Results of a single-arm pilot study of 32P microparticles in unresectable locally advanced pancreatic adenocarcinoma with gemcitabine/nab-paclitaxel or FOLFIRINOX chemotherapy

Background

Unresectable locally advanced pancreatic cancer (LAPC) is generally managed with chemotherapy or chemoradiotherapy, but prognosis is poor with a median survival of ∼13 months (or up to 19 months in some studies). We assessed a novel brachytherapy device, using phosphorous-32 (³²P) microparticles, combined with standard-of-care chemotherapy.

Patients and methods

In this international, multicentre, single-arm, open-label pilot study, adult patients with histologically or cytologically proven unresectable LAPC received ³²P microparticles, via endoscopic ultrasound-guided fine-needle implantation, planned for week 4 of 5-fluorouracil, leucovorin, irinotecan and oxaliplatin (FOLFIRINOX) or gemcitabine/nab-paclitaxel chemotherapy, per investigator’s choice. The primary endpoint was safety and tolerability measured using Common Terminology Criteria for Adverse Events version 4.0. The lead efficacy endpoint was local disease control rate at 16 weeks.

Results

Fifty patients were enrolled and received chemotherapy [intention-to-treat (ITT) population]. Forty-two patients received ³²P microparticle implantation [per protocol (PP) population]. A total of 1102 treatment-emergent adverse events (TEAEs) were reported in the ITT/safety population (956 PP), of which 167 (139 PP) were grade ≥3. In the PP population, 41 TEAEs in 16 (38.1%) patients were possibly or probably related to ³²P microparticles or implantation procedure, including 8 grade ≥3 in 3 (7.1%) patients, compared with 609 TEAEs in 42 (100%) patients attributed to chemotherapy, including 67 grade ≥3 in 28 patients (66.7%). The local disease control rate at 16 weeks was 82.0% (95% confidence interval: 68.6% to 90.9%) (ITT) and 90.5% (95% confidence interval: 77.4% to 97.3%) (PP). Tumour volume, carbohydrate antigen 19-9 levels, and metabolic tumour response at week 12 improved significantly. Ten patients (20.0% ITT; 23.8% PP) had surgical resection and median overall survival was 15.2 and 15.5 months for ITT and PP populations, respectively.

Conclusions

Endoscopic ultrasound-guided ³²P microparticle implantation has an acceptable safety profile. This study also suggests clinically relevant benefits of combining ³²P microparticles with standard-of-care systemic chemotherapy for patients with unresectable LAPC.

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PanCO is the first prospective study of intratumoural ³²P microparticles for locally advanced pancreatic cancer (LAPC).

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This single-arm study assessed a novel brachytherapy (³²P microparticles) combined with standard-of-care chemotherapy.

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Treatment-emergent adverse events attributable to ³²P microparticle implantation were relatively infrequent.

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Local disease control rate at 16 weeks (82%) and resection rate (20%) suggest a clinical benefit of ³²P microparticles.

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The results suggest that ³²P microparticles may address a significant unmet need in patients with unresectable LAPC.

HNF4A and GATA6 Loss Reveals Therapeutically Actionable Subtypes in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) can be divided into transcriptomic subtypes with two broad lineages referred to as classical (pancreatic) and squamous. We find that these two subtypes are driven by distinct metabolic phenotypes. Loss of genes that drive endodermal lineage specification, HNF4A and GATA6, switch metabolic profiles from classical (pancreatic) to predominantly squamous, with glycogen synthase kinase 3 beta (GSK3β) a key regulator of glycolysis. Pharmacological inhibition of GSK3β results in selective sensitivity in the squamous subtype; however, a subset of these squamous patient-derived cell lines (PDCLs) acquires rapid drug tolerance. Using chromatin accessibility maps, we demonstrate that the squamous subtype can be further classified using chromatin accessibility to predict responsiveness and tolerance to GSK3β inhibitors. Our findings demonstrate that distinct patterns of chromatin accessibility can be used to identify patient subgroups that are indistinguishable by gene expression profiles, highlighting the utility of chromatin-based biomarkers for patient selection in the treatment of PDAC.

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1-3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10-18.

