KRAS Allelic Variants in Biliary Tract Cancers

Importance

Biliary tract cancers (BTCs) contain several actionable molecular alterations, including FGFR2, IDH1, ERBB2 (formerly HER2), and KRAS. KRAS allelic variants are found in 20% to 30% of BTCs, and multiple KRAS inhibitors are currently under clinical investigation.

Objectives

To describe the genomic landscape, co-sequence variations, immunophenotype, genomic ancestry, and survival outcomes of KRAS-mutated BTCs and to calculate the median overall survival (mOS) for the most common allelic variants.

Design, Setting, and Participants

This retrospective, multicenter, pooled cohort study obtained clinical and next-generation sequencing data from multiple databases between January 1, 2017, and December 31, 2022. These databases included Princess Margaret Cancer Centre, MD Anderson Cancer Center, Foundation Medicine, American Association for Cancer Research Project GENIE, and cBioPortal for Cancer Genomics. The cohort comprised patients with BTCs who underwent genomic testing.

Main Outcome and Measure

The main outcome was mOS, defined as date of diagnosis to date of death, which was measured in months.

Results

A total of 7457 patients (n = 3773 males [50.6%]; mean [SD] age, 63 [5] years) with BTCs and genomic testing were included. Of these patients, 5813 had clinical outcome data available, in whom 1000 KRAS-mutated BTCs were identified. KRAS allelic variants were highly prevalent in perihilar cholangiocarcinoma (28.6%) and extrahepatic cholangiocarcinoma (36.1%). Thirty-six KRAS allelic variants were identified, and the prevalence rates in descending order were G12D (41%), G12V (23%), and Q61H (8%). The variant G12D had the highest mOS of 25.1 (95% CI, 22.0-33.0) months compared with 22.8 (95% CI, 19.6-31.4) months for Q61H and 17.8 (95% CI, 16.3-23.1) months for G12V variants. The majority of KRAS-mutated BTCs (98.9%) were not microsatellite instability-high and had low tumor mutational burden (ranging from a median [IQR] of 1.2 (1.2-2.5) to a mean [SD] of 3.3 [1.3]). Immune profiling through RNA sequencing of KRAS and NRAS-mutated samples showed a pattern toward a more immune-inflamed microenvironment with higher M1 macrophage activation (0.16 vs 0.12; P = .047) and interferon-γ expression compared with wild-type tumors. The G12D variant remained the most common KRAS allelic variant in all patient ancestries. Patients with admixed American ancestry had the highest proportion of G12D variant (45.0%).

Conclusions and Relevance

This cohort study found that KRAS allelic variants were relatively common and may be potentially actionable genomic alterations in patients with BTCs, especially perihilar cholangiocarcinoma and extrahepatic cholangiocarcinoma. The findings add to the growing data on genomic and immune landscapes of KRAS allelic variants in BTCs and are potentially of value to the planning of specific therapies for this heterogeneous patient group.

Plasma Growth Hormone as a Prognostic Biomarker to Durvalumab and Tremelimumab in Patients with Advanced Hepatocellular Carcinoma

Introduction

In this study, we explored the potential of plasma growth hormone (GH) as a prognostic biomarker in patients with advanced HCC treated with durvalumab plus tremelimumab (D+T).

Methods

In this study, we included 16 patients with advanced HCC who received D+T at MD Anderson Cancer Center between 2022 and 2023 and had plasma GH measurements recorded before treatment. Plasma GH levels were measured from prospectively collected blood samples and were correlated with progression-free survival (PFS) and overall survival (OS). The cutoff for normal GH levels in women and men was defined as ≤3.7 μg/L and ≤0.9 μg/L, respectively. The Kaplan-Meier method was employed to compute the median OS and PFS, while the Log rank test was applied to compare the survival outcomes between the GH-high and GH-low groups.

Results

Sixteen patients were included in this analysis, two female and fourteen male, with a median age of 65.5 years. At the time of the analysis, the 6-month OS rate was 100% among GH-low patients (6 patients) and 30% among GH-high patients (10 patients). OS was significantly longer in GH-low patients (not evaluable) compared to GH-high patients (3.94 months) (p = 0.030). PFS was also significantly longer in GH-low patients (not evaluable) compared to the GH-high patients (1.87 months) (p = 0.036).

Conclusion

Plasma GH is a prognostic biomarker in patients with advanced HCC treated with D+T. Given the relatively small patient cohort size, this finding should be further validated in larger randomized clinical trials in advanced HCC patients.

