Tumor and Peritoneum-Associated Macrophage Gene Signature as a Novel Molecular Biomarker in Gastric Cancer

A spectrum of immune states resulting from tumor resident macrophages and T-lymphocytes in the solid tumor microenvironment correlates with patient outcomes. We hypothesized that in gastric cancer (GC), macrophages in a polarized immunosuppressive transcriptional state would be prognostic of poor survival. We derived transcriptomic signatures for M2 (M2TS, MRC1; MS4A4A; CD36; CCL13; CCL18; CCL23; SLC38A6; FGL2; FN1; MAF) and M1 (M1TS, CCR7; IL2RA; CXCL11; CCL19; CXCL10; PLA1A; PTX3) macrophages, and cytolytic T-lymphocytes (CTLTS, GZMA; GZMB; GZMH; GZMM; PRF1). Primary GC in a TCGA stomach cancer dataset was evaluated for signature expressions, and a log-rank test determined overall survival (OS) and the disease-free interval (DFI). In 341 TCGA GC entries, high M2TS expression was associated with histological types and later stages. Low M2TS expression was associated with significantly better 5-year OS and DFI. We validated M2TS in prospectively collected peritoneal fluid of a GC patient cohort (n = 28). Single-cell RNA sequencing was used for signature expression in CD68+CD163+ cells and the log-rank test compared OS. GC patients with high M2TS in CD68+CD163+ cells in their peritoneal fluid had significantly worse OS than those with low expression. Multivariate analyses confirmed M2TS was significantly and independently associated with survival. As an independent predictor of poor survival, M2TS may be prognostic in primary tumors and peritoneal fluid of GC patients.

Emerging therapeutic approaches for peritoneal metastases from gastrointestinal cancers

Peritoneal metastases from gastrointestinal malignancies present difficult management decisions, with options consisting primarily of systemic chemotherapy or major surgery with or without hyperthermic intraperitoneal chemotherapy. Current research is investigating expanding therapeutic modalities, and the aim of this review is to provide an overview of the existing and emerging therapies for the peritoneal metastases from gastrointestinal cancers, primarily through the recent literature (2015 and newer). These include the current data with systemic therapy and cytoreduction with hyperthermic intraperitoneal or pressurized intraperitoneal aerosol chemotherapy, as well as novel promising modalities under investigation, including dominating oncolytic viral therapy and adoptive cellular, biologic, and bacteria therapy, or nanotechnology. The novel diverse strategies, although preliminary and preclinical in murine models, individually and collectively contribute to the treatment of peritoneal metastases, offering hope for improved outcomes and quality of life. We foresee that these evolving treatment approaches will facilitate the transfer of knowledge and data among studies and advance discovery of new drugs and optimized treatments for patients with peritoneal metastases.

Reversing immunosuppression in the tumor microenvironment of fibrolamellar carcinoma via PD-1 and IL-10 blockade

Fibrolamellar carcinoma (FLC) is a rare liver tumor driven by the DNAJ-PKAc fusion protein that affects healthy young patients. Little is known about the immune response to FLC, limiting rational design of immunotherapy. Multiplex immunohistochemistry and gene expression profiling were performed to characterize the FLC tumor immune microenvironment and adjacent non-tumor liver (NTL). Flow cytometry and T cell receptor (TCR) sequencing were performed to determine the phenotype of tumor-infiltrating immune cells and the extent of T cell clonal expansion. Fresh human FLC tumor slice cultures (TSCs) were treated with antibodies blocking programmed cell death protein-1 (PD-1) and interleukin-10 (IL-10), with results measured by cleaved caspase-3 immunohistochemistry. Immune cells were concentrated in fibrous stromal bands, rather than in the carcinoma cell compartment. In FLC, T cells demonstrated decreased activation and regulatory T cells in FLC had more frequent expression of PD-1 and CTLA-4 than in NTL. Furthermore, T cells had relatively low levels of clonal expansion despite high TCR conservation across individuals. Combination PD-1 and IL-10 blockade signficantly increased cell death in human FLC TSCs. Immunosuppresion in the FLC tumor microenvironment is characterized by T cell exclusion and exhaustion, which may be reversible with combination immunotherapy.