Tailored first-line and second-line CDK4-targeting treatment combinations in mouse models of pancreatic cancer

OBJECTIVE

Extensive molecular heterogeneity of pancreatic ductal adenocarcinoma (PDA), few effective therapies and high mortality make this disease a prime model for advancing development of tailored therapies. The p16-cyclin D-cyclin-dependent kinase 4/6-retinoblastoma (RB) protein (CDK4) pathway, regulator of cell proliferation, is deregulated in PDA. Our aim was to develop a novel personalised treatment strategy for PDA based on targeting CDK4.

DESIGN

Sensitivity to potent CDK4/6 inhibitor PD-0332991 (palbociclib) was correlated to protein and genomic data in 19 primary patient-derived PDA lines to identify biomarkers of response. In vivo efficacy of PD-0332991 and combination therapies was determined in subcutaneous, intrasplenic and orthotopic tumour models derived from genome-sequenced patient specimens and genetically engineered model. Mechanistically, monotherapy and combination therapy were investigated in the context of tumour cell and extracellular matrix (ECM) signalling. Prognostic relevance of companion biomarker, RB protein, was evaluated and validated in independent PDA patient cohorts (>500 specimens).

RESULTS

Subtype-specific in vivo efficacy of PD-0332991-based therapy was for the first time observed at multiple stages of PDA progression: primary tumour growth, recurrence (second-line therapy) and metastatic setting and may potentially be guided by a simple biomarker (RB protein). PD-0332991 significantly disrupted surrounding ECM organisation, leading to increased quiescence, apoptosis, improved chemosensitivity, decreased invasion, metastatic spread and PDA progression in vivo. RB protein is prevalent in primary operable and metastatic PDA and may present a promising predictive biomarker to guide this therapeutic approach.

CONCLUSION

This study demonstrates the promise of CDK4 inhibition in PDA over standard therapy when applied in a molecular subtype-specific context.

The Evolving Understanding of the Molecular and Therapeutic Landscape of Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is the third leading cause of cancer-related deaths, characterised by poor survival, marked molecular heterogeneity and high intrinsic and acquired chemoresistance. Only 10⁻20% of pancreatic cancer patients present with surgically resectable disease and even then, 80% die within 5 years. Our increasing understanding of the genomic heterogeneity of cancer suggests that the failure of definitive clinical trials to demonstrate efficacy in the majority of cases is likely due to the low proportion of responsive molecular subtypes. As a consequence, novel treatment strategies to approach this disease are urgently needed. Significant developments in the field of precision oncology have led to increasing molecular stratification of cancers into subtypes, where individual cancers are selected for optimal therapy depending on their molecular or genomic fingerprint. This review provides an overview of the current status of clinically used and emerging treatment strategies, and discusses the advances in and the potential for the implementation of precision medicine in this highly lethal malignancy, for which there are currently no curative systemic therapies.

Metastatic pancreatic ductal adenocarcinoma: diagnosis and treatment with a view to the future

Metastatic pancreatic ductal adenocarcinoma (mPDAC) is a lethal disease with a poor 5-year survival. Systemic treatments can be used to control symptoms and prolong life. Cytotoxic chemotherapies are commonly administered, with combination treatments, such as fluorouracil, folinic acid, irinotecan and oxaliplatin (FOLFIRINOX) or nab-paclitaxel and gemcitabine showing the largest clinical benefits. Newer genomic classifications of PDAC may provide a rationale for targeted therapies or immunotherapies, although at present these remain largely experimental. This review discusses the evidence behind the currently used regimens, while introducing the potential future of pancreatic cancer care.

Corrigendum: Whole-genome landscape of pancreatic neuroendocrine tumours

This corrects the article DOI: 10.1038/nature21063.

Transient tissue priming via ROCK inhibition uncouples pancreatic cancer progression, sensitivity to chemotherapy, and metastasis

The emerging standard of care for patients with inoperable pancreatic cancer is a combination of cytotoxic drugs gemcitabine and Abraxane, but patient response remains moderate. Pancreatic cancer development and metastasis occur in complex settings, with reciprocal feedback from microenvironmental cues influencing both disease progression and drug response. Little is known about how sequential dual targeting of tumor tissue tension and vasculature before chemotherapy can affect tumor response. We used intravital imaging to assess how transient manipulation of the tumor tissue, or "priming," using the pharmaceutical Rho kinase inhibitor Fasudil affects response to chemotherapy. Intravital Förster resonance energy transfer imaging of a cyclin-dependent kinase 1 biosensor to monitor the efficacy of cytotoxic drugs revealed that priming improves pancreatic cancer response to gemcitabine/Abraxane at both primary and secondary sites. Transient priming also sensitized cells to shear stress and impaired colonization efficiency and fibrotic niche remodeling within the liver, three important features of cancer spread. Last, we demonstrate a graded response to priming in stratified patient-derived tumors, indicating that fine-tuned tissue manipulation before chemotherapy may offer opportunities in both primary and metastatic targeting of pancreatic cancer.

