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Recent advances in small cell lung cancer (SCLC) treatments necessitate a better understanding of real-world health utility scores (HUS) in patients treated under current standards to facilitate robust pharmaco-economic assessments.In this single institution cohort observational study, HUS were evaluated in patients with SCLC through EQ-5D questionnaires at outpatient visits (encounters). In addition, patients completed questionnaires relating to treatment toxicities and cancer symptoms. Clinical and pathological variables were abstracted from electronic medical records and disease status at each patient visit was documented. The impact of these variables on HUS were explored.There were 282 clinical encounters (12% newly diagnosed; 37% stable on treatment; 22% progressing on treatment; 29% stable off therapy/other) in 111 SCLC patients (58% male; 64% extensive stage (ES) SCLC). At the first encounter 29% of patients had an ECOG performance status (PS) ≥ 2. ES-SCLC, bone metastases, female sex, progressive disease and/or PS were each significantly associated with decreased HUS in multivariable analyses. Patients clinically stable on first line therapy had generally steady HUS longitudinally, with differences in HUS between limited disease (LD) and ES patients emerging as treatment progressed. Decreased HUS were associated with increased severity of the majority of measured symptoms (fatigue/tiredness, loss of appetite, pain, drowsiness, shortness of breath, anxiety, depression, and overall well-being; each p0.001), supporting the value of EQ-5D-derived HUS in assessing health utility.Our HUS values in chemotherapy-treated SCLC are clinically relevant and are associated with specific clinico-demographic, symptom and toxicity factors.

AimsThe majority of pancreatic ductal adenocarcinomas (PDACs) harbour oncogenic mutations inKRASwith variants inTP53,CDKN2AandSMAD4also prevalent. The presence of oncogenic fusions includingNTRKfusions are rare but important to identify. Here we ascertain the prevalence ofNTRKfusions and document their genomic characteristics in a large series of PDAC.MethodsWhole genome sequencing and RNAseq were performed on a series of patients with resected or locally advanced/metastatic PDAC collected between 2008 and 2020 at a single institution. A subset of specimens underwent immunohistochemistry (IHC) analysis. Clinical and molecular characterisation and IHC sensitivity and specificity were evaluated.Results400 patients were included (resected n=167; locally advanced/metastatic n=233). Three patients were identified as harbouring anNTRKfusion, twoEML4-NTRK3(KRAS-WT) and a single novelKANK1-NTRK3fusion. The latter occurring in the presence of a subclonalKRASmutation. Typical PDAC drivers were present including mutations inTP53andCDKN2A. Substitution base signatures and tumour mutational burden were similar to typical PDAC. The prevalence ofNTRKfusions was 0.8% (3/400), while inKRASwild-type tumours, it was 6.25% (2/32). DNA prediction alone documented six false-positive cases. RNA analysis correctly identified the in-frame fusion transcripts. IHC analysis was negative in theKANK1-NTRK3fusion but positive in aEML4-NTRK3case, highlighting lower sensitivity of IHC.ConclusionNTRKfusions are rare; however, with emerging therapeutic options targeting these fusions, detection is vital. Reflex testing forKRASmutations and subsequent RNA-based screening could help identify these cases in PDAC.

Aims The aims of the study were to identify predictors of locoregional failure (LRF) following surgery for pancreatic adenocarcinoma, develop a prediction risk score model of LRF and evaluate the impact of postoperative radiation therapy (PORT) on LRF. Materials and methods A retrospective review was conducted on patients with stages I–III pancreatic adenocarcinoma who underwent surgery at our institution (2005–2016). Univariable and then multivariable analyses were used to evaluate clinicopathological factors associated with LRF for patients who did not receive PORT. The risk score of LRF was calculated based on the sum of coefficients of the predictors of LRF. The model was applied to the entire cohort to evaluate the impact of PORT on the high- and low-risk groups for LRF. Results In total, 467 patients were identified (median follow-up 22 months). Among patients who did not receive PORT (n = 440), predictors of LRF were pN+, involved or close ≤1 mm margin(s), moderately and poorly differentiated tumour grade and lymphovascular invasion. After adding patients who received PORT, the 2-year LRF in the high-risk group was 57% for patients who did not receive PORT (n = 242) and 32% among patients who received PORT (n = 22), with an absolute benefit to LRF of 25% (95% confidence interval 5–52%, P = 0.07). The 2-year overall survival for the high-versus the low-risk group was 36% versus 67% (P Conclusion This risk group classification could be used to identify pancreatic adenocarcinoma patients with higher risk of LRF who may benefit from PORT. However, validation and prospective evaluation are warranted.

While adjuvant treatment of colon cancers that penetrate the serosa (T4) have been well-established, neoadjuvant strategies have yet to be formally evaluated. Our objective was to perform a scoping review of eligibility criteria, treatment regimens, and primary outcomes for neoadjuvant approaches to T4 colon cancer. A librarian-led, systematic search of MEDLINE, Embase, Cochrane Library, Web of Science, and CINAHL up to 11 February 2020 was performed. Primary research evaluating neoadjuvant treatment in T4 colon cancer were included. Screening and data abstraction were performed in duplicate; analyses were descriptive or thematic. A total of twenty studies were included, most of which were single-arm, single-center, and retrospective. The primary objectives of the literature to date has been to evaluate treatment feasibility, tumor response, disease-free survival, and overall survival in healthy patients. Conventional XELOX and FOLFOX chemotherapy were the most commonly administered interventions. Rationale for selecting a specific regimen and for treatment eligibility criteria were poorly documented across studies. The current literature on neoadjuvant strategies for T4 colon cancer is overrepresented by single-center, retrospective studies that evaluate treatment feasibility and efficacy in healthy patients. Future studies should prioritize evaluating clear selection criteria and rationale for specific neoadjuvant strategies. Validation of outcomes in multi-center, randomized trials for XELOX and FOLFOX have the most to contribute to the growing evidence for this poorly managed disease.

Skeletal muscle mass is a prognostic factor in pancreatic ductal adenocarcinoma (PDAC). However, it remains unclear whether changes in body composition provide an incremental prognostic value to established risk factors, especially the Response Evaluation Criteria in Solid Tumors version 1.1 (RECISTv1.1). The aim of this study was to determine the prognostic value of CT-quantified body composition changes in patients with unresectable PDAC starting chemotherapy. We retrospectively evaluated 105 patients with unresectable (locally advanced or metastatic) PDAC treated with FOLFIRINOX (n = 64) or gemcitabine-based (n = 41) first-line chemotherapy within a multicenter prospective trial. Changes (Δ) in skeletal muscle index (SMI), subcutaneous (SATI), and visceral adipose tissue index (VATI) between pre-chemotherapy and first follow-up CT were assessed. Cox regression models and covariate-adjusted survival curves were used to identify predictors of overall survival (OS). At multivariable analysis, adjusting for RECISTv1.1-response at first follow-up, ΔSMI was prognostic for OS with a hazard ratio (HR) of 1.2 (95% CI: 1.08–1.33, p = 0.001). No significant association with OS was observed for ΔSATI (HR: 1, 95% CI: 0.97–1.04, p = 0.88) and ΔVATI (HR: 1.01, 95% CI: 0.99–1.04, p = 0.33). At an optimal cutoff of 2.8 cm2/m2 per 30 days, the median survival of patients with high versus low ΔSMI was 143 versus 233 days (p < 0.001). Patients with a lower rate of skeletal muscle loss at first follow-up demonstrated improved survival for unresectable PDAC, regardless of their RECISTv1.1-category. Assessing ΔSMI at the first follow-up CT may be useful for prognostication, in addition to routine radiological assessment. • In patients with unresectable pancreatic ductal adenocarcinoma, change of skeletal muscle index (ΔSMI) in the early phase of chemotherapy is prognostic for overall survival, even after adjusting for Response Evaluation Criteria in Solid Tumors version 1.1 (RECISTv1.1) assessment at first follow-up. • Changes in adipose tissue compartments at first follow-up demonstrated no significant association with overall survival. • Integrating ΔSMI into routine radiological assessment may improve prognostic stratification and impact treatment decision-making at the first follow-up.

Purpose: With the rising incidence of early-onset pancreatic cancer (EOPC), molecular characteristics that distinguish early-onset pancreatic ductal adenocarcinoma (PDAC) tumors from those arising at a later age are not well understood. Experimental Design: We performed bioinformatic analysis of genomic and transcriptomic data generated from 269 advanced (metastatic or locally advanced) and 277 resectable PDAC tumor samples. Patient samples were stratified into EOPC (age of onset ≤55 years; n = 117), intermediate (age of onset 55–70 years; n = 264), and average (age of onset ≥70 years; n = 165) groups. Frequency of somatic mutations affecting genes commonly implicated in PDAC, as well as gene expression patterns, were compared between EOPC and all other groups. Results: EOPC tumors showed significantly lower frequency of somatic single-nucleotide variant (SNV)/insertions/deletions (indel) in CDKN2A (P = 0.0017), and were more likely to achieve biallelic mutation of CDKN2A through homozygous copy loss as opposed to heterozygous copy loss coupled with a loss-of-function SNV/indel mutation, the latter of which was more common for tumors with later ages of onset (P = 1.5e-4). Transcription factor forkhead box protein C2 (FOXC2) was significantly upregulated in EOPC tumors (P = 0.032). Genes significantly correlated with FOXC2 in PDAC samples were enriched for gene sets related to epithelial-to-mesenchymal transition (EMT) and included VIM (P = 1.8e-8), CDH11 (P = 6.5e-5), and CDH2 (P = 2.4e-2). Conclusions: Our comprehensive analysis of sequencing data generated from a large cohort of PDAC patient samples highlights a distinctive pattern of biallelic CDKN2A mutation in EOPC tumors. Increased expression of FOXC2 in EOPC, with the correlation between FOXC2 and EMT pathways, represents novel molecular characteristics of EOPC. See related commentary by Lou, p. 8

Purpose: RNA-sequencing–based subtyping of pancreatic ductal adenocarcinoma (PDAC) has been reported by multiple research groups, each using different methodologies and patient cohorts. “Classical” and “basal-like” PDAC subtypes are associated with survival differences, with basal-like tumors associated with worse prognosis. We amalgamated various PDAC subtyping tools to evaluate the potential of such tools to be reliable in clinical practice. Experimental Design: Sequencing data for 574 PDAC tumors was obtained from prospective trials and retrospective public databases. Six published PDAC subtyping strategies (Moffitt regression tools, clustering-based Moffitt, Collisson, Bailey, and Karasinska subtypes) were used on each sample, and results were tested for subtype call consistency and association with survival. Results: Basal-like and classical subtype calls were concordant in 88% of patient samples, and survival outcomes were significantly different (P < 0.05) between prognostic subtypes. Twelve percent of tumors had subtype-discordant calls across the different methods, showing intermediate survival in univariate and multivariate survival analyses. Transcriptional profiles compatible with that of a hybrid subtype signature were observed for subtype-discordant tumors, in which classical and basal-like genes were concomitantly expressed. Subtype-discordant tumors showed intermediate molecular characteristics, including subtyping gene expression (P < 0.0001) and mutant KRAS allelic imbalance (P < 0.001). Conclusions: Nearly 1 in 6 patients with PDAC have tumors that fail to reliably fall into the classical or basal-like PDAC subtype categories, based on two regression tools aimed toward clinical practice. Rather, these patient tumors show intermediate prognostic and molecular traits. We propose close consideration of the non-binary nature of PDAC subtypes for future incorporation of subtyping into clinical practice.