Safety and Efficacy of Oxaliplatin Pressurized Intraperitoneal Aerosolized Chemotherapy (PIPAC) in Colorectal and Appendiceal Cancer with Peritoneal Metastases: Results of a Multicenter Phase I Trial in the USA

BACKGROUND

Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a laparoscopic locoregional treatment for peritoneal metastases (PM) from colorectal cancer (CRC) or appendiceal cancer (AC) in patients who cannot undergo cytoreductive surgery (CRS). While PIPAC has been studied in Europe and Asia, it has not been investigated in the USA.

PATIENTS AND METHODS

We evaluated PIPAC with 90 mg/m2 oxaliplatin alone (cycle 1) and preceded by systemic chemotherapy with fluorouracil (5-FU) and leucovorin (LV) (cycle 2-3) as a multicenter prospective phase I clinical trial (NCT04329494). The primary endpoint was treatment-related adverse events (AEs). Secondary endpoints included survival and laparoscopic, histologic, and radiographic response.

RESULTS

12 patients were included: 8 with CRC and 4 with AC. Median prior chemotherapy cycles was 2 (interquartile range (IQR) 2-3). All patients were refractory to systemic oxaliplatin-based chemotherapy. Median peritoneal carcinomatosis index (PCI) was 28 (IQR 19-32). Six (50%) of twelve patients completed three PIPAC cycles. No surgical complications or dose-limiting toxicities were observed. Two patients developed grade 3 treatment-related toxicities (one abdominal pain and one anemia). Median overall survival (OS) was 12.0 months, and median progression-free survival (PFS) was 2.9 months. OS was correlated with stable disease by Response Evaluation Criteria in Solid Tumors (RECIST) criteria but not with laparoscopic response by PCI or histologic response by peritoneal regression grading system (PRGS).

CONCLUSIONS

This phase I trial in the USA demonstrated safety, feasibility, and early efficacy signal of PIPAC with oxaliplatin and chemotherapy in patients with PM from AC or CRC who are refractory to standard lines of systemic chemotherapy.

Production of an interleukin-10 blocking antibody by genetically engineered macrophages increases cancer cell death in human gastrointestinal tumor slice cultures

Although it can promote effector T-cell function, the summative effect of interleukin-10 (IL-10) in the tumor microenvironment (TME) appears to be suppressive; therefore, blocking this critical regulatory cytokine has therapeutic potential to enhance antitumor immune function. As macrophages efficiently localize to the TME, we hypothesized that they could be used as a delivery vehicle for drugs designed to block this pathway. To test our hypothesis, we created and evaluated genetically engineered macrophages (GEMs) that produce an IL-10-blocking antibody (αIL-10). Healthy donor human peripheral blood mononuclear cells were differentiated and transduced with a novel lentivirus (LV) encoding BT-063, a humanized αIL-10 antibody. The efficacy of αIL-10 GEMs was assessed in human gastrointestinal tumor slice culture models developed from resected specimens of pancreatic ductal adenocarcinoma primary tumors and colorectal cancer liver metastases. LV transduction led to sustained production of BT-063 by αIL-10 GEMs for at least 21 days. Transduction did not alter GEM phenotype as evaluated by flow cytometry, but αIL-10 GEMs produced measurable quantities of BT-063 in the TME that was associated with an ~5-fold higher rate of tumor cell apoptosis than control.

Medicare Advantage: A Disadvantage for Complex Cancer Surgery Patients

PURPOSE

Nearly half of all Medicare beneficiaries are enrolled in privatized Medicare insurance plans (Medicare Advantage [MA]). Little comparative information is available about access, outcomes, and cost of inpatient cancer surgery between MA and Traditional Medicare (TM) beneficiaries. We set out to assess and compare access, postoperative outcomes, and estimated cost of inpatient cancer surgery among MA and TM beneficiaries.

METHODS

Retrospective cohort analysis of MA or TM beneficiaries undergoing elective inpatient cancer surgery (for cancers located in lung, esophagus, stomach, pancreas, liver, colon, or rectum) was performed using the Office of Statewide Health Planning Inpatient Database linked to California Cancer Registry from 2000 to 2020. For each cancer site, risk-standardized access to high-volume hospitals, postoperative 30-day mortality, complications, failure to rescue, and surgery-specific estimated costs were compared between MA and TM beneficiaries.

