Diferencias en las respuestas fisiológicas entre triatletas masculinos y femeninos

Los objetivos de este estudio fueron analizar las diferencias entre triatletas masculinos y femeninos amateurs en el rendimiento en un test incremental máximo y en una competición simulada y describir si existe asociación entre el rendimiento en el test máximo incremental y la prueba simulada de competición. Un total de catorce triatletas recreacionales, 8 mujeres (35,0  8,1  años; 166,8  7,2  cm; 69,4  14,6 kg; 24,7  3,2 kg.m-2) y 6 hombres (47,7  14,3  años; 179,9  8,6  cm; 77,8  5,8  kg; 24,0  1,3 kg.m-2) realizaron un test incremental máximo y en una competición simulada (20 km bici y 5 km carrera a pie). A pesar de que no se observaron diferencias significativas entre el grupo masculino y femenino en el test máximo incremental, a efectos prácticos, el grupo masculino obtuvo valores mayores para VO2max, Pmax, PVT1, PVT2 y VO2VT2 (p > 0,05, ES = -0,8 a -1.9, alto). Con respecto a la competición simulada, si bien no se obtuvieron diferencias en función de sexo en los 5 km de carrera, el grupo femenino obtuvo valores significativamente inferiores para las variables velocidad (media y máxima) (p < 0,05 y p < 0,01, ES = -1,3- -4,1, alto) y potencia (media y máxima) (p < 0,01, ES = -2.4- -2.8, alto) durante los 20 km de ciclismo, así como un tiempo de ejecución del sector ciclista significativamente mayor que el grupo masculino (p < 0,01, ES = 1,6, alto).  Por otro lado, un mejor rendimiento durante el test máximo incremental se asoció a un mejor rendimiento durante los 20 km de ciclismo en el grupo masculino (r = 0,848, p < 0,05), mientras que en el grupo femenino se asoció tanto a los 20 km en bici como a los 5 km corriendo (r = -0,714 a -0,822, p < 0,05). Los resultados obtenidos en el estudio ponen de manifiesto que los triatletas masculinos tienen un mejor rendimiento en un test incremental máximo y en el sector bici en una competición simulada y que la asociación entre el rendimiento en un test incremental y el rendimiento en los sectores de la prueba simulada depende del sexo.

Abstract OT2-06-05: A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard peri-operative care in women with residual triple negative early stage/resectable breast cancer after standard-of-care neoadjuvant chemotherapy

Background: Triple negative breast cancer (TNBC) is a biologically distinct subtype with high risk of early relapse, particularly for patients who do not achieve a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC), with an event free survival of &lt; 60% at 3 years. Physical disruption of tumors with cryoablation (cryo) induces inflammation and releases antigens that can activate tumor-specific immune responses. In pre-clinical studies, the combination of cryo with checkpoint inhibition augmented tumor-specific immune responses and prevented cancer recurrence. In clinical studies, the combination of pre-operative ipilimumab (ipi)- +/- nivolumab (nivo)-mediated checkpoint blockade with cryo was safely administered in women with operable, early stage breast cancer and generated intra-tumoral and systemic immune responses (NCT01502592, NCT02833233). In this multi-center, randomized study, we evaluate the disease specific impact of peri-operative ipi, nivo and cryo versus standard care in women with residual TNBC after neoadjuvant taxane-based chemotherapy (NCT03546686).

Methods:Eligible pts are aged ≥18 years, with ER, PR and HER2 negative operable tumors ≥ 1.0 cm after neoadjuvant taxane-based chemotherapy. Approximately 160 patients will be randomized to one of two arms: standard-of-care breast surgery (control arm) or ipi/nivo/cryo followed by standard-of-care breast surgery (intervention arm). Subjects randomized to the intervention arm will undergo percutaneous, ultrasound- (or MRI-) guided cryoablation with concurrent research core biopsy 7-10 days prior to surgery, and will receive a pre-operative infusion with ipilimumab at the dose of 1mg/kg IV, and nivolumab 240mg flat dose IV (1 to 5 days prior to cryoablation). After surgery, patients will receive three additional doses of nivolumab 240mg flat dose IV Q2 weeks. Adjuvant capecitabine is recommended for all participants and will be administered per standard-of-care at the treating physician's discretion. Patients will be stratified by prior platinum administration, prior anthracycline administration, and clinical nodal status (positive versus negative) at enrollment. The primary endpoint is 3-year Event Free Survival (EFS). Secondary end points include Invasive Disease-Free Survival (IDFS), Distant Disease-Free Survival (DDFS), overall survival (OS) and safety. Exploratory correlative studies will be performed on tumor and serum to characterize the immunologic impact of the intervention and to explore predictors of efficacy and toxicity.

Citation Format: McArthur HL, Comen EA, Solomon S, Rodine M, DiLauro Abaya C, Leal JHS, Patil S, Norton L. A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard peri-operative care in women with residual triple negative early stage/resectable breast cancer after standard-of-care neoadjuvant chemotherapy [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 OT2-06-05.

Abstract P6-20-03: Tumor epichaperome expression using 124I PU-H71 PET (PU-PET) as a biomarker of response for PU-H71 plus nab-paclitaxel in HER2 negative (HER2-) metastatic breast cancer (MBC)

Background: The epichaperome is a new cancer target required for tumor survival (Joshi et al. Nature Reviews Cancer 2018). PU-H71 is a synthetic, purine scaffold epichaperome inhibitor that binds to the ATP-binding site of HSP90 specifically when HSP90 is integrated into the epichaperome (Rodina et al. Nature 2016). It has demonstrated antitumor activity in multiple xenograft models. Furthermore, sequential administration of nab-paclitaxel and PU-H71 in TNBC xenograft models augmented epichaperome levels, and in turn resulted in super-synergistic drug action with ablation of xenografted tumors and cures in mice.

Methods: This is an open label phase1b study of PU-H71 + nab-paclitaxel in pts with HER2- MBC. Pts received nab-paclitaxel at a standard dose of 260mg/m2 IV Q 3weeks. PU-H71 was administered IV 6 hrs (+/-1 hr) post nab-paclitaxel Q3weeks in 2 escalating dose levels (225mg/m2 and 300 mg/m2). All pts underwent FDG PET/CT every 6 weeks. Additionally, patients had the option to enroll on a separate diagnostic PU-PET protocol to measure epichaperome expression prior to initiating treatment on the phase 1b study, wherein they received a single dose of up to 11mci of 124I-PU-H71 IV and underwent imaging at 3-4hrs and 20-24 hrs. Primary objective was to establish the MTD/RP2D of this regimen. Secondary objectives were to assess PK of PU-H71 + nab-paclitaxel and clinical efficacy. Exploratory analysis included correlation of epichaperome expression at baseline using PU-PET with tumor response.

Results: 12 patients (5 ER+/HER2- ; 7 TNBC) were enrolled (6 at 225mg/m2 of PU-H71 and 6 at 300mg/m2). Median Age: 54 yrs (range: 37-71). Median ECOG: 0. Median lines of therapy in the metastatic setting: 6 (range 1-11) including prior taxanes in 75% of pts. Most common toxicities included diarrhea G1 58%; G2 7%, G3 7%) that was easily managed with anti-diarrheal agents, G1 fatigue (25%), G1/2 peripheral neuropathy (17%), G1 hyperglycemia (67%), G1 increases in alk phos (58%), AST (50%) and ALT (42%). Hematological toxicities included G3 leukopenia (42%), G3/4 neutropenia (67%), G3 anemia (50%) and G2 thrombocytopenia (17%). There were no DLTs. 33% (4/12) had PR, 58% (7/12) achieved SD with only 1 PD at the time of first scan; 5 pts are currently ongoing including 2 TNBC pts with PR who have been on therapy &gt; 7 months. PK data will be presented. 8/12 patients also underwent PU-PET at baseline. A higher tumor to muscle SUV ratio at 24 hrs on PU-PET predicted response and increased PU-H71 retention on PU-PET at 24 hrs correlated with a longer duration of response.

Conclusion: The RP2D of PU-H71 was 300mg/m2 with 260mg/m2 of nab-paclitaxel administered IV every 3 weeks. The regimen is well tolerated with promising clinical activity in this heavily pre-treated cohort. Tumor epichaperome expression at baseline using PU-PET has the potential to serve as a predictive biomarker of response. A Phase 2 trial of this combination along with baseline PU-PET is currently planned.

Citation Format: Jhaveri K, Dunphy M, Wang R, Comen E, Fornier M, Moynahan ME, Bromberg J, Ma W, Patil S, Taldone T, Rodina A, Sterlin V, Khoshi S, Lewis J, Norton L, Chiosis G, Modi S. Tumor epichaperome expression using 124I PU-H71 PET (PU-PET) as a biomarker of response for PU-H71 plus nab-paclitaxel in HER2 negative (HER2-) metastatic breast cancer (MBC) [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 P6-20-03.

Abstract P2-01-02: Whole exome sequencing analysis of the progression from ductal carcinoma in situ to invasive ductal carcinoma

Introduction: Ductal carcinoma in situ (DCIS) is a bona fide non-obligate precursor of invasive carcinoma. Single cell sequencing studies have revealed intra-lesion genetic heterogeneity in DCIS and shown that progression to invasive ductal carcinoma (IDC) may occur through different mechanisms, including the selection of a subpopulation of tumor cells, acquisition of new genetic alterations or multi-clonal invasion. Here, we sought to investigate the genetic heterogeneity of DCIS, and to document further the clonal selection process accompanying progression to IDC.

Materials and methods: Synchronous DCIS (n=16) and IDC (n=15) samples from 14 patients were microdissected separately, and DNA samples of tumor and matched normal tissues were subjected to whole-exome sequencing (WES; n=27) or massively parallel targeted sequencing of all coding regions of ≥410 cancer-related genes (n=4). Somatic genetic alterations and mutational signatures were identified using state-of-the-art bioinformatics algorithms. PyClone was employed to define the clonal architecture of each DCIS and IDC and infer the clonal shifts accompanying progression from DCIS to IDC.

