7)1.0% (0.6-1.4)22.5% (1.5-3.5)2.8% (2.1-3.5)35.7% (4.1-7.2)7.6% (6.4-8.8)412.4% (10.1-14.6)19.8% (17.6-22.0)525.8% (22.0-29.5)46.1% (40.2-51.4)

Citation Format: Sestak I, Martin M, Dubsky P, Rojo F, Cuzick J, Filipits M, Ruiz A, Buus R, Hlauschek D, Rodriguez-Lescure A, Dowsett M, Gnant M. Prediction of distant recurrence by EndoPredict in patients with estrogen receptor-positive, HER2-negative breast cancer who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET) [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 P2-08-04.

Biomarkers in breast cancer: A consensus statement by the Spanish Society of Medical Oncology and the Spanish Society of Pathology

This consensus statement revises and updates the recommendations for biomarkers use in the diagnosis and treatment of breast cancer, and is a joint initiative of the Spanish Society of Medical Oncology and the Spanish Society of Pathology. This expert group recommends determining in all cases of breast cancer the histologic grade and the alpha-estrogen receptor (ER), progesterone receptor, Ki-67 and HER2 status, in order to assist prognosis and establish therapeutic options, including hormone therapy, chemotherapy and anti-HER2 therapy. One of the four available genetic prognostic platforms (MammaPrint^®, Oncotype DX^®, Prosigna^® or EndoPredict^®) may be used in node-negative ER-positive patients to establish a prognostic category and decide with the patient whether adjuvant treatment may be limited to hormonal therapy. Newer technologies including next-generation sequencing, liquid biopsy, tumour-infiltrating lymphocytes or PD-1 determination are at this point investigational.

Abstract OT1-01-02: A multicenter phase II trial to evaluate the efficacy and safety of pembrolizumab and gemcitabine in patients with HER2-negative advanced breast cancer: GEICAM/2015-04 PANGEA-Breast

Background: Treatment options for advanced breast cancer (ABC) are multiple but unable to properly respond to current clinical needs. In particular, improved therapies are needed for triple negative and hormone receptor (HR)-positive but heavily pretreated patients. Pembrolizumab (P) is a human monoclonal antibody that blocks the PD-1/PD-L1 interaction hence potentiates anticancer T cell responses. Gemcitabine (G) is a cytotoxic drug with well-known immunostimulatory properties. Here, we report an ongoing phase II clinical trial to identify the Recommended Phase II Dose (RP2D) and the efficacy of the combination of these two agents in ABC patients. We hypothesize that these agents may synergize to induce responses with long term clinical benefit (ClinicalTrials.gov Identifier: NCT03025880).

Trial Design:

Eligible patients are HER2-negative ABC patients who received prior treatment with anthracyclines and taxanes and two or more prior lines of hormone therapy, if HR-positive disease. Patients with CNS involvement are also eligible if clinically stable. Treatment consists of 21-day cycles with 200 mg P on day 1 and G on days 1 and 8. In the safety dose testing, we use a standard 6+6 design with 2 dose levels (DL) of G: 1250 mg/m2 (DL0) and 1000 mg/m2 (DL1). Patients are treated until radiologic or symptomatic progression, or unacceptable toxicity. The primary objectives are RP2D and objective response rate (ORR) of the combination; secondary objectives include evaluation of safety and tolerability and other efficacy variables (progression-free survival [PFS], clinical benefit rate [CBR], response duration [RD] and overall survival [OS]). Efficacy is measured by RECIST 1.1. and irRECIST. Safety is measured using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) 4.0. As exploratory objectives, immunological biomarkers are analyzed in tumor biopsies and blood samples and correlated with (1) clinical efficacy and (2) disease outcomes.Sequential tumor samples are collected at baseline, cycle 3 and at progression. Blood samples are drawn at baseline, cycle 3, and cycle 6, or at post-treatment visit (whatever occurs first). Tumor samples are characterized for intratumoral and stromal tumor-infiltrating lymphocytes, tumor-associated macrophages and myeloid-derived suppressor cells, PD-L1 expression in tumor cells and stroma. Moreover, molecular and genetic profiling will be performed. Blood samples are characterized for peripheral blood mononuclear cell (PBMC) phenotype (including expression of co-activatory and co-inhibitory receptors), cytokine profile, and activity of other immunosuppressive pathways (e.g., IDO1-dependent tryptophan catabolism). These results will be compared with data from a cohort of healthy volunteers.