RESULTS

This analysis of 76,655 Medicare beneficiaries (median age 74 years, 51% female, 39% MA) included 31,913 colectomies, 10,358 proctectomies, 4,604 hepatectomies, 2,895 pancreatectomies, 3,639 gastrectomies, 1,555 esophagectomies, and 21,691 lung resections. Except for colon surgery, MA beneficiaries were less likely to receive care at a high-volume hospital. Mortality was significantly higher among MA beneficiaries (v TM) for gastrectomy (adjusted risk difference [ARD], 1.5%; 95% CI, 0.01 to 2.9; P = .036), pancreatectomy (ARD, 2.0%; CI, 0.80 to 3.3; P = .002), and hepatectomy (ARD, 1.4%; 95% CI, 0.1 to 2.9; P = .04). By contrast, compared with TM, MA beneficiaries incurred lower estimated hospital costs.

CONCLUSION

Enrollment in MA plan is associated with lower estimated hospital costs. However, compared with TM, MA beneficiaries had lower access to high-volume hospitals and increased 30-day mortality for stomach, pancreas, or liver surgery.

Blockade of interleukin 10 potentiates antitumour immune function in human colorectal cancer liver metastases

OBJECTIVE

Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of interleukin 10 (IL-10) blockade on endogenous T cell and chimeric antigen receptor T (CAR-T) cell antitumour function in CRLM slice cultures.

DESIGN

We created organotypic slice cultures from human CRLM (n=38 patients' tumours) and tested the antitumour effects of a neutralising antibody against IL-10 (αIL-10) both alone as treatment and in combination with exogenously administered carcinoembryonic antigen (CEA)-specific CAR-T cells. We evaluated slice cultures with single and multiplex immunohistochemistry, in situ hybridisation, single-cell RNA sequencing, reverse-phase protein arrays and time-lapse fluorescent microscopy.

RESULTS

αIL-10 generated a 1.8-fold increase in T cell-mediated carcinoma cell death in human CRLM slice cultures. αIL-10 significantly increased proportions of CD8⁺ T cells without exhaustion transcription changes, and increased human leukocyte antigen - DR isotype (HLA-DR) expression of macrophages. The antitumour effects of αIL-10 were reversed by major histocompatibility complex class I or II (MHC-I or MHC-II) blockade, confirming the essential role of antigen presenting cells. Interrupting IL-10 signalling also rescued murine CAR-T cell proliferation and cytotoxicity from myeloid cell-mediated immunosuppression. In human CRLM slices, αIL-10 increased CEA-specific CAR-T cell activation and CAR-T cell-mediated cytotoxicity, with nearly 70% carcinoma cell apoptosis across multiple human tumours. Pretreatment with an IL-10 receptor blocking antibody also potentiated CAR-T function.

CONCLUSION

Neutralising the effects of IL-10 in human CRLM has therapeutic potential as a stand-alone treatment and to augment the function of adoptively transferred CAR-T cells.

Multicenter dose-escalation Phase I trial of mitomycin C pressurized intraperitoneal aerosolized chemotherapy in combination with systemic chemotherapy for appendiceal and colorectal peritoneal metastases: rationale and design

Objectives

Peritoneal metastasis (PM) from appendiceal cancer or colorectal cancer (CRC) has significant morbidity and limited survival. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a minimally invasive approach to treat PM. We aim to conduct a dose-escalation trial of mitomycin C (MMC)-PIPAC combined with systemic chemotherapy (FOLFIRI) in patients with PM from appendiceal cancer or CRC.

Methods

This is a multicenter Phase I study of MMC-PIPAC (NCT04329494). Inclusion criteria include treatment with at least 4 months of first- or second-line systemic chemotherapy with ineligibility for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Exclusion criteria are: progression on chemotherapy; extraperitoneal metastases; systemic chemotherapy intolerance; bowel obstruction; or poor performance status (ECOG>2). Escalating MMC-PIPAC doses (7-25 mg/m2) will be administered in combination with standard dose systemic FOLFIRI. Safety evaluation will be performed on 15 patients (dose escalation) and six expansion patients: 21 evaluable patients total.