Whole-genome landscape of pancreatic neuroendocrine tumours

The diagnosis of pancreatic neuroendocrine tumours (PanNETs) is increasing owing to more sensitive detection methods, and this increase is creating challenges for clinical management. We performed whole-genome sequencing of 102 primary PanNETs and defined the genomic events that characterize their pathogenesis. Here we describe the mutational signatures they harbour, including a deficiency in G:C > T:A base excision repair due to inactivation of MUTYH, which encodes a DNA glycosylase. Clinically sporadic PanNETs contain a larger-than-expected proportion of germline mutations, including previously unreported mutations in the DNA repair genes MUTYH, CHEK2 and BRCA2. Together with mutations in MEN1 and VHL, these mutations occur in 17% of patients. Somatic mutations, including point mutations and gene fusions, were commonly found in genes involved in four main pathways: chromatin remodelling, DNA damage repair, activation of mTOR signalling (including previously undescribed EWSR1 gene fusions), and telomere maintenance. In addition, our gene expression analyses identified a subgroup of tumours associated with hypoxia and HIF signalling.

Hypermutation In Pancreatic Cancer

Pancreatic cancer is molecularly diverse, with few effective therapies. Increased mutation burden and defective DNA repair are associated with response to immune checkpoint inhibitors in several other cancer types. We interrogated 385 pancreatic cancer genomes to define hypermutation and its causes. Mutational signatures inferring defects in DNA repair were enriched in those with the highest mutation burdens. Mismatch repair deficiency was identified in 1% of tumors harboring different mechanisms of somatic inactivation of MLH1 and MSH2. Defining mutation load in individual pancreatic cancers and the optimal assay for patient selection may inform clinical trial design for immunotherapy in pancreatic cancer.

Resolution of Novel Pancreatic Ductal Adenocarcinoma Subtypes by Global Phosphotyrosine Profiling

Comprehensive characterization of signaling in pancreatic ductal adenocarcinoma (PDAC) promises to enhance our understanding of the molecular aberrations driving this devastating disease, and may identify novel therapeutic targets as well as biomarkers that enable stratification of patients for optimal therapy. Here, we use immunoaffinity-coupled high-resolution mass spectrometry to characterize global tyrosine phosphorylation patterns across two large panels of human PDAC cell lines: the ATCC series (19 cell lines) and TKCC series (17 cell lines). This resulted in the identification and quantification of over 1800 class 1 tyrosine phosphorylation sites and the consistent segregation of both PDAC cell line series into three subtypes with distinct tyrosine phosphorylation profiles. Subtype-selective signaling networks were characterized by identification of subtype-enriched phosphosites together with pathway and network analyses. This revealed that the three subtypes characteristic of the ATCC series were associated with perturbations in signaling networks associated with cell-cell adhesion and epithelial-mesenchyme transition, mRNA metabolism, and receptor tyrosine kinase (RTK) signaling, respectively. Specifically, the third subtype exhibited enhanced tyrosine phosphorylation of multiple RTKs including the EGFR, ERBB3 and MET. Interestingly, a similar RTK-enriched subtype was identified in the TKCC series, and 'classifier' sites for each series identified using Random Forest models were able to predict the subtypes of the alternate series with high accuracy, highlighting the conservation of the three subtypes across the two series. Finally, RTK-enriched cell lines from both series exhibited enhanced sensitivity to the small molecule EGFR inhibitor erlotinib, indicating that their phosphosignature may provide a predictive biomarker for response to this targeted therapy. These studies highlight how resolution of subtype-selective signaling networks can provide a novel taxonomy for particular cancers, and provide insights into PDAC biology that can be exploited for improved patient management.