A maximum of 65 patients will be included. The study is approved by the ethical committee and Competent Authority of Spain and already open for patient recruitment in 2 of the 10 participating sites.

Keywords:

Breast

HER2 negative

Pembrolizumab

Immunotherapy

Citation Format: de la Cruz L, Sánchez-Margalet V, Berraondo P, Benito S, Escudero MJ, Caballero R, Carrasco E, Galluzzi L, Rojo F. A multicenter phase II trial to evaluate the efficacy and safety of pembrolizumab and gemcitabine in patients with HER2-negative advanced breast cancer: GEICAM/2015-04 PANGEA-Breast [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 OT1-01-02.

Abstract P1-09-01: Impact of MAF gene amplification on disease recurrence and effects of adjuvant zoledronic acid in early breast cancer

Background: Meta-analysis of clinical trials has shown that adjuvant bisphosphonates reduce bone metastases and improve survival in postmenopausal (PM) pts1. However, we are unable to select pts most likely to benefit. To address this, the recently identified early breast cancer bone relapse biomarker, 16q23(MAF) gain (MAF+)2, was tested retrospectively in the large prospectively randomized AZURE trial3 of standard adjuvant therapy +/- zoledronic acid (ZOL) to determine the prognostic value of MAF and its potential to predict the effects of ZOL on disease outcomes.

Materials and methods: All analyses were performed with ethics approval and consent. The biomarker analysis was completed on TMAs from primary tumors. Quadruplicate cores of breast tumor tissue were arrayed across replicate TMAs. MAF+ was detected using a validated (MAF/D16Z3) FISH test (Inbiomotion SL, Barcelona, Spain). A central laboratory (Targos, Kassel, Germany) validated the assay for analytic and diagnostic performance, established acceptance criteria, included appropriate quality controls for each assay, and performed the analyses in a blinded fashion. A copy number cut-off ≥2.5 was preset for MAF+. Invasive disease free (IDFS), overall (OS) survival and time to bone metastases multivariate analyses were performed in control and ZOL pts separately. Subsequently, interactions between MAF+ and effects of ZOL on disease outcomes by menopausal status were evaluated.

Results: 1769 of the 3360 AZURE pts donated primary tumor samples. Median follow-up was 84 months. 865 pts (49%) had 2 FISH evaluable cores and were included in the analysis of which 184 (21%) had MAF+ tumors. Tumors that were MAF+ were more likely to be of higher grade, ER-ve and Her2+.

In control pts, MAF was not prognostic for IDFS or OS although there were differences in IDFS by menopause (HR for MAF-/MAF+ in PM=0.47 [95%CI 0.25-0.88]; HR in non-PM=1.58 [0.82-3.03], test for interaction (TFI) by menopause P=0.007). In ZOL pts, MAF was prognostic for IDFS (HR=0.52 [0.36-0.75] and OS (HR=0.48 [0.31-0.75]). There were insufficient bone events (19 MAF+, 73 MAF-) in this sample set to reliably assess the impact of MAF+ on relapse in bone.

In pts with MAF- tumors, ZOL was associated with improved IDFS (HR=0.74 [0.56-0.98]) and OS (HR=0.78 [0.55-1.10]). However, the effects of ZOL in MAF+ were profoundly influenced by menopausal status with possibly better outcomes in PM women (HR for IDFS=0.74 [0.35-1.58]) but clearly worse IDFS and OS outcomes in ZOL treated MAF+ pts who were non-PM (HR for IDFS 2.46 [1.23-4.92], TFI by treatment P=0.002 and HR for OS=2.27 [1.04-4.93], TFI by treatment P=0.032). The interactions between disease outcomes, ZOL use and menopause were driven largely by an association between MAF+ and an increased risk of extra-skeletal recurrence with the use of ZOL in women who were not PM.

