Ado-trastuzumab emtansine (T-DM1) in HER2+ advanced breast cancer patients: does pretreatment with pertuzumab matter?

Aim: We evaluated the outcomes of patients treated with ado-trastuzumab emantasine (T-DM1) after first-line pertuzumab/trastuzumab, compared with those receiving a trastuzumab-only-based regimen. Patients & methods: Patients who received second-line T-DM1 after pertuzumab/trastuzumab (n = 34) were compared with those who received only trastuzumab (n = 73). Results: Overall response rate was 33.3% in patients with prior pertuzumab and 57.1% in the remaining subjects. Disease control rate was 47 and 43%, respectively, and the clinical benefit rate was 43.3 and 71.1%, respectively. Median progression-free survival was 5.0 and 11.0 months, respectively (hazard ratio: 2.02; 95% CI: 1.14–3.58; p = 0.01). Conclusion: Patients treated with T-DM1 who previously received pertuzumab present poorer clinical outcomes compared with those receiving a trastuzumab-only-based regimen in the first-line setting.

Efficacy and safety of Everolimus and Exemestane in hormone-receptor positive (HR+) human-epidermal-growth-factor negative (HER2-) advanced breast cancer patients: New insights beyond clinical trials. The EVA study

BACKGROUND

The BOLERO-2 trial reported efficacy and safety of Everolimus (EVE) and Exemestane (EXE) combination in HR+ advanced breast cancer (ABC) patients. The BALLET trial further evaluated the safety of EVE-EXE in HR+ ABC patients, without reporting efficacy data. Aim of the EVA real-life study was to collect data of efficacy and safety of EVE-EXE combination in the clinical setting, as well as exploring efficacy according to EVE Dose-Intensity (DI) and to previous treatment with Fulvestrant.

PATIENTS AND METHODS

This study aimed to describe the outcome of ABC pts treated with EVE-EXE combination in terms of median duration of EVE treatment and ORR in a real-life setting.

RESULTS

From July 2013 to December 2015, the EVA study enrolled 404 pts. Median age was 61 years (33-83). Main metastatic sites were: bone (69.1%), soft tissue (34.7%) and viscera (33.2%). Median number of previous treatments was 2 (1-7). 43.3% of the pts had received Fulvestrant. Median exposure to EVE was 31.0 weeks (15.4-58.3) in the whole population. No difference was observed in terms of EVE exposure duration according to DI (p for trend = 0.27) or type of previous treatments (p = 0.33). ORR and Disease Control Rate (DCR) were observed in 31.6% and 60.7% of the patients, respectively, with the lowest ORRs confined in CHT pre-treated patients or in those who received the lowest DI of EVE. Grade 3-4 adverse events (AEs) were reported in 37.9% of the patients. Main AEs were: stomatitis (11.2%), non-infectious pneumonitis - NIP (3.8%), anaemia (3.8%) and fatigue (3.2%).

CONCLUSIONS

The EVA study provided new insights in the use of EVE-EVE combination in HR+ ABC pts many years after the publication of the pivotal trial. The combination is safe and the best response could be obtained in patients receiving the full dose of EVE and/or after hormone-therapy as Fulvestrant in ABC.

Optimisation and validation of a remote monitoring system (Onco-TreC) for home-based management of oral anticancer therapies: an Italian multicentre feasibility study

INTRODUCTION

Despite the growing number of oral agents available for cancer treatment, their efficacy may be reduced due to the lack of adherence, inappropriate adverse event self-management and arbitrary dose adjustment. The management of anticancer therapies could exponentially benefit from the introduction of mobile health technologies in a highly integrated electronic oncology system.

METHODS AND ANALYSIS

We plan to customise and fine-tune an existing monitoring TreC platform used in different chronic diseases in the oncology setting. This project follows a multistep approach with two major purposes: 1. participatory design techniques driven by Health Literacy and Patient Reported Outcomes principles in order to adapt the system to the oncology setting involving patients and healthcare providers; 2. a prospective training-validation, interventional, non-pharmacological, multicentre study on a series of consecutive patients with cancer (20 and 60 patients in the training and validation steps, respectively) in order to assess system capability, usability and acceptability. The novel Onco-TreC 2.0 is expected to contribute to improving the adherence and safety of cancer care, promoting patient empowerment and patient-doctor communication.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Independent Ethics Committees of the participating institutions (CEIIAV protocol Number 2549/2015; reference Number 1315-PU). Informed consent will be obtained from all study participants. Findings will be disseminated through peer-reviewed journals, conferences and event presentations.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT02921724); (Pre-results). Other study ID Number: IRST100.18.