The Gut Microbiome as a Biomarker and Therapeutic Target in Hepatocellular Carcinoma

The microbiome is pivotal in maintaining health and influencing disease by modulating essential inflammatory and immune responses. Hepatocellular carcinoma (HCC), ranking as the third most common cause of cancer-related fatalities globally, is influenced by the gut microbiome through bidirectional interactions between the gut and liver, as evidenced in both mouse models and human studies. Consequently, biomarkers based on gut microbiota represent promising non-invasive tools for the early detection of HCC. There is a growing body of evidence suggesting that the composition of the gut microbiota may play a role in the efficacy of immunotherapy in different types of cancer; thus, it could be used as a predictive biomarker. In this review, we will dissect the gut microbiome's role as a potential predictive and diagnostic marker in HCC and evaluate the latest progress in leveraging the gut microbiome as a novel therapeutic avenue for HCC patients, with a special emphasis on immunotherapy.

Pancreatic tail cancer in the setting of pancreatitis with a review of the literature: A case report

Environmental risk factors for pancreatic cancer include acute and chronic pancreatitis, obesity, and tobacco use. Differentiating a pancreatic neoplasm in a patient with pancreatitis can be challenging due to their similar presentations. A 57-year-old African American man with a history of congestive heart failure, pancreatitis, and incomplete pancreas divisum presented with an epigastric abdominal pain that radiated to his back. Imaging showed necrotizing pancreatitis, a developing splenic infarct, and a mass at the pancreas tail. The patient was discharged with pain medications and was recommended follow-up imaging after resolution of his pancreatitis. He was readmitted to the emergency department 2 weeks later with recurrent acute abdominal pain. Computed tomography scan of abdomen and pelvis followed by magnetic resonance imaging and endoscopic ultrasound revealed an infiltrative pancreatic tail mass. Biopsy of the mass confirmed a locally advanced pancreatic tail adenocarcinoma. Chronic pancreatitis is associated with pancreatic cancer. Practitioners should be aware of the co-existence of chronic pancreatitis and pancreatic cancer, and the initial steps to evaluate a malignancy in chronic pancreatitis.

Clinical and Prognostic Biomarker Value of Blood-Circulating Inflammatory Cytokines in Hepatocellular Carcinoma

INTRODUCTION

Circulating inflammatory cytokines play critical roles in tumor-associated inflammation and immune responses. Recent data have suggested that several interleukins (ILs) mediate carcinogenesis in hepatocellular carcinoma (HCC). However, the predictive and prognostic value of circulating ILs is yet to be validated. Our study aimed to evaluate the association of the serum ILs with overall survival (OS) and clinicopathologic features in a large cohort of HCC patients.

METHODS

We prospectively collected data and serum samples from 767 HCC patients treated at the University of Texas MD Anderson Cancer Center between 2001 and 2014, with a median follow-up of 67.4 months (95% confidence interval [CI]: 52.5, 83.3). Biomarker association with OS was evaluated by the log-rank method.

RESULTS

The median OS in this cohort was 14.2 months (95% CI: 12, 16.1 months). Clinicopathologic features were more advanced, and OS was significantly inferior in patients with high circulating levels of IL1-R1, IL-6, IL-8, IL-10, IL-15, IL-16, and IL-18.

CONCLUSION

Our study shows that several serum IL levels are valid prognostic biomarker candidates and potential targets for therapy in HCC.

Efficacy of adjuvant fluoropyrimidine with or without oxaliplatin therapy in older adults with mismatch repair deficient stage III colorectal cancer

112

Background: Standard adjuvant chemotherapy regimens for Stage III colorectal cancer (CRC) include FOLFOX/CAPOX, 5-FU/capecitabine, or observation alone. There is uncertainty around the therapeutic benefit of adding oxaliplatin to fluorouracil in older adults over the age of 70 with Stage III CRC, including in those with mismatch repair–deficient (MMR-D) CRC. In this single institutional study, we evaluate progression free survival (PFS) across a 12-year period in patients who receive FOLFOX/CAPOX or 5-FU/capecitabine compared to active surveillance in older adults with MMR-D Stage III CRC. Methods: We identified patients diagnosed with MMR-D Stage III CRC after the age of 70 who received care at our institution and affiliates between 2005-2019. We performed a retrospective chart review of patient outcomes during the 12-year follow up period based on chemotherapy regimen to determine PFS. Patients without MMR-D staining performed at initial time of diagnosis had MMR protein immunohistochemistry performed currently and included in the analysis. Results: Among patients with MMR-D stage III CRC, 50%, 62.5%, and 76% of patients were alive at the end of year 12 with no disease progression in the observation, 5-FU/capecitabine, and FOLFOX/CAPOX groups. The PFS probabilities at one year are 69.6%, 87.5%, and 87.0%, and at five years are 41.8%, 62.5%, and 87.0% in these groups, respectively. Finally, there was a statistically significant difference (P=0.039) in PFS across all chemotherapy regimens in the MMR-D cohort. Conclusions: Based on this study, older adult patients with stage III MMR-D colorectal cancer have an improved progression free survival when treated with oxaliplatin containing chemotherapy compared to active surveillance alone. [Table: see text]