Results: DCIS were found to harbor recurrent somatic mutations affecting PIK3CA (50%), GATA3 (44%), TP53 (38%), CBFB (19%), PTEN (13%), and AKT1 (13%), which are genes known to be significantly mutated in invasive breast cancers. Despite the genomic similarities between matched DCIS and IDCs, NOTCH2 and MYC were found to be amplified solely in the IDC component of two cases, and PPM1D amplification was restricted to the DCIS component of another case. The mutational signature ascribed to aging (i.e. signature 1) was the predominant mutational signature in the DCIS and IDCs analyzed. PyClone analysis revealed that all synchronous DCIS and IDC studied here were clonally related and confirmed the previous observation that DCIS displays intra-lesion genetic heterogeneity. Evidence of clonal selection in the progression from DCIS to IDC was observed in three cases, whereby a minor DCIS subclone likely constituted the substrate for the development of IDC. In one of these cases, from a patient with a BRCA1 germline pathogenic mutation, we observed a shift from the mutational signature associated with defective homologous recombination DNA repair (i.e. signature 3) to the APOBEC-related mutational signatures (i.e. signatures 2 and 13) in the progression from DCIS to IDC.

Conclusion: Intra-lesion genetic heterogeneity is a common feature in DCIS synchronously diagnosed with IDC. Our findings corroborate the notion that DCIS is a direct non-obligate precursor of IDC, and that clonal selection in the progression of DCIS to IDC may be present in a subset of cases, but is unlikely to constitute the most frequent mechanism of progression.

Citation Format: Lee JY, Bi R, Pareja F, Geyer FC, Brown D, Wen HY, Norton L, Hicks J, Weigelt B, Reis-Filho JS. Whole exome sequencing analysis of the progression from ductal carcinoma in situ to invasive ductal carcinoma [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 P2-01-02.

Abstract P6-18-30: Phase Ib/II study of capecitabine 7/7 schedule with neratinib in patients with HER2-positive metastatic breast cancer (MBC)

Background: Neratinib (N) is a potent irreversible inhibitor of HER1, HER2, and HER4 and has been shown to have antitumor activity in patients (pts) with human epidermal growth factor receptor 2 (HER2) - positive breast cancer. A previous study of combination of neratinib with capecitabine (X) was associated with &gt; G 3 diarrhea in &gt; 20% of patients. Currently, the NALA study is evaluating this combination of N with X at standard schedule against control. X at 7 day on and 7 day off schedule (7/7) has been shown to be well-tolerated with less ≥G3 toxicities. We are conducting a phase Ib/II study of N with X (7/7) in pts with pretreated HER2+ MBC (NCT03377387). Methods: Eligible pts had HER2+ MBC, normal left ventricular ejection fraction (LVEF ≥ 50%); pts can have any and up to 4 prior chemotherapy-based treatments in phase Ib and II portions, respectively. Primary endpoints are to define maximum tolerated dose and efficacy in phase I and phase II portions, respectively. Secondary endpoints include safety and tolerability; exploratory endpoint is to quantify cell-free DNA to correlate with response for phase II portion. There were 4 cohorts for phase Ib with dose level 1 with starting dose of X at 1500 mg BID at 7/7 schedule with N at 240 mg daily. Results: As of July 1, 2018 8 pts have been enrolled in 2 cohorts. The median age is 63y (range: 57-79), and median ECOG is 0 (range: 0-1). 4 patients were treated at dose level 1 and 2 of 4 patients experienced dose-limiting toxicity with G3 diarrhea during cycle 1. Other significant toxicities included G3 hand foot syndrome (n=1), G3 fatigue (n=1) and G3 nausea (n=1). Three pts have now been treated at dose level -1 (X at 1000 mg twice daily 7/7 and N at 240 mg daily) and no ≥ G3 toxicities has been noted. Once MTD is reached, the phase II portion will occur to assess the efficacy and to further establish the safety and tolerability of capecitabine and neratinib at the MTD. Conclusions: The phase Ib/II study combining neratinib and capecitabine 7/7 is ongoing and updated result will be presented.

Citation Format: Wang R, Singh J, Sterlin V, Goldstein M, Lake D, Wong S, Baselga J, Norton L, Dang C. Phase Ib/II study of capecitabine 7/7 schedule with neratinib in patients with HER2-positive metastatic breast cancer (MBC) [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 P6-18-30.

Abstract P3-07-02: Metaplastic breast carcinomas and uterine carcinosarcomas are histologically and genetically related

Introduction: Metaplastic breast carcinomas (MBCs) and uterine carcinosarcomas (UCSs) are histologically similar, being often characterized by an admixture of adenocarcinoma areas with areas displaying sarcomatoid differentiation. We sought to investigate whether their histologic similarities would be paralleled by similar patterns of genetic alterations, and to determine whether the different histologic components of MBCs and UCSs would be clonally related.

Methods: Whole exome sequencing (WES) data from 35 MBCs previously analyzed by our group and 57 UCSs from The Cancer Genome Atlas (TCGA) study were reanalyzed. Somatic single nucleotide variants were detected with MuTect and indels with Strelka, Varscan2, Scalpel and Lancet. Copy number alterations were inferred using FACETS and functional annotation of the non-synonymous somatic mutations, amplifications or homozygous deletions was performed. We further microdissected the histologically distinct components of 11 MBCs and six UCSs and subjected each component to WES. Clonal decomposition was performed using PyClone.

Results: The most frequent somatic mutations identified in MBCs were TP53 (69%), PIK3CA (29%), FAT3 (26%) and PTEN (14%), whereas the most frequently mutated genes in UCSs were TP53 (84%), FBXW7 (35%), PIK3CA (29%), PTEN (15%) and PPP2R1A (15%). MBCs displayed a significantly higher frequency of mutations targeting FAT3 (26% vs 4%, P&lt;0.01), FAT1 (11% vs 0%, P&lt;0.05) and CHERP (11% vs 0%, P&lt;0.05) than UCSs. UCSs more frequently harbored mutations affecting FBXW7 (35% vs 0%; P&lt;0.01) and PPP2R1A (15% vs 0%, P&lt;0.05) than MBCs. MBCs and UCSs displayed similar copy number alteration profiles, with frequent gains/ amplification of 8q, 3q and 1q, and losses of 8p. Pathway analysis based on the genes targeted by somatic genetic alterations revealed that both MBCs and UCSs were underpinned by genetic alterations resulting in activation of similar pathways, including PI3K, p53, Wnt and Notch signaling. Analysis of the separate components of MBCs and UCSs revealed that the histologically distinct components of MBCs and UCSs are clonally-related, with a median of 71% (range 26%-93%) and 78% (range 30%-93%) of somatic mutations being shared by the distinct components in MBCs and UCSs, respectively. In MBCs, clonal TP53, NOTCH3, KMT2D, FAT4 and PIK3CA mutations and several copy number alterations were shared by the histologically distinct components. Mutations private to each of the histologically distinct components included PIK3R1, CHERP and MAPK14 mutations. The carcinomatous and sarcomatous components of UCSs shared clonal TP53, PIK3CA, CDKN2A, ITGB7 and FGFR2 mutations. Private KMT2B mutations were identified in the UCS carcinomatous components. PyClone analysis revealed that the clonally-related histologically distinct components of each case harbored intra-component genetic heterogeneity coupled with parallel evolution.

Conclusions: Our findings support the contention that UCSs constitute the uterine counterpart of MBCs due to their similar histology and patterns of genetic alterations affecting the same signaling pathways (i.e. TP53, PI3K, Wnt and Notch). In each MBC and UCS analyzed here, the histologically distinct components were found to be clonally related.

Citation Format: Da Cruz Paula A, Brown D, Geyer FC, Smith E, Pareja F, Papanastasiou AD, Fusco N, Marchio C, Brogi E, Wen HY, Vincent-Salomon A, Norton L, Weigelt B, Reis-Filho JS. Metaplastic breast carcinomas and uterine carcinosarcomas are histologically and genetically related [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 P3-07-02.

Abstract P2-05-08: Mucinous breast carcinomas: A genomically distinct subtype of estrogen receptor-positive invasive breast cancers

Introduction: Mucinous carcinoma of the breast (MCB) is a rare histologic form of estrogen receptor (ER)-positive invasive carcinoma, accounting for up to 2% of breast cancers. MCBs are characterized by clusters of tumor cells floating in lakes of extracellular mucin, and are classified into mucinous A (paucicellular) and mucinous B (hypercellular) subtypes. Some MCBs are found admixed with invasive ductal carcinoma components, and then classified as mixed MCBs. The aims of this study were to determine the repertoire of somatic mutations of MCBs and to ascertain whether these genetic alterations are distinct from those identified in common forms of ER+/HER2- invasive breast cancers (IBCs). We also sought to determine whether the mucinous and ductal components of mixed MCBs would be clonally related.

Materials and methods: Thirty MCBs including 25 pure MCBs (n=13 mucinous A, n=12 mucinous B) and five mixed MCBs were microdissected and subjected to whole exome sequencing. Each tumor component of mixed cases was microdissected and analyzed separately. Somatic mutations, copy number alterations and mutational signatures were defined using state-of-the-art bioinformatics methods. The mutational repertoire of MCBs was compared with that of ER+/HER2- IBCs (n = 240) from The Cancer Genome Atlas (TCGA) breast cancer study.

Results: The genes most frequently mutated in MCBs were GATA3 (27%, 8/30, all frameshift mutations), KMT2C (13%, 4/30) and MAP3K1 (10%, 3/30). No significant differences were identified in single gene comparisons between mucinous A and mucinous B MCBs or between pure MCBs and the mucinous component of mixed MCBs (Fisher's exact tests, p&gt;0.05). As compared to common forms of ER+/HER2- IBC, MCBs had a lower frequency of PIK3CA mutations (7% vs 42%, p&lt;0.001) and a higher frequency of GATA3 mutations (27% vs 12%, p=0.04). Mucinous B MCBs had a higher frequency of KMT2C mutations than ER+/HER2- IBCs (25% vs 6%, p=0.04). Most MCBs displayed the mutational signature 1 (aging-related; 20/30, 67%), and no differences in the frequency of specific mutational signatures according to the type of MCBs were observed. Concurrent 1q gains and 16q losses, which are the hallmark genetic alterations of low-grade ER+/HER2- breast cancers, were not observed in pure MCBs, but were found in three of the five mixed MCBs analyzed. The mucinous and ductal components of all five mixed MCBs shared a median of 58% of somatic mutations (range 42%-64%), including clonal GATA3 frameshift mutations in two of them, as well as a similar pattern of copy number alterations, supporting their clonal relatedness. Additional somatic mutations found to be restricted to the ductal or mucinous components of all mixed MCBs analyzed were identified, including clonal missense mutations in PIK3C2B and PIK3R2 in the ductal component of one case, and a PIK3R5 missense mutation in the mucinous component of another case.