Purpose:Pancreatic ductal adenocarcinoma (PDAC) arising in patients with a germline BRCA1 or BRCA2 (gBRCA) mutation may be sensitive to platinum and PARP inhibitors (PARPi). However, treatment stratification based on gBRCA mutational status alone is associated with heterogeneous responses.Experimental Design:We performed a seven-arm preclinical trial consisting of 471 mice, representing 12 unique PDAC patient-derived xenografts, of which nine were gBRCA mutated. From 179 patients whose PDAC was whole-genome and transcriptome sequenced, we identified 21 cases with homologous recombination deficiency (HRD), and investigated prognostic biomarkers.Results:We found that biallelic inactivation of BRCA1/BRCA2 is associated with genomic hallmarks of HRD and required for cisplatin and talazoparib (PARPi) sensitivity. However, HRD genomic hallmarks persisted in xenografts despite the emergence of therapy resistance, indicating the presence of a genomic scar. We identified tumor polyploidy and a low Ki67 index as predictors of poor cisplatin and talazoparib response. In patients with HRD PDAC, tumor polyploidy and a basal-like transcriptomic subtype were independent predictors of shorter survival. To facilitate clinical assignment of transcriptomic subtype, we developed a novel pragmatic two-marker assay (GATA6:KRT17).Conclusions:In summary, we propose a predictive and prognostic model of gBRCA-mutated PDAC on the basis of HRD genomic hallmarks, Ki67 index, tumor ploidy, and transcriptomic subtype.

ObjectiveTo describe the clinical, pathological and genomic characteristics of pancreatic cancer with DNA mismatch repair deficiency (MMRD) and proficiency (MMRP).DesignWe identified patients with MMRD and MMRP pancreatic cancer in a clinical cohort (N=1213, 519 with genetic testing, 53 with immunohistochemistry (IHC)) and a genomic cohort (N=288 with whole-genome sequencing (WGS)).Results12 out of 1213 (1.0%) in the clinical cohort were MMRD by IHC or WGS. Of the 14 patients with Lynch syndrome, 3 (21.4%) had an MMRP pancreatic cancer by IHC, and 4 (28.6%) were excluded because tissue was unavailable for testing. MMRD cancers had longer overall survival after surgery (weighted HR after coarsened exact matching 0.11, 95% CI 0.02 to 0.78, p=0.001). One patient with an unresectable MMRD cancer has an ongoing partial response 3 years after starting treatment with PD-L1/CTLA-4 inhibition. This tumour showed none of the classical histopathological features of MMRD. 9 out of 288 (3.1%) tumours with WGS were MMRD. Despite markedly higher tumour mutational burden and neoantigen loads, MMRD cancers were significantly less likely to have mutations in usual pancreatic cancer driver genes like KRAS and SMAD4, but more likely to have mutations in genes that drive cancers with microsatellite instability like ACV2RA and JAK1. MMRD tumours were significantly more likely to have a basal-like transcriptional programme and elevated transcriptional markers of immunogenicity.ConclusionsMMRD pancreatic cancers have distinct clinical, pathological and genomic profiles. Patients with MMRD pancreatic cancer should be considered for basket trials targeting enhanced immunogenicity or the unique genomic drivers in these malignancies.

Next-generation sequencing of solid tumors has revealed variable signatures of immunogenicity across tumors, but underlying molecular characteristics driving such variation are not fully understood. Although expression of endogenous retrovirus (ERV)-containing transcripts can provide a source of tumor-specific neoantigen in some cancer models, associations between ERV levels and immunogenicity across different types of metastatic cancer are not well established. We performed bioinformatics analysis of genomic, transcriptomic, and clinical data across an integrated cohort of 199 patients with metastatic breast, colorectal, and pancreatic ductal adenocarcinoma tumors. Within each cancer type, we identified a subgroup of viral mimicry tumors in which increased ERV levels were coupled with transcriptional signatures of autonomous antiviral response and immunogenicity. In addition, viral mimicry colorectal and pancreatic tumors showed increased expression of DNA demethylation gene TET2. Taken together, these data demonstrate the existence of an ERV-associated viral mimicry phenotype across three distinct metastatic cancer types, while indicating links between ERV abundance, epigenetic dysregulation, and immunogenicity.

Small cell lung cancer (SCLC) is a highly fatal disease associated with significant morbidity, with a need for real-world symptom and health utility score (HUS) data. HUS can be measured using an EQ-5D-5L questionnaire, however most captured data is available in non-SCLC (NSCLC) only. As new treatment regimens become available in SCLC it becomes important to understand factors which influence health-related quality of life and health utility. A prospective observational cohort study (2012–2017) of ambulatory histologically confirmed SCLC evaluated patient-reported EQ-5D-5L-derived HUS, toxicity and symptoms. A set of NSCLC patients was used to compare differential factors affecting HUS. Clinical and demographic factors were evaluated for differential interactions between lung cancer types. Comorbidity scores were documented for each patient. In 75 SCLC and 150 NSCLC patients, those with SCLC had lower mean HUS ((SCLC vs NSCLC: mean 0.69 vs 0.79); (p

Purpose: To determine the impact of basal-like and classical subtypes in advanced pancreatic ductal adenocarcinoma (PDAC) and to explore GATA6 expression as a surrogate biomarker. Experimental Design: Within the COMPASS trial, patients proceeding to chemotherapy for advanced PDAC undergo tumor biopsy for RNA-sequencing (RNA-seq). Overall response rate (ORR) and overall survival (OS) were stratified by subtypes and according to chemotherapy received. Correlation of GATA6 with the subtypes using gene expression profiling, in situ hybridization (ISH) was explored. Results: Between December 2015 and May 2019, 195 patients (95%) had enough tissue for RNA-seq; 39 (20%) were classified as basal-like and 156 (80%) as classical. RECIST response data were available for 157 patients; 29 basal-like and 128 classical where the ORR was 10% versus 33%, respectively (P = 0.02). In patients with basal-like tumors treated with modified FOLFIRINOX (n = 22), the progression rate was 60% compared with 15% in classical PDAC (P = 0.0002). Median OS in the intention-to-treat population (n = 195) was 9.3 months for classical versus 5.9 months for basal-like PDAC (HR, 0.47; 95% confidence interval, 0.32–0.69; P = 0.0001). GATA6 expression by RNA-seq highly correlated with the classifier (P < 0.001) and ISH predicted the subtypes with sensitivity of 89% and specificity of 83%. In a multivariate analysis, GATA6 expression was prognostic (P = 0.02). In exploratory analyses, basal-like tumors, could be identified by keratin 5, were more hypoxic and enriched for a T-cell–inflamed gene expression signature. Conclusions: The basal-like subtype is chemoresistant and can be distinguished from classical PDAC by GATA6 expression. See related commentary by Collisson, p. 4715

Purpose: Identification of clinically actionable molecular subtypes of pancreatic ductal adenocarcinoma (PDAC) is key to improving patient outcome. Intertumoral metabolic heterogeneity contributes to cancer survival and the balance between distinct metabolic pathways may influence PDAC outcome. We hypothesized that PDAC can be stratified into prognostic metabolic subgroups based on alterations in the expression of genes involved in glycolysis and cholesterol synthesis. Experimental Design: We performed bioinformatics analysis of genomic, transcriptomic, and clinical data in an integrated cohort of 325 resectable and nonresectable PDAC. The resectable datasets included retrospective The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) cohorts. The nonresectable PDAC cohort studies included prospective COMPASS, PanGen, and BC Cancer Personalized OncoGenomics program (POG). Results: On the basis of the median normalized expression of glycolytic and cholesterogenic genes, four subgroups were identified: quiescent, glycolytic, cholesterogenic, and mixed. Glycolytic tumors were associated with the shortest median survival in resectable (log-rank test P = 0.018) and metastatic settings (log-rank test P = 0.027). Patients with cholesterogenic tumors had the longest median survival. KRAS and MYC-amplified tumors had higher expression of glycolytic genes than tumors with normal or lost copies of the oncogenes (Wilcoxon rank sum test P = 0.015). Glycolytic tumors had the lowest expression of mitochondrial pyruvate carriers MPC1 and MPC2. Glycolytic and cholesterogenic gene expression correlated with the expression of prognostic PDAC subtype classifier genes. Conclusions: Metabolic classification specific to glycolytic and cholesterogenic pathways provides novel biological insight into previously established PDAC subtypes and may help develop personalized therapies targeting unique tumor metabolic profiles. See related commentary by Mehla and Singh, p. 6

Dose painting of hypoxic tumour sub-volumes using positron-emission tomography (PET) has been shown to improve tumour control in silico in several sites. Pancreatic cancer presents a more stringent challenge, given its proximity to critical organs-at-risk (OARs) and anatomic motion. A radiobiological model was developed to estimate clonogen survival fraction (SF), using 18F-fluoroazomycin arabinoside PET (FAZA PET) images from ten patients with pancreatic cancer to quantify oxygen enhancement effects. For each patient, four simulated five-fraction stereotactic body radiotherapy (SBRT) plans were generated: 1) a standard SBRT plan aiming to cover the planning target volume with 40 Gy, 2) dose painting plans delivering escalated doses to FAZA-avid hypoxic sub-volumes, 3) dose painting plans with simulated spacer separating the duodenum and pancreatic head, and 4), plans with integrated boosts to geometric contractions of the tumour (GTV). All plans saturated at least one OAR dose limit. SF was calculated for each plan and sensitivity of SF to simulated hypoxia quantification errors was evaluated. Dose painting resulted in a 55% reduction in SF as compared to standard SBRT; 78% with spacer. Integrated boosts to hypoxia-blind geometric contractions resulted in a 41% reduction in SF. The reduction in SF for dose-painting plans persisted for all hypoxia quantification parameters studied, including registration and rigid motion errors that resulted in shifts and rotations of the GTV and hypoxic sub-volumes by as much as 1 cm and 10 degrees. Although proximity to OARs ultimately limited dose escalation, with estimated SFs (~10^-5) well above levels required to completely ablate a ~10 cm^3 tumour, dose painting robustly reduced clonogen survival when accounting for expected treatment and imaging uncertainties and thus, may improve local response and associated morbidity.