Randomized phase II trial of encorafenib and cetuximab with or without nivolumab for patients with previously treated, microsatellite stable, BRAFV600E metastatic and/or unresectable colorectal cancer: SWOG S2107

TPS265

Background: Patients with microsatellite stable (MSS), BRAFV600E metastatic colorectal cancer (mCRC) experience poor survival outcomes. Treatment with the BRAF inhibitor encorafenib (E) and anti-EGFR antibody cetuximab (C) is an approved treatment combination, with a reported overall response rate (ORR) of 20% and median progression-free survival (PFS) of 4.1 months. Anti-PD-1 antibodies like nivolumab (N) are ineffective as monotherapy for patients with MSS, BRAFV600E mCRC. In preclinical models of MSS, BRAFV600E CRC, inhibition of BRAF and EGFR induces a loss of expression of mismatch repair genes and promotes a microsatellite instability-high phenotype, which may prime these tumors for response to immunotherapy. In support of these findings, a single-institution clinical trial of E + C + N for 26 patients with MSS, BRAFV600E mCRC reported an ORR of 50% and median PFS of 7.2 months. We hypothesize that the addition of N to E + C will improve median PFS for patients with MSS, BRAFV600E mCRC. Methods: In this prospective phase II clinical trial (N = 75), patients with previously treated MSS, BRAFV600E mCRC will be randomized 2:1 into 2 arms, respectively: experimental treatment (E + C + N) or standard treatment (E + C). No prior BRAF, EGFR, or immunotherapy agents are allowed. All patients will receive E (300 mg PO daily) and C (500 mg/m2 IV every 14 days), and patients in the experimental arm will receive N (480 mg IV every 28 days). The primary endpoint is PFS. Secondary endpoints include overall survival, best overall response, duration of response, and safety/tolerability. Using a one-sided α = .10 and power 80%, we target an improvement in median PFS from 4.2 to 7.3 months and a hazard ratio of 0.57. Additional patient specimens will be collected for exploratory correlative research. The study activated across the United States in June 2022 and as of September 2022 has enrolled 2 of 75 planned participants. Funding: NIH/National Cancer Institute grants U10CA180888, U10CA180819, U10CA180820, U10CA180821, U10CA180868; and in part by The Hope Foundation for Cancer Research STrS award. Clinical trial information: NCT05308446 .

Bleeding and thrombotic events in patients with colorectal cancer treated with bevacizumab and receiving novel oral anticoagulants and antiplatelet medications

104

Background: Bevacizumab is a humanized monoclonal VEGF antibody given in combination with fluorouracil-based chemotherapy for metastatic colorectal cancer (mCRC). Many patients with mCRC also have cardiovascular comorbidities requiring anticoagulation or antiplatelet therapy. The bleeding and thrombotic event rates in the setting of concurrent novel oral anticoagulants (NOACs) and bevacizumab treatment in patients with mCRC remain unclear. Methods: 462 patients with mCRC at Barnes-Jewish Hospital were identified between December 1, 2016 and December 1, 2021 and screened for concurrent treatment with bevacizumab and anticoagulant or antiplatelet therapy. Demographic and clinical information was extracted by electronic chart review. Results: 21 patients were identified who received bevacizumab and either apixaban or rivaroxaban for mCRC treatment. Aspirin was prescribed in some of these patients within 3 years of starting apixaban or rivaroxaban. Of the 13 patients who had no history of aspirin prescription, 9 were given apixaban, and 4 were given rivaroxaban while on bevacizumab. 44.4% of the patients who received apixaban experienced bleeding. All these events were epistaxis, and only 25% of the cases resulted in any treatment discontinuation. 75% of the patients who received rivaroxaban experienced bleeding events, which 33.3% of the time resulted in discontinuation of either rivaroxaban or bevacizumab. We also looked at 8 patients who had received aspirin in the last three years: 7 patients were on apixaban, and one was on rivaroxaban while on concomitant aspirin and bevacizumab. 28.6% of the patients who received apixaban with bevacizumab and aspirin experienced an adverse bleeding event that resulted in some form of treatment discontinuation. Meanwhile, the patient who received rivaroxaban with bevacizumab and aspirin experienced a bleeding event that resulted in discontinuation of a medication. No patient experienced any adverse thrombotic events. Conclusions: Patients with mCRC treated with bevacizumab and apixaban with no history of prior aspirin use within three years have a relatively low risk of developing bleeding events that warrant treatment discontinuation. The addition of NOAC to bevacizumab therapy does not appear to increase the risk of adverse thrombotic events.