Genomic analyses identify molecular subtypes of pancreatic cancer

Integrated genomic analysis of 456 pancreatic ductal adenocarcinomas identified 32 recurrently mutated genes that aggregate into 10 pathways: KRAS, TGF-β, WNT, NOTCH, ROBO/SLIT signalling, G1/S transition, SWI-SNF, chromatin modification, DNA repair and RNA processing. Expression analysis defined 4 subtypes: (1) squamous; (2) pancreatic progenitor; (3) immunogenic; and (4) aberrantly differentiated endocrine exocrine (ADEX) that correlate with histopathological characteristics. Squamous tumours are enriched for TP53 and KDM6A mutations, upregulation of the TP63∆N transcriptional network, hypermethylation of pancreatic endodermal cell-fate determining genes and have a poor prognosis. Pancreatic progenitor tumours preferentially express genes involved in early pancreatic development (FOXA2/3, PDX1 and MNX1). ADEX tumours displayed upregulation of genes that regulate networks involved in KRAS activation, exocrine (NR5A2 and RBPJL), and endocrine differentiation (NEUROD1 and NKX2-2). Immunogenic tumours contained upregulated immune networks including pathways involved in acquired immune suppression. These data infer differences in the molecular evolution of pancreatic cancer subtypes and identify opportunities for therapeutic development.

Second-line treatment in inoperable pancreatic adenocarcinoma: A systematic review and synthesis of all clinical trials

There remains uncertainty regarding the optimal second-line chemotherapy in advanced pancreatic ductal adenocarcinoma (PDAC). The current recommendation of 5-fluorouracil and oxaliplatin may not be relevant in current practice, as FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan and oxaliplatin) has become a more popular first line therapy in fit patients. The majority of studies in this setting are single-arm Phase II trials with significant heterogeneity of patient populations, treatments and outcomes. In this review, we sought to systematically review and synthesise all prospective data available for the second-line treatment of advanced PDAC.

Rho-associated kinase signalling and the cancer microenvironment: novel biological implications and therapeutic opportunities

The Rho/ROCK pathway is involved in numerous pivotal cellular processes that have made it an area of intense study in cancer medicine, however, Rho-associated coiled-coil containing protein kinase (ROCK) inhibitors are yet to make an appearance in the clinical cancer setting. Their performance as an anti-cancer therapy has been varied in pre-clinical studies, however, they have been shown to be effective vasodilators in the treatment of hypertension and post-ischaemic stroke vasospasm. This review addresses the various roles the Rho/ROCK pathway plays in angiogenesis, tumour vascular tone and reciprocal feedback from the tumour microenvironment and explores the potential utility of ROCK inhibitors as effective vascular normalising agents. ROCK inhibitors may potentially enhance the delivery and efficacy of chemotherapy agents and improve the effectiveness of radiotherapy. As such, repurposing of these agents as adjuncts to standard treatments may significantly improve outcomes for patients with cancer. A deeper understanding of the controlled and dynamic regulation of the key components of the Rho pathway may lead to effective use of the Rho/ROCK inhibitors in the clinical management of cancer.

Precision Medicine for Advanced Pancreas Cancer: The Individualized Molecular Pancreatic Cancer Therapy (IMPaCT) Trial

PURPOSE

Personalized medicine strategies using genomic profiling are particularly pertinent for pancreas cancer. The Individualized Molecular Pancreatic Cancer Therapy (IMPaCT) trial was initially designed to exploit results from genome sequencing of pancreatic cancer under the auspices of the International Cancer Genome Consortium (ICGC) in Australia. Sequencing revealed small subsets of patients with aberrations in their tumor genome that could be targeted with currently available therapies.

EXPERIMENTAL DESIGN

The pilot stage of the IMPaCT trial assessed the feasibility of acquiring suitable tumor specimens for molecular analysis and returning high-quality actionable genomic data within a clinically acceptable timeframe. We screened for three molecular targets: HER2 amplification; KRAS wild-type; and mutations in DNA damage repair pathways (BRCA1, BRCA2, PALB2, ATM).

RESULTS

Tumor biopsy and archived tumor samples were collected from 93 patients and 76 were screened. To date 22 candidate cases have been identified: 14 KRAS wild-type, 5 cases of HER2 amplification, 2 mutations in BRCA2, and 1 ATM mutation. Median time from consent to the return of validated results was 21.5 days. An inability to obtain a biopsy or insufficient tumor content in the available specimen were common reasons for patient exclusion from molecular analysis while deteriorating performance status prohibited a number of patients from proceeding in the study.

CONCLUSIONS

Documenting the feasibility of acquiring and screening biospecimens for actionable molecular targets in real time will aid other groups embarking on similar trials. Key elements include the need to better prescreen patients, screen more patients, and offer more attractive clinical trial options.