Efficacy and safety of T-DM1 in the 'common-practice' of HER2+ advanced breast cancer setting: a multicenter study

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate approved for the treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive, metastatic breast cancer (mBC). The aim of this ‘field-practice’ study was to investigate the efficacy and safety of T-DM1, focusing on treatment line, previous lapatinib treatment and patterns of metastasis. Three hundred and three patients with HER2-positive mBC who received T-DM1 were identified by reviewing the medical records of 24 Italian Institutions. One hundred fourty-nine (49%) and 264 (87%) had received prior hormonal treatment and/or anti-HER2 targeted therapy, respectively. Particularly, 149 patients had been previously treated with lapatinib. The objective response rate (ORR) was 36.2%, and 44.5% when T-DM1 was administrated as second-line therapy. Considering only patients with liver metastases, the ORR was 44.4%. The median progression-free survival (PFS) was 7.0 months in the overall population, but it reached 9.0 and 12.0 months when TDM-1 was administered as second- and third-line treatment, respectively.

In conclusion, in this ‘real-word’ study evaluating the effects of T-DM1 in patients with HER2-positive mBC who progressed on prior anti-HER2 therapies, we observed a clinically-relevant benefit in those who had received T-DM1 in early metastatic treatment-line and in subjects previously treated with lapatinib.

Abstract P4-21-11: T-DM1 in HER2 positive advanced breast cancer patients: Real world practice from a multicenter observational study

Background: T-DM1 showed remarkable activity in metastatic HER-2 positive breast cancer (mBC) and it was recently approved for clinical use in patients (pts) who previously failed Trastuzumab- and Taxanes-based therapies. Currently, little is known on the performance of T-DM1 in a “real life” scenario. Therefore, we investigated effectiveness and safety of T-DM1 in Italian daily practice.

Methods: Pts baseline characteristics and clinical outcome of pts with HER-2 positive mBC treated with T-DM1 between 2013 and 2015 at 20 Italian Institutions were retrospectively collected and analyzed.

Results: 300 pts were included in our analysis. Median age was 51 years (27-78); visceral metastases were present in 204 (68%) pts and brain metastases in 86 (29%). It is noteworthy that 111 (37%) pts received T-DM1 as pure second line, 83 (28%) as third line and 96 (32%) as further lines. Moreover 10 (3%) pts had T-DM1 as first line because disease recurrence occurred during or adjuvant trastuzumab of within 6 months of its completion. The overall response rate (ORR) was 40%, global disease control rate (gDCR) 64%, median progression-free survival (PFS) 7.0 months (C.I.95%: 5.6-8.4) and overall survival (OS) at 2 years 63%. Pts with 1, 2 and 3 or more metastatic site had OS at 2 years of 87%, 67% and 46%, respectively (p<0.0001). When T-DM1 was given as second line the PFS was 8.0 months and beyond second-line was 6.8 months. Interestingly, for 38 (13%) pts who progressed after Pertuzumab-plus trastuzumab and taxanes as first line treatment, ORR and gDCR were similar to pertuzumab-naïve patients (38% and 62%, respectively) However PFS was 5.0 months (C.I.95%: 4.3-5.7) compared to 9.0 (95% C.I. 5.5-12.4) achieved in pts not receiving a previous pertuzumab-based treatment. Most frequent grade ≥3 toxicities were thrombocytopenia (2.6%), alopecia (2.1%), hypertransaminasemia (2.2%), neutropenia (1.3%), asthenia (1.3%) and diarrhea (0.4%).