Immune checkpoint inhibitors unleash pathogenic immune responses against the microbiota

Immune checkpoint inhibitors (ICIs) are essential components of the cancer therapeutic armamentarium. While ICIs have demonstrated remarkable clinical responses, they can be accompanied by immune-related adverse events (irAEs). These inflammatory side effects are of unclear etiology and impact virtually all organ systems, with the most common being sites colonized by the microbiota such as the skin and gastrointestinal tract. Here, we establish a mouse model of commensal bacteria-driven skin irAEs and demonstrate that immune checkpoint inhibition unleashes commensal-specific inflammatory T cell responses. These aberrant responses were dependent on production of IL-17 by commensal-specific T cells and induced pathology that recapitulated the cutaneous inflammation seen in patients treated with ICIs. Importantly, aberrant T cell responses unleashed by ICIs were sufficient to perpetuate inflammatory memory responses to the microbiota months following the cessation of treatment. Altogether, we have established a mouse model of skin irAEs and reveal that ICIs unleash aberrant immune responses against skin commensals, with long-lasting inflammatory consequences.

Phase I trial of CA-4948, an IRAK4 inhibitor, in combination with FOLFOX/PD-1 inhibitor +/- trastuzumab for untreated unresectable gastric and esophageal cancer

TPS4168

Background: Activated NFκB has been linked to aggressive phenotype, poor survival outcomes and resistance to chemotherapy in multiple gastrointestinal cancers including gastroesophageal cancer (GEC). Preclinical studies established that: 1) Genotoxic stress incurred by chemotherapy induces TLR9, which signals through IRAK4 to drive pro-survival NFκB signaling; 2) The survival mechanism through IRAK4 is independent of cancer types and mutational profiles based on colorectal and pancreatic cancer models; and 3) IRAK4 inhibition reduces tumor desmoplasia and revitalizes intratumoral T cells, setting the stage for successful combination with immune checkpoint inhibitors in a highly aggressive autochthonous pancreatic cancer mouse model. These data combined provide a strong rationale to add CA-4948 to systemic therapy for multiple advanced gastrointestinal malignancies, where resistance to chemotherapy is inevitable and benefit of PD-1 inhibitors is limited to small population. CA-4948 is a novel, first-in-class reversible inhibitor of IRAK4. In a phase I trial, patients with relapsed/refractory hematologic malignancies tolerated CA-4948 monotherapy well with mild fatigue, neutropenia, and nausea as most common adverse events. Recommended phase 2 dose (RP2D) was determined as 300 mg orally twice daily. CA-4948 has not been tested in combination with cytotoxic chemotherapy or immune checkpoint inhibitors for solid tumors in clinic. We hypothesize that inhibition of IRAK4 with CA-4948 will potentiate the effect of immune checkpoint inhibitor while deepening the efficacy of cytotoxic chemotherapy in GEC. Methods: This is a phase I trial of CA-4948 in combination with FOLFOX/PD-1 inhibitor with or without trastuzumab for unresectable GEC. During Dose Escalation, we will investigate CA-4948 in combination with FOLFOX/nivolumab by BOIN algorithm evaluating 4 different dose levels. Starting dose of CA-4948 for Part A will be 200 mg twice daily. Once RP2D is determined, the study will proceed to Dose Expansion, including Cohorts A and B. Cohort A will enroll up to 12 patients with HER2 negative disease at the RP2D of CA-4948 determined at the Dose Escalation phase. Cohort B will investigate CA-4948 in combination with FOLFOX/pembrolizumab and trastuzumab. The initial 6 patients in Cohort B will be considered safety lead-in to confirm the safety and tolerability at the RP2D, followed by additional patients, up to 12 patients treated at the RP2D. The primary objective is to determine the safety and RP2D of CA-4948 in combination with FOLFOX/PD-1 inhibitor with or without trastuzumab. Secondary objectives are to determine the preliminary efficacy of the combination. Correlative studies to evaluate pharmacodynamic effects and to identify biomarkers associated with disease response are planned. Clinical trial information: NCT05187182.