Background As the treatment landscape in patients with non‐small cell lung cancer (NSCLC) harboring mutations in the epidermal growth factor receptor (EGFRm) continues to evolve, real‐world health utility scores (HUS) become increasingly important for economic analyses. Methods In an observational cohort study, questionnaires were completed in EGFRm NSCLC outpatients, to include demographics, EQ‐5D‐based HUS and patient‐reported toxicity and symptoms. Clinical and radiologic characteristics together with outcomes were extracted from chart review. The impact of health states, treatment type, toxicities, and clinical variables on HUS were evaluated. Results Between 2014 and 2018, a total of 260 patients completed 994 encounters. Across treatment groups, patients with disease progression had lower HUS compared to controlled disease (0.771 vs 0.803; P = .01). Patients predominantly received gefitinib as the first‐line EGFR tyrosine kinase inhibitor (TKI) (n = 157, mean‐HUS = 0.798), whereas osimertinib (n = 62, mean‐HUS = 0.806) and chemotherapy (n = 38, mean‐HUS = 0.721) were more likely used in subsequent treatment lines. In longitudinal analysis, TKIs retained high HUS (>0.78) compared to chemotherapy (HUS, Real‐world health utility scores (HUS) in epidermal growth factor receptor mutations (EGFRm) non‐small cell lung cancer outpatients were similar between those treated by first‐ and second‐line tyrosine kinase inhibitors, which were superior to chemotherapy. Treatment‐associated toxicities corresponded to HUS of treatment groups.

IntroductionTranscriptional analyses have identified several distinct molecular subtypes in pancreatic ductal adenocarcinoma (PDAC) that have prognostic and potential therapeutic significance. However, to date, an indepth, clinicomorphological correlation of these molecular subtypes has not been performed. We sought to identify specific morphological patterns to compare with known molecular subtypes, interrogate their biological significance, and furthermore reappraise the current grading system in PDAC.DesignWe first assessed 86 primary, chemotherapy-naive PDAC resection specimens with matched RNA-Seq data for specific, reproducible morphological patterns. Differential expression was applied to the gene expression data using the morphological features. We next compared the differentially expressed gene signatures with previously published molecular subtypes. Overall survival (OS) was correlated with the morphological and molecular subtypes.ResultsWe identified four morphological patterns that segregated into two components (‘gland forming’ and ‘non-gland forming’) based on the presence/absence of well-formed glands. A morphological cut-off (≥40% ‘non-gland forming’) was established using RNA-Seq data, which identified two groups (A and B) with gene signatures that correlated with known molecular subtypes. There was a significant difference in OS between the groups. The morphological groups remained significantly prognostic within cancers that were moderately differentiated and classified as ‘classical’ using RNA-Seq.ConclusionOur study has demonstrated that PDACs can be morphologically classified into distinct and biologically relevant categories which predict known molecular subtypes. These results provide the basis for an improved taxonomy of PDAC, which may lend itself to future treatment strategies and the development of deep learning models.

We hypothesize that the incidence of screen-detected lung cancer (LC), in participants with previously negative scans, will be highest in the cohort with the highest baseline risk score.Individuals with negative baseline screening results from the Princess Margaret International Early Lung Cancer Action Program before 2009 underwent low-dose computed tomography rescreening from 2015 to 2018. Individuals were contacted in order of descending risk, as determined by the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial's PLCOOf the 1261 participants we attempted to re-contact, 359 participants returned for a rescreening scan (mean of 7.6 years between scans). Participants were divided into low (2%), moderate (≥2% to3.5%), and high baseline risk (≥3.5%) cohorts. On average, those in the high-risk cohort compared to the moderate- and low-risk cohorts were older (66 years versus 62 and 59 years) and had a greater smoking history (54 pack-years versus 47 and 29 pack-years). The incidence of cancer in the high-risk cohort was significantly higher than in the moderate-risk cohort (11% versus 1.7%, p = 0.002).There was a significantly higher incidence of LC in the high-risk cohort than in the moderate-risk cohort. The cut-point between the high- and moderate-risk was determined to be greater than or equal to 3.5% of the 6-year baseline risk.

KEY POINTS The incidence of pancreatic ductal adenocarcinoma (PDAC) is rising and PDAC is projected to become the third leading cause of cancer death in Canada.[1][1] Although risk factors for PDAC are known, the reason for its rising incidence is not. Overall survival for this disease at 5 years

SummaryPancreatic ductal adenocarcinoma (PDAC) remains resistant to most treatments and demonstrates a complex pathobiology. Here, we deconvolute regional heterogeneity in the human PDAC tumor microenvironment (TME), a long-standing obstacle, to define precise stromal contributions to PDAC progression. Large scale integration of histology-guided multiOMICs with clinical data sets and functional in vitro models uncovers two microenvironmental programs in PDAC that were anchored in fibroblast differentiation states. These sub-tumor microenvironments (subTMEs) co-occurred intratumorally and were spatially confined, producing patient-specific cellular and molecular heterogeneity associated with shortened patient survival. Each subTME was uniquely structured to support discrete aspects of tumor biology: reactive regions rich in activated fibroblast communities were immune-hot and promoted aggressive tumor progression while deserted regions enriched in extracellular matrix supported tumor differentiation yet were markedly chemoprotective. In conclusion, PDAC regional heterogeneity derives from biologically distinct reactive and protective TME elements with a defined, active role in PDAC progression.Graphical Abstract & Key findingsPDAC regional heterogeneity originates in sub-tumor microenvironments (subTMEs)SubTMEs exhibit distinct immune phenotypes and CAF differentiation statesDifferent subTMEs are either tumor-promoting or chemoprotectiveIntratumoral subTME co-occurrence links stromal heterogeneity to patient outcome

Tyrosine kinase inhibitors (tkis) have dramatically improved the survival of patients with ALK-rearranged (ALK+) non-small-cell lung cancer (nsclc). Clinical trial data can generally compare drugs in a pair-wise fashion. Real-world collection of health utility data, symptoms, and toxicities allows for the direct comparison between multiple tki therapies in the population with ALK+ nsclc. In a prospective cohort study, outpatients with ALK+ recruited between 2014 and 2018, treated with a variety of tkis, were assessed every 3 months for clinico-demographic, patient-reported symptom and toxicity data and EQ-5D-derived health utility scores (hus). In 499 longitudinal encounters of 76 patients with ALK+ nsclc, each tki had stable longitudinal hus when disease was controlled, even after months to years: the mean overall hus for each tki ranged from 0.805 to 0.858, and longitudinally from 0.774 to 0.912, with higher values associated with second- or third-generation tkis of alectinib, brigatinib, and lorlatinib. Disease progression was associated with a mean hus decrease of 0.065 (95% confidence interval: 0.02 to 0.11). Health utility scores were inversely correlated to multiple symptoms or toxicities: rho values ranged from &minus, 0.094 to &minus, 0.557. Fewer symptoms and toxicities were associated with the second- and third-generation tkis compared with crizotinib. In multivariable analysis, only stable disease state and baseline Eastern Cooperative Oncology Group performance status were associated with improved hus. There was no significant decrease in hus when patients with ALK+ disease were treated longitudinally with each tki, as long as patients were clinically stable. Alectinib, brigatinib, and lorlatinib had the best toxicity profiles and exhibited high mean hus longitudinally in the real-world setting.

Background: Radiomic features in pancreatic ductal adenocarcinoma (PDAC) often lack validation in independent test sets or are limited to early or late stage disease. Given the lethal nature of PDAC it is possible that there are similarities in radiomic features of both early and advanced disease reflective of aggressive biology. Purpose: To assess the performance of prognostic radiomic features previously published in patients with resectable PDAC in a test set of patients with unresectable PDAC undergoing chemotherapy. Methods: The pre-treatment CT of 108 patients enrolled in a prospective chemotherapy trial were used as a test cohort for 2 previously published prognostic radiomic features in resectable PDAC (Sum Entropy and Cluster Tendency with square-root filter[Sqrt]). We assessed the performance of these 2 radiomic features for the prediction of overall survival (OS) and time to progression (TTP) using Cox proportional-hazard models. Results: Sqrt Cluster Tendency was significantly associated with outcome with a hazard ratio (HR) of 1.27(for primary pancreatic tumor plus local nodes), (Confidence Interval(CI):1.01 -1.6, P-value = 0.039) for OS and a HR of 1.25(CI:1.00 -1.55, P-value = 0.047) for TTP. Sum entropy was not associated with outcomes. Sqrt Cluster Tendency remained significant in multivariate analysis. Conclusion: The CT radiomic feature Sqrt Cluster Tendency, previously demonstrated to be prognostic in resectable PDAC, remained a significant prognostic factor for OS and TTP in a test set of unresectable PDAC patients. This radiomic feature warrants further investigation to understand its biologic correlates and CT applicability in PDAC patients.

Summary Around the world, recommendations for cancer treatment are being adapted in real time in response to the pandemic of COVID-19. We, as a multidisciplinary team, reviewed the standard management options, according to the Barcelona Clinic Liver Cancer classification system, for hepatocellular carcinoma. We propose treatment recommendations related to COVID-19 for the different stages of hepatocellular carcinoma (ie, 0, A, B, and C), specifically in relation to surgery, locoregional therapies, and systemic therapy. We suggest potential strategies to modify risk during the pandemic and aid multidisciplinary treatment decision making. We also review the multidisciplinary management of intrahepatic cholangiocarcinoma as a potentially curable and incurable diagnosis in the setting of COVID-19.