Conclusions: To our knowledge, this is the first real life, multicenter retrospective analysis evaluating efficacy and safety of T-DM1 in pretreated HER-2 positive mBC pts. We observed remarkable results in terms of PFS and OS, especially when T-DM1 was given early in the course of metastatic disease. Shortened PFS in patients progressing after pertuzumab suggest further analyses to better define possible molecular mechanisms of cross-resistences between two molecules. As a whole there was no evidence of significant or unexpected toxicities. Although these findings should be taken with caution due to the retrospective analysis and the different lines of previous treatment considered, we confirmed the potential therapeutic role of T-DM1 across a heterogeneous population of HER-2 positive mBC patients. The final analysis will be presented to the meeting.

Citation Format: Fabi A, De Laurentiis M, Caruso M, Valle E, Moscetti L, Santini D, Cannita K, Carbognin L, Ciccarese M, Rossello R, Arpino G, Leonardi V, Montemurro F, La Verde N, Generali DG, Zambelli A, Scandurra G, Russillo M, Paris I, D'Ottavio AM, Filippelli G, Giampaglia M, Stani S, Fabbri A, Alesini D, Giannarelli D, Cognetti F. T-DM1 in HER2 positive advanced breast cancer patients: Real world practice from a multicenter observational 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 P4-21-11.

Antitumour activity of trabectedin in myelodysplastic/myeloproliferative neoplasms

BACKGROUND

Juvenile myelomonocytic leukaemia (JMML) and chronic myelomonocytic leukaemia (CMML) are myelodysplastic myeloproliferative (MDS/MPN) neoplasms with unfavourable prognosis and without effective chemotherapy treatment. Trabectedin is a DNA minor groove binder acting as a modulator of transcription and interfering with DNA repair mechanisms; it causes selective depletion of cells of the myelomonocytic lineage. We hypothesised that trabectedin might have an antitumour effect on MDS/MPN.

METHODS

Malignant CD14+ monocytes and CD34+ haematopoietic progenitor cells were isolated from peripheral blood/bone marrow mononuclear cells. The inhibition of CFU-GM colonies and the apoptotic effect on CD14+ and CD34+ induced by trabectedin were evaluated. Trabectedin's effects were also investigated in vitro on THP-1, and in vitro and in vivo on MV-4-11 cell lines.

RESULTS

On CMML/JMML cells, obtained from 20 patients with CMML and 13 patients with JMML, trabectedin - at concentration pharmacologically reasonable, 1-5 nM - strongly induced apoptosis and inhibition of growth of haematopoietic progenitors (CFU-GM). In these leukaemic cells, trabectedin downregulated the expression of genes belonging to the Rho GTPases pathway (RAS superfamily) having a critical role in cell growth and cytoskeletal dynamics. Its selective activity on myelomonocytic malignant cells was confirmed also on in vitro THP-1 cell line and on in vitro and in vivo MV-4-11 cell line models.

CONCLUSIONS

Trabectedin could be good candidate for clinical studies in JMML/CMML patients.

A Network-Based Data Integration Approach to Support Drug Repurposing and Multi-Target Therapies in Triple Negative Breast Cancer

The integration of data and knowledge from heterogeneous sources can be a key success factor in drug design, drug repurposing and multi-target therapies. In this context, biological networks provide a useful instrument to highlight the relationships and to model the phenomena underlying therapeutic action in cancer. In our work, we applied network-based modeling within a novel bioinformatics pipeline to identify promising multi-target drugs. Given a certain tumor type/subtype, we derive a disease-specific Protein-Protein Interaction (PPI) network by combining different data-bases and knowledge repositories. Next, the application of suitable graph-based algorithms allows selecting a set of potentially interesting combinations of drug targets. A list of drug candidates is then extracted by applying a recent data fusion approach based on matrix tri-factorization. Available knowledge about selected drugs mechanisms of action is finally exploited to identify the most promising candidates for planning in vitro studies. We applied this approach to the case of Triple Negative Breast Cancer (TNBC), a subtype of breast cancer whose biology is poorly understood and that lacks of specific molecular targets. Our “in-silico” findings have been confirmed by a number of in vitro experiments, whose results demonstrated the ability of the method to select candidates for drug repurposing.