Clinician utilization of a plasma-only, multiomic minimal residual disease (MRD) assay in 2,000 consecutive patients with colorectal cancer (CRC)

e15586

Background: Circulating tumor DNA (ctDNA) for detection of MRD in resected CRC is a prognostic factor for recurrence. However, current utilization of available commercial tests has not been investigated. We report real world clinician use of a validated, plasma-only, multiomic MRD assay (Guardant Reveal) in a large unselected CRC cohort. Methods: Results from Guardant Reveal MRD testing ordered for clinical care in the US were retrospectively queried for the first 2,000 consecutive CRC cases. Pts could be enrolled in a post-operative program to inform adjuvant treatment (PostOP, up to 3 tests within 3-16 weeks post-resection) or a surveillance program (SP) for recurrent tests post-treatment. Pts could have tests across both programs and/or one-time tests. All subsequent tests for the first 2,000 patients were included for analysis (data cut-off: 1/15/2022). Recurrent programs were analyzed for stage (stg) II/III only. Clinical factors were derived from test requisition forms. Results: 2681 tests from 1993 pts were analyzed; 7 pts were excluded due to missing cancer stage. Median age was 64 years (range: 21-65), 55% were male, most (94%) had stg II/III disease (Table). ctDNA was detected in 25% of all pts; detection increased with stage (Table) as expected. Among stg II/III pts, 330 (21%) had only PostOP test/s, 950 (51%) SP only, 54 (3%) had both PostOP and SP; the remainder had one-time test/s outside defined programs. In Stg II/III pts with >1 PostOP test (26%/17% respectively), ctDNA was detected in 102/384 (27%), of whom 72% had it detected on the first test. The median time from surgery to first result was 5 weeks (10 weeks for a second result). 95% of all stg II/III pts had results from PostOP testing before week 12 post-resection. In Stg II/III pts with >1 SP test (47%/54% respectively), ctDNA was detected in 244/1024 (24%), of whom 87% had it detected on a first test. The average time from date of surgery to first surveillance test was 305 days (median: 489, range:51-4618). Conclusions: ctDNA detection rates by a plasma-only multiomic MRD assay in this large CRC clinical cohort are similar to published rates. ctDNA orders by clinicians were most frequent in Stg II/III surveillance settings followed by PostOp, consistent with the population size of eligible patients for PostOp vs. Surveillance use-case. Importantly, nearly all pts tested PostOP had results prior to 12 weeks post-resection, which may inform adjuvant therapy decisions. These findings should be correlated with clinical outcomes to improve the utilization and utility of MRD testing in adjuvant management of CRC. [Table: see text]

Evolving Paradigms in the Systemic Treatment of Advanced Gallbladder Cancer: Updates in Year 2022

Gallbladder cancer (GBC) is a biological, anatomical, and clinically distinct subset of biliary tract cancers (BTC), which also include extra- and intra-hepatic cholangiocarcinoma. The advent of next-generation sequencing (NGS) clearly shows that GBC is genetically different from cholangiocarcinoma. Although GBC is a relatively rare cancer, it is highly aggressive and carries a grave prognosis. To date, complete surgical resection remains the only path for cure but is limited to patients with early-stage disease. The majority of the patients are diagnosed at an advanced, inoperable stage when systemic treatment is administered as an attempt to enable surgery or for palliation. Gemcitabine and platinum-based chemotherapies have been the main treatment modality for unresectable, locally advanced, and metastatic gallbladder cancer. However, over the past decade, the treatment paradigm has evolved. These include the introduction of newer chemotherapeutic strategies after progression on frontline chemotherapy, incorporation of targeted therapeutics towards driver mutations of genes including HER2, FGFR, BRAF, as well as approaches to unleash host anti-tumor immunity using immune checkpoint inhibitors. Notably, due to the rarity of BTC in general, most clinical trials included both GBC and cholangiocarcinomas. Here, we provide a review on the pathogenesis of GBC, past and current systemic treatment options focusing specifically on GBC, clinical trials tailored towards its genetic mutations, and emerging treatment strategies based on promising recent clinical studies.

A randomized phase II trial of nab-paclitaxel and gemcitabine with tarextumab or placebo in patients with untreated metastatic pancreatic cancer

Purpose

Notch signaling dysregulation is implicated in the development of pancreatic adenocarcinoma (PDAC). Tarextumab is a fully human IgG2 antibody that inhibits Notch2/3 receptors.