Whole genomes redefine the mutational landscape of pancreatic cancer

Pancreatic cancer remains one of the most lethal of malignancies and a major health burden. We performed whole-genome sequencing and copy number variation (CNV) analysis of 100 pancreatic ductal adenocarcinomas (PDACs). Chromosomal rearrangements leading to gene disruption were prevalent, affecting genes known to be important in pancreatic cancer (TP53, SMAD4, CDKN2A, ARID1A and ROBO2) and new candidate drivers of pancreatic carcinogenesis (KDM6A and PREX2). Patterns of structural variation (variation in chromosomal structure) classified PDACs into 4 subtypes with potential clinical utility: the subtypes were termed stable, locally rearranged, scattered and unstable. A significant proportion harboured focal amplifications, many of which contained druggable oncogenes (ERBB2, MET, FGFR1, CDK6, PIK3R3 and PIK3CA), but at low individual patient prevalence. Genomic instability co-segregated with inactivation of DNA maintenance genes (BRCA1, BRCA2 or PALB2) and a mutational signature of DNA damage repair deficiency. Of 8 patients who received platinum therapy, 4 of 5 individuals with these measures of defective DNA maintenance responded.

Clinical and pathologic features of familial pancreatic cancer

BACKGROUND

Inherited predisposition to pancreatic cancer contributes significantly to its incidence and presents an opportunity for the development of early detection strategies. The genetic basis of predisposition remains unexplained in a high proportion of patients with familial PC (FPC).

METHODS

Clinicopathologic features were assessed in a cohort of 766 patients who had been diagnosed with pancreatic ductal adenocarcinoma (PC). Patients were classified with FPC if they had ≥1 affected first-degree relatives; otherwise, they were classified with sporadic PC (SPC).

RESULTS

The prevalence of FPC in this cohort was 8.9%. In FPC families with an affected parent-child pair, 71% in the subsequent generation were 12.3 years younger at diagnosis. Patients with FPC had more first-degree relatives who had an extrapancreatic malignancy (EPM) (42.6% vs 21.2; P<.0001), particularly melanoma and endometrial cancer, but not a personal history of EPM. Patients with SPC were more likely to be active smokers, have higher cumulative tobacco exposure, and have fewer multifocal precursor lesions, but these were not associated with differences in survival. Long-standing diabetes mellitus (>2 years) was associated with poor survival in both groups.

CONCLUSIONS

FPC represents 9% of PC, and the risk of malignancy in kindred does not appear to be confined to the pancreas. Patients with FPC have more precursor lesions and include fewer active smokers, but other clinicopathologic factors and outcome are similar to those in patients with SPC. Furthermore, some FPC kindreds may exhibit anticipation. A better understanding of the clinical features of PC will facilitate efforts to uncover novel susceptibility genes and the development of early detection strategies.

Preexisting MEK1P124 mutations diminish response to BRAF inhibitors in metastatic melanoma patients

BACKGROUND

MEK1 mutations in melanoma can confer resistance to BRAF inhibitors, although preexisting MEK1(P124) mutations do not preclude clinical responses. We sought to determine whether recurrent, preexisting MEK1(P124) mutations affected clinical outcome in BRAF inhibitor-treated patients with melanoma.

METHODS

Data from four published datasets were analyzed to determine whether preexisting MEK1(P124) mutations affect radiologic response or progression-free survival (PFS) in patients with BRAF(V600)-mutant metastatic melanoma treated with vemurafenib or dabrafenib. The effects of MEK1(P124) mutations on MAPK pathway activity and response to BRAF inhibition were also investigated in a series of cell models.

RESULTS

In a pooled analysis of 123 patients, the presence of a pretreatment MEK1(P124) mutation (N = 12, 10%) was associated with a poorer RECIST response (33% vs. 72% in MEK1(P124Q/S) vs. MEK1(P124) wild-type, P = 0.018), and a shorter PFS (median 3.1 vs. 4.8 months, P = 0.004). Furthermore, MEK1(P124Q/S) mutations were shown to have independent kinase activity and introduction of these mutations into a BRAF-mutant melanoma cell line diminished inhibition of ERK phosphorylation by dabrafenib and enhanced clonogenic survival in the presence of dabrafenib compared with cells ectopically expressing wild-type MEK1. Consistent with these data, two BRAF-mutant cell lines with endogenous MEK1(P124) mutations showed intermediate sensitivity to dabrafenib, but were highly sensitive to downstream inhibition of MEK or ERK.