Proteasome machinery is instrumental in a common gain-of-function program of the p53 missense mutants in cancer

In cancer, the tumour suppressor gene TP53 undergoes frequent missense mutations that endow mutant p53 proteins with oncogenic properties. Until now, a universal mutant p53 gain-of-function program has not been defined. By means of multi-omics: proteome, DNA interactome (chromatin immunoprecipitation followed by sequencing) and transcriptome (RNA sequencing/microarray) analyses, we identified the proteasome machinery as a common target of p53 missense mutants. The mutant p53-proteasome axis globally affects protein homeostasis, inhibiting multiple tumour-suppressive pathways, including the anti-oncogenic KSRP-microRNA pathway. In cancer cells, p53 missense mutants cooperate with Nrf2 (NFE2L2) to activate proteasome gene transcription, resulting in resistance to the proteasome inhibitor carfilzomib. Combining the mutant p53-inactivating agent APR-246 (PRIMA-1MET) with the proteasome inhibitor carfilzomib is effective in overcoming chemoresistance in triple-negative breast cancer cells, creating a therapeutic opportunity for treatment of solid tumours and metastasis with mutant p53.

Cellular and molecular determinants of all-trans retinoic acid sensitivity in breast cancer: Luminal phenotype and RARα expression

Forty-two cell lines recapitulating mammary carcinoma heterogeneity were profiled for all-trans retinoic acid (ATRA) sensitivity. Luminal and ER⁺ (estrogen-receptor-positive) cell lines are generally sensitive to ATRA, while refractoriness/low sensitivity is associated with a Basal phenotype and HER2 positivity. Indeed, only 2 Basal cell lines (MDA-MB157 and HCC-1599) are highly sensitive to the retinoid. Sensitivity of HCC-1599 cells is confirmed in xenotransplanted mice. Short-term tissue-slice cultures of surgical samples validate the cell-line results and support the concept that a high proportion of Luminal/ER⁺ carcinomas are ATRA sensitive, while triple-negative (Basal) and HER2-positive tumors tend to be retinoid resistant. Pathway-oriented analysis of the constitutive gene-expression profiles in the cell lines identifies RARα as the member of the retinoid pathway directly associated with a Luminal phenotype, estrogen positivity and ATRA sensitivity. RARα3 is the major transcript in ATRA-sensitive cells and tumors. Studies in selected cell lines with agonists/antagonists confirm that RARα is the principal mediator of ATRA responsiveness. RARα over-expression sensitizes retinoid-resistant MDA-MB453 cells to ATRA anti-proliferative action. Conversely, silencing of RARα in retinoid-sensitive SKBR3 cells abrogates ATRA responsiveness. All this is paralleled by similar effects on ATRA-dependent inhibition of cell motility, indicating that RARα may mediate also ATRA anti-metastatic effects. We define gene sets of predictive potential which are associated with ATRA sensitivity in breast cancer cell lines and validate them in short-term tissue cultures of Luminal/ER⁺ and triple-negative tumors. In these last models, we determine the perturbations in the transcriptomic profiles afforded by ATRA. The study provides fundamental information for the development of retinoid-based therapeutic strategies aimed at the stratified treatment of breast cancer subtypes.

Abstract P6-04-09: Cellular and molecular determinants of breast cancer sensitivity to all-trans retinoic acid: Identification of a gene expression fingerprint predicting responsiveness