Results

The primary endpoints are recommended MMC dose and safety of MMC-PIPAC with FOLFIRI. Secondary endpoints are assessment of response (by peritoneal regression grade score; Response Evaluation Criteria in Solid Tumors [RECIST 1.1], and peritoneal carcinomatosis index), progression free survival, overall survival, technical failure rate, surgical complications, conversion to curative-intent CRS-HIPEC, patient-reported outcomes, and functional status. Longitudinal blood and tissue specimens will be collected for translational correlatives including pharmacokinetics, circulating biomarkers, immune profiling, and single-cell transcriptomics.

Conclusions

This Phase I trial will establish the recommended dose of MMC-PIPAC in combination with FOLFIRI. Additionally, we expect to detect an early efficacy signal for further development of this therapeutic combination.

Variability in antibiotic duration for necrotizing enterocolitis and outcomes in a large multicenter cohort

OBJECTIVES

To evaluate variability in antibiotic duration for necrotizing enterocolitis (NEC) and associated clinical outcomes.

STUDY DESIGN

Five-hundred ninety-one infants with NEC (315 medical; 276 surgical) were included from 22 centers participating in Children's Hospitals Neonatal Consortium (CHNC). Multivariable analyses were used to determine predictors of variability in time to full feeds (TFF) and length of stay (LOS).

RESULTS

Median (IQR) antibiotic duration was 12 (9, 17) days for medical and 17 (14, 21) days for surgical NEC. Wide variability in antibiotic use existed both within and among centers. Duration of antibiotic therapy was associated with longer TFF in both medical (OR 1.04, 95% CI [1.01, 1.05], p < 0.001) and surgical NEC (OR 1.02 [1, 1.03] p = 0.046); and with longer LOS in medical (OR 1.03 [1.02, 1.04], p < 0.001) and surgical NEC (OR 1.01 [1.01, 1.02], p = 0.002).

CONCLUSION

Antibiotic duration for both medical and surgical NEC remains variable within and among high level NICUs.

Abstract 6144: Novel M2 macrophage gene signature as a biomarker of poor outcomes independent of TNM stage in peritoneal liquid biopsy of gastric cancer patients

Introduction: The infiltration or density of immunosuppressive or M2-macrophages has been correlated with worse prognosis in gastric cancer (GC). We hypothesized that a highly polarized transcriptional phenotype of M2 macrophages would be prognostic if detected in primary and peritoneal fluid samples of GC.

Methods: We derived a novel transcriptomic gene signature (MRC1, MS4A4A, CD36, CCL13, CCL18, CCL23, SLC38A6, FGL2, FN1, MAF) from published highly differentially expressed M2 genes that were identified from peripheral blood. We also evaluated a M1 signature (CCR7, IL2RA, CXCL11, CCL19, CXCL10, PLA1A, PTX3) and T cell cytolytic signature (GZMA, GZMB, GZMH, GZMM, PRF1). In primary GC, we used the UCSC Xena tool to analyze the TCGA Stomach Cancer cohort and compared transcriptional signature expression to histologic subtype and pathologic stage. We used log-rank test to compare Kaplan-Meier curves of overall survival (OS) and disease-free interval (DFI) for high versus low signature expression. In our institutional cohort consisting of GC patients with a range of T and N stages as well as with and without metastatic disease (n=28), we evaluated peritoneal fluid samples using single cell RNA sequencing for high and low signature expression in CD68+CD163+ monocytes and used log-rank test to compare OS.

Results: A total of 341 TCGA entries of primary GC were included. High expression of the M2 signature in GC was associated with diffuse- and mucinous-type adenocarcinoma, compared to tubular- and papillary-type adenocarcinoma (p&lt;0.001). High M2 signature expression was associated with later stage (Stage II or above) compared to early-stage GC (stage I) (p=0.02). Low M2 signature was associated with significantly improved 5-year OS (p=0.03) and DFI (p=0.04). M1 signature and T cell cytolytic signature were not associated with stage, OS, or DFI in primary GC. In GC peritoneal fluid samples, we identified patients with high (n=15) and low (n=13) signature expression in M2 cells. Independent of TNM-stage, high M2 signature expression in CD68+CD163+ cells within the peritoneal fluid of GC patients was associated with worse OS (median OS not reached at 30 months for low signature expression and 5.5 months for high expression, hazard ratio 2.82, p=0.048).