CONCLUSION

Taken together, our data indicate that preexisting MEK1(P124) mutations are associated with a reduced response to BRAF inhibitor therapy and identify a subset of patients with BRAF-mutant melanoma likely to benefit from combination therapies involving MEK or ERK inhibitors.

Personalising pancreas cancer treatment: When tissue is the issue

The treatment of advanced pancreatic cancer has not moved much beyond single agent gemcitabine until recently when protocols such as FOLFIRINOX (fluorouracil, leucovorin, irinotecan and oxaliplatin) and nab-paclitaxel-gemcitabine have demonstrated some improved outcomes. Advances in technology especially in massively parallel genome sequencing has progressed our understanding of the biology of pancreatic cancer especially the candidate signalling pathways that are involved in tumourogenesis and disease course. This has allowed identification of potentially actionable mutations that may be targeted by new biological agents. The heterogeneity of pancreatic cancer makes tumour tissue collection important with the aim of being able to personalise therapies for the individual as opposed to a one size fits all approach to treatment of the condition. This paper reviews the developments in this area of translational research and the ongoing clinical studies that will attempt to move this into the everyday oncology practice.

Gemcitabine and CHK1 inhibition potentiate EGFR-directed radioimmunotherapy against pancreatic ductal adenocarcinoma

PURPOSE

To develop effective combination therapy against pancreatic ductal adenocarcinoma (PDAC) with a combination of chemotherapy, CHK1 inhibition, and EGFR-targeted radioimmunotherapy.

EXPERIMENTAL DESIGN

Maximum tolerated doses were determined for the combination of gemcitabine, the CHK1 inhibitor PF-477736, and Lutetium-177 ((177)Lu)-labeled anti-EGFR antibody. This triple combination therapy was investigated using PDAC models from well-established cell lines, recently established patient-derived cell lines, and fresh patient-derived xenografts. Tumors were investigated for the accumulation of (177)Lu-anti-EGFR antibody, survival of tumor-initiating cells, induction of DNA damage, cell death, and tumor tissue degeneration.

RESULTS

The combination of gemcitabine and CHK1 inhibitor PF-477736 with (177)Lu-anti-EGFR antibody was tolerated in mice. This triplet was effective in established tumors and prevented the recurrence of PDAC in four cell line-derived and one patient-derived xenograft model. This exquisite response was associated with the loss of tumor-initiating cells as measured by flow cytometric analysis and secondary implantation of tumors from treated mice into treatment-naïve mice. Extensive DNA damage, apoptosis, and tumor degeneration were detected in the patient-derived xenograft. Mechanistically, we observed CDC25A stabilization as a result of CHK1 inhibition with consequent inhibition of gemcitabine-induced S-phase arrest as well as a decrease in canonical (ERK1/2 phosphorylation) and noncanonical EGFR signaling (RAD51 degradation) as a result of EGFR inhibition.

CONCLUSIONS

Our study developed an effective combination therapy against PDAC that has potential in the treatment of PDAC.

Adjuvant chemotherapy in elderly patients with pancreatic cancer

BACKGROUND

Adjuvant chemotherapy improves survival for patients with resected pancreatic cancer. Elderly patients are under-represented in Phase III clinical trials, and as a consequence the efficacy of adjuvant therapy in older patients with pancreatic cancer is not clear. We aimed to assess the use and efficacy of adjuvant chemotherapy in older patients with pancreatic cancer.

METHODS

We assessed a community cohort of 439 patients with a diagnosis of pancreatic ductal adenocarcinoma who underwent operative resection in centres associated with the Australian Pancreatic Cancer Genome Initiative.

RESULTS

The median age of the cohort was 67 years. Overall only 47% of all patients received adjuvant therapy. Patients who received adjuvant chemotherapy were predominantly younger, had later stage disease, more lymph node involvement and more evidence of perineural invasion than the group that did not receive adjuvant treatment. Overall, adjuvant chemotherapy was associated with prolonged survival (median 22.1 vs 15.8 months; P<0.0001). Older patients (aged ≥70) were less likely to receive adjuvant chemotherapy (51.5% vs 29.8%; P<0.0001). Older patients had a particularly poor outcome when adjuvant therapy was not delivered (median survival=13.1 months; HR 1.89, 95% CI: 1.27-2.78, P=0.002).