Conclusions: The repertoire of somatic mutations in MCBs is distinct from that of common forms of ER+/HER2- IBCs. These differences include the lack of concurrent 1q gains/16q losses, a lower frequency of PIK3CA mutations and a higher frequency of GATA3 mutations in pure MCBs.

Citation Format: Pareja F, Geyer FC, Piscuoglio S, Selenica P, Kumar R, Lim RS, Guerini-Rocco E, Marchio C, Mariani O, Ng CKY, Brogi E, Norton L, Vincent-Salomon A, Weigelt B, Reis-Filho JS. Mucinous breast carcinomas: A genomically distinct subtype of estrogen receptor-positive invasive breast cancers [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 P2-05-08.

Abstract P2-05-03: Novel driver genetic alterations in MYB-NFIB-negative breast adenoid cystic carcinomas

Introduction: Breast adenoid cystic carcinoma (AdCC) is a rare type of triple-negative breast cancer associated with an indolent clinical behavior. AdCCs provide a clear example of genotypic-phenotypic correlation with the majority harboring the MYB-NFIB fusion gene. In this study, we sought to identify alternative driver genetic alterations in breast AdCCs lacking the MYB-NFIB fusion gene.

Methods: Nucleic acids obtained from four breast AdCCs lacking the MYB-NFIB fusion gene as defined by reverse transcription (RT)-PCR and/or fluorescence in situ hybridization (FISH) were subjected to RNA-sequencing (n=3), whole-genome (n=2) and/or targeted (n=1) massively parallel sequencing. Sequencing data were analyzed using state-of-the-art bioinformatics algorithms, and potential alternative driver genetic alterations were validated using orthogonal sequencing and molecular pathology methods.

Results: RNA-sequencing revealed the presence of MYBL1-ACTN1 or MYBL1-NFIB fusion genes in two breast AdCCs, which were validated by whole-genome sequencing and/or MYBL1 FISH analysis. Both MYBL1 fusion gene-positive cases were found to overexpress MYBL1 as defined by quantitative RT-PCR analysis. In the third MYB-NFIB-negative breast AdCC studied, a high-level MYB gene amplification coupled with overexpression of MYB at the mRNA and protein levels was identified. In the fourth breast AdCC, which expressed high levels of MYB, whole-genome and RNA-sequencing revealed no definite alternative driver alteration, however, a MYBL2 intronic mutation was found in this case, which was associated with high levels of MYBL2 mRNA expression. In this case, single sample gene set enrichment analysis revealed activation of pathways similar to those activated in AdCCs harboring the MYB-NFIB or MYBL1 fusions genes.

Conclusion: We demonstrate that in breast AdCCs lacking the MYB-NFIB fusion gene MYBL1 rearrangements and MYB amplification are likely alternative driver genetic events. Given that activation of MYB/MYBL1 and their downstream targets can be driven by the MYB-NFIB fusion gene, MYBL1 rearrangements, MYB amplification or other yet to be validated mechanisms (e.g. MYBL2 non-coding mutations), our findings further suggest that breast AdCCs constitute a convergent phenotype.

Citation Format: Kim J, Geyer FC, Martelotto LG, Ng CKY, Lim RS, Selenica P, Li A, Pareja F, Fusco N, Edelweiss M, Mariani O, Badve S, Vincent-Salomon A, Norton L, Reis-Filho JS, Weigelt B. Novel driver genetic alterations in MYB-NFIB-negative breast adenoid cystic carcinomas [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 P2-05-03.

Abstract PD8-09: Bi-allelic alterations in homologous recombination (HR) DNA repair-related genes as the basis for HR defects in human cancers: A pan-cancer genomics and functional analysis

Background: BRCA1 and BRCA2 are involved in homologous recombination (HR) DNA repair and are germ-line cancer pre-disposition genes that result in the hereditary breast and ovarian cancer (HBOC) syndrome. Whether germ-line or somatic alterations in these genes or other members of the HR pathway and if mono- or bi-allelic alterations of HR-related genes have a phenotypic impact in breast and other cancers remains to be fully elucidated. Here we took a combined genomic and functional approach to identify the role of mutations in HR-related genes and their impact on HR DNA repair.

Methods: Whole-exome sequencing and Affymetrix SNP6 array data from 8,178 tumors, comprising 24 different cancer types including breast cancer, were retrieved from The Cancer Genome Atlas (TCGA). We identified the prevalence of missense and pathogenic (frame-shift, nonsense, start/stop codon and splice site variants) somatic and germline mutations in 102 HR-related genes curated from the literature. For each mutation, we determined if the alterations were bi-allelic. We evaluated genomic signatures of HR-deficiency in each tumor using large-scale state transitions (LSTs) and a mutational signature of HR-deficiency (signature 3). An independent set of 24 fresh sporadic breast cancer tissue specimens from our institution was subjected to i) an ex-vivo assay that assesses the ability of cancer cells to form RAD51 foci in response to ex-vivo irradiation (IR), and ii) whole exome-sequencing to define whether RAD51 deficient tumors would display LSTs, signature 3 and bi-allelic inactivation of HR-related genes.

Results: 13% and 5% of all TCGA cases displayed pathogenic mono- and bi-allelic alterations of HR-related genes, respectively. Of the biallelic alterations, only 45% occurred in traditional BRCA1/2 associated hereditary cancers (HBOCs, namely breast, ovarian and prostate cancer). Bi-allelic, but not mono-allelic, pathogenic genetic alterations in HR-related genes were significantly associated with genomic evidence of HR deficiency across cancer types, in HBOCs and within breast cancer. In HBOCs, bi-allelic alterations in HR-related genes were mutually exclusive (p=0.02). In breast cancer, bi-allelic inactivation of HR DNA repair-related genes was observed in 9.8%, of which 7.8% involved a germline pathogenic mutation and 2.0% were solely somatic. In breast cancer, in addition to BRCA1 and BRCA2, bi-allelic inactivation of PALB2 (0.2%), ATM (1.1%) and POLQ (0.3%) were found to be associated with genomic features of HR deficiency. In the 24 additional breast cancers, 9 were classified by the functional ex-vivo RAD51 assay as HR-deficient, 8 of which displayed bi-allelic inactivation of one HR-related gene, whereas only 1 of the 15 HR-proficient breast cancers harbored bi-allelic inactivation of HR-related genes (p&lt;0.001).

Conclusion: Bi-allelic germline and somatic alterations of HR-related genes in addition to BRCA1 and BRCA2 are present in breast and other cancer types. Irrespective of the gene, these bi-allelic alterations are associated with HR deficiency as defined by genomic methods and functional assays, expanding the potential opportunities for therapies targeting HR DNA repair defects.

Citation Format: Riaz N, Blecua P, Lim RS, Shen R, Higginson DS, Weinhold N, Norton L, Weigelt B, Powell SN, Reis-Filho JS. Bi-allelic alterations in homologous recombination (HR) DNA repair-related genes as the basis for HR defects in human cancers: A pan-cancer genomics and functional analysis [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 PD8-09.

Abstract PD4-13: Estrogen receptor-negative breast adenomyoepitheliomas are driven by co-occurring HRAS hotspot and PI3K pathway gene mutations: A genetic and functional analysis

Introduction:Adenomyoepithelioma (AME) of the breast is a rare biphasic tumor, characterized by epithelial and myoepithelial differentiation. Although AMEs have an indolent clinical course, a subset may progress to carcinoma and metastasize. We sought to define the mutational landscape of AMEs and investigate the functional impact of recurrent pathogenic mutations identified in these tumors.

Methods: Thirty-one AMEs were subjected to whole-exome sequencing (WES, n=8) or massively parallel sequencing targeting all coding regions of 410 key cancer genes and intronic and regulatory regions of selected genes (n=23). Somatic genetic alterations were defined using state-of-the-art bioinformatics algorithms. In an additional set of 12 AMEs, Sanger sequencing analysis of HRAS, PIK3CA and AKT1 was performed. Non-tumorigenic estrogen receptor (ER)-negative mammary epithelial cells (i.e. MCF10A, MCF10A with a PIK3CA H1047R mutation knock-in and MCF12A) were utilized for functional studies using both conventional monolayer and three-dimensional (3D) culture assays.

Results: 27 (63%) and 16 (37%) AMEs were ER-positive and ER-negative, respectively. ER-negativity was significantly associated with histologic features predictive of a more aggressive behavior, with a higher number of mutations and copy number alterations, and with a distinct mutational profile as compared to ER-positive AMEs. Of the 27 ER-positive AMEs, 12 cases (44%) harbored PIK3CA hotspot mutations, and 5 PIK3CA wild-type cases displayed E17K AKT1 hotspot mutations. By contrast, of the 16 ER-negative AMEs, 9 (56%), 9 (56%) and 3 (19%) harbored HRAS, PIK3CA (mostly E545K and H1047R hotspots) and PIK3R1 mutations, respectively. Strikingly, all HRAS mutations were restricted to ER-negative AMEs, affected the hotspot codon Q61 (Q61R/K), and all but one co-occurred with PIK3CA or PIK3R1 mutations. In addition, HRAS Q61 hotspot mutations were significantly associated with necrosis (p=0.01) and high mitotic rates (p=0.03). CDKN2A homozygous deletions were also detected only in ER-negative AMEs (19%) and found to be significantly associated with progression to carcinoma (p=0.001). Forced expression of HRAS Q61R in MCF10A and MCF12A cells resulted in i) increased proliferation and transformation, ii) an irregular growth pattern in 3D organotypic cell cultures, iii) partial loss of the epithelial phenotype, and iv) acquisition of myoepithelial differentiation, which was more overt in PIK3CA-mutant MCF10A cells. HRAS Q61Rinduced hyperactivation of the PI3K pathway, but both PI3K and MAPK pathways likely contributed to the RAS-mediated proliferation, which was completely arrested by combined AKT and MEK inhibition.

Conclusion: AMEs are phenotypically and genetically heterogeneous. Whilst pathogenic mutations in PI3K pathway-related genes occur across the spectrum of lesions, HRAS Q61 hotspot mutations are restricted to ER-negative AMEs. Our genomic and functional analyses indicate that HRAS Q61 mutations are driver events in the pathogenesis of ER-negative AMEs and, in conjunction with mutant PIK3CA, may lead to the acquisition of myoepithelial differentiation in breast epithelial cells.