Conclusions: Absence of MAF amplification is associated with improved disease outcomes with adjuvant ZOL. However, the use of adjuvant ZOL in women with MAF+ tumors who are not PM at the start of treatment is associated with extraskeletal spread and worse DFS and OS.

1EBCTCG Lancet 2015;386:1353–1361; 2Pavlovic M et al JNCI 2015;107(12):djv256; 3Coleman RE et al Lancet Oncol 2014;15:997-1006.

Citation Format: Coleman R, Hall A, Bell R, Cameron D, Marshall H, Jean-Mairet J, Tercero J, Rojo F, Albanell J, Gomis R. Impact of MAF gene amplification on disease recurrence and effects of adjuvant zoledronic acid in early breast cancer [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 P1-09-01.

Abstract OT3-02-07: A phase II study to compare fulvestrant (F) 500mg plus placebo versus (vs) F 500mg plus palbociclib (P) as first line treatment for postmenopausal women with hormone receptor (HR)-positive advanced breast cancer (BC) sensitive to endocrine therapy (ET). “The FLIPPER study” (GEICAM/2014-12)

Background: Delaying/overcoming resistance to ET in HR-positive HER2-negative BC patients (pts) is a major need to futhrt improve safe and efficacious treatment options. F is a selective estrogen receptor (ER) downregulator currently indicated for the treatment of HR-positive metastatic BC in postmenopausal women with disease progression following anti-estrogen therapy. In FIRST trial F 500mg improved median time to progression (TTP) over anastrozole (23.4 vs 13.1 months, respectively) in untreated metastatic BC. P is a selective reversible inhibitor of cyclin-dependent kinase 4/6. FDA granted its accelerated approval based on progression-free survival (PFS) in combination with letrozole for postmenopausal women with ER-positive and HER2-negative advanced BC as initial ET (PALOMA-1). In another study, after progression to ET, P in combination with F resulted in longer PFS than F alone (PALOMA-3).

The high median TTP achieved with F alone (FIRST) coupled with the significant benefit of adding P to F (PALOMA-3) suggest that F 500mg in combination with P in the first-line setting may significantly improve long-term disease control.

Trial Design:This is an international, randomized, double-blind, multicentre phase II study comparing F 500mg in combination with P vs F 500mg plus placebo as first line therapy in postmenopausal women with HR-positive, HER2-negative metastatic BC who have received ≥5 years of adjuvant ET for early disease and remained disease free for >12 months following its completion or have “de novo” metastatic disease. HR and HER2 status will be based on central testing on the most recent tumour biopsy. Patients will be randomized 1:1. The primary objective is to compare the efficacy of both treatment arms in terms of PFS at 1 year according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 by investigator assessment. As secondary efficacy objectives,PFS, Objective Response Rate (ORR), Clinical Benefit Rate (CBR), Overall Survival (OS), and 1-year and 2-year survival probabilities, have been considered. Other secondary objectives include the comparison of safety, tolerability and health-related quality of life between the treatment arms. As exploratory objectives, the identification of promising biomarkers related with response to study therapy and primary/acquired drug resistance. Pts will be stratified by the site of disease (visceral vs non-visceral) and disease presentation at study entry (recurrent disease vs metastatic “de novo”). With a sample size of 190 pts, the analysis would have 80% power to detect a difference between both treatment arms, assuming PFS proportions of 0.545 and 0.695, respectively. This study is sponsored by GEICAM and Cancer Trials Ireland (formerly ICORG) is also participating. Recruitment started in February 2016 with 14 pts included. Analysis of the primary endpoint is planned for Q1 2018. ClinicalTrials.gov identifier:NCT02690480.

Citation Format: Moreno F, Martínez-Jañez N, Garau I, Guerra JA, Alarcón J, Bermejo B, Gonzalez-Cortijo L, Bueno C, Lao J, Bezares S, Rosell L, Blanch A, Caballero R, Carrasco E, Rojo F, Martín M, O'Connor M, Hernando A, Albanell J. A phase II study to compare fulvestrant (F) 500mg plus placebo versus (vs) F 500mg plus palbociclib (P) as first line treatment for postmenopausal women with hormone receptor (HR)-positive advanced breast cancer (BC) sensitive to endocrine therapy (ET). “The FLIPPER study” (GEICAM/2014-12) [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 OT3-02-07.