CONCLUSION

Patients aged ≥70 are less likely to receive adjuvant therapy although it is associated with improved outcome. Increased use of adjuvant therapy in older individuals is encouraged as they constitute a large proportion of patients with pancreatic cancer.

Clinical and molecular characterization of HER2 amplified-pancreatic cancer

Background

Pancreatic cancer is one of the most lethal and molecularly diverse malignancies. Repurposing of therapeutics that target specific molecular mechanisms in different disease types offers potential for rapid improvements in outcome. Although HER2 amplification occurs in pancreatic cancer, it is inadequately characterized to exploit the potential of anti-HER2 therapies.

Methods

HER2 amplification was detected and further analyzed using multiple genomic sequencing approaches. Standardized reference laboratory assays defined HER2 amplification in a large cohort of patients (n = 469) with pancreatic ductal adenocarcinoma (PDAC).

Results

An amplified inversion event (1 MB) was identified at the HER2 locus in a patient with PDAC. Using standardized laboratory assays, we established diagnostic criteria for HER2 amplification in PDAC, and observed a prevalence of 2%. Clinically, HER2- amplified PDAC was characterized by a lack of liver metastases, and a preponderance of lung and brain metastases. Excluding breast and gastric cancer, the incidence of HER2-amplified cancers in the USA is >22,000 per annum.

Conclusions

HER2 amplification occurs in 2% of PDAC, and has distinct features with implications for clinical practice. The molecular heterogeneity of PDAC implies that even an incidence of 2% represents an attractive target for anti-HER2 therapies, as options for PDAC are limited. Recruiting patients based on HER2 amplification, rather than organ of origin, could make trials of anti-HER2 therapies feasible in less common cancer types.

Abstract 1156: A molecular pre-operative prognostic nomogram for resectable pancreatic cancer

Purpose: Defining clinically and biologically relevant phenotypes to inform treatment decisions in other cancers have led to substantial improvements in overall outcomes. About 80% of patients with pancreatic cancer (PC) succumb to the disease despite curative resection, many of whom recur within 6 months of surgery. These early recurrences demonstrate that current staging is inadequate and that there is a clear need to better define prognostic phenotypes prior to significant intervention. This study aimed to evaluate the potential clinical utility of biologically relevant molecules as prognostic factors in resected PC to define strategies that may improve current preoperative staging accuracy and inform treatment decisions.

Method: We assessed the relationship of aberrant expression of two pro-metastatic calcium-binding proteins, S100A2 and S100A4 with disease-specific survival in four independent cohorts of patients (total n = 547) who underwent operative resection for PC. A preoperative nomogram using pre-operatively assessable variables including biomarkers was derived and was compared to traditional prognostic variables and the postoperative nomogram.

Results: High S100A2 and S100A4 expressions were an independent poor prognostic factor in both the training (n = 76; HR = 2.00, 95% CI = 1.15 - 3.49, P = 0.0216 and HR = 3.34, 95% CI = 1.69 - 6.62, P = 0.0005 respectively) and validation (n = 316; HR = 1.73, 95% CI = 1.20 - 2.48, P = 0.0030 and HR = 1.65, 95% CI = 1.23 - 2.22, P = 0.0009 respectively) cohorts. These results were further validated in a prospective cohort (ICGC-APGI, n = 100) and another retrospective population based cohort (NCI SEER, n = 55). Aberrant expression of S100A2/A4 protein again stratified the cohorts into 3 distinct prognostic groups. A preoperative nomogram using only variables that could be measured preoperatively (age, tumour size, tumour location and molecular biomarkers), predicted survival better than nomograms derived using clinico-pathological variables, which are only determinable after surgery. A proof-of-principle study demonstrated that biomarker expression can be reliably assessed in preoperative EUS-FNA cell block samples.

Conclusion: S100A4 and S100A2 are one of the very few biomarkers that have been independently validated in multiple patient cohorts. Their aberrant expression stratifies PC into distinct prognostic groups and potentially enables more accurate preoperative prognostication through a nomogram. Biomarker assessment potentially enables accurate preoperative prognostication, which is more accurate than current staging methods. The development and application of such nomograms has the potential to improve patient selection for surgery and assist clinicians in making “tie-breaker” decisions that would ultimately improve the overall survival and quality of life for patients with PC.