Conclusions: Our study validates a unique M2-associated transcriptomic gene signature as a biomarker of poor outcomes in both primary gastric tumors and peritoneal fluid of GC patients. Because both endoscopic biopsy and laparoscopy with peritoneal fluid collection are part of the standard workup for locoregional GC, an ubiquitous immune signature detected in primary tumor and peritoneal fluid of patients across TNM stages may serve as a clinically valuable indicator of an immunosuppressive patient state associated with poor survival.

Citation Format: Kevin M. Sullivan, Haiqing Li, Kelly Mahuron, Yate-Ching Yuan, Joseph Chao, Benjamin Paz, Haiyong Han, Yuman Fong, Yanghee Woo. Novel M2 macrophage gene signature as a biomarker of poor outcomes independent of TNM stage in peritoneal liquid biopsy of gastric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6144.

Protocol for tissue slice cultures from human solid tumors to study therapeutic response

The impact of systemic therapy on the tumor microenvironment has been difficult to study in human solid tumors. Our protocol describes steps for establishing slice cultures to investigate response to chemotherapies, immunotherapies, or adoptive cell therapies. Endpoints include changes in viability, histology, live-cell imaging, and multi-omics analyses. The protocol has been applied to a broad array of gastrointestinal malignancies. Culture conditions and treatment parameters can be modified for specific experiments. The platform is highly flexible and easy to manipulate.

For complete details on the use and execution of this protocol, please refer to Kenerson et al. (2020), Jabbari et al. (2020), Brempelis et al. (2020), and Jiang et al. (2017).

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Organotypic tumor slice cultures (TSCs) can be utilized to study human cancer

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TSCs provide a model to study effects of chemo-, immuno-, and cell-based therapies

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Tumor response to treatment can be assessed using multiple readouts

IWATE criteria are associated with perioperative outcomes in robotic hepatectomy: a retrospective review of 225 resections

Background

Robotic hepatectomy (RH) is increasingly utilized for minor and major liver resections. The IWATE criteria were developed to classify minimally invasive liver resections by difficulty. The objective of this study was to apply the IWATE criteria in RH and to describe perioperative and oncologic outcomes of RH over the last decade at our institution.

Methods

Perioperative and oncologic outcomes of patients who underwent RH between 2011 and 2019 were retrospectively collected. The difficulty level of each operation was assessed using the IWATE criteria, and outcomes were compared at each level. Univariate linear regression was performed to characterize the relationship between IWATE criteria and perioperative outcomes (OR time, EBL, and LOS), and a multivariable model was also developed to address potential confounding by patient characteristics (age, sex, BMI, prior abdominal surgery, ASA class, and simultaneous non-hepatectomy operation).

Results

Two hundred and twenty-five RH were performed. Median IWATE criteria for RH were 6 (IQR 5–9), with low, intermediate, advanced, and expert resections accounting for 23% (n = 51), 34% (n = 77), 32% (n = 72), and 11% (n = 25) of resections, respectively. The majority of resections were parenchymal-sparing approaches, including anatomic segmentectomies and non-anatomic partial resections. 30-day complication rate was 14%, conversion to open surgery occurred in 9 patients (4%), and there were no deaths within 30 days postoperatively. In the univariate linear regression analysis, IWATE criteria were positively associated with OR time, EBL, and LOS. In the multivariable model, IWATE criteria were independently associated with greater OR time, EBL, and LOS. Two-year overall survival for hepatocellular carcinoma and intrahepatic cholangiocarcinoma was 94% and 50%, respectively.

Conclusion

In conclusion, the IWATE criteria are associated with surgical outcomes after RH. This series highlights the utility of RH for difficult hepatic resections, particularly parenchymal-sparing resections in the posterosuperior sector, extending the indication of minimally invasive hepatectomy in experienced hands and potentially offering select patients an alternative to open hepatectomy or other less definitive liver-directed treatment options.

Modulation of Immune Checkpoints by Chemotherapy in Human Colorectal Liver Metastases

Metastatic colorectal cancer (CRC) is a major cause of cancer-related death, and incidence is rising in younger populations (younger than 50 years). Current chemotherapies can achieve response rates above 50%, but immunotherapies have limited value for patients with microsatellite-stable (MSS) cancers. The present study investigates the impact of chemotherapy on the tumor immune microenvironment. We treat human liver metastases slices with 5-fluorouracil (5-FU) plus either irinotecan or oxaliplatin, then perform single-cell transcriptome analyses. Results from eight cases reveal two cellular subtypes with divergent responses to chemotherapy. Susceptible tumors are characterized by a stemness signature, an activated interferon pathway, and suppression of PD-1 ligands in response to 5-FU+irinotecan. Conversely, immune checkpoint TIM-3 ligands are maintained or upregulated by chemotherapy in CRC with an enterocyte-like signature, and combining chemotherapy with TIM-3 blockade leads to synergistic tumor killing. Our analyses highlight chemomodulation of the immune microenvironment and provide a framework for combined chemo-immunotherapies.