All-trans retinoic acid (ATRA) and derived natural as well as synthetic retinoids are promising agents in the treatment and chemoprevention of various types of neoplasia, including mammary tumors. ATRA is an important component of the therapeutic schemes used for the treatment of a rare form of Acute Myelogenous Leukemia known as Acute Promyelocytic Leukemia. A rational use of the paradigmatic retinoid, ATRA, in a heterogeneous disease, like breast cancer, requires the definition of the cellular and molecular determinants of sensitivity to the agent. The major aim of the study was the definition of a predictive gene expression fingerprint that can be used for the selection of patients who may benefit from treatment protocols containing ATRA. To this purpose, we selected 45 breast cancer cell lines characterized for the constitutive whole genome gene expression profiles. The sensitivity of 30 cell lines (training set) to the anti-proliferative action of ATRA was defined after challenge with increasing concentrations of the retinoid for 3, 6 and 9 days. This analysis established that Luminal and ER-positive cell lines are enriched within the ATRA sensitive group. In contrast, cell lines characterized by a Basal-like phenotype, according to the PAM50 gene expression signature, are generally refractory to the growth inhibitory action of ATRA. The sensitivity of Luminal-A and Luminal-B and the general refractoriness of Basal-like tumors to ATRA was validated in short-term tissue slice cultures of surgical breast cancer specimens. The training set was used to define a gene-expression fingerprint consisting of approximately 50 genes significantly associated with ATRA sensitivity. The fingerprint was generated by reprocessing the RNA sequencing data contained in the CCLE (Cancer Cell line Encyclopedia) of the Broad Institute and it was built from approximately 60,000 coding and non-coding loci. The approach involved the use of general linear models (machine learning algorithm). The identified gene-expression fingerprint was subsequently used to successfully predict ATRA sensitivity in a test set consisting of the remaining 15 cell lines. As a first step towards the use of the fingerprint for the stratification of patients, we evaluated the proportion of predicted ATRA sensitive breast tumors in the TCGA dataset. In accordance with the cell line and primary tumor data, approximately 30% of the Luminal tumors present with a high similarity score to the identified gene expression fingerprint associated with ATRA sensitivity. In contrast, only 5% of the Basal-like or Triple-negative mammary tumors are characterized by the same high similarity score. Curiously, the ATRA sensitivity signature seems to be tumor context independent, as it correctly identifies the 20 Acute Promyelocytic Leukemia patients present in the 198 Acute Myelogenous Leukemia patients present in the TCGA dataset.

Citation Format: Garattini E, Bolis M, Paroni G, Fratelli M, Zambelli A, Terao M. Cellular and molecular determinants of breast cancer sensitivity to all-trans retinoic acid: Identification of a gene expression fingerprint predicting responsiveness. [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 P6-04-09.

Trabectedin for the treatment of breast cancer

INTRODUCTION

Trabectedin is an anti-tumor compound registered in Europe and in several other countries, for the second-line treatment of soft tissue sarcoma (STS) and for ovarian cancer in combination with liposomal doxorubicin. Trabectedin inhibits cancer cell proliferation mainly affecting the transcription regulation. Trabectedin also acts as a modulator of tumor microenvironment by reducing the number of tumor associated macrophages (TAM). Because of its unique mechanism of action, trabectedin has the potential to act as antineoplastic agent also in several solid malignancies, including breast cancer (BC).

AREAS COVERED

This article reviews the preclinical and clinical data of trabectedin focusing on development in metastatic BC (mBC). Comments regarding the nature and the results of these trials are included.

EXPERT OPINION

Trabectedin is thought to have a crucial activity with defective DNA-repair machinery and also in modulating the tumor micro-environment and the immune-system of cancer patients. From the current available data, we recognize a potential activity of trabectedin in mBC and support the renewed efforts to better elucidate the value of trabectedin in this indication.

Trastuzumab for HER2+ metastatic breast cancer in clinical practice: Cardiotoxicity and overall survival

The evidence on efficacy and safety of trastuzumab in metastatic breast cancers (MBC) mainly derives from randomized clinical trials. We assessed short- and long-term overall survival (OS) and cardiotoxicity in a large cohort of women with MBC treated with trastuzumab in clinical settings. Using healthcare administrative data of Lombardy (10 millions inhabitants), we identified a cohort of women receiving trastuzumab for MBC between 2006 and 2009. The cumulative risk of severe cardiac events and the OS from the first trastuzumab administration were estimated using the Kaplan-Meier method. Their predictors were assessed using Cox regression models. We found 681 trastuzumab MBC users. Thirty two (4.7%) women experienced severe cardiac adverse events. The cumulative risk increased sharply, reaching a value of 2.4% and 4.3% during the first and second year; thereafter it increased of about 1% per year. Age was a strong predictor of cardiotoxicity. The OS was 81.8%, 64.0%, 50.2%, 41.1% and 37.2% at 1, 2, 3, 4 and 5 years, respectively. Independent predictors of worse OS were: age, brain liver or lung metastasis compared to other metastasis, use of taxanes and other chemotherapies, a cardiac adverse event after trastuzumab use, and a higher time between metastasis and BC diagnoses. The incidence of cardiotoxicity among women treated with trastuzumab for HER2-positive MBC appeared higher than that reported in RCTs, particularly in elder patients. In spite of this, median survival, was, if anything, better.