Citation Format: Geyer FC, Li A, Papanastasiou AD, Smith A, Selenica P, Burke KA, Edelweiss M, Wen H-C, Piscuoglio S, Schultheis AM, Martelotto LG, Pareja F, Kumar R, Brandes A, Lozada J, Macedo GS, Muenst S, Terracciano LM, Jungbluth A, Foschini MP, Wen HY, Brogi E, Palazzo J, Rubin BP, Ng CKY, Norton L, Varga Z, Ellis IO, Rakha E, Chandarlapatty S, Weigelt B, Reis-Filho JS. Estrogen receptor-negative breast adenomyoepitheliomas are driven by co-occurring HRAS hotspot and PI3K pathway gene mutations: A genetic and functional analysis [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 PD4-13.

Abstract P4-21-34: Phase II study of gemcitabine, trastuzumab, and pertuzumab for HER2-Positive metastatic breast cancer after prior pertuzumab-based therapy

Background: The combination of taxanes with trastuzumab (H) and pertuzumab (P) for first line treatment of HER2-positive metastatic breast cancer (MBC) is associated with improved progression-free survival (PFS) and overall survival (OS). Treatment per physician's choice with anti-HER2 therapy after second line therapy is associated with a median PFS of 3 months. While continued use of H in therapeutic combinations after progression on H-based therapy is common, the efficacy of continuing HP-based treatment after progression on P-based therapy is unknown.

Methods: This is a single arm phase II trial of gemcitabine (G) with HP. Eligible patients had HER2-positive (IHC 3+ or FISH ≥ 2.0) MBC with prior HP-based treatment and ≤ 3 prior chemotherapies. Patients received G (1200 mg/m2) on days 1 and 8 of a q 3 week (w) cycle, and H (8 mg/kg load → 6 mg/kg) and P (840 mg load → 420 mg) q3w. The primary endpoint is PFS at 3 months. Secondary endpoints include OS, safety and tolerability. An exploratory endpoint is to compare PFS by RECIST criteria versus 18-F FDG-PET response criteria. Using a Simon optimal 2-stage design, 21 patients were enrolled in stage 1. The successful 3-month PFS rate for stage 1 was set at 57% to allow accrual to stage 2 for a total of 45 patients. The study therapy will be considered successful if at least 27/45 (60%) patients are progression free at 3 months.

Results: As of June 9, 2016, 28 patients are enrolled; 21 are evaluable at 3 months and 7 have not had 3-month evaluation. At 3 months, 16/21 (76%) are progression free; 5 patients have progressed. The 3 month-PFS results for evaluable patients will be updated. There are no cardiac or febrile neutropenic events to date. Initially, 5 of 22 (23%) patients required G dose reduction (4 due to grade 3 neutropenia and 1 due to grade 3 vomiting) and the study was amended to lower initial G dose to 1000 mg/m2.

Conclusions: The preliminary 3 month-PFS is 76% (95% CI 55% to 89%) in evaluable patients, and updated data will be presented. These findings suggest clinical benefit when P is continued beyond progression.

Citation Format: Iyengar NM, Smyth L, Lake D, Gucalp A, Singh JC, Traina TA, DeFusco P, Dickler MN, Fornier MN, Goldfarb S, Jhaveri K, Modi S, Troso-Sandoval T, Argolo D, Jack K, Ulaner G, Jochelson M, Baselga J, Norton L, Hudis CA, Dang CT. Phase II study of gemcitabine, trastuzumab, and pertuzumab for HER2-Positive metastatic breast cancer after prior pertuzumab-based therapy [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 P4-21-34.

Abstract P1-09-14: Breast carcinoma with 21-gene recurrence score lower than 18: Rate of distant metastases in a large series with clinical follow-up

Background: The 21-gene recurrence score (RS) estimates the likelihood of distant recurrence and the benefit from chemotherapy in patients with early-stage node-negative, estrogen receptor (ER)-positive, HER2-negative breast carcinoma. The use of the assay resulted in a substantial reduction in adjuvant chemotherapy usage. In this study, we reviewed the outcome of patients with node-negative, ER+/HER2- breast cancer and low recurrence score treated at our center to further verify the prognostic value of the assay.

Design: We identified breast cancer patients treated at our center between 09/2008 and 08/2013 with ER-positive, HER2-negative breast cancer and known RS. We reviewed clinicopathological characteristics, RS, treatment and outcome data. The Institutional Review Board approved the study.

Results: We identified 1406 consecutive patients with early stage node negative ER+/HER2- breast cancer and low RS [RS 0-10: 510 (36%), RS 11-17: 896 (64%)] in the study period. The median age at breast cancer diagnosis was 56 years (range 22-90). Sixty-three (4%) patients were &lt;40 years old at breast cancer diagnosis. A total of 1362 (97%) patients received endocrine therapy, and 170 (12%) received chemotherapy. The median follow up time was 46 months (range 1-85). Six (0.4%) of the 1406 patients developed biopsy proven distant metastases within 5 years of breast cancer diagnosis, 5 of which were in the RS 11-17 group (Table 1). Three of the 5 patients with RS 11-17 and distant metastases were younger than 40 years old at breast cancer diagnosis. In the RS 11-17 group, the absolute incidence of distant metastases among patients with breast cancer diagnosed at age younger than 40 years old is 7.1% (3/42), whereas the absolute incidence of distant metastases among patients ≥40 years is 0.2% (2/854).

Conclusion: Our results suggest that young age (&lt;40 years old) might be a negative prognostic factor even in patients with low RS. Analysis of data from other studies is necessary to further validate this observation.

Table 1. Clinicopathologic characteristics of the 6 patients with ER-positive, HER2-negative, node-negative breast carcinoma of recurrence score &lt;18 who developed distant metastasisPatients#1#2#3#4#5#6Age at diagnosis (years)505437713839Family history of breast/ ovarian cancerNoYesNoNoNoYesPersonal history of breast carcinomaNoIpsilateral DCISNoIpsilateral DCISNoNoTumor typeILCIDCIDCIDCIDCIDCTumor size (cm)2.11.32.72.31.62.1Tumor Grade222223LVINoNoNoNoYesNoER (%)909595959595PR (%)30585757595Oncotype DX RS51212131417SurgeryBTMTMBTMBCSBCSBTMRadiationNoNoNoYesYesNoEndocrine therapyYesYesYesYesNoYesChemoNoNoCMFNoNoNoTime interval to metastasis (months)584125204812Site of metastasisBoneMultipleLungMultipleMultipleBoneFollow-up (months)725359647142SurvivalAWDAWDAWDDODAWDAWDAbbreviations: RS, recurrence score; ILC, invasive lobular carcinoma; IDC, invasive ductal carcinoma; LVI, lymphovascular invasion; BTM, bilateral total mastectomy; TM, total mastectomy; BCS, breast conserving surgery; CMF, cyclofosphamide, metotrexate and 5-fluorouracil. AWD, alive with disease; DOD, died of disease.

Citation Format: Wen HY, Krystel-¬Whittemore M, Patil S, Pareja F, Bowser ZL, Dickler M, Norton L, Morrow M, Hudis C, Brogi E. Breast carcinoma with 21-gene recurrence score lower than 18: Rate of distant metastases in a large series with clinical follow-up [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 P1-09-14.

Abstract P1-05-04: Intra-tumor genetic heterogeneity and histologic heterogeneity within metaplastic breast cancers: Genotypic-phenotypic correlations

Introduction: Metaplastic breast carcinoma (MBC) is characterized by the presence of neoplastic cells displaying squamous and/or mesenchymal differentiation. Morphologic intra-tumor heterogeneity is frequent in MBCs and reported to be reflected at the transcriptomic level: whilst squamous and chondroid MBCs are preferentially of basal-like subtype, spindle cell MBCs are of claudin-low subtype. Likewise, histologically distinct components within MBCs have been shown to display distinct focal copy number alterations. Here we sought to investigate whether histologically distinct components within MBCs would be underpinned by different mutational profiles and mutational signatures.

Methods: Ten MBCs with two histologically distinct components (spindle, chondroid, osseous, squamous and/ or ductal) were retrieved from the Department of Pathology of the authors' institution. The distinct components of each case and, in two cases, two regions of the same component were separately microdissected. DNA extracted from tumor samples (n=22) and matched normal tissues was subjected to whole-exome sequencing. Somatic genetic alterations were identified using state-of-the-art bioinformatics algorithms. Somatic mutations were classified as clonal (i.e., present virtually in all tumor cells) or subclonal using ABSOLUTE and FACETS. Mutational signatures were defined using non-negative matrix factorization.

Results: Medians of 146 (56-290) somatic mutations and 108 non-synonymous somatic mutations (39-222) per tumor component were identified. The histologically distinct components of each case harbored identical clonal TP53 mutations. Additional recurrent mutations in cancer genes included those affecting PI3K pathway genes (PIK3CA, 2 cases; PIK3R1, 2 cases). Shared mutations between components of each case ranged from 34% to 99% of all mutations, with a median of 84%, of which 24% (12%-53%) were truncal (i.e., shared by and clonal in both components). Private mutations (i.e., found in only one component) ranged from 1% to 66%, with a median of 16%, of which 72% (0-100%) were non-synonymous and 1% (0-52%) were clonal. In two cases, the comparison of two histologically similar regions revealed less heterogeneity, with 94% (87%-100%) of shared mutations, whereas in these samples the median of private mutations was 6% (0-13%), of which 70% (0-100%) were non-synonymous and none were clonal. Private non-synonymous mutations affecting cancer genes included those in PIK3R1, MED12 and NOTCH1. The mutational signatures (e.g. aging or BRCA) were concordant between distinct components of each case; however, differences in the mutational signatures were observed between truncal somatic mutations and mutations restricted to individual components.

Conclusions: MBCs display substantial genetic intra-tumor heterogeneity, which is more overt between histologically distinct components than between regions of similar histology. Our data suggest a genotypic-phenotypic correlation and corroborate the notion that distinct components within MBCs, although clonally related, may be driven by distinct somatic genetic alterations.

Citation Format: Geyer FC, Burke KA, Papanastatiou AD, Macedo GS, Brogi E, Norton L, Wen YH, Weigelt B, Reis-Filho JS. Intra-tumor genetic heterogeneity and histologic heterogeneity within metaplastic breast cancers: Genotypic-phenotypic correlations [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 P1-05-04.

Abstract P1-05-03: The genomic landscape of breast metaplastic carcinoma

Introduction: Metaplastic breast carcinoma (MBC) is a rare histologic type of triple-negative breast cancer (TNBC), characterized by the presence of cells displaying squamous and/or mesenchymal differentiation. The transcriptomic profiles of MBCs have been reported to vary according to the type of metaplastic elements. The somatic genetic alterations that underpin this breast cancer subtype remain to be fully characterized. Here we sought to define the genomic landscape of MBCs, whether different subtypes of MBC would be driven by distinct constellations of genetic alterations, and to investigate functionally the impact of mutations affecting WNT pathway genes using non-malignant breast epithelial cells.