Breast Cancer Immunology and Immunotherapy: Current Status and Future Perspectives

Cancer immunology has gained renewed interest in the past few years due to emerging findings on mechanisms involved in tumoral immune evasion. Indisputably, immune edition is currently considered a critical hallmark of cancer. Basic research has revealed new targets which can be modulated in the clinical setting with new compounds and strategies. As recent evidence confirms, breast cancer (BC) is a complex and heterogeneous disease in which host immune responses play a substantial role. T-infiltrating lymphocytes measurement is suggested as a powerful new tool necessary to predict early BC evolution, especially in HER2-positive and triple negative subtypes. However, T-infiltrating lymphocytes, genomic platforms, and many other biomarkers in tissue and peripheral blood (e.g., regulatory T cells and myeloid-derived suppressor cells) are not the only factors being evaluated regarding their potential role as prognostic and/or predictive factors. Many ongoing clinical trials are exploring the activity of immune checkpoint modulators in BC treatment, both in the advanced and neoadjuvant setting. Although this field is expanding with exciting new discoveries and promising clinical results-and creating great expectations-there remain many uncertainties yet to be addressed satisfactorily before this long awaited therapeutic promise can come to fruition.

Abstract P3-07-42: Predicting outcome and benefit to first-line bevacizumab in advanced/metastatic hormone receptor (HR)+/HER2-negative breast cancer (BC) treated with endocrine therapy: A correlative science study from the LEA phase III clinical trial (GEICAM/2006-11_GBG 051)

Introduction: The role of bevacizumab in combination with chemotherapy in metastatic BC is controversial, and no biomarker exists as of today that predicts benefit to this agent. In the LEA clinical trial, a numerical, statistically non-significant benefit from the addition of bevacizumab to endocrine therapy (ET) was observed in the first-line metastatic setting (18.4 vs. 13.8 months of Progression-Free Survival (PFS), p=0.14). Here, we explored various gene expression-based predictors of outcome and benefit to bevacizumab.

Methods and materials: LEA trial randomized 380 patients with HR+/HER2- advanced disease to bevacizumab in combination with ET (ET+B) vs. ET alone. Primary endpoint was PFS. Expression of BC selected genes was evaluated in formalin-fixed paraffin-embedded (FFPE) primary tumors using the nCounter platform from patients randomized in Spain that consent for biomarker analyses. The following variables were evaluated: 1) research-based PAM50 intrinsic subtypes (categorical variable; Luminal A, Luminal B, HER2-enriched, Basal-like and Normal-like); 2) research-based PAM50 signatures (continuous variable; scores showing the distant of the gene expression values of an individual sample compared to the centroid gene values for each PAM50 intrinsic subtype); 3) risk of recurrence (ROR) groups (low, medium and high); 4) the 13-gene hypoxia/VEGF signature (continuous); and 5) Ki67 by immunohistochemistry (continuous). Uni- and multivariable Cox models for PFS were used to test the prognostic significance of each variable. To determine whether each variable is predictive of bevacizumab benefit, we tested the interaction term of each variable by treatment arm in a Cox model.

Results: Tumor samples from 103 patients were analyzed: 55 (53%) in ET+B arm and 49 (47%) in ET arm. Subtype distribution was as follows: 57 (55.3%) Luminal A, 32 (31.1%) Luminal B, 5 (4.9%) HER2-enriched, 1 (1.0%) Basal-like, and 8 (7.8%) normal-like. In a univariate analysis, Luminal B tumors had a poorer outcome using Luminal A as reference (13.8 vs. 21.3 months, respectively; (hazard ratio, HR=1.80, 95% CI 1.10-2.95, p=0.019). Concordant with this finding, Luminal A signature was associated with a better outcome. Similarly, ROR-P high group showed a poorer outcome than ROR-P low group (8.5 vs. 19.4 months; HR=2.88, 95% CI 1.30-6.35, p=0.009). Neither VEGF-13 signature nor Ki67 were found to be associated with PFS. Similar findings were obtained after adjustment for treatment, age, previous ET, ECOG, visceral disease and number of metastatic sites. In terms of treatment benefit, the HER2-enriched signature was the only variable found predictive of bevacizumab PFS benefit in univariate (p=0.010) and multivariate (p=0.015) analyses.