CRLM slice culture can assess immune response to chemotherapy

Single-cell analysis identifies cancer subtypes with differing response to chemotherapy

5-FU+irinotecan modulates interferon and PD-L1 pathways in stem-like CRLM

Combining chemotherapy with TIM-3 blockade is synergistic in enterocyte-like CRLM

Dopamine secreting adrenal tumor-ganglioneuroma rather than pheochromocytoma: case report

Ganglioneuromas are rare, benign, well-differentiated neural crest tumors arising in the paravertebral sympathetic chain, and are classically non-secretory and clinically asymptomatic. As the diagnosis of ganglioneuroma is based on histopathology, the clinical presentation prior to surgical excision often mirrors that of pheochromocytoma or adrenal cortical adenoma. We describe a case of an incidentally found right sided calcified adrenal mass with evidence of marked dopamine excess, suspicious for pheochromocytoma in a 70-year-old female. The patient endorsed a 6-month history of intermittent right flank pain and a 2-year history of weight loss and fatigue. She reported mild symptoms of hypomania but denied other symptoms of dopamine excess including agitation, anxiety, nausea, and vomiting. Exam revealed isolated mild hypertension. The imaging features of this mass were concerning for malignancy including the presence of macrocalcification and irregular borders. After preoperative alpha blockade, the patient underwent open right adrenalectomy and the final pathology was consistent with ganglioneuroma rather than pheochromocytoma. Following resection, the dopamine level normalized, confirming the resected right adrenal ganglioneuroma as the source of dopamine excess. This case represents a rare presentation of dopamine-secreting adrenal ganglioneuroma. This illustrates that although rare, ganglioneuroma should be included on the differential diagnosis for functional adrenal tumors.

Pre-Transplant Marital Status and Hematopoietic Cell Transplantation Outcomes

Background

Evidence about the impact of marital status before hematopoietic cell transplantation (hct) on outcomes after hct is conflicting.

Methods

We identified patients 40 years of age and older within the Center for International Blood and Marrow Transplant Research registry who underwent hct between January 2008 and December 2015. Marital status before hct was declared as one of: married or living with a partner, single (never married), separated or divorced, and widowed. We performed a multivariable analysis to determine the association of marital status with outcomes after hct.

Results

We identified 10,226 allogeneic and 5714 autologous hct cases with, respectively, a median follow-up of 37 months (range: 1-102 months) and 40 months (range: 1-106 months). No association between marital status and overall survival was observed in either the allogeneic (p = 0.58) or autologous (p = 0.17) setting. However, marital status was associated with grades 2-4 acute graft-versus-host disease (gvhd), p < 0.001, and chronic gvhd, p = 0.04. The risk of grades 2-4 acute gvhd was increased in separated compared with married patients [hazard ratio (hr): 1.13; 95% confidence interval (ci): 1.03 to 1.24], and single patients had a reduced risk of grades 2-4 acute gvhd (hr: 0.87; 95% ci: 0.77 to 0.98). The risk of chronic gvhd was lower in widowed compared with married patients (hr: 0.82; 95% ci: 0.67 to 0.99).

Conclusions

Overall survival after hct is not influenced by marital status, but associations were evident between marital status and grades 2-4 acute and chronic gvhd. To better appreciate the effects of marital status and social support, future research should consider using validated scales to measure social support and patient and caregiver reports of caregiver commitment, and to assess health-related quality of life together with health care utilization.