Methods: Thirty-five MBCs were retrieved from the pathology department of the authors' institutions and classified into the MBC histologic subtypes. All but one of the MBCs were of triple-negative phenotype. DNA was extracted from microdissected tumor-normal pairs and subjected to whole-exome sequencing. Somatic genetic alterations were identified using state-of-the-art bioinformatics algorithms. The genomic profiles of MBCs were compared to those of 69 common type TNBCs from The Cancer Genome Atlas. Overall mutation rates were compared using the Mann Whitney U test, and the frequency of mutations in each gene was compared using Fisher's exact test. RNA was extracted from a subset of MBCs and subjected to WNT signaling pathway activation analysis with the RT2 Profiler PCR Array. Triple-negative non-malignant breast epithelial cells (MCF10A and MCF12A) and cancer cell lines were utilized for 2D and 3D functional studies.

Results: Whole-exome analysis revealed that MBCs displayed a median of 103 (15-344) somatic mutations, which did not differ from the median number of somatic mutations in common type TNBCs (76, range 14-233). The most frequent recurrently mutated cancer genes included TP53 (69%) and PIK3CA (29%). MBCs more frequently harbored mutations in PI3K pathway genes than common type TNBCs (57% vs 22%, P&lt;0.05), including mutations affecting PIK3CA (29% vs 7%), PIK3R1 (11% vs 0) and PTEN (11% vs 1%). MBCs also more frequently harbored mutations affecting WNT signaling pathway genes (46% vs 26%, P&lt;0.05), including AXIN1 (6% vs 1%), WNT5A (6% vs 0) and APC (3% vs 0). MBC subtype analysis revealed that PIK3CA mutations were only detected in non-chondroid MBCs (53% vs 0), CHERP mutations were only found in chondroid MBCs (25% vs 0), whereas USP5 mutations only found in squamous MBCs (33% vs 0). MBCs with somatic mutations in WNT pathway genes had significantly higher WNT pathway activation than MBCs lacking mutations in these genes (P=0.0244). Consistent with the mesenchymal phenotype frequently exhibited by MBCs, in vitro experiments provided functional evidence that aberrant WNT pathway activation induces an epithelial-to-mesenchymal transition (EMT) phenotype, with downregulation of epithelial markers and upregulation of EMT transcriptional inducers.

Conclusions: MBCs are significantly enriched for mutations affecting PI3K and WNT pathways, highlighting the importance of the dysregulation of the WNT pathway in MBC carcinogenesis. Moreover, our findings suggest that specific mutations are significantly associated with distinct histologic subtypes of MBCs.

Citation Format: Geyer FC, Ng CK, Piscuoglio S, Wen YH, Wen H-C, Pareja F, Eberle CA, Burke KA, Lim RS, Natrajan R, Mariani O, Brogi E, Norton L, Vincent-Salomon A, Weigelt B, Reis-Filho JS. The genomic landscape of breast metaplastic carcinoma [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 P1-05-03.

Abstract P6-10-05: A pilot study of radiation (RT) and CTLA4-mediated checkpoint blockade with tremelimumab for the treatment of breast cancer brain metastases (BCBM)

This abstract was withdrawn by the authors.

Weekly paclitaxel with trastuzumab and pertuzumab in patients with HER2-overexpressing metastatic breast cancer: overall survival and updated progression-free survival results from a phase II study

We previously reported progression-free survival (PFS) results on a phase II trial of weekly paclitaxel, trastuzumab, and pertuzumab in patients with human epidermal growth factor receptor 2(HER2)-positive metastatic breast cancer (MBC) treated in the first- and second-line setting. Here, we report results for overall survival (OS) and updated PFS after an additional year of follow-up. Patients with HER2-positive MBC with 0-1 prior treatment were eligible. Treatment consisted of paclitaxel (80 mg/m(2)) weekly, and trastuzumab (loading dose 8 mg/kg → 6 mg/kg) and pertuzumab (loading dose 840 mg → 420 mg) every 3 weeks, all given intravenously. Primary endpoint was 6-month PFS. Secondary endpoints included median PFS, 6-month and median OS. Evaluable patients received at least one full dose of treatment. From January 2011 to December 2013, 69 patients were enrolled: 51 (74 %) and 18 (26 %) treated in first- and second-line metastatic settings, respectively. As of July 1, 2015, the median follow-up was 33 months (range 3-49 months; 67 patients were evaluable for efficacy). The median OS was 44 months (95 % CI 37.5-NR) overall and 44 months (95 % CI 38.3-NR) and 37.5 months (95 % CI 30.3-NR) for patients with 0 and 1 prior metastatic treatment, respectively; 6-month OS was 98 % (95 % CI 90-1). The 6-month PFS was 86 % (95 % CI 75-93) overall and 89 % (95 % CI 76-95) and 78 % (95 % CI 51-91) for patients with 0 and 1 prior therapy, respectively; and median PFS was 21.4 months (95 % CI 14.1-NR) overall and 25.7 months (95 % CI 14.1-NR) and 16.9 months (95 % CI 8.5-NR) for patients with 0-1 prior treatment, respectively. Treatment was well tolerated. Updated analysis demonstrates that weekly paclitaxel, when added to trastuzumab and pertuzumab, is associated with a favorable OS and PFS and offers an alternative to docetaxel-based therapy. http://www.ClinicalTrials.gov NCT0127604.

Revitalization of pioglitazone: the optimum agent to be combined with a sodium-glucose co-transporter-2 inhibitor

The recently completed EMPA-REG study showed that empagliflozin significantly decreased the major adverse cardiac events (MACE) endpoint, which comprised cardiovascular death, non-fatal myocardial infarction (MI) and stroke, in patients with high-risk type 2 diabetes (T2DM), primarily through a reduction in cardiovascular death, without a significant decrease in either MI or stroke. In the PROactive study, pioglitazone decreased the MACE endpoint by a similar degree to that observed in the EMPA-REG study, through a marked reduction in both recurrent MI and stroke and a modest reduction in cardiovascular death. These observations suggest that pioglitazone might be an ideal agent to combine with empagliflozin to further reduce cardiovascular events in patients with high-risk diabetes as empagliflozin also promotes salt/water loss and would be expected to offset any fluid retention associated with pioglitazone therapy. In the present paper, we provide an overview of the potential benefits of combined pioglitazone/empagliflozin therapy to prevent cardiovascular events in patients with T2DM.

Abstract OT2-01-03: A phase 1/2 study of once-daily oral VT-464 in patients with advanced androgen receptor (AR) positive triple negative (TNBC) or estrogen receptor (ER) positive breast cancer (BC)

VT-464, an oral dual lyase-selective CYP17 inhibitor and AR antagonist (wild-type and mutated forms [e.g., F876L and T877A]), is in multiple Phase (Ph) 2 studies as treatment for men with castration-resistant prostate cancer (CRPC). VT-464 inhibits the growth of multiple BC cell lines in vitro including MCF7 (ER(+)/AR low), tamoxifen-resistant MCF7, and MDA-MB-453 (ER(-)/AR(+)) in a dose-dependent manner and with greater potency/efficacy than enzalutamide (submitted, Ellison et al., 2015). A subset of TNBC and most ER(+) BC express AR, making them potential targets for VT-464 since it directly inhibits both androgen/estrogen synthesis and AR transcriptional activity.

Objectives: The primary objective of Ph 1, now enrolling, is to establish the once-daily dose of VT-464 in women. Secondary objectives include safety, PK and efficacy endpoints, including determination of clinical benefit rate (CBR) which is the primary objective of Ph 2. Exploratory objectives include the determination of the extent of AR expression and signaling in breast tissue and to evaluate the relationship of expression with VT-464 effects on circulating tumor biomarkers, circulating hormones and clinical outcomes.

Study Design: This study is an open-label, single arm, Ph 1/2 study of VT-464 in women with AR(+) TNBC or ER(+)/HER2 normal unresectable locally advanced or metastatic BC. Ph 1 will follow a modified 3+3 Fibonacci design with cohort expansion to 6 patients following a single DLT in the first 28-days of treatment. Approximately 2-3 dose-levels will be explored in Ph 1. Ph 1 start dose will be the MTD for men with CRPC. AR(+) TNBC and ER(+)/HER2 BC cohorts will be expanded in Ph 2 using the MTD from Ph 1. Ph 2 will follow a Simon's two-stage design with pre-determined futility parameters. Eligible patients will have ER≥1% BC or AR≥1% (as determined by central IHC testing using the Dako antibody) TNBC. ER(+) patients must be postmenopausal and must have received at least 1 prior line of endocrine therapy. Additional eligibility criteria include: ≥ 18 years of age, ECOG PS ≤ 1, unresectable locally advanced or metastatic BC, available representative tumor specimen to enable correlative science.

Treatment Plan: Eligible patients will receive VT-464 once-nightly with dinner in a continuous dosing schedule. Adverse events and concomitant medications will be collected from the time of signing of informed consent until 30 days after end of study visit (EOS). Safety labs will be monitored monthly through EOS. Dense PK will be collected after the first dose of study drug in Ph 1 and single morning samples collected approximately every two cycles thereafter in Ph 1 and Ph 2 until EOS. Blood samples for steroids, circulating tumor DNA and circulating tumor cells will be collected through Cycle 2 and then at EOS. Tumor biopsy will be collected at baseline and at disease progression. Radiographic response will be assessed every 8 weeks and EOS.

Patient Accrual: Accrual is ongoing with 12-18 patients expected to be enrolled in Ph 1.

Citation Format: Gucalp A, Hudis C, Norton L, Patil S, Kurman MR, Eisner JR, Moore WR, Traina TA. A phase 1/2 study of once-daily oral VT-464 in patients with advanced androgen receptor (AR) positive triple negative (TNBC) or estrogen receptor (ER) positive breast cancer (BC). [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 OT2-01-03.

Abstract P1-14-17: Pathologic complete response rate with doxorubicin and cyclophosphamide followed by weekly paclitaxel with trastuzumab and pertuzumab in patients with HER2-positive early stage breast cancer: A single institution experience

Background:

Trastuzumab and pertuzumab (HP) with standard chemotherapy is approved for use in the neoadjuvant setting. We performed a retrospective analysis of patients (pts) treated with dose-dense doxorubicin and cyclophosphamide (AC) → paclitaxel, trastuzumab, pertuzumab (THP) in the neoadjuvant setting. Here we report the pathologic complete response (pCR) rate.