Translating Proteomic Into Functional Data: An High Mobility Group A1 (HMGA1) Proteomic Signature Has Prognostic Value in Breast Cancer

Cancer is a very heterogeneous disease, and biological variability adds a further level of complexity, thus limiting the ability to identify new genes involved in cancer development. Oncogenes whose expression levels control cell aggressiveness are very useful for developing cellular models that permit differential expression screenings in isogenic contexts. HMGA1 protein has this unique property because it is a master regulator in breast cancer cells that control the transition from a nontumorigenic epithelial-like phenotype toward a highly aggressive mesenchymal-like one. The proteins extracted from HMGA1-silenced and control MDA-MB-231 cells were analyzed using label-free shotgun mass spectrometry. The differentially expressed proteins were cross-referenced with DNA microarray data obtained using the same cellular model and the overlapping genes were filtered for factors linked to poor prognosis in breast cancer gene expression meta-data sets, resulting in an HMGA1 protein signature composed of 21 members (HRS, HMGA1 reduced signature). This signature had a prognostic value (overall survival, relapse-free survival, and distant metastasis-free survival) in breast cancer. qRT-PCR, Western blot, and immunohistochemistry analyses validated the link of three members of this signature (KIFC1, LRRC59, and TRIP13) with HMGA1 expression levels both in vitro and in vivo and wound healing assays demonstrated that these three proteins are involved in modulating tumor cell motility. Combining proteomic and genomic data with the aid of bioinformatic tools, our results highlight the potential involvement in neoplastic transformation of a restricted list of factors with an as-yet-unexplored role in cancer. These factors are druggable targets that could be exploited for the development of new, targeted therapeutic approaches in triple-negative breast cancer.

Neoadjuvant Model in Cancer Treatment: From Clinical Opportunity to Health-Care Utility

In the last few decades, research has demonstrated that cancer can be treated and cured if diagnosed at very early stage and a proper therapeutic strategy is adopted. Recent omics-based approaches have unveiled the molecular mechanisms of cancer tumorigenesis and have aided in identifying next-generation molecular markers for early diagnosis, prognosis, and targeted therapy. New tests based on genomic profiling, circulating tumor cells, or mutation profiling are appraised for purpose by Health Technology Assessment. The potential clinical utility of these tests lies on their ability to discriminate between patients who will benefit to a greater or lesser extent from a therapeutic intervention. Assessment of new technologies for the management of cancer could be of interest to other countries given the potentially high impact that they can have on the quality and cost of health care services.

A male patient with acromegaly and breast cancer: treating acromegaly to control tumor progression

Background

Acromegaly is a rare disease associated with an increased risk of developing cancer.

Case presentation

We report the case of a 72-year-old man who was diagnosed with acromegaly (IGF-1 770 ng/ml) and breast cancer. Four years before he suffered from a colon-rectal cancer. Pituitary surgery and octreotide-LAR treatment failed to control acromegaly. Normalization of IGF-1 (97 ng/ml) was obtained with pegvisomant therapy. Four years after breast cancer surgery, 2 pulmonary metastases were detected at chest CT. The patient was started on anastrozole, but, contrary to medical advice, he stopped pegvisomant treatment (IGF-I 453 ng/ml). Four months later, chest CT revealed an increase in size of the metastatic lesion of the left lung. The patient was shifted from anastrozole to tamoxifen and was restarted on pegvisomant, with normalization of serum IGF-1 levels (90 ng/ml). Four months later, a reduction in size of the metastatic lesion of the left lung was detected by CT. Subsequent CT scans throughout a 24-month follow-up showed a further reduction in size and then a stabilization of the metastasis.

Conclusions

This is the first report of a male patient with acromegaly and breast cancer. The clinical course of breast cancer was closely related to the metabolic control of acromegaly. The rapid progression of metastatic lesion was temporally related to stopping pegvisomant treatment and paralleled a rise in serum IGF-1 levels. Normalization of IGF-1 after re-starting pegvisomant impressively reduced the progression of metastatic breast lesions. Control of acromegaly is mandatory in acromegalic patients with cancer.