Single institution experience looking at efficacy of PD-1 inhibitors after progression on PD-L1 inhibitors or vice-versa in metastatic non-small cell lung cancer (NSCLC)

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Background: The treatment landscape for metastatic NSCLC has changed dramatically with emergence of checkpoint inhibitors (CPI). Even though all currently approved CPI target engagement of PD-1 with PD-L1 and have similar efficacy in NSCLC, there are some differences in their mechanisms of action. Current guidelines do not recommend switching to another CPI after progression of disease (POD) or toxicity on one CPI. For some patients, however, therapeutic options may be limited due to comorbidities, lack of trial prospects, performance status, or reluctance towards chemotherapy making switch to alternate CPI an attractive strategy. We report outcomes of patients who were treated with second CPI after POD on initial CPI for metastatic NSCLC between 2015 and 2019 at our institution. Methods: Data collection included demographics, clinic-pathologic factors, CPI agents, disease control rate (DCR), progression free survival (PFS), and immune-related adverse events (irAE). DCR was defined as response or stable disease based on RECIST. PFS was measured from date of initiation of CPI to POD or death. Results: Of 169 patients with NSCLC treated with CPI (median age 71 years, range 30-93), 26 received 2 lines of CPI. Two patients received first CPI as part of front line chemoimmunotherapy whereas all others received CPI alone. First CPI was PD-1 inhibitor in 20 patients and PD-L1 inhibitor in 6. DCR for first CPI was 88% and median PFS of 5 months (range: 1 –24). There were no irAE over grade 2 with initial CPI. Six patients were treated with PD-1 inhibitors after PD-L1, 16 with PD-L1 after PD-1, and 4 with an alternate agent in same class. Median PFS for 2nd CPI was 3 months (range: 1 - 36) for all patients and DCR for evaluable patients was 63% (n = 16). One patient experienced steroid-responsive grade 2 pneumonitis. Responses with either line of CPI did not correlate with PD-L1 expression. Conclusions: Our data suggests that switching from one CPI to another may be a reasonable, potentially effective option in select patient population. Prospective studies exploring this strategy is warranted.

Tumor slice culture as a biologic surrogate of human cancer

Background

The tumor microenvironment (TME) is critical to every aspect of cancer biology. Organotypic tumor slice cultures (TSCs) preserve the original TME and have demonstrated utility in predicting drug sensitivity, but the association between clinicopathologic parameters and in vitro TSC behavior has not been well-defined.

Methods

One hundred and eight fresh tumor specimens from liver resections at a tertiary academic center were procured and precisely cut with a Vibratome to create 250 μm × 6 mm slices. These fixed-dimension TSCs were grown on polytetrafluoroethylene inserts, and their metabolic activities were determined by a colorimetric assay. Correlation between baseline activities and clinicopathologic parameters was assessed. Tissue CEA mRNA expression was determined by RNAseq.

Results

By standardizing the dimensions of a slice, we found that adjacent tumor slices have equivalent metabolic activities, while those derived from different tumors exhibit >30-fold range in baseline MTS absorbances, which correlated significantly with the percentage of tumor necrosis based on histologic assessment. Extending this to individual cancers, we were able to detect intra-tumoral heterogeneity over a span of a few millimeters, which reflects differences in tumor cell density and Ki-67 positivity. For colorectal cancers, tissue CEA expression based on RNAseq of tumor slices was found to correlate with clinical response to chemotherapies.

Conclusions

We report a standardized method to assess and compare human cancer growth ex vivo across a wide spectrum of tumor samples. TSC reflects the state of tumor behavior and heterogeneity, thus providing a simple approach to study of human cancers with an intact TME.

Center, Gestational Age, and Race Impact End-of-Life Care Practices at Regional Neonatal Intensive Care Units

OBJECTIVE

To assess the impact of intercenter variation and patient factors on end-of-life care practices for infants who die in regional neonatal intensive care units (NICUs).

STUDY DESIGN

We conducted a retrospective cohort analysis using the Children's Hospital Neonatal Database during 2010-2016. A total of 6299 nonsurviving infants cared for in 32 participating regional NICUs were included to examine intercenter variation and the effects of gestational age, race, and cause of death on 3 end-of-life care practices: do not attempt resuscitation orders (DNR), cardiopulmonary resuscitation within 6 hours of death (CPR), and withdrawal of life-sustaining therapies (WLST). Factors associated with these practices were used to develop a multivariable equation.

RESULTS

Dying infants in the cohort underwent DNR (55%), CPR (21%), and WLST (73%). Gestational age, cause of death, and race were significantly and differently associated with each practice: younger gestational age (<28 weeks) was associated with CPR (OR 1.7, 95% CI 