Central nervous system (CNS) metastases most commonly arise from lung cancer, with the majority of patients affected during their disease course. The prognosis for patients with untreated brain metastases is poor, with surgical resection and/or radiotherapy as classic therapeutic options. However, the value of systemic therapy in the management of CNS metastases from lung cancer is growing. Novel targeted agents for the treatment of non-small cell lung cancer (NSCLC) have demonstrated activity in treating patients with CNS involvement, and are potential alternatives to radiation and surgery. These agents include anaplastic lymphoma kinase (ALK) inhibitors such as alectinib, crizotinib, ceritinib, lorlatinib, and others; epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, including the recently developed third-generation inhibitor osimertinib, and even immune checkpoint inhibitors such as nivolumab, pembrolizumab, and atezolizumab. This review summarizes current activity of systemic agents in the management of CNS metastases from NSCLC, as well as potential mechanisms of action of these small and large molecules.

Pancreatic adenocarcinoma (PDAC) remains a highly fatal disease that is increasing in incidence. PDAC can be classified according to resectability status with 3 nonmetastatic groups defined: resectable, borderline resectable, and locally advanced PDAC (LAPC). Delineating these subtypes is important with the optimal treatment approach dictated by high-quality CT imaging and multidisciplinary team discussion. Patients with LAPC are thought unresectable and are therefore rarely cured. In these patients, chemotherapy remains the mainstay of treatment. Aggressive approaches in this cohort are increasingly employed. Local therapies after induction chemotherapy including standard fractionation radiation, stereotactic body radiotherapy (SBRT), and irreversible electroporation (IRE) are being investigated in an attempt to improve long-term control. In some cases, responses to neoadjuvant therapy may facilitate surgical resection. Biomarkers that can select patients most likely to benefit from these options are urgently needed. This review aims to highlight the emerging treatment of patients with LAPC and to discuss current trials.

Purpose Current guidelines recommend somatic genomic sequencing for patients with advanced pancreatic cancer to identify targetable alterations amenable to targeted therapy. The benefit of somatic genomic sequencing in pancreatic cancer remains unclear. This study aims to assess the evidence supporting genomic sequencing to inform treatment selection for patients with advanced pancreatic cancer. Methods A systematic review identified prospective studies of exocrine pancreatic cancer patients published before August 2020 which conducted genomic sequencing to inform treatment selection. Outcomes of interest included the proportion of patients with targetable alterations, the proportion that received targeted treatments, and the impact of targeted treatments on overall survival. Meta-analysis for proportions and hazard ratios was performed using Dersimonian and Laird random effect models. Results 19 studies (representing 2048 pancreatic cancer patients) were included. Sequencing methodologies, definitions of targetable alterations, and approaches treatment selection varied across studies and were incompletely reported. 590 of 1382 sequenced patients harboured a targetable alteration (random effects meta-analysis estimate of the proportion 0.46, 95% confidence interval 0.32–0.61). The proportion of patients with targetable alterations was highly heterogenous between studies (I2 93%, P Conclusions Genomic sequencing frequently identifies targetable alterations in pancreatic cancers. Further research is required to standardize the definitions of targetable alterations, the approach to treatment matching, and quantify the benefit of targeted therapy.

Intratumoral heterogeneity is a critical frontier in understanding how the tumor microenvironment (TME) propels malignant progression. We recently deconvoluted regional heterogeneity in the human PDAC stroma to assess its role in disease progression and discovered two types of ‘sub-tumor microenvironments’ (subTMEs), called ‘reactive’ and ‘deserted’. These histologically definable tissue states exhibit strong regional relationships with tumor immunity, subtypes, differentiation, and treatment response. Here, we set out to define their cell biological underpinnings through a combination of subTME-specific cancer-associated fibroblast (CAF) models, integrative histopathology, quantitative image analysis, multiOMICs, scRNAseq, and controlled functional assays. Remarkably, the growth patterns of CAF cultures closely recapitulated the characteristic histomorphology of their originating subTMEs, and these distinct phenotypes were accompanied by behavioral differences. Unsupervised graph-based clustering of scRNAseq profiles showed that CAFs largely grouped by their originating subTME yet comprised up to 10 individual clusters. The subTME-specific multi-subpopulation CAF communities self-organized into distinct ‘coordinated states’, represented by cluster-overarching functional profiles and distinct morpho-histological and behavioral phenotypes. These differences originated in cellular differentiation trajectories, with an ‘intermediate’ transitory state evident both in single cell transcriptomics and in situ. Noticeably, this CAF differentiation potential was associated with distinct tumor-related functions and, similar to stem cells, was marked by RNA diversity and pluripotency markers. Therefore, regional TME programs in PDAC appear to result largely from transitions between subpopulation-overarching fibroblast differentiation states that guide multifaceted CAF and immune cell communities into recurrent tissue self-organizational units. Citation Format: Barbara T. Grünwald, Curtis McCloskey, Antoine Devisme, Foram Vyas, Geoffroy Andrieux, Kazeera Aliar, Faiyaz Notta, Grainne O’Kane, Julie Wilson, Jennifer Knox, Sandra Fischer, Thomas Kislinger, Melanie Boerries, Steven Gallinger, Rama Khokha. Fibroblast differentiation trajectories elicit regional tissue states in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-107.

Intratumoral heterogeneity is a critical frontier in understanding how the tumor microenvironment (TME) propels malignant progression. Here, we deconvolute the human pancreatic TME through large-scale integration of histology-guided regional multiOMICs with clinical data and patient-derived preclinical models. We discover "subTMEs," histologically definable tissue states anchored in fibroblast plasticity, with regional relationships to tumor immunity, subtypes, differentiation, and treatment response. "Reactive" subTMEs rich in complex but functionally coordinated fibroblast communities were immune hot and inhabited by aggressive tumor cell phenotypes. The matrix-rich "deserted" subTMEs harbored fewer activated fibroblasts and tumor-suppressive features yet were markedly chemoprotective and enriched upon chemotherapy. SubTMEs originated in fibroblast differentiation trajectories, and transitory states were notable both in single-cell transcriptomics and in situ. The intratumoral co-occurrence of subTMEs produced patient-specific phenotypic and computationally predictable heterogeneity tightly linked to malignant biology. Therefore, heterogeneity within the plentiful, notorious pancreatic TME is not random but marks fundamental tissue organizational units.

Introduction: GATA6, a transcription factor involved in pancreaticogenesis, correlates with major transcriptomic subtypes of pancreatic cancer, and early evidence suggests a potential role as a prognostic biomarker. In this study, we tested whether semi-automated digital quantification of GATA6 immunohistochemistry (IHC) was associated with overall survival (OS) after surgical resection of pancreatic cancer in randomized trials of adjuvant chemotherapy. Materials and Methods: Tissue microarrays of pancreatic adenocarcinoma specimens were stained for GATA6 expression using IHC. Specimens came from patients in the ESPAC-3 and ESPAC-4 randomized phase III trials comparing adjuvant chemotherapy regimens. Two pathologists blinded to clinical data independently assessed GATA6 protein expression in cores using a customized computer algorithm from the open-source digital pathology software QuPath. Briefly, the digital assistant provided GATA6 IHC semiquantitative scores (0-4) for individual cells, which were made available to the pathologist for review. This semi-automated digital quantification of GATA6 expression was compared to manual quantification as previously reported (Grant et al., AACR Pancreatic Cancer, 2020). Concordance between pathologists across tissue cores was calculated using a weighted kappa statistic for scores 0 through 4, and an unweighted kappa statistic for high (3-4) and low (0-2) expression levels. Discrepancies were resolved through consensus. Median OS was estimated in GATA6 high and low subgroups using Kaplan-Meier curves. OS was compared using Cox proportional hazard regressions adjusting for adjuvant chemotherapy treatment, lymph node status, and post-operative CA-19-9. Results: GATA6 expression was quantified in 230 patients using the semi-automated digital and manual approaches. Inter-observer concordance markedly improved with digital assistance compared to the manual approach (weighted kappa statistic across all scores 0.69 versus 0.41, unweighted kappa statistic comparing high and low expression 0.71 versus 0.25). GATA6 expression measured using the semi-automated digital approach was significantly associated with OS: median OS was 25.7 months in GATA6 low cancers versus 42.4 months in GATA6 high cancers, with an adjusted hazard ratio of 1.58 (95% confidence interval 1.10-2.28, P=0.014). Conclusion: GATA6 IHC is a prognostic biomarker for pancreatic cancers treated with surgical resection and adjuvant chemotherapy that can be consistently and reliably quantified using digital assistance. Citation Format: Robert C. Grant, Kai Duan, Richard Jackson, William Greenhalf, Eithne Costello-Goldring, Paula Ghaneh, Christopher Halloran, Daniel Palmer, Thilo Hackert, Markus Buchler, Shawn Hutchison, Stephanie Ramotar, Anna Dodd, Julie Wilson, Faiyaz Notta, Grainne O'Kane, Jennifer Knox, John Neoptolemos, Steven Gallinger, Sandra Fischer. Digital quantification of GATA6 expression from immunohistochemistry is associated with overall survival after surgery for pancreatic cancer in the ESPAC trials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1193.