Citation Format: David K. Chang, Mark Pinese, Christopher J. Scarlett, Marina Pajic, Emily K. Colvin, Amber L. Johns, Jianmin Wu, Mark J. Cowley, Jeremy L. Humphris, Angela Chou, Nam Q. Nguyen, Adnan M. Nagrial, Lorraine Chantrill, Venessa T. Chin, Elizabeth A. Musgrove, Sean Altekruse, Anthony J. Gill, James G. Kench, Andrew V. Biankin. A molecular pre-operative prognostic nomogram for resectable pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1156. doi:10.1158/1538-7445.AM2013-1156

Histomolecular phenotypes and outcome in adenocarcinoma of the ampulla of vater

PURPOSE

Individuals with adenocarcinoma of the ampulla of Vater demonstrate a broad range of outcomes, presumably because these cancers may arise from any one of the three epithelia that converge at that location. This variability poses challenges for clinical decision making and the development of novel therapeutic strategies.

PATIENTS AND METHODS

We assessed the potential clinical utility of histomolecular phenotypes defined using a combination of histopathology and protein expression (CDX2 and MUC1) in 208 patients from three independent cohorts who underwent surgical resection for adenocarcinoma of the ampulla of Vater.

RESULTS

Histologic subtype and CDX2 and MUC1 expression were significant prognostic variables. Patients with a histomolecular pancreaticobiliary phenotype (CDX2 negative, MUC1 positive) segregated into a poor prognostic group in the training (hazard ratio [HR], 3.34; 95% CI, 1.69 to 6.62; P < .001) and both validation cohorts (HR, 5.65; 95% CI, 2.77 to 11.5; P < .001 and HR, 2.78; 95% CI, 1.25 to 7.17; P = .0119) compared with histomolecular nonpancreaticobiliary carcinomas. Further stratification by lymph node (LN) status defined three clinically relevant subgroups: one, patients with histomolecular nonpancreaticobiliary (intestinal) carcinoma without LN metastases who had an excellent prognosis; two, those with histomolecular pancreaticobiliary carcinoma with LN metastases who had a poor outcome; and three, the remainder of patients (nonpancreaticobiliary, LN positive or pancreaticobiliary, LN negative) who had an intermediate outcome.

CONCLUSION

Histopathologic and molecular criteria combine to define clinically relevant histomolecular phenotypes of adenocarcinoma of the ampulla of Vater and potentially represent distinct diseases with significant implications for current therapeutic strategies, the ability to interpret past clinical trials, and future trial design.

Prognostic and clinicopathologic associations of oncogenic BRAF in metastatic melanoma

PURPOSE

To assess the frequency and type of oncogenic BRAF mutations in metastatic melanoma and correlate BRAF status with clinicopathologic features and outcome.

PATIENTS AND METHODS

Consecutive BRAF-tested Australian patients with metastatic melanoma (n = 197) were observed prospectively. A comprehensive range of clinicopathologic variables were correlated with BRAF mutation status, and a survival analysis was conducted.

RESULTS

Forty-eight percent of patients had a BRAF mutation; 70 patients (74%) had V600E, 19 (20%) had V600K, and six (6%) had other genotypes. Other than age at diagnosis of distant metastasis (median age, 56 v 63 years for BRAF-mutant v BRAF wild-type patients, respectively; P < .001), there was no significant difference in clinical features of patients with metastatic melanoma by mutation status. Features of the antecedent primary melanoma significantly associated with a BRAF mutation (P < .05) were histopathologic subtype, presence of mitoses, single or occult primary melanoma, truncal location, and age at diagnosis of primary tumor ≤ 50 years. The interval from diagnosis of first-ever melanoma to distant metastasis was not significantly different between BRAF-mutant and BRAF wild-type patients; however, the median survival of patients with newly diagnosed metastatic melanoma was 5.7 months for BRAF-mutant patients not treated with a BRAF inhibitor, 8.5 months for BRAF wild-type patients, and not reached for BRAF-mutant patients treated with a BRAF inhibitor.

CONCLUSION

V600K mutations comprised 20% of BRAF mutations. Characteristics of the antecedent primary melanoma and age at diagnosis differed in BRAF-mutant and BRAF wild-type patients. The presence of mutant BRAF had no impact on the disease-free interval from diagnosis of first-ever melanoma to first distant metastasis; however, it may have impacted survival thereafter.