Conclusions: In advanced HR+/HER2- disease, intrinsic subtype (i.e. Luminal A vs. B) independently predicts PFS following first-line ET. In addition, HR+/HER2-negative tumors with high expression of the HER2-enriched signature, a biomarker of estrogen-independence, benefit the most from bevacizumab. Further validation of these prognostic and predictive biomarkers is warranted.

Citation Format: Prat A, de la Haba-Rodriguez J, Guerrero Á, García-Sáenz JA, Morales S, Antón A, Muñoz M, Ramos M, Martínez-Jáñez N, Margelí M, Servitja S, Rojo F, Galván P, González S, Cruz J, Sánchez-Rovira P, Perelló A, Rodríguez-Martin C, Casas M, Carrasco E, Caballero R, Martín M. Predicting outcome and benefit to first-line bevacizumab in advanced/metastatic hormone receptor (HR)+/HER2-negative breast cancer (BC) treated with endocrine therapy: A correlative science study from the LEA phase III clinical trial (GEICAM/2006-11_GBG 051). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-42.

Abstract OT3-01-02: A phase I-II trial of dasatinib in combination with trastuzumab (T) and paclitaxel in the first line treatment of HER2 positive metastatic breast cancer (MBC) patients: GEICAM/2010-04

Background: Resistance to targeted-therapies is a current problem in our clinical practice. In HER2 overexpressing tumors, resistance to trastuzumab-based therapies is widely observed. Expression of SRC has been pre-clinically linked to trastuzumab resistance and the addition of the multi-tyrosine kinase inhibitor dasatinib to trastuzumab increases its antitumor activity (Seoane S, et al. J Natl Cancer Inst. 2010). On previous studies, Dasatinib showed a good toxicity profile, with low grade 3-4 toxicity rates (E. Mayer, et al. J Clin Oncol 2009). We have designed a phase I-II trial combining dasatinib with standard trastuzumab/paclitaxel. (ClinicalTrials.gov Identifier: NCT01306942). In this abstract we report the description of the phase II part of the trial which is ongoing.

Trial Design: Eligible patients must be HER2+ (evaluated by central laboratory and assessed by immunohistochemistry and fluorescent in-situ hybridization) MBC and candidates for trastuzumab + chemotherapy as first line treatment. Taxanes and trastuzumab administered in the adjuvant setting are permitted if given >12 months before the inclusion. Patients with CNS involvement are eligible if treated and clinically stable without medication. Treatment consists of trastuzumab 2 mg/kg weekly (following a loading dose of 4 mg/kg in cycle 1), weekly paclitaxel (80 mg/m2, 3 weeks on-one week off) and dasatinib 100 mg once daily (based on the recommended phase II dose from the phase I part, Gil-Martin M, et al. European Breast Cancer Conference 2014, P-041) in a 28-days cycle. Patients are treated until radiologic or symptomatic progression or unacceptable toxicity.

The primary objective for this phase II is efficacy, measured by Objective Response Rate (ORR according to RECIST 1.1). Secondary objectives are: Safety (evaluated using NCI-CTCAE v 4.03), Clinical Benefit Rate, Time to Progression, Progression Free Survival and Response Duration. Pharmacodynamic biomarkers include pAKT, pS6, pSRC, pErk1/2 in tumor tissue samples, mononuclear cells in blood samples and in skin tissue. An additional exploratory objective is to evaluate the correlation between the early presence of lymphocytosis and efficacy. The study will be considered positive if ORR increases 25% from a 50% ORR observed in previous studies with paclitaxel + trastuzumab. We need to include 28 evaluable patients to demonstrate this hypothesis (with an alpha error of 0.05 and a statistical power of 80%), assuming a 10% drop-out rate. Twenty one patients have already been included. Recruitment is expected to finish by the end of 2015.