ILCCO Data Repository was supported by Cancer Care Ontario Research Chair of Population Health, National Institute of Health (U19 CA148127), and Lunenfeld-Tanenbuaum Research Institute, Sinai Health System. The Cancer de Pulmon en Asturias (CAPUA) study (PI: Adonina Tardón) was supported by Fondo de investigación sanitaria. Instituto de Salud Carlos III. Consorcio de Investigación Biomédica en Red (CIBER) del Área de Epidemiología y Salud Pública and University of Oviedo. The Environment And Genetics in Lung cancer Etiology (EAGLE) study (PI: Maria Teresa Landi) was supported by the Intramural Research Program of NIH, NCI, Division of Cancer Epidemiology and Genetics. The Epidemiology & Genetics of Lung cancer (EGLC) study (PI: Ping Yang) was supported by the National Cancer Institute and National Institute of Health (R03-CA77118, R01s-CA80127, CA84354, and HL107612). The Carotene and Retinol Efficacy Trial (CARET) (PIs: Gary E. Goodman, Chu Chen) was supported by the National Cancer Institute and National Institute of Health (5-UM1-CA-167462, U01-CA63673, and R01-CA111703) The Harvard Lung Cancer Study (LCS) (PI: David C. Christiani) was supported by National Institute of Health grants (R01CA092824, R01CA074386, and P30 ES000002) The Japan lung cancer study (PI: Kouya Shiraishi) was supported by the National Cancer Center Research and Development Fund (NCC Biobank). Kentucky Lung Cancer Research Initiative (LCRI) (PI: Susanne M. Arnold) was supported by the Department of Defense [Congressionally Directed Medical Research Program, U.S. Army Medical Research and Materiel Command Program] under award number: 10153006 (W81XWH-11-1-0781). This research was also supported by unrestricted infrastructure funds from the UK Center for Clinical and Translational Science, NIH grant UL1TR000117 and Markey Cancer Center NCI Cancer Center Support Grant (P30 CA177558) Shared Resource Facilities: Cancer Research Informatics, Biospecimen and Tissue Procurement, and Biostatistics and Bioinformatics. The Liverpool Lung Project (LLP) (PI: John K. Field) is supported by the Roy Castle Lung Cancer Foundation, UK. The work performed for the Toronto lung cancer study (PIs: Rayjean J. Hung, Geoffrey Liu) was supported by Ontario Institute for Cancer Research, the Canadian Cancer Society Research Institute (020214), Ontario Institute of Cancer and Cancer Care Ontario Chair Award to R.J.H. and G.L. and the Alan Brown Chair and Lusi Wong Programs at the Princess Margaret Hospital Foundation. The Total Lung Cancer (TLC) study (PI: Matthew B. Schabath) was supported by the following funding sources: James & Esther King Biomedical Research Program Grant (09KN-15), National Institutes of Health Specialized Programs of Research Excellence (SPORE) Grant (P50 CA119997), and an American Cancer Society Institutional Research Grant (93-032-13)., Lohavanichbutr, P., Sakoda, L.C., Amos, C.I., Arnold, S.M., Christiani, D.C., Davies, M.P.A., Field, J.K., Haura, E.B., Hung, R.J., Kohno, T., Landi, M.T., Liu, G., Liu, Y., Marcus, M.W., O'Kane, G.M., Schabath, M.B., Shiraishi, K., Slone, S.A., Tardón, A., Yang, P., Yoshida, K., Zhang, R., Zong, X., Goodman, G.E., Weiss, N.S., Chen, C.

Investigations of carcinogenesis have evolved from the identification of clonal driver mutations in candidate genes to the integration of large volumes of genomic and transcriptomic data revealing recurrently altered pathways and signatures of mutational processes. Inactivation of BRCA1, BRCA2, or PALB2 impairs efficient double-strand break repair (DSBR), giving rise to a spectrum of homologous recombination deficiency (HRD) cancer phenotypes. Harnessing HRD therapeutically has been promising in a number of tumors; these approaches include leveraging synthetic lethality by targeting alternative repair pathways via PARP inhibition, inducing HRD to modulate potential tumor vulnerabilities, and preventing mechanisms of drug resistance. It is therefore crucial to develop assays for accurate HRD detection and to broaden the patient population who can avail of novel treatment options.

Molecular profiling in advanced non-small cell lung cancer (NSCLC) has allowed for the detection of actionable mutations, which has revolutionized the treatment paradigm in this highly fatal disease. Mutations involving the epidermal growth factor receptor (EGFR) gene are most common and the 'classical mutations', exon 19 deletions and the point mutation L858R at exon 21, predict response to EGFR tyrosine kinase inhibitors (TKIs). The 'uncommon' EGFR mutations account for 10-18% of all EGFR mutations and primarily consist of exon 20 insertions, exon 18 point mutations and complex mutations. Improved detection techniques have broadened the spectrum of reported aberrations within the 'uncommon group' but response to TKIs is variable and not fully elucidated. This review provides an overview of the biology and incidence of uncommon EGFR mutations and summarizes reported outcomes when treated with EGFR-TKIs.

Reflex immunohistochemistry (rIHC) for mismatch repair (MMR) protein expression can be used as a screening tool to detect Lynch Syndrome (LS). Increasingly the mismatch repair‐deficient (dMMR) phenotype has therapeutic implications. We investigated the pattern and consequence of testing for dMMR in three Irish Cancer Centres (CCs). CRC databases were analyzed from January 2005–December 2013. CC1 performs IHC upon physician request, CC2 implemented rIHC in November 2008, and CC3 has been performing rIHC since 2004. The number of eligible patients referred to clinical genetic services (CGS), and the number of LS patients per center was determined. 3906 patients were included over a 9‐year period. dMMR CRCs were found in 32/153 (21%) of patients at CC1 and 55/536 (10%) at CC2, accounting for 3% and 5% of the CRC population, respectively. At CC3, 182/1737 patients (10%) had dMMR CRCs (P

Purpose: The molecular drivers of antitumor immunity in pancreatic ductal adenocarcinoma (PDAC) are poorly understood, posing a major obstacle for the identification of patients potentially amenable for immune-checkpoint blockade or other novel strategies. Here, we explore the association of chemokine expression with effector T-cell infiltration in PDAC. Experimental Design: Discovery cohorts comprised 113 primary resected PDAC and 107 PDAC liver metastases. Validation cohorts comprised 182 PDAC from The Cancer Genome Atlas and 92 PDACs from the Australian International Cancer Genome Consortium. We explored associations between immune cell counts by immunohistochemistry, chemokine expression, and transcriptional hallmarks of antitumor immunity by RNA sequencing (RNA-seq), and mutational burden by whole-genome sequencing. Results: Among all known human chemokines, a coregulated set of four (CCL4, CCL5, CXCL9, and CXCL10) was strongly associated with CD8+ T-cell infiltration (P < 0.001). Expression of this “4-chemokine signature” positively correlated with transcriptional metrics of T-cell activation (ZAP70, ITK, and IL2RB), cytolytic activity (GZMA and PRF1), and immunosuppression (PDL1, PD1, CTLA4, TIM3, TIGIT, LAG3, FASLG, and IDO1). Furthermore, the 4-chemokine signature marked tumors with increased T-cell activation scores (MHC I presentation, T-cell/APC costimulation) and elevated expression of innate immune sensing pathways involved in T-cell priming (STING and NLRP3 inflammasome pathways, BATF3-driven dendritic cells). Importantly, expression of this 4-chemokine signature was consistently indicative of a T-cell–inflamed phenotype across primary PDAC and PDAC liver metastases. Conclusions: A conserved 4-chemokine signature marks resectable and metastatic PDAC tumors with an active antitumor phenotype. This could have implications for the appropriate selection of PDAC patients in immunotherapy trials.

Background Peripheral blood sampling for detection of EGFR T790M in cell-free circulating tumour (ct) DNA in TKI-resistant EGFR mutant (EGFRm) lung cancer is now standard. The value of more comprehensive sequencing is unknown. Methods Prospective ctDNA analysis in patients with EGFRm NSCLC was performed using a next generation sequencing (NGS) panel of regions of 11 genes detecting single nucleotide variants and small insertions/deletions at ≥0.1% variant allele frequency (VAF) was performed. Patients were grouped according to treatment phase, including: (A) pre EGFR-TKI, (B) stable or responding to EGFR-TKI, (C) radiographic progression during EGFR-TKI, and (D) during chemotherapy treatment. Results Seventy-two patients with stage IV EGFRm NSCLC were enrolled and first blood samples were analysed. Primary sensitizing mutations in del19 or L858R were present in 66 (92%) and uncommon EGFRm in 6 (8%). Mutations in ctDNA were found in 53 samples (74%). T790M was detected in 3 of 4 patients with T790M-negative tissue. Other co-occurring EGFRm were found in 10 patients (7%) including K745R during first-line osimertinib. TP53 (n = 10), KRAS (n = 1), PI3KCA (n = 1) and ALK (n = 3) gene mutations also were detected. The presence of an EGFRm (excluding T790M) was associated with untreated or progressive disease, p = 0.04. In TKI-treated patients without radiologic progression, median progression free survival (PFS) was 10 months versus 2.1 months (HR 2.22, 95% CI: 0.89–5.54, p = 0.08) if an EGFRm in ctDNA was detected. If T790M was present in ctDNA, median PFS was 3.0 months versus 9.7 months (HR 4.59, 95% CI: 1.43–14.73, p = 0.005). High % VAF of both EGFRm and T790M correlated with inferior PFS (p = 0.01 and p = 0.03 respectively). Conclusion In addition to the emergence of resistance mutations, the presence of the primary or co-occurring EGFRm in patients receiving EGFR-TKIs may associate with shorter PFS and may be useful in longitudinal analyses of ctDNA to direct therapy.

3003 Background: NRG1 fusion proteins are oncogenic drivers in pancreas cancer and other solid tumors. They bind HER3, leading to HER2/HER3 heterodimerization and oncogenic transformation. The activity of zenocutuzumab (MCLA-128; zeno), a bispecific antibody targeting NRG1 fusion signaling in NRG1 fusion positive ( NRG1+) cancers, is being evaluated in the ongoing global multicenter phase 2 part of the eNRGy study and a global early access program (EAP). Methods: Enrolled patients (pts) have advanced NRG1+ pancreas cancer, non-small cell lung cancer (NSCLC), and other solid tumors previously treated with standard therapy, are ≥ 18 years-old, have ECOG ≤1, adequate organ function, and measurable disease (RECIST v1.1). Zeno dosing: 750 mg IV every 2 weeks until progression or unacceptable toxicity. Primary endpoint: investigator (INV)-assessed objective response rate (ORR). Secondary endpoints: ORR per central independent radiologist review, duration of response (DOR), and safety. Tumor imaging is conducted every 8 weeks. Results: 51 pts with NRG1+ cancer have received zeno, 37 in the eNRGy study and 14 pts in the EAP. As of 12 Jan 2021, treatment is ongoing in 27/51 pts (8/13 pancreas, 10/25 NSCLC, 9/13 other solid tumors). Among the 51 pts, 10 pts with pancreas cancer, 18 pts with NSCLC, and 5 pts with other solid tumors had measurable disease and had the opportunity for ≥1 tumor assessment (TA) and are included in this analysis. Among the 10 pts with pancreas cancer, median age was 49 y (range 34-72), 50% were male, 6/4 pts had ECOG 0/1, and all had metastatic disease and were KRAS wild-type. The median number of prior therapies was 3 (range 1-6). The INV-assessed confirmed ORR was 40% (4/10; 90% CI, 15;70), and for this cohort of pts, responses occurred at the first TA. Tumor regression was seen in 7/10 pts, and the disease control rate was 90% (90% CI, 61-100). A CA 19-9 decline of ≥ 50% was observed in 9/9 (100%) pts. DOR is pending. In the overall NRG1+ population, tumor regression was observed in 25 of 33 pts and confirmed INV-assessed responses were seen in 9 of 33 pts (ORR 27%; 90% CI, 15;43), including in pts who previously received afatinib. Zeno was well tolerated with no pts requiring dose reduction for toxicity. Across all cohorts, for individual AEs, grade 3 events were reported in ≤5% of pts, and there was a notable lack of cardiotoxicity and severe gastrointestinal or skin toxicity. Updated data from all cohorts (pancreas, NSCLC, other solid tumors) will be presented. Conclusions: Zeno induces rapid and major radiologic tumor regression and biomarker responses in heavily-pretreated metastatic KRAS wild-type NRG1+ pancreas cancer, with minimal toxicity. Zeno is a promising novel targeted therapeutic option for pts with NRG1+ cancers. Clinical trial information: NCT02912949.