Patients and Methods

Aphase 2, randomized, placebo‐controlled, multicenter trial evaluated the activity of tarextumab in combination with nab‐paclitaxel and gemcitabine in patients with metastatic PDAC. Patients were stratified based on ECOG performance score and Ca 19‐9 level and randomized 1:1 to nab‐paclitaxel, gemcitabine with either tarextumab or placebo. Based on preclinical and phase Ib results suggesting a positive correlation between Notch3 gene expression and tarextumab anti‐tumor activity, patients were also divided into subgroups of low, intermediate, and high Notch3 gene expression. Primary endpoint was overall survival (OS) in all and in patients with the three Notch3 gene expression subgroups (≥25th, ≥50% and ≥75% percentiles); secondary end points included progression‐free survival (PFS), 12‐month OS, overall response rate (ORR), and safety and biomarker investigation.

Results

Median OS was 6.4 months in the tarextumab group vs 7.9 months in the placebo group (HR = 1.34 [95% CI = 0.95, 1.89], P = .0985). No difference observed in OS in the Notch3 gene expression subgroups. PFS in the tarextumab‐treated group (3.7 months) was significantly shorter compared with the placebo group (5.5 months) (hazard ratio was 1.43 [95% CI = 1.01, 2.01]; P = .04). Grade 3 diarrhea and thrombocytopenia were more common in the tarextumab group.

Conclusions

The addition of tarextumab to nab‐paclitaxel and gemcitabine did not improve OS, PFS, or ORR in first‐line metastatic PDAC, and PFS was specifically statistically worse in the tarextumab‐treated patients.

Clinical trial registry no

NCT01647828.

Circulating tumor cell (CTC) enumeration in patients (pts) with metastatic genitourinary (mGU) tumors treated in a phase I study of cabozantinib and nivolumab (CaboNivo) +/- ipilimumab (CaboNivoIpi)

4555

Background: CTCs may serve as biomarkers for clinical outcomes in GU tumor pts. We examined the association between baseline CTC enumeration, CTC heterogeneity, CTC morphologic subtypes, and progression-free-survival, overall survival and response to therapy with combination CaboNivo or CaboNivoIpi. Methods: 123 samples from 52 pts with mGU tumors treated with CaboNivo (38 pts) or CaboNivoIpi (14 pts) drawn at Baseline, Cycle (C) 2 Day (D) 1, and C3D1 were processed using the Epic Sciences platform. CTCs were defined as cytokeratin (CK)+, CD45-, distinct morphology, intact nucleus. PD-L1 expression was also assessed. Results: From 07/20/2016-09/01/2018, 52 pts [urothelial carcinoma (UC) N = 33; plasmacytoid N = 1; Clear cell renal cell carcinoma N = 4; bladder adenocarcinoma N = 8; bladder squamous cell carcinoma N = 2; bladder small cell N = 2; renal medullary N = 2] were treated. Median age was 61.5 years (range 20-82); 35 (67%) were male. N = 37 (71%) had visceral involvement, N = 15 (29%) with liver involvement, N = 11 (21%) with bone involvement. CTCs were found in the peripheral blood of 26/40 (65%) pts at baseline. 1/40 pts (bladder adenocarcinoma) had PDL1+ CTCs at Baseline. Median CTC/mL at Baseline, C2D1, C3D1, were not significantly different. CTC counts of > 2 and > 4 at C2D1 were potentially associated with shorter OS (p = 0.071 and p = 0.045 without adjustment for multiple cutoffs for evaluation). PFS results exhibited similar trends. Unsupervised clustering of CTC images identified 5 main CTC subtypes, of which the presence of one was significantly associated with shorter OS (p = 0.0014, not adjusted for multiple testing). Additionally, we observed a trend towards patients with higher CTC heterogeneity at C2D1 having longer OS, when adjusting for the risk associated with CTC enumeration (p = 0.084). Conclusions: CTC were detected in pts with mGU tumors treated with CaboNivo and CaboNivoIpi. CTC values were somewhat but not statistically lower in responders vs. non-responders. On treatment lower CTCs and the absence of aggressive CTC subtypes were associated with better clinical outcomes. Ongoing analyses include single cell genomics, and analysis of T-cell populations. Clinical trial information: NCT02496208.

Acquired resistance to immunotherapy in MMR-D pancreatic cancer

Background

MMR-D pancreatic cancer have been reported to respond to checkpoint inhibitor therapy. Here, we report the first case of acquired resistance to immunotherapy in MMR-D pancreatic cancer.