Citation Format: Ocaña A, Ruiz Borrego M, Gil-Martín M, Antolín S, Guerrero Á, Vidal Boixader L, Martín M, Trigo Pérez JM, Rojo F, Jerez Y, Atienza M, Pernas S, Hernando A, Carrasco E, Benito S, Caballero R, Pandiella A. A phase I-II trial of dasatinib in combination with trastuzumab (T) and paclitaxel in the first line treatment of HER2 positive metastatic breast cancer (MBC) patients: GEICAM/2010-04. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-01-02.

Abstract P6-05-02: Intrinsic subtype and gene expression changes between primary and metastatic breast cancer

Background: A better understanding of the biological changes occurring during metastatic progression of breast cancer is needed to identify new biomarkers, targets and novel treatment strategies. Here, we compared the intrinsic subtype and the expression of a gene panel across a large dataset of paired primary and metastatic tissues.

Methods: Expression profiling of 105 breast cancer-related genes was performed on 254 (127 pairs) formalin-fixed paraffin-embedded tumor tissues using the nCounter platform. Tumor samples were obtained from 3 independent sources (ConvertHER trial [BCRT 2014] and two in-house datasets). Tumors were classified into each intrinsic subtype using the research-based PAM50 classifier (Parker et al. J Clin Oncol 2009). Chi-square tests were performed to determine the differences in the distribution of variables. Paired two-class Significance of Microarrays (SAM) was performed to determine the genes differentially expressed between paired primary and metastatic tissues. In vitro stable transfection of FGFR4-GFP was performed on Luminal B MCF7 cell line. RNA was purified on control vs. transfected cell lines. 7-AAD cell viability was performed following estrogen deprivation for 6 days.

Results: Subtype distribution in primary vs. metastatic disease was 39.0% vs. 26.8% for Luminal A (p=0.012), 26.0% vs. 35.0% for Luminal B (p=0.322), 11.4% vs. 20.3% for HER2-enriched (p=0.115) and 10.6% vs. 13.0% for Basal-like tumors (p=0.843). The rate of subtype conversion was 7.7% in Basal-like, 23.1% in HER2-enriched, 30.0% in Luminal B and 54.3% in Luminal A disease. The majority of subtype conversions in Luminal A disease were to Luminal B (72.0%) and HER2-enriched (24.0%). Overall, 13.2% of primary Luminal A/B tumors progressed to a HER2-E subtype despite 70% of them being clinically HER2-negative. In a paired analysis using all samples, 10- and 12- genes were found up- and down- regulated in metastatic tissues (False Discovery Rate [FDR] <5%). The up-regulated gene list in metastatic disease was composed of FGFR4 (top gene) and proliferation genes (CDC6, CCNB1, CEP55). The down-regulated gene list in metastatic disease was enriched for luminal-related genes (ESR1, PGR, NAT1 and MAPT). A similar paired analysis within Luminal A, Luminal B, HER2-enriched and Basal-like disease revealed 22, 8, 7 and 0 differentially expressed genes (FDR<5%), respectively. Finally, MCF7 cell line transfected with FGFR4 showed a relative increase in the HER2-enriched profile compared with transfected control. In vitro, MCF7-FGFR4 cells showed estrogen independent growth compared to transfected controls.

Conclusions: Metastatic tissues are relatively more proliferative and less luminal compared to primary tumors. This is especially relevant in primary Luminal A disease. In contrast, metastatic tissues from Basal-like primary disease remain largely unchanged. In luminal disease, a significant increase in the HER2-enriched profile is observed in metastatic disease despite most tumors being clinically HER2-negative. A potential driver of the HER2-enriched profile and estrogen independence in clinically HER2-negative metastatic tissues might be FGFR4.

Citation Format: Prat A, Martínez de Dueñas E, Galván P, Garcia S, Burgués O, Paré L, Antolín S, Martinello R, Blancas I, Adamo B, Guerrero Á, Muñoz M, Nuciforo P, Vidal M, Pérez RM, Chacón JI, Caballero R, Gascón P, Carrasco E, Rojo F, Perou CM, Cortés J, Adamo V, Albanell J, Lluch A. Intrinsic subtype and gene expression changes between primary and metastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-05-02.