Methods:

We abstracted medical records of patients who were treated with pertuzumab-based therapy in the neoadjuvant setting from September 1, 2013 to March 1, 2015. Charts were analyzed for pt demographics, stage of breast cancer, pathology reports, surgical data, and information on systemic therapy.

Results:

Charts from 66 pts were reviewed; 60 pts were evaluable for pCR defined as absence of invasive disease in the breast, and 6 were not (3-no anthracycline, 1-incomplete chart, 1-no surgery yet, 1-metastatic). Median age was 47 years (range 28-68 years). Of 60 pts, 52 (86%) had operable breast cancer (T1-3, N0-1, M0) of which 7 had clinical stage I disease (T1N0)]; 7 (12%) had locally advanced disease (T2-3, N2-3, M0 or T4a-c, any N, M0), and 1 (2%) had inflammatory breast cancer (T4d, any N, M0). 49 (82%) and 11 (18%) had hormone receptor (HR)-positive and negative diseases, respectively. All patients had HER2-positive breast cancer defined as immunohistochemistry (IHC) 3+ and/or fluorescent in-situ hybridization (FISH) of &gt; 2.0. 30 pts (50%) underwent mastectomy and lumpectomy, respectively. Out of 60 evaluable pts, 41 (68%) had pCR; 32/49 (65%) with HR-positive and 9/11 (82%) with HR-negative diseases had pCR, respectively. Overall 58/60 (97%) pts completed neoadjuvant therapy; 2 did not (1 developed Steven Johnson Syndrome after one cycle of AC and 1 developed pneumonitis after third weekly dose of T with HP).

Conclusions:

At our single center experience the pCR rate of dose dense AC→THP is high at 68 %. These data are similar to results seen in the TRYPHAENA study, and we await the results from the BERENICE trial evaluating pCR as a secondary endpoint.

Patient Demographics Age, years &lt;4525 (42%)45-5419 (32%)&gt;5516 (26%) ECOG Performace Status 031 (52%)129 (48%) Hormone receptor (HR) status HR+ Her2+49 (82%)HR- Her2+11 (18%) Status of Her-2 Positivity IHC positive52 (86%)FISH positive8 (14%) Median tumor size2.6cm (range: 1-8.4cm) Stage Operable (T1-2, N0-1, M0)52 (86%)Operable Stage I7 (12%)Operable Stage II/III45 (74%)Locally advanced (T2-3, N2-3, M0 or T4a-c, any N, M0))7 (12%)Inflammatory (T4d, any N, M0)1 (2%) Type of surgery Lumpectomy30 (50%)Mastectomy30 (50%)

Citation Format: Singh JC, Sugarman S, Jones L, Boafo C, Patil S, Schweber S, Yu A, Argolo D, Modi S, Iyengar N, Smyth L, Norton L, Baselga J, Hudis C, Dang C. Pathologic complete response rate with doxorubicin and cyclophosphamide followed by weekly paclitaxel with trastuzumab and pertuzumab in patients with HER2-positive early stage breast cancer: A single institution experience. [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 P1-14-17.

Abstract P4-13-20: Activity of HP-based therapies as third and later lines for the treatment of HER2-positive metastatic breast cancer: A retrospective study from a single institution

Background: Dual anti-HER2 blockade with trastuzumab and pertuzumab (HP) plus chemotherapy is an effective therapy (Rx) in the 1st-line setting for HER2-positive metastatic breast cancer (MBC). Our single arm phase II study included patients (pts) treated with HP plus paclitaxel in the 2nd-line setting with progression-free survival (PFS) benefit. Recently, we reported results from a retrospective study of pts treated at our institution, suggesting a longer PFS for those who received HP-based Rxs when compared to any other anti-HER2 based Rxs in the 2nd-line setting. To further assess the activity of this combination in later Rx lines, we conducted a retrospective analysis of pts with HER2-positive MBC who had progressive disease after 2nd-line and were treated with HP-based Rxs in the 3rd and later lines at MSKCC. Historically, the median (med) PFS in this setting with trastuzumab-based Rx is about 3-4 months.

Methods: Pts diagnosed with HER2-positive MBC and treated with HP-based Rxs at MSKCC between 1-1-2011 and 03-30-2015 and who progressed on 2nd-line Rx were identified through an institutional database. Primary endpoint was PFS in 3rd and later treatment lines.

Results: 70 pts who received any HP-based Rx in the 3rd or later lines of treatment were eligible. The med number of prior anti-HER2 Rx was 3. The baseline characteristics and Rxs are summarized in Table 1. The med PFS for the entire cohort was 5.7 months (95% CI, 4.8-6.5).

Conclusions: In this retrospective analysis involving heavly pretreated patients, HP-based Rx appears to be an active regimen and compares favorably to historical data. This supports the NCCN endorsement of HP-based Rx in later lines if HP has not been delivered previously.

Baseline Characteristics and treatments (n=70)Characteristic(n)(%)Age  Median56 Range27-83 Gender  Female70100.0Male00.0Race  Black1014.3White5477.1Other68.6Ethnicity  Non Hispanic6694.3Hispanic45.7ER/PR status  ER and PR negative2738.6ER and/or PR positive4361.4Type of disease  Non visceral1622.9Visceral5477.1Visceral CNS2130.0Anti-HER2 in early stage  Yes2941.4No4158.6Line of therapy  3rd line1927.14th line1521.45th line912.96th line912.97th line811.48th line and beyond1014.3HP-based regimens  Chemotherapy + HP5477.1Endocrine therapy + HP57.1HP alone912.9Other22.9

Citation Format: Argolo D, Friedman M, Smyth L, Iyengar N, Singh J, Patil S, Norton L, Baselga J, Hudis C, Dang C. Activity of HP-based therapies as third and later lines for the treatment of HER2-positive metastatic breast cancer: A retrospective study from a single institution. [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 P4-13-20.

Abstract OT1-01-05: Phase 1b/2 study of intratumoral Ad-RTS-hIL-12 + veledimex in patients with chemotherapy-responsive locally advanced or metastatic breast cancer

Background: Immune-based strategies involving T-cell activation have recently shown significant activity in multiple tumor types. The presence of immune elements in breast cancers has prognostic and predictive impact. Thus, strategies that optimize the interplay between a breast cancer and the effected individual's immune system may be therapeutic. Interleukin-12 (IL-12), a pro-inflammatory cytokine, reverses immune escape mechanisms induced by myeloid derived suppressor and dendritic cells which, in turn, improves the function of activated CD8+ T cells and promotes tumor stroma collapse. Because tumor neoantigens may be generated in response to chemotherapy, IL12-mediated immune modulation may be optimal in patients with chemotherapy-sensitive metastatic breast cancer. Ad-RTS-hIL-12 (Ad) is a novel gene therapy candidate expressing IL-12 under the control of an orally-administered activator ligand, veledimex (V) through the proprietary RheoSwitch Therapeutic System® (RTS).

Trial Design: Open-label, phase 1b/2, single-arm, single-center study of Ad+V in women with stable or responsive disease after ≥ 12-weeks of 1st or 2nd-line chemotherapy. Eligible patients will be placed on chemotherapy-holiday and enter the immunotherapy phase, consisting of a single cycle of Ad administered intratumorally (Day 1), along with V (80 mg QDx7). HER2-directed antibody therapy may be continued during the immunotherapy phase for women with HER2- disease.

Key Eligibility Criteria: Women ≥18 years with histologically-confirmed locally advanced or metastatic breast cancer of any subtype who have achieved a partial response (PR) or stable disease (SD) to 1st or 2nd-line chemotherapy are eligible. Exclusion criteria include use of immunosuppressive drugs, compromised immune function, autoimmune disorder, or brain metastases.

Specific Aims: To evaluate the safety and tolerability of Ad+V immunotherapy in eligible women. Secondary endpoints include 12 week overall response rate, 12 week disease control rate and the impact of treatment on exploratory immune biomarkers.

Statistical Methods: Safety and efficacy will be evaluated separately for HER2-/HER2+ patients. Tumor response will be evaluated by RECIST v1.1 at 6 and 12 weeks. To ensure safety, stopping rules defined by grade 3/4 adverse events and12-week progression rate were adopted.

Target Accrual: Up to 40 patients, including up to 8 patients (20%) with HER2+ disease.

Summary: Ad+V is a novel gene therapy which controls local expression of IL-12 and may induce tumor stroma collapse and stimulation of an anti-cancer T cell immune response. The ability to regulate the production of IL-12 by modulating V dosing may result in an improved therapeutic index in combination with standard of care. The data from this study will directly inform future studies.

Study Contact (Clinical Trials.gov: NCT02423902).

Citation Format: McArthur HL, Page D, Proverbs-Singh T, Solomon S, Hudis C, Norton L, Patil S, Barrett JA, Lebel F. Phase 1b/2 study of intratumoral Ad-RTS-hIL-12 + veledimex in patients with chemotherapy-responsive locally advanced or 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 OT1-01-05.

Abstract P4-14-24: Optimization of intermittent high dose lapatinib administration with or without capecitabine: A rational approach to drug dosing and scheduling using Norton-Simon modeling

Background: Systemic treatment of central nervous system (CNS) metastases remains a challenge partially due to poor drug penetration. Lapatinib and capecitabine are drugs with modest efficacy in treatment of brain metastases from HER2-positive (+) breast cancer (BC) and were shown to cross the blood-tumor barrier in clinical craniotomy specimens (Lin N et al., CCR 2009, Morikawa A et al., Neuro Oncol 2015). However, intratumoral drug concentrations observed were sub-optimal and heterogeneous. Administration of shorter-duration, high dose tyrosine kinase inhibitor is proposed as a way to improve efficacy and tolerability based on Norton-Simon modeling and drug exposure in the CNS (Traina T et al., JCO 2008, Grommes C et al., Neuro Oncol 2011, Chien AJ et al., J Clin Oncol 2014) . In this study, we examined optimization of high dose lapatinib administration with or without capecitabine to inform the design of a phase I trial for BC patients with HER2+ CNS metastases.

Methods: Mice bearing BT-474 BC xenograft tumors were treated with various lapatinib doses and schedules. A standard continuous daily dose (100mg/kg) was compared to various intermittent dosing schedules (at 100mg/kg, 400mg/kg, and 800mg/kg). In addition, high dose lapatinib (800mg/kg) was administered with capecitabine either concurrently or in tandem. Xenografts were treated when tumors reached 100mm3. Tumor volumes were evaluated for antitumor efficacy, and mice weights were measured for toxicity. Significance testing for between-group comparisons was conducted using a mixed effect model for repeated measures.