4142 Background: KRAS mutations (m) (KRASm) are present in over 90% of pancreatic adenocarcinomas (PDAC) with a predominance of G12 substitutions. KRAS wildtype (WT) PDAC relies on alternate oncogenic drivers, and the prognostic impact of these remains unknown. We evaluated alterations in WT PDAC and explored the impact of specific KRASm and WT status on survival. Methods: WGS and RNAseq were performed on 570 patients (pts) ascertained through our translational research program from 2012-2021, of which 443 were included for overall survival (OS) analyses. This included 176 pts with resected and 267 pts with advanced PDAC enrolled on the COMPASS trial (NCT02750657). The latter cohort underwent biopsies prior to treatment with first line gemcitabine-nab-paclitaxel or mFOLFIRINOX as per physician choice. The Kaplan-Meier and Cox proportional hazards methods were used to estimate OS. Results: KRAS WT PDAC (n = 52) represented 9% of pts, and these cases trended to be younger than pts with KRASm (median age 61 vs 65 years p = 0.1). In resected cases, the most common alterations in WT PDAC (n = 23) included GNASm (n = 6) and BRAFm/fusions (n = 5). In advanced WT PDAC (n = 27), alterations in BRAF (n = 11) and ERBB2/3/4 (n = 6) were most prevalent. Oncogenic fusions (NTRK, NRG1, BRAF/RAF, ROS1, others) were identified in 9 pts. The BRAF in-frame deletion p.486_491del represented the most common single variant in WT PDAC, with organoid profiling revealing sensitivity to both 3rd generation BRAF inhibitors and MEK inhibition. In resected PDAC, multivariable analyses documented higher stage (p = 0.043), lack of adjuvant chemotherapy (p < 0.001), and the KRAS G12D variant (p = 0.004) as poor prognostic variables. In advanced disease, neither WT PDAC nor KRAS specific alleles had an impact on prognosis (median OS WT = 8.5 mths, G12D = 8.2, G12V = 10.0, G12R = 12.0, others = 9.2, p = 0.73); the basal-like RNA subtype conferred inferior OS (p < 0.001). A targeted therapeutic approach following first line chemotherapy was undertaken in 10% of pts with advanced PDAC: MMRd (n = 1), homologous recombination deficiency (HRD) (n = 19), KRASG12C (n = 1), CDK4/6 amplification (n = 3), ERBB family alterations (n = 2), BRAF variants (n = 2). OS in this group was superior (14.7 vs 8.8 mths, p = 0.04), mainly driven by HRD-PDAC where KRASm were present in 89%. Conclusions: In our dataset, KRAS G12D is associated with inferior OS in resected PDAC, however KRAS mutational status was not prognostic in advanced disease. This suggests that improved OS in the WT PDAC population can only be achieved if there is accelerated access to targeted drugs for pts.

4011 Background: Human equilibrative nucleoside transporter 1 (hENT1) belongs to a family of nucleoside transporters critical to entry of gemcitabine into cells. The prognostic and predictive characteristics of this biomarker in pancreatic ductal adenocarcinoma (PDAC) have primarily been evaluated by immunohistochemistry, with conflicting results. We explored the impact of hENT1 gene expression in the Comprehensive Molecular Characterization of Advanced Ductal Pancreas Adenocarcinoma for Better Treatment Selection (COMPASS) trial. Methods: Patients were enrolled on COMPASS from December 2015 to June 2020 and underwent a biopsy for whole genome sequencing (WGS) and RNA sequencing prior to first chemotherapy in the advanced setting. Biopsies underwent laser capture microdissection to enrich for tumour epithelium. Chemotherapy regimen was determined based on clinician preference. The cut-off thresholds for hENT1 expression were determined using the maximal chi-squared statistic. Response rates and overall survival (OS) were computed based on hENT1 expression and chemotherapy regimen. Results: 254 patients were included in the analyses with a median follow-up time of 18 months. 146 patients were treated with modified FOLFIRINOX (FFX), 104 with gemcitabine and nab-paclitaxel (GnP), and 16 received no systemic therapy. Based on gene expression levels, 133 patients were classified as hENT1 high and 121 as hENT1 low. hENT1 expression was significantly associated with the modified Moffitt classifier with higher expression seen in classical tumours (p < 0.001). In the entire cohort, median OS was 10.0 months in hENT1 high vs. 8.3 months in hENT1 low (adjusted HR 0.78, 95% confidence interval 0.59 - 1.03, p = 0.08). In patients receiving modified FFX, there was no difference in response rates (32% vs. 31%, p = 1.00) or OS (10.6 vs. 10.6 months, p = 0.94) between the hENT1 high and hENT1 low groups, respectively. However, in patient treated with GnP, response rates were significantly higher in hENT1 high patients compared to those with hENT1 low tumors (45% vs. 21%, p = 0.035). Median OS in this GnP treated cohort was 9.8 months in hENT1 high vs. 6.1 months hENT1 low (p = 0.003). In an interaction analysis, hENT was predictive of treatment response to GnP (p = 0.0002). Conclusions: Biomarkers predictive of response to GnP and FFX are urgently needed. Here we demonstrate that hENT1 gene expression is a predictor of response to GnP in advanced PDAC.

396 Background: BRCA1/2 and PALB2 are genes critical to the faithful repair of double strand breaks through the homologous recombination repair (HRR) pathway. Alterations in these genes serve as predictive biomarkers to both platinum and PARP inhibitors. Ataxia-telangiectasia mutated ( ATM) is also indirectly involved in HRR; however, its role as a predictive biomarker to DNA damage response agents is debated. Herein we evaluated the genomic characteristics and clinical outcomes of patients with ATM alterations on the Comprehensive Molecular Characterization of Advanced Ductal Pancreas Adenocarcinoma for Better Treatment Selection (COMPASS) trial. Methods: Patients on this study undergo a biopsy for whole genome sequencing (WGS) and RNA sequencing prior to chemotherapy; those with germline variants in ATM were reviewed by a genetics counsellor and defined as pathogenic, likely pathogenic, variant of unknown significance (VUS) or benign/likely benign. Genomic characteristics were reviewed and published classifiers of homologous recombination deficiency (HRD) were applied to all cases and included the percentage of substitution base signature (SBS) 3, the HRDetect score, the computed algorithm of large scale transitions, telomeric allelic imbalances and loss of heterozygosity (LOH), otherwise known as the genomic instability score (GIS). Results: As of January 2020, 304 patients were enrolled and 245 patients had both WGS and clinical data available. 86 germline variants in ATM were present in 70 patients. The majority of these (80%) were classified as benign or likely benign. 10 VUS were detected and 4 patients (2%) had pathogenic/likely pathogenic variants (PV). Of these 4 patients, LOH or a second somatic hit was evident in 1 case. Upon review of the PVs and VUS, SBS were consistent with typical PDAC and tumour mutational burden was low. HRDetect scores were low ( < 0.1) for 13/14 cases with either a VUS or PV; one VUS without biallelic loss, had a high HRDetect score, with presence of SBS 3 and a high GIS. This particular case was also found to have a tandem duplicator phenotype. None of the 4 cases with PV had evidence of HRD. Furthermore all four were treated with platinum based regimens without evidence of response. Conclusions: In a large series of sequenced pancreatic cancers, the presence of pathogenic germline variants in ATM was rare, with none of the cases demonstrating evidence of HRD. This suggests that this population is unlikely to benefit from PARP inhibition.

430 Background: Familial pancreatic cancer (FPC) is broadly defined as kindreds with at least a pair of first-degree relatives with pancreatic ductal adenocarcinoma (PDA). The role of DNA damage response agents, including platinum has not been well studied in this patient population. Methods: In this retrospective analysis, treatment details and clinical outcomes were analyzed in pts with FPC with advanced, unresectable or recurrent disease enrolled in the Ontario Pancreatic Cancer Study database. The primary outcome, overall survival (OS) was calculated from the initial diagnosis of advanced disease until death. 179 non-FPC patients from the COMPASS trial [NCT02750657] served as a control cohort all of whom had full molecular profiling and family history documented. OS between pts that received platinum-based therapy, and those that did not was compared using multivariable Cox proportional hazards model adjusting for age, sex, diagnosis year and FPC status. Interaction between FPC status and platinum was evaluated. Results: A total of 205 FPC pts were identified, 71% of pts had full germline testing and 16 (8%) had germline pathogenic variants in BRCA1/2. 104 (51%) were female and 101 (49%) male. Median age was 63 years (20-93) and 58 (28%) received platinum-based chemotherapy. Within the control arm (n=179), 71 (40%) were female, and 108 (60%) male; the median age was 64 years (29-84) and 106 (59%) received platinum-based therapy. In univariable analysis, median OS in pts with FPC was 16.9 months compared to 9.6 months (HR 0.46 [95% CI 0.37-0.58]). FPC patients receiving platinum had a superior median OS of 19 months compared to 15.5 months without platinum. In a multivariable analysis, both FPC (HR 0.33 [95% CI 0.21-0.51]) and receipt of platinum HR 0.53 [95% CI 0.38-0.73]) were prognostic. No interaction was seen with FPC and receipt of platinum (p=0.15). Conclusions: FPC status is prognostic but not predictive of platinum response in this study. Further molecular profiling of this unique cohort of patients will provide insights into putative predisposing germline alterations, and novel treatment strategies.