Case presentation

A 45-year-old woman with unresectable MMR-D pancreatic cancer was initially treated with FOLFIRINOX, FOLFIRI, and stereotactic body radiation with stable disease burden. After 3 months, imaging showed progression of disease with an increase in CA19-9. She was subsequently enrolled in a clinical trial of an anti-PD-L1 antibody in combination with an IDO1 inhibitor. She demonstrated a partial response to therapy by RECIST 1.1 criteria with declining tumor markers. Twenty-two months after beginning immunotherapy, imaging revealed an increasing left ovarian cystic mass. There were no other sites of progressive disease. The patient underwent a total hysterectomy and bilateral salpingo-oophorectomy, appendectomy, omentectomy and pelvic lymphadenopathy. Pathology was consistent with a metastasis from the pancreas involving the endometrium and left ovary. Thereafter, the patient continued with PD-1 blockade therapy off protocol with no further progressive disease. Immune profiling showed high levels of CD8+ T cells and PD-1 positive immune cells infiltrating the tumor, with a moderate level of PD-L1 expression in both the immune cells and the tumor cells. Next generation sequencing found only the KRAS G12D and RNF43 G659Vfs*41 mutations were retained from the pre-treatment tumor in the treatment-resistant tumor.

Conclusions

This is the first report describing acquired resistance to immunotherapy in MMR-D pancreatic cancer with accompanying genomic and immune profiling. This case of oligoprogression in the setting of immunotherapy demonstrates the feasibility of localized treatment followed by continuation of immunotherapy to sustain ongoing response.

Immunotherapy in pancreatic ductal adenocarcinoma: an emerging entity?

The genomic-plasticity of the immune system creates a broad immune repertoire engaged to tackle cancer cells. Promising clinical activity has been observed with several immune therapy strategies in solid tumors including melanoma, lung, kidney, and bladder cancers, albeit as yet immunotherapy-based treatment approaches in pancreatic ductal adenocarcinoma (PDAC) remain to have proven value. While translational and early clinical studies have demonstrated activation of antitumor immunity, most recent late-phase clinical trials have not confirmed the early promise in PDAC except in MSI-High PDAC patients. These results may in part be explained by multiple factors, including the poorly immunogenic nature of PDAC along with immune privilege, the complex tumor microenvironment, and the genetic plasticity of PDAC cells. These challenges have led to disappointments in the field, nonetheless they have also advanced our understanding that may tailor the future steps for immunotherapy for PDAC. Therefore, there is significant hope that progress is on the horizon.

Clinical characterization of pancreatic ductal adenocarcinomas (PDAC) with mismatch repair (MMR) gene mutations

e15791

Background: Tumors with mismatch repair-deficiency (MMRD) have a high mutational burden and have good responses to immunotherapy (Le, NEJM, 2015). We describe the natural course, clinicopathological, and genomic status of MMRD PDAC patients (pts) at Memorial Sloan Kettering Cancer Center (MSKCC). Methods: MSKCC institutional registry and ICD billing database queried from 2006-2016 for PDAC pts with genetically confirmed mutations in mismatch repair (MMR) genes. Mutation # determined via MSK-IMPACT, a targeted tumor next generation sequencing (NGS) test (Cheng, J Mol Diagn, 2015). Results: 5/607 (0.8%) PDAC pts had Lynch syndrome (LS) (confirmed germline mutations) (Table 1). Of the 5 LS pts, all had > 10 mutations in NGS, with 4 of 5 having > 50 mutations. 4 of 5 (80%) are alive at last follow-up (survival 30-314 months). N=4 had extensive personal/family history of cancer. Of N=3 who had resected disease, all 3 had recurrence at 11, 49 and 311 months, and all are alive (survival: 69-314 months). Of N= 2 pts that had unresectable tumors, one passed away at 30 months while the other is on checkpoint inhibitor trial and is alive at 30 months. In contrast, 7/607 (1.1%) PDAC pts had somatic mutations in MMR genes with an average of 5.7 mutations in NGS, with 4/7 having <5 mutations. 4/7 (57%) are deceased at last follow-up (survival: 10-42 months). Conclusions: All cases with germline mutations in the MMR genes, with one exception, had high mutation #. All cases with somatic mutations in the MMR genes had low mutation #. Germline mutations in MMR genes and high mutational burden may predict for a prognostically favorable subgroup of PDAC pts with high susceptibility to immune oncology agents. [Table: see text]

Intracystic Papillary Carcinoma of the Breast in a Male Patient

We report a case of intracystic papillary carcinoma of the right breast in a 59-year old man presenting with bloody nipple discharge for 1 week prior to presentation. Mammography, ultrasonography, and core needle aspiration were consistent with intracystic papillary carcinoma. The patient underwent right simple mastectomy. Pathology was also consistent with low grade intracystic papillary carcinoma. The 21-gene assay revealed a recurrence score of 0, corresponding to a 3% risk of distant recurrence at 10 years. A patient did not receive chemotherapy or post-mastectomy radiotherapy. The patient was placed on tamoxifen and has been free of disease to date.