Results: Intermittent schedules of lapatinib at 100mg/kg given as 3 days on/11 days off (3/11), 5 days on/9 days off (5/9), and 7 days on/7days off (7/7) had a similar efficacy in tumor control: percent change in tumor volume of 225% (7/7), 222% (5/9), and 223% (3/11) (NS). Therefore, the 3 days on (with 4 days off or 11 days off ) schedule was subsequently chosen to evaluate for tolerability and antitumor efficacy of higher lapatinib dose. The 3 days on/4 days off (3/4) group at 800mg/kg demonstrated the highest tumor reduction (-69%) compared to the daily continuous dosing group (-18%) (p=0.04), but a trend toward higher toxicity was observed (p=0.12). Evaluation of concurrent vs. tandem administration of capecitabine with lapatinib at 800mg/kg given in 3 days on/11 days off was conducted. The concurrent treatment was discontinued early due to high toxicity. However, tandem administration of capecitabine with high dose lapatinib was tolerable without a significant difference in weight changes (p=0.62).

Conclusions: The intermittent schedule allows delivery of high dose lapatinib, which has better anti-tumor activity than standard continuous dosing. If given intermittently, high dose lapatinib is tolerable, even with capecitabine if given in tandem/sequence. Based on the result of these experiments, a phase I trial of high dose lapatinib using 3 days on/11 days off schedule in tandem with capecitabine is currently proposed for treatment of HER2-positive BC patient with CNS metastases.

Citation Format: Morikawa A, De Stanchina E, Patil S, Chandarlapaty S, Li BT, Norton L, Seidman AD. Optimization of intermittent high dose lapatinib administration with or without capecitabine: A rational approach to drug dosing and scheduling using Norton-Simon modeling. [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 P4-14-24.

Abstract P2-01-02: Capturing intra-tumor genetic heterogeneity in cell-free plasma DNA from patients with oligometastatic breast cancer

Background: The analysis of cell-free tumor DNA (ctDNA) from plasma has been heralded as a non-invasive technique for disease monitoring and as a means to overcome the challenges posed by intra-tumor genetic heterogeneity. ctDNA levels have been shown to correlate with tumor burden in breast cancer patients. Hence, we sought to define whether massively parallel sequencing of cell-free plasma DNA would capture the entire repertoire of somatic mutations present in the primary tumors and/ or metastases from patients with oligometastatic breast cancer.

Methods: Frozen diagnostic biopsies from primary tumors and their distant metastases were obtained from five prospectively accrued treatment-naïve patients with stage IV breast cancer at presentation (1 estrogen receptor (ER)+/HER2+, 2 ER+/HER2-, 2 ER-/HER2+). A second, independent formalin-fixed paraffin-embedded (FFPE) diagnostic biopsy was obtained from the primary tumor and metastasis from 4 patients. Plasma samples were obtained from all patients. DNA samples from microdissected frozen tumors and peripheral blood, as well as plasma from one patient, were subjected to high-depth whole exome sequencing. DNA samples from all biopsies (frozen/FFPE), plasma and peripheral blood were subjected to targeted capture massively parallel sequencing, with baits for all somatic mutations detected by whole exome sequencing and all exons of the 100 genes most frequently mutated in breast cancer. Driver mutations were defined by state-of-the-art bioinformatic methods and literature search.

Results: We identified and confirmed a median of 54 (range 25-75) and 53 (range 26-85) non-synonymous mutations in the primary tumors and metastases from the 5 cases analyzed, respectively. By sequencing the plasma DNA to a median depth of 248x (range 92-431x), state-of-the-art mutation callers revealed 0-4 mutations (0%-8% of mutations) per patient, and direct interrogation of the sequencing data, based on prior knowledge of the mutations present in the lesions, resulted in the identification of 2-18 mutations (3%-38% of mutations) per patient. Of the bona fide driver mutations, 2/3 TP53 mutations, 0/1 PIK3CA hotspot mutation, 0/1 BRCA2 frameshift mutation, 0/1 GATA3 frameshift mutation and 0/1 ERBB3 activating mutation were captured in the plasma DNA. A SMAD4 pathogenic mutation and a TCF7L2 truncating mutation were found in two diagnostic biopsies of metastatic lesions but not in two biopsies of the primary tumors in one patient each. Whilst the SMAD4 mutation was detected in the plasma DNA from the respective patient, the TCF7L2 mutation was not. Of the 62 mutations restricted to the primary tumors (0-42 per patient) and 74 restricted to the metastatic tumors (1-41 per patient), 4 and 7, respectively, were captured in the plasma DNA.

Conclusions: Massively parallel sequencing assessment of plasma DNA allows for the identification of mutations found in primary tumors and/ or their metastases, however, only a subset of these could be detected at up to 431x depth. These observations suggest that current approaches for whole exome or targeted massively parallel sequencing may not be sufficient to capture the genetic heterogeneity of breast cancers in patients with oligometastatic disease.

Citation Format: Ng CKY, Bidard F-C, Piscuoglio S, Lim RS, Pierga J-Y, Cottu P, Vincent-Salomon A, Viale A, Norton L, Sigal B, Weigelt B, Reis-Filho JS. Capturing intra-tumor genetic heterogeneity in cell-free plasma DNA from patients with oligometastatic 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 P2-01-02.

Response to dual HER2 blockade in a patient with HER3-mutant metastatic breast cancer

BACKGROUND

HER3 activating mutations have been shown in preclinical models to be oncogenic and ligand-independent, but to depend on kinase-active HER2.

PATIENTS AND METHODS

Whole-exome sequencing of the primary HER2-negative breast cancer and its HER2-negative synchronous liver metastasis from a 46-year-old female revealed the presence of an activating and clonal HER3 G284R mutation.

RESULTS

HER2 dual blockade with trastuzumab and lapatinib as third-line therapy led to complete metabolic response in 2 weeks and confirmed radiological partial response after 8 weeks. Following the resection of the liver metastasis, the patient remains disease-free 40 weeks after initiation of the HER2 dual blockade therapy. Immunohistochemical analysis demonstrated a substantial reduction of phospho-rpS6 and phospho-AKT in the post-therapy biopsy of the liver metastasis.

DISCUSSION

This is the first-in-man evidence that anti-HER2 therapies are likely effective in breast cancers harboring HER3 activating mutations.

The AURORA initiative for metastatic breast cancer

Metastatic breast cancer is one of the leading causes of cancer-related mortality among women in the Western world. To date most research efforts have focused on the molecular analysis of the primary tumour to dissect the genotypes of the disease. However, accumulating evidence supports a molecular evolution of breast cancer during its life cycle, with metastatic lesions acquiring new molecular aberrations. Recognising this critical gap of knowledge, the Breast International Group is launching AURORA, a large, multinational, collaborative metastatic breast cancer molecular screening programme. Approximately 1300 patients with metastatic breast cancer who have received no more than one line of systemic treatment for advanced disease will, after giving informed consent, donate archived primary tumour tissue, as well as will donate tissue collected prospectively from the biopsy of metastatic lesions and blood. Both tumour tissue types, together with a blood sample, will then be subjected to next generation sequencing for a panel of cancer-related genes. The patients will be treated at the discretion of their treating physicians per standard local practice, and they will be followed for clinical outcome for 10 years. Alternatively, depending on the molecular profiles found, patients will be directed to innovative clinical trials assessing molecularly targeted agents. Samples of outlier patients considered as 'exceptional responders' or as 'rapid progressors' based on the clinical follow-up will be subjected to deeper molecular characterisation in order to identify new prognostic and predictive biomarkers. AURORA, through its innovative design, will shed light onto some of the unknown areas of metastatic breast cancer, helping to improve the clinical outcome of breast cancer patients.

Capturing intra-tumor genetic heterogeneity by de novo mutation profiling of circulating cell-free tumor DNA: a proof-of-principle

BACKGROUND

Plasma-derived cell-free tumor DNA (ctDNA) constitutes a potential surrogate for tumor DNA obtained from tissue biopsies. We posit that massively parallel sequencing (MPS) analysis of ctDNA may help define the repertoire of mutations in breast cancer and monitor tumor somatic alterations during the course of targeted therapy.

PATIENT AND METHODS

A 66-year-old patient presented with synchronous estrogen receptor-positive/HER2-negative, highly proliferative, grade 2, mixed invasive ductal-lobular carcinoma with bone and liver metastases at diagnosis. DNA extracted from archival tumor material, plasma and peripheral blood leukocytes was subjected to targeted MPS using a platform comprising 300 cancer genes known to harbor actionable mutations. Multiple plasma samples were collected during the fourth line of treatment with an AKT inhibitor.

RESULTS

Average read depths of 287x were obtained from the archival primary tumor, 139x from the liver metastasis and between 200x and 900x from ctDNA samples. Sixteen somatic non-synonymous mutations were detected in the liver metastasis, of which 9 (CDKN2A, AKT1, TP53, JAK3, TSC1, NF1, CDH1, MML3 and CTNNB1) were also detected in >5% of the alleles found in the primary tumor sample. Not all mutations identified in the metastasis were reliably identified in the primary tumor (e.g. FLT4). Analysis of ctDNA, nevertheless, captured all mutations present in the primary tumor and/or liver metastasis. In the longitudinal monitoring of the patient, the mutant allele fractions identified in ctDNA samples varied over time and mirrored the pharmacodynamic response to the targeted therapy as assessed by positron emission tomography-computed tomography.

CONCLUSIONS

This proof-of-principle study is one of the first to demonstrate that high-depth targeted MPS of plasma-derived ctDNA constitutes a potential tool for de novo mutation identification and monitoring of somatic genetic alterations during the course of targeted therapy, and may be employed to overcome the challenges posed by intra-tumor genetic heterogeneity.

REGISTERED CLINICAL TRIAL

www.clinicaltrials.gov, NCT01090960.

Abstract S6-06: High-depth massively parallel sequencing reveals heterogeneity between primary tumor and metastatic deposits in de novo metastatic breast cancer patients prior to exposure to systemic therapy

Background: Breast cancers are often composed of mosaics of tumor cells that in addition to the founder genetic events harbor private genetic aberrations. Previous studies comparing the repertoire of mutations in primary breast cancers and their metachronous metastatic deposits that developed after systemic therapy revealed differences in their clonal composition and mutational repertoire. It is unclear, however, whether the differences documented could be attributed to the metastatic process itself or because of selective pressure from systemic therapies. Hence we sought to investigate whether the metastatic process would constitute a biological ‘bottleneck’ resulting in the selection of clones fittest to metastasize. We subjected primary breast cancers and their synchronous metastatic deposits from patients who presented with de novo metastatic disease and who had not received any systemic therapy to gene copy number analysis and high-depth massively parallel sequencing.