340 Background: Cholangiocarcinoma (CCA) is a lethal malignancy with limited treatment options. Molecular profiling of these tumours has revealed a number of actionable mutations and four clusters have been defined through integrative genomic analysis. We sought to explore whole genome sequencing (WGS) data in 20 patients enriched for CCA arising in the setting of cirrhosis or inflammatory disorders. Methods: A previously established Biliary Tract Cancer (BTC) database at the Princess Margaret Cancer Centre (PMCC)/University Health Network (UHN) was used to identify patients of clinical interest including long-term survivors, those with germ-line mutations, and those with chronic inflammatory disorders. WGS and bioinformatic analyses were performed at the Ontario Institute for Cancer Research. Results: The 20 resected samples included 12 patients (pts) with intrahepatic CCA, 7 perihilar CCA, and 1 distal CCA. 8 pts were alive > 8 years post resection and one patient harboured a germline MLH1 pathogenic variant (MLH1 G67R). 3 pts had documented cirrhosis (hepatitis B n = 2, haemochromatosis n = 1); other inflammatory disorders (n = 4) included ulcerative colitis (UC) without documented PSC (n = 1), PSC alone (n = 1), UC with PSC (n = 1), and ankylosing spondylitis (n = 1). The remaining cases were randomly selected. The predominant COSMIC single base substitution (SBS) mutational signatures were 1, 8 and 5, and the median TMB was 1.75 mutations per MB (0.73-33.23). The pt with an MLH1 mutation exhibited a TMB of 33.23 with predominance of SBS26. Actionable variants were enriched in the 8 pts who are alive and disease free including 2 predicted FGFR fusions and mutations in IDH1 (n = 1), BRAF V600E (n = 1), and BAP1 (n = 1). TP53 mutations (n = 7) were present exclusively in patients with cirrhosis or inflammatory disorders and the median survival in the group was 12 months (3 -21 months). Although SBS signatures were similar in this group, in the two cases of UC, SBS17 (unknown etiology) was evident. SBS17 was also dominant in one case where the TMB was 13 mutations per MB and the patient died within 3 months of diagnosis. A somatic case of homologous recombination deficiency, with no causative genetic alteration identified, was evident in a further patient receiving maintenance rituximab for a coexisting stage 4 mantle cell lymphoma. Conclusions: WGS may provide additional biological information in CCA particularly in patients with underlying inflammatory disorders, where TP53 mutations are prevalent and mutational signatures are distinct.

TPS145 Background: Although most cancers are initially susceptible to existing anticancer therapies, over time cancer cells develop resistance. BOLD-100 is a first-in-class therapy that targets the GRP78 pathway, a major regulator of cellular stress and resistance. This therapy suppresses drug resistance, survival and proliferation by restraining stress-induced upregulation of GRP78 in tumor cells, leading to inhibition of the cell survival response. BOLD-100 successfully completed a Phase 1 monotherapy trial, with a manageable safety profile; it has demonstrated synergy in established preclinical models in combination with a wide variety of anticancer therapies and shown to restore sensitivity of drug-resistant cell lines. Methods: BOLD-100-001 is a multicenter, prospective, two-stage, non-randomized Phase 1b dose escalation and expansion study of BOLD-100 in combination with FOLFOX chemotherapy for selected advanced solid gastrointestinal (GI) tumors: colorectal (CRC), pancreatic (PANC), gastric (GC) and bile duct cancers (BDC). Each patient will receive BOLD-100 along with FOLFOX chemotherapy on Day 1 of each 14-day cycle. In the dose-escalation phase (Part A), patients will be enrolled to determine the combination recommended dose using a standard 3+3 design. In the dose-expansion phase (Part B), up to 80 patients with selected GI tumors will be enrolled in 5 cohorts (comprising the 4 GI cancers referred) and treated with BOLD-100 at the recommended dose and FOLFOX, until progressive disease or unacceptable toxicity. In Part A dose-escalation, the primary objective is to assess the safety, tolerability and maximum tolerated dose. The Part B dose-expansion will assess the efficacy (progression free survival, overall survival and response rate), of FOLFOX chemotherapy plus BOLD-100. Secondary objectives in Part A and B include the assessment of pharmacokinetic and pharmacodynamic parameters and potential biomarkers predictive of efficacy. Eligible patients will have previously treated histologically/cytologically confirmed metastatic/unresectable GI tumor (CRC, PANC, GC or BDC), measurable disease per RECIST criteria, an ECOG performance score of 0 or 1, and adequate organ function. In Part A, no formal statistical hypotheses will be tested; analysis of the data will focus on comparisons of safety and dose-limiting toxicities between cohorts and only descriptive methods will be used. In Part B, Bayesian modelling will be used to continually reassess the efficacy endpoints: progression free survival, overall survival and objective response rates. The study was opened for enrollment in August 2020; approximately 25-30 patients will be screened to achieve up to 20 patients in Part A and up to 80 patients will be enrolled in Part B with a maximum of 25 patients per arm. Clinical trial information: NCT04421820.

Brain metastases occur in approximately half of patients with non-small cell lung cancer (NSCLC) and are associated with a poor prognosis and an inferior quality of life. Historically systemic therapy has had a limited role in CNS disease with a reliance placed on local treatments. The emergence of targeted therapies and immune checkpoint inhibitors (ICIs) in recent years has dramatically changed the treatment landscape of NSCLC. Programmed cell death-1 (PD-1) inhibitors have demonstrated efficacy in three randomized trials and now represent standard second line therapy after platinum failure. Trials have largely excluded patients with symptomatic or untreated CNS disease as the brain has been considered an 'immune-privileged' organ. We review the evidence and future prospects of ICIs in treating brain metastases in NSCLC.

Keywords: pancreatic cancer, patient-derived organoids, transcriptomic signatures, PASS-01 Background: Patients with advanced pancreatic ductal adenocarcinoma (PDAC) continue to have a dire prognosis and only a minority of patients is fit enough to receive second-line treatment. Using patient-derived organoids (PDOs), we have identified transcriptomic signatures of chemotherapy sensitivity that may be able to stratify patients such that they receive maximal benefit from the currently approved, first-line chemotherapy regimens [1-3]. We will now test this hypothesis in the Pancreatic Adenocarcinoma Signature Stratification for treatment (PASS) – 01 trial, which is a multi-institutional randomized phase II trial between FOLFIRINOX (mFFX) and gemcitabine/nab-paclitaxel (GA). Methods: The overall aim of PASS-01 is to evaluate biomarkers and gene signatures that may predict response to mFFX and GA. The primary objective is to determine the progression free survival (PFS) benefit of mFFX compared to GA. Using 1:1 randomization, 131 evaluable patients with untreated metastatic PDAC will be recruited to provide 80% power to detect a 2-month improvement in PFS with mFFX (one-sided alpha 0.2). Secondary and exploratory objectives include determine the objective response rate, duration of response and overall survival associated with mFFX or GA, whether the chemotherapy sensitivity signature predictions correlate with responders, if PDO transcriptomic profiles parallel those obtained from patient samples, whether GATA6 expression can serve as a biomarker of response [4], the use of serial cell free circulating tumor DNA and circulating tumour cell analysis to identify emerging or de novo resistance and evaluate biomarkers of immune-oncologic sensitivity. The main inclusion and exclusion criteria are similar to major efficacy trials, with the mandatory requirement that a minimum of 4 x 18G good quality tumour core biopsies can be safely obtainable under CT or US guidance. At progression, as per RECIST 1.1 criteria, chemotherapy sensitivity signatures (RNA) and/or PDO pharmacotyping and WGS data will be used where possible to guide second-line therapy in an effort to continually provide the most active therapeutic regimens to each patient. The trial is anticipated to open Q4 2020. Conclusions: PASS-01 will provide candidate biomarkers and gene signatures that predict response to mFFX and GA, which will be further investigated in a subsequent adaptive, stratified trial.

Pancreatic ductal adenocarcinoma (PDAC) remains mostly untreatable while its incidence is on the rise. PDAC stroma should be a reservoir for novel therapeutic targets. Yet, stromal cellular complexity and an extensive intratumoral heterogeneity in human patients have left the functions of PDAC stroma poorly understood and likely hamper its targeting. Here, we set out to deconvolute regional heterogeneity in human PDAC stroma and assess its role in disease progression. Using resected & advanced biospecimens with known patient outcome, we mapped the stromal and epithelial landscapes of PDAC by combining integrative histopathology, quantitative image analysis of a 30-marker IHC panel, genomics and proteomics, machine learning, scRNAseq of PDAC-derived fibroblasts, and controlled functional assays. This histology-guided multidimensional approach revealed two overarching types of sub-tumormicroenvironments (subTMEs) in PDAC, present across stages and primary and metastatic sites. These subTMEs co-occurred intratumourally but were spatially confined, producing patient-specific cellular and molecular heterogeneity in PDAC stroma. SubTME-resolved IHC characterization of PDAC specimens and multiplexed functional analyses with subTME-specific patient-derived fibroblasts and organoids then identified how both microenvironmental programs were uniquely structured to support crucial aspects of tumour biology. Forming a complementary stromal support system, reactive subTME regions rich in fibroblasts and immune cells were vascularized and promoted features of aggressive tumour progression, while protective subTME regions enriched in ECM supported tumour differentiation yet were markedly chemoprotective and translated into poor treatment response during 1st line chemotherapy. Consequently, tumours benefited from concomitant presence of both subTMEs and patients with phenotypically heterogenous stroma displayed shortened survival. Our patient-matched multidimensional data were then used to train a Random Forest model for prediction of subTME presence from bulk RNAseq samples. This again stratified PDAC patients in the independent TCGA cohort into distinct clinical outcomes by stromal phenotypic heterogeneity. In conclusion, we have delineated human PDAC stroma to subtype its heterogeneity into phenotypically distinct reactive and protective elements. This defines the active role of two overarching sub-microenvironment types in PDAC progression and sets a path towards developing novel stroma-instructed therapies. Citation Format: Barbara T. Grünwald, Antoine Devisme, Foram Vyas, Geoffroy Andrieux, Gun Ho Jang, Kazeera Aliar, Curtis McCloskey, Andrew Macklin, Joan Miguel Romero, Laura Tamblyn, Nikolina Radulovich, Peter Bronsert, Grainne O’Kane, Julie Wilson, Jennifer Knox, Sandra Fischer, Thomas Kislinger, Melanie Boerries, Steven Gallinger, Rama Khokha. Stromal phenotypic heterogeneity fosters pancreatic cancer progression [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PR-002.