Cancer Screening Rates in a Student-Run Free Clinic

BACKGROUND

In the United States and in New York State, individuals with no health insurance have consistently lower screening rates for breast and cervical cancer than those with health insurance and are also more likely to be diagnosed with advanced stages of cancer. Our objective was to compare the cancer screening rates among patients at a free student-run clinic to state and national data. To our knowledge, ours is the first study examining breast and cervical screening rates and their relation to insurance status, income level, education level, race, and marital status in a suburban free student-run clinic.

METHODS

As part of their intake from fall 2012 to spring 2013, patients at the Stony Brook Health Outreach and Medical Education Clinic in Stony Brook, NY, filled out a 26-item survey that included questions about race, income, education level, marital status, and cancer screening status. We compared the screening rates reported by our patients to published state and national rates.

RESULTS

Breast and cervical cancer screening rates reported by 165 patients treated at our free student-run clinic were lower than the overall state and national averages. No significant associations between race, income, education level, or marital status and cancer screening rates were detected.

CONCLUSION

Cancer screening rates at our free student-run clinic for the uninsured were lower than the overall state and national rates. These findings are consistent with previous reports of lower cancer preventive care utilization among the uninsured and suggest that insurance status has been a significant barrier to obtaining cancer screenings among our clinic population. Increasing cancer screening rates at student-run clinics may be a cost-effective secondary prevention activity that can decrease cancer mortality.

Merkel Cell Carcinoma With Gastric Metastasis and Review of Literature

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, highly aggressive cutaneous neoplasm, with a propensity for recurrence and metastasis. Very few cases of metastases to the gastrointestinal tract have been reported in the medical literature.

OBJECTIVES

The aim of this study was to report a case of MCC metastasizing to the stomach, its clinical presentation, and its management.

METHODS

A PubMed search was made using the following search terms: "Merkel cell carcinoma," "gastric," and "metastasis."

RESULTS

The investigators report a case of MCC metastatic to the stomach presenting with melena, syncope, early satiety, increasing fatigue, and unintentional weight loss. The other known cases of gastrointestinal metastasis of MCC are summarized and critically reviewed.

CONCLUSIONS

Although MCC spreading to the stomach is exceedingly rare, because of MCC's high recurrence rate and metastatic potential, it should be considered in patients with histories of MCC presenting with recent weight loss, early satiety, and gastrointestinal bleeding.

Dysphagia and Neck Swelling in a Case of Undiagnosed Lhermitte-Duclos Disease and Cowden Syndrome

We report a case of a 37-year-old woman presenting with dysphagia and thyroid masses who was subsequently diagnosed with Lhermitte-Duclos disease (LDD) based on MRI scan and histopathology. Additional imaging subsequently revealed the presence of thyroid nodules and bilateral breast cancers. Genetic testing later confirmed the diagnosis of Cowden syndrome. This case illustrates the importance of the overlap between LDD, Cowden syndrome, thyroid disease, and breast cancer.

Absence of Nitric Oxide Synthase 3 Increases Amyloid β-Protein Pathology in Tg-5xFAD Mice

AIM

The abnormal accumulation, assembly and deposition of the amyloid β-protein (Aβ) are prominent pathological features of patients with Alzheimer's disease (AD) and related disorders. A number of factors in the brain can influence Aβ accumulation and associated pathologies. The aim of the present study was to determine the consequences of deleting nitric oxide synthase (NOS) 3, the endothelial form of NOS, in Tg-5xFAD mice, a model of parenchymal AD-like amyloid pathology.

METHODS

Tg-5xFAD mice were bred with NOS3^-/- mice. Cohorts of Tg-5xFAD mice and bigenic Tg-5xFAD/NOS3^-/- mice were aged to six months followed by collection of the blood and brain tissues from the mice for biochemical and pathological analyses.

RESULTS

ELISA analyses show that the absence of NOS3 results in elevated levels of cerebral and plasma Aβ peptides in Tg-5xFAD mice. Immunohistochemical analyses show that the absence of NOS3 increased the amount of parenchymal Aβ deposition and fibrillar amyloid accumulation in Tg-5xFAD mice. The elevated levels of Aβ were not due to changes in the expression levels of transgene encoded human amyloid precursor protein (APP), endogenous β-secretase, or increased proteolytic processing of APP.

CONCLUSIONS

The results from this study suggest that the loss of NOS3 activity enhances Aβ pathology in Tg-5xFAD mice. These findings are similar to previous studies of NOS2 deletion suggesting that reduced NOS activity and NO levels enhance amyloid-associated pathologies in human APP transgenic mice.