Materials and Methods: Frozen primary tumor and distant metastases biopsies were obtained from 7 patients with de novo metastatic disease (i.e. stage IV breast cancer at presentation) enrolled in the ESOPE study (Institut Curie, Paris). DNA samples extracted from microdissected tumors and from peripheral blood were subjected to high-depth (250x) whole exome sequencing and SNP6 copy number profiling. The impact of spatial heterogeneity was further assessed by targeted sequencing of paraffin-embedded samples from additional, independent pre-treatment biopsies of the primary tumor and matched metastasis from the same patients. Driver mutations were defined by bioinformatic methods; for single nucleotide variants (SNVs), CHASM and FATHMM were employed and for insertions/ deletions (indels), only frameshift or truncating mutations in genes normally expressed in breast tissue were included.

Results: In de novo metastatic breast cancers, without any pretreatment, significant genomic differences were observed between primary and metastatic deposits in all cases. A median number of 105 (32-224) and 54 (10-57) SNVs and indels were found, respectively, of which 36 (9-139) and 11 (1-19) were shared between the primary tumors and the de novo metastases, respectively. Although a substantial proportion of driver SNVs and indels were found in common between primary tumors and their respective metastatic deposits (median: 29% (17%-38%)), 50% (25%-78%) of driver SNVs and 79% (60%-90%) of the potentially pathogenic indels were restricted either to the primary or the metastatic deposit, including driver mutations affecting epithelial-to-mesenchymal transition (EMT)-related genes in 3 patients, namely TGFB1, SMAD4 and TCF7L2.

Conclusions: This is, to the best of our knowledge, the first study reporting on the differences in the mutational repertoire between primary tumors and metastatic deposits in de novo metastatic breast cancer patients who have not received systemic therapy. Our findings suggest that the breast cancer metastatic process likely constitutes a biological bottleneck with selection of subclones harboring specific driver genetic aberrations, often affecting EMT-related genes.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S6-06.

Abstract P2-16-12: An exploratory analysis of the role of dasatinib in preventing progression of disease in bone in patients with metastatic breast cancer

Introduction: The role of dasatinib, an oral SRC inhibitor is being explored for the treatment of metastatic breast cancer. In a phase I study, we previously established that the combination of dasatinib and weekly paclitaxel was feasible. The activity of this combination is currently being explored in an ongoing phase II trial. Since Src kinase has a major role in osteoclast function and dasatinib has established anabolic and anti-resorptive effects in bone in vitro, we hypothesized that patients receiving this combination would have good control of osseous metastases and primarily develop progression of disease in sites other than bone.

Patients and methods: Patients were included in this analysis if they participated in the phase I or II metastatic breast cancer studies and received dasatinib at or above the recommended phase II dose of 120mg with paclitaxel (80mg/m2 day 1 and 8 of each 21day cycle). Patients who discontinued therapy for reasons other than progression were excluded. Per protocol, patients were required to discontinue bisphosphonates or other bone modulating agents for the first 8 weeks of study due to the potential for hypocalcaemia. Thereafter, they were permitted to receive these agents at the discretion of their treating physician. Patients provided serum samples for correlative studies. Assessment of N-telopeptide of type 1 collagen (NTX), a product of mature bone collagen that reflects bone specific resorption, is planned.

Results: The median age of the 24 patients who met criteria for analysis was 50y (37 - 66y). Of these, 15 (63%) had ER+ disease, and 24 (100%) were negative for human epidermal growth factor receptor (HER2). At study entry, 17 (71%) patients had bone involvement. Following the initial eight week moratorium, 7 (29%) patients received a bisphosphonate or rank ligand inhibitor during treatment with dasatinib + paclitaxel. Patients received a median 2 months (range 1-23) of dasatinib + paclitaxel therapy. To date, 3 (13%) continue on therapy, and 21 (88%) have had progression of disease. Among patients who progressed, 18 (86%) have progressed in visceral sites and only 3 (14%) progressed in bone. Analyses of serum NTX levels are ongoing and will be compared by site of progression.

Conclusion: The potential role of serum NTX as a predictive biomarker of benefit from dasatinib and paclitaxel is being explored and updated results will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-12.

Abstract P5-02-01: Regulated intratumoral expression of IL-12 in combination with cytotoxic agents as a strategy for the treatment of metastatic breast cancer

Major obstacles for the development of immunotherapeutics are the ability of tumors to escape the immune system coupled with toxicity associated with systemic administration. To overcome these challenges, we have developed an adenoviral vector, Ad-RTS-IL-12 (AD), administered intratumorally (IT) under control of the RheoSwitch Therapeutic System® (RTS) technology platform. Expression of IL-12 mRNA and IL-12 protein is tightly regulated by the oral administration of a small molecule activator ligand, veledimex (AL).

We have previously demonstrated a concentration-related increase in IL-12 mRNA concomitant with increase in expression of IL-12 protein in HT1080 cells transduced with AD and incubated with AL. Removal of AL from the media resulted in a return to baseline IL-12 expression within 48 hours. Results from the subcutaneous 4T1 syngeneic BALB/c mouse mammary tumor model demonstrated an AL dose-related increase in tumor IL-12 mRNA and IL-12 protein expression with the maximum IL-12 tumor protein level of 280 ng/mg achieved at 150 mg/m2 AL + 1e10 vp AD. In addition, a return to baseline IL-12 mRNA and IL-12 protein expression was observed on cessation of AL.

The effect of AD + AL on tumor growth rate was evaluated in a subcutaneous 4T1 syngeneic BALB/c mouse mammary tumor model. A single intratumoral injection of 1e10 vp AD combined with oral administration of AL (15, 30, 75 or 150 mg/m2) on a Q1Dx5 schedule led to significant AL dose-related tumor growth inhibition with tumor size reduction of 27%, 37%, 57% and 60%, respectively when compared to vehicle on Day 33. Neither AD or AL alone had an effect on tumor growth rate relative to vehicle control. No change in clinical signs or body weight was observed when compared to vehicle alone. Tumor growth inhibition correlated with an increase in tumor IL-12 levels, a decrease in Tregs, and an increase in cytotoxic T cells. Results from a phase 1 study in melanoma have shown dose-related production of IL-12 and clinical activity in injected and non-injected lesions at 100 and 160 mg of AL.

Cytotoxic agents at low doses have been shown to prime the immune system and combination with immunotherapy may augment tumor specific T-cell immune responses resulting in enhanced efficacy. In the 4T1 mouse mammary tumor model Ad-RTS-mIL12 (1e10vp) + AL (30 mg/m2) combined with palifosfamide (40 or 120 mg/m2 QD IP for 3 days) significantly inhibited tumor growth (∼71-90% vs. control) concomitant with increased median survival when compared to the single agents alone. Based on these findings in a multicenter, open-label, randomized, phase 2 study evaluating the safety and efficacy of AD + AL alone or in combination with cytotoxic agents in subjects with recurrent/metastatic breast cancer with accessible tumor(s) is ongoing. This study assesses AD + AL administered as a monotherapy and a combination therapy. In the monotherapy arm, AD is administered IT on Day 1 and AL 140 mg is administered orally on either a Q1Dx7 or QODx14 schedule. In the combination arm, palifosfamide 120 mg/m2 IV Q1Dx3 is be administered with AD + AL QODx14 (28 day cycle). Preliminary data show that AD + AL is safe and well tolerated. Preclinical and clinical data will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-02-01.

Abstract P5-01-07: Select neutrophils inhibit breast cancer metastases in patients via chemokine-mediated mechanisms

Background: In both breast cancer patients and healthy women, we have previously demonstrated that select neutrophils found in breast cancer patients as opposed to healthy women are cytotoxic to breast cancer cell lines. (Granot Z et al. Cancer Cell. 2010) This work stemmed from our prior research in murine breast cancer models indicating that primary breast tumors can mobilize select neutrophils, termed Tumor Entrained Neutrophils (“TENS”); these entrained neutrophils have the unique capacity to inhibit metastatic seeding in the lung through cell-kill mechanisms. (Granot Z et al. Cancer Cell. 2010) In this study, we evaluated the relationship between select chemokines and neutrophil cytotoxicity in breast cancer patients versus healthy volunteers.

Methods: Neutrophils were purified from the blood of 75 randomly selected newly diagnosed pre-operative breast cancer patients without evidence of metastatic disease, and 47 healthy female volunteers with no history of cancer. Cytotoxicity was evaluated by incubating neutrophils with luciferase labeled MDA-MB-231 cells. Luciferase activity was measured as a reflection of% cytotoxicity. Serum was also isolated from breast cancer patients and healthy volunteers. Based on prior experiments, we used the Millipore® Milliplex Human Cytokine Plex Kit to evaluate Il-1Ra, MCP-1 and TNFa in our serum samples in 50/75 of the cancer patients and 25/47 controls. We used multiple linear regression to develop a model to predict cytotoxicity as a function of the chemokines.

Results: In comparison to healthy volunteers whose mean neutrophil cytotoxicity to MDA-MB-231 cells was 6.5%, pre-operative breast cancer patients demonstrated a mean neutrophil cytotoxicity of 12.7%, p&lt;0.0001. We then evaluated the serum chemokine levels of 50 of the breast cancer patients; 31/50 had high neutrophil cytotoxicity (&gt;10%), and 19/50 had low neutrophil cytotoxicity (&lt;10%). We compared the serum chemokine levels in the patients to the levels found in the 25 controls. Using a multiple linear regression model, we found that the levels of these three chemokines are associated with cytotoxicity (R2 = 0.126, p = 0.022). An ANOVA decomposition of the model suggested that Il.1RA was the most predictive (p = 0.018) followed by MCP.1 (p = 0.088) and TNF.alpha (p = 0.245).

Conclusion: Our work demonstrates the cytotoxic role of select neutrophils in the peripheral blood of breast cancer patients as contrasted with neutrophils from healthy women. We further demonstrate that select chemokines appear to be correlated with neutrophil cytotoxicity. We are currently evaluating the prognostic and therapeutic roles of cytotoxic neutrophils and their related chemokines in breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-01-07.