Introduction No biomarker is clinically available to predict prognosis after surgical resection of pancreatic cancer beyond CA-19-9, a classical tumor marker. GATA6 is a transcription factor necessary for pancreaticogenesis that associates with the major transcriptomic subtypes of pancreatic cancer. In this study, we evaluated the prognostic utility of GATA6 expression in randomised adjuvant chemotherapy trials. Materials and Methods We retrospectively analyzed resection specimens in tissue microarrays from patients who participated in two international randomized phase III trials of adjuvant chemotherapy after resection of pancreatic ductal adenocarcinoma: ESPAC-3, which compared fluorouracil plus folinic acid with gemcitabine; and ESPAC-4, which compared gemcitabine plus capecitabine with gemcitabine alone. GATA6 expression was measured using immunohistochemistry. Expression levels from 0 to 4 were scored through consensus between two pathologists who were blinded to clinical characteristics and outcome. Concordance on each tissue core was assessed using a weighted kappa score. Overall survival (OS) was assessed using Kaplan-Meier curves and compared between GATA6 expression levels using univariate Cox proportional hazard regression models and multivariate models that adjusted for lymph node status, post-operative CA-19-9, and treatment arms. After an initial analysis of all five levels, expression levels were regrouped into low (0-2) and high (3-4). Our primary objective was to assess for a prognostic association between GATA6 and OS. Secondary analyses considered predictive associations with the addition of capecitabine to gemcitabine using an interaction term, and associations with baseline characteristics using Wilcoxon and Fisher-exact tests. Results: 26 patients from ESPAC-3 and 205 patients from ESPAC-4 were included. 7, 18, 130, 74, and 2 patients had GATA6 expression levels of 0, 1, 2, 3, and 4, respectively. Concordance between pathologists was moderate (weighted kappa 0.41). GATA6 expression was significantly associated with overall survival when regrouped into low (0–2, N=155) and high (3–4, N=76) expression. Low GATA6 expression was associated with shorter OS (median OS 26.1 months, 95% confidence interval (CI) 22.9–30.4 versus 42.4 months, 95% CI 30.2–56.5, univariate hazard ratio (HR) 1.70, 95% CI 1.31–2.41, P=0.002), which persisted after adjustment for potential confounders (multivariate HR 1.57, 95% CI 1.09–2.62, P=0.016). GATA6 expression was not significantly associated with baseline characteristics or predictive of differential benefit from the addition of capecitabine to gemcitabine. Conclusion: Low GATA6 expression is significantly associated with inferior OS after surgical resection of pancreatic cancer. Future research will automate the measurement of GATA6 expression using image analyses. Citation Format: Robert C. Grant, Kai Duan, Richard Jackson, William Greenhalf, Eithne Costello-Goldring, Paula Ghaneh, Christopher Halloran, Daniel Palmer, Thilo Hackert, Markus Buchler, Shawn Hutchison, Stephanie Ramotar, Anna Dodd, Julie Wilson, Faiyaz Notta, Grainne O'Kane, Jennifer Knox, John Neoptolemos, Steven Gallinger, Sandra Fischer. GATA6 expression is prognostic after surgical resection of pancreatic cancer: results from the ESPAC trials [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-005.

Background: Predictors of response to DNA damaging agents may expand the population of patients who could benefit from platinum and/or PARP inhibition in pancreatic cancer (PDAC). The HRDetect score derived from whole genome sequencing (WGS) incorporates patterns of substitution base signatures and structural variation and is associated with tumours deficient in homologous recombination repair (HRD). Methods: The prospective COMPASS trial (NCT 02750657) enrolls patients with advanced PDAC prior to systemic treatment for WGS and RNAseq. Choice of combination chemotherapy is at the discretion of the physician. HRD tumours are identified by the presence of a number of known genomic characteristics including evidence of biallelic inactivation of BRCA/PALB2 or the RAD51 family of genes, the presence of signature 3, the number and proportion of indels that are deletions of at least 4 base pairs (bp), and the presence of rearrangement signatures 3 and 5. We ascertained the number of patients with high HRDetect scores (>0.7) and evaluated outcomes and response to chemotherapy including platinum regimens. Results: As of 1st May 2019 204 eligible patients were enrolled. High HRDetect scores (HRDetecthi ) were present in 26/204 (13%). Only half of these cases were represented by HRD tumours including: 9 germline BRCA1/2 or PALB2 cases with biallelic inactivation and 3 tumours with somatic biallelic inactivation of BRCA2, RAD51C and XRCC2. 1 additional HRD case was of unknown aetiology. All HRD cases were HRDetecthi. Two germline carriers of BRCA2 without a second somatic hit were HR intact with low HRDetect scores. Of the remaining 13 non-HRD tumours identified as HRDetecthi, 6 exhibited a tandem duplicator phenotype (TDP) with tandem duplications ranging from 10Kbp to 1Mbp in size. These tumours did not have any other genomic characteristics of HRD. Notably, of the 204 patients included in this analysis, a TDP was present in 15 (7%), of which 40% were HRDetecthi. In patients treated with modified FOLFIRINOX(mFFX) (n=111, *includes 2 patients treated with cisplatin/gemcitabine) the response rate in HRDetecthi patients (n=16) was 56% vs 20% in HRDetectlo patients (n=95) p=0.005. There was no difference in response rates according to HRDetect score in patients treated with gemcitabine-nab-paclitaxel; HRDetecthi (n=7) 14.3% vs. HRDetectlo(n=71) 32.8%, p=0.42. Median OS in all patients receiving mFFX (n=111) was 10.2 months; in patients with HRDetecthi PDAC, median OS was 15.5 mths vs. 9.9 mths in HRDetectlo PDAC, (HR 0.42, 95% CI 0.24-0.87, p=0.01). In all patients (n=78) receiving gemcitabine based combination treatment the median OS was 8.1 mths; in HRDetecthi patients median OS was 11.5mths vs 7.8 mths in HRDetectlo patients (HR 0.94, 95% CI 0.42-2.13, p=0.8). Conclusions: In patients with advanced PDAC with high HRDetect scores, response rate to FFX is over 50% and survival is significantly longer compared to patients with PDAC and low HRDetect scores. HRDetect identifies an additional population of patients with non-HRD PDAC who benefit from DNA damaging agents. Citation Format: Grainne M. O'Kane, Robert E. Denroche, Amy Zhang, Sarah Picardo, Robert C. Grant, MIchael J. Allen, Gun Ho Jang, Yifan Wang, Anna Dodd, Stephanie Rampotar, Shawn Hutchinson, Mustaphe Tehfe, James J. Biagi, Dianne Chadwick, Bernard Lam, Julie Wilson, Faiyaz Notta, Sandra E. Fischer, George Zogopoulos, Steven Gallinger, Jennifer J. Knox. HRDetect as a predictive score of platinum response in advanced PDAC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5465.

Background: Emergence of the EGFR T790M mutation accounts for acquired first generation EGFR TKI resistance in over half of patients with EGFR mutant NSCLC. In patients without emergent T790M, resistance mechanisms are less well understood. We explored the impact of DNA methylation status and TKI treatment failure in these patients. Methods: Using a prospective cohort of patients with acquired TKI resistance, tumour tissue samples pre/post TKI exposure were identified. DNA was extracted from FFPE tissue using the Qiagen AllPrep DNA/RNA FFPE Extraction Protocol, and subsequently analyzed using the Illumina Infinium EPIC array. Raw microarray data files were processed using the software package minfi for data normalization (Illumina method) and extraction of methylation levels (M-values). Samples were split into two groups according to the T790M status of each sample (T790M + or T790M-). The set of most informative probes, those whose M-value profiles align most closely with the T790M status of the study samples, was generated by selecting the 1,000 probes with lowest ANOVA's p-value. The stability of the resulting sample clustering was assessed by hierarchical clustering (Euclidean distance), classification with internal cross-validation (SVM leave-one-out), and non-parametric dimensional reduction (t-SNE). Results: 40 samples from 36 EGFR mutant NSCLC patients were successfully profiled. Pre TKI samples were available in 10 patients with an EGFR mutation of which 4 had matched post TKI tissue (3 T790M+, 1 T790M-). The remaining 26 samples in post TKI patients included 17 T790M + and 9 T790M- cases. A DNA methylation-based signature was developed by selecting the array probes that best discriminated T790M+ from T790M- cases. Group membership was stable, as shown by cross-validation by three different methods (hierarchical clustering, SVM leave-one-out and t-SNE). The 1,000 probe cut-off was arbitrarily selected; however, identical sample clusters were obtained using 500 or 2,000 methylation array probes. When analyzing the genomic location of the set of probes that form the signature, we found broad distribution across all chromosomes, thus, ruling out the possibility of selection bias due to focal or chromosome-level aberrations. Several genes contained a higher number of the selected probes, including EGFR, whose expression levels are known to be regulated at the methylation level in certain cancer types. Cluster analysis using the 1,000-probe signature revealed a high degree of concordance between EGFR T790M and DNA methylation status. All post-TKI (n=20) T790M+ samples concentrated within epi-group 2, whereas 8/10 T790M- samples were found within epi-group 1. Of the 4 patients with matched samples, 2 had baseline samples within epi-group 2 and went on to develop EGFR T790M post TKI. Of the 2 with baseline samples within epi-group 1, one went on to develop T790M (post-TKI epigroup 2) and one did not (post-TKI epigroup 1). Conclusions: We observed a concordance between T790M status and epi-group suggesting that the development of resistance to EGFR-TKIs may be associated with distinct DNA methylation signatures. This signature may be present at baseline and predict for subsequent emergence of T790M. Citation Format: Grainne M. O'Kane, Alberto J. León, Muqdas Shabir, Jennifer H. Law, Penelope A. Bradbury, Geoff Liu, Adrian Sacher, Frances A. Shepherd, Dax Torti, Tracy L. Stockley, Ming Tsao, Trevor J. Pugh, Natasha B. Leighl. Methylation signatures associated with T790M status in progressive NSCLC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1869.