Abstract P5-19-25: Multi-institutional retrospective analysis of clinical and pathological factors predicting resistance to lapatinib-based therapy in HER2 positive metastatic breast cancer (HER2+ MBC)

Background

The combination of the dual HER1/HER2 inhibitor lapatinib (L) and capecitabine (C) is a therapeutic option for patients (pts) with HER2+MBC whose disease progresses after treatment with the monoclonal antibody trastuzumab. At present time, no clinical or pathological factors except HER2 status are clearly recognized as predictors of the activity of LC. We conducted a retrospective analysis of pts with HER2-positive metastatic breast cancer receiving LC after trastuzumab failure to identify factors associated with resistance to LC.

Materials and methods

We collected clinical and pathological data from 151 pts with HER2+ MBC receiving LC after failing a prior trastuzumab-based treatment (either adjuvant or for metastatic disease) treated at 13 Italian Institutions between March 2007 and December 2013. Time to progression (TTP) and overall survival (OS), calculated by the Kaplan Meier (KM) method, were from LC treatment beginning to disease progression or to death in the absence of progression (TTP), and to the date of death or to the date of last follow-up (OS), respectively. LC resistance was defined as TTP from treatment initiation lower or equal to the median TTP for the overall population. KM curves were compared by the Log-rank test. Logistic regression analysis was used to study predictors of TTP below the median value for patients receiving LC. Analyses were performed using SPSS version 17.0 (SPSS Inc., Chicago, IL).

Results

At a median follow-up of 41 months (IQR 23-62), median TTP to LC therapy was 7 months (IQR 5.5-8.5) and median OS was 18 months (IQR 10-28). Fifteen pts were excluded because of short follow-up (i.e. on LC treatment and <7 months of fu). Of the remaining 136, a total of 74 pts with a PFS≤7 months were defined LC-resistant (LC-R) and a total of 62 pts were defined LC-sensitive (LC-S). All clinical and pathological variables analyzed resulted evenly distributed between the two groups, except best tumor response (CR+PR) to LC, which was higher in patients with LC-S disease (72% vs 29%, p<0.001). Conversely, best tumor response in LC-R patients showed higher rates of PD (43% vs 2%, p<0.001). Median OS was 14 months (IC 95% 11.4-22.6) and 26 months (IC 95% 22.5-29.5) in LC-R and LC-S pts, respectively (p<0.001). Although we could not find independent predictors of LC-R, factors indicating failure of the first-line trastuzumab based therapy, as PD as best tumor response and short duration of first-line trastuzumab, were associated to LC-R.

Conclusions

A short time to progression during capecitabine and lapatinib (LC-R) is associated with reduced OS in patients failing prior trastuzumab based therapy for HER2+ MBC. Patients who had modest clinical benefit from previous trastuzumab-based therapy could experience LC-R indicating the possibility of primary resistance to anti HER2-treatment. For these patients, alternative targeting strategies are urgently needed.

Citation Format: Stefania Gori, Valentina Rossi, Monica Turazza, Elena Fiorio, Alessandra Fabi, Giancarlo Bisagni, Jennifer Foglietta, Daniele Santini, Ida Pavese, Alberto Zambelli, Patrizia Vici, Vita Leonardi, Sandro Barni, Silvana Saracchini, Giuseppe Bogina, Simona Duranti, Alessandro Inno, Gianluigi Lunardi, Filippo Montemurro. Multi-institutional retrospective analysis of clinical and pathological factors predicting resistance to lapatinib-based therapy in HER2 positive metastatic breast cancer (HER2+ MBC) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-19-25.

Profiling cancer gene mutations in longitudinal epithelial ovarian cancer biopsies by targeted next-generation sequencing: a retrospective study

BACKGROUND

The majority of patients with stage III-IV epithelial ovarian cancer (EOC) relapse after initially responding to platinum-based chemotherapy, and develop resistance. The genomic features involved in drug resistance are unknown. To unravel some of these features, we investigated the mutational profile of genes involved in pathways related to drug sensitivity in a cohort of matched tumors obtained at first surgery (Ft-S) and second surgery (Sd-S).

PATIENTS AND METHODS

Matched biopsies (33) taken at Ft-S and Sd-S were selected from the 'Pandora' tumor tissue collection. DNA libraries for 65 genes were generated using the TruSeq Custom Amplicon kit and sequenced on MiSeq (Illumina). Data were analyzed using a high-performance cluster computing platform (Cloud4CARE project) and independently validated.

RESULTS

A total of 2270 somatic mutations were identified (89.85% base substitutions 8.19% indels, and 1.92% unknown). Homologous recombination (HR) genes and TP53 were mutated in the majority of Ft-S, while ATM, ATR, TOP2A and TOP2B were mutated in the entire dataset. Only 2% of mutations were conserved between matched Ft-S and Sd-S. Mutations detected at second surgery clustered patients in two groups characterized by different mutational profiles in genes associated with HR, PI3K, miRNA biogenesis and signal transduction.

CONCLUSIONS

There was a low level of concordance between Ft-S and Sd-S in terms of mutations in genes involved in key processes of tumor growth and drug resistance. This result suggests the importance of future longitudinal analyses to improve the clinical management of relapsed EOC.

Adipose-derived Mesenchymal Stem Cells (ASCs) may favour breast cancer recurrence via HGF/c-Met signaling

Adipose tissue is a reservoir of Mesenchymal Stem Cells (Adipose-derived Mesenchymal Stem Cells, ASCs), endowed with regenerative properties. Fat graft was proposed for breast reconstruction in post-surgery cancer patients achieving good aesthetic results and tissues regeneration. However, recent findings highlight a potential tumorigenic role that ASCs may have in cancer recurrence, raising some concerns about their safety in clinical application.

To address this issue, we established a model where autologous ASCs were combined with primary normal or cancer cells from breast of human donors, in order to evaluate potential effects of their interactions, in vitro and in vivo.

Surprisingly, we found that ASCs are not tumorigenic per sè, as they are not able to induce a neoplastic transformation of normal mammary cells, however they could exhacerbate tumorigenic behaviour of c-Met-expressing breast cancer cells, creating an inflammatory microenvironment which sustained tumor growth and angiogenesis.

Pharmacological c-Met inhibition showed that a HGF/c-Met crosstalk between ASCs and breast cancer cells enhanced tumor cells migration, acquiring a metastatic signature, and sustained tumor self-renewal.

The master role of HGF/c-Met pathway in cancer recurrence was further confirmed by c-Met immunostaining in primary breast cancer from human donors, revealing a strong positivity in patients displaying a recurrent pathology after fat grafts and a weak/moderate staining in patients without signs of recurrence.

Altogether our findings, for the first time, suggest c-Met expression, as predictive to evaluate risk of cancer recurrence after autologous fat graft in post-surgery breast cancer patients, increasing the safety of fat graft in clinical application.

Effectiveness of trastuzumab in first-line HER2+ metastatic breast cancer after failure in adjuvant setting: a controlled cohort study

BACKGROUND

The evidence supporting the use of trastuzumab (T) in a metastatic setting comes from studies that included (almost) only patients who never received prior T. We investigated the effectiveness of T as first-line therapy for metastatic breast cancer (mBC) in women previously treated with T in the adjuvant setting.

MATERIALS AND METHODS

By using record linkage of five administrative health care databases of Lombardy, Italy, we identified 2,046 women treated with T for early breast cancer (eBC) in 2006-2009, 96 of whom developed a metastasis and were retreated with T in first-line treatment for mBC (treatment group). We compared the overall survival (OS) of these women with that of 197 women treated with T in first-line treatment for mBC, who were treated with therapies other than T for early disease (control group). We computed Kaplan-Meier 2-year OS and used a proportional hazard model to estimate the multivariate hazard ratio (HR) of death in the intervention group compared with the control group, adjusted by age, use of endocrine therapy, and site of metastasis.

RESULTS

Two-year OS was 60.0% in the treatment group and 59.5% in the control group. The adjusted HR of death in the treatment group compared with the control group was 0.79 (95% confidence interval, 0.50-1.26).

CONCLUSION

Our data provide convincing evidence that the outcome of women receiving first-line T treatment for mBC after T failure in the adjuvant setting is comparable to that of women not receiving T for eBC. These data are of specific interest, given the unavailability of data from randomized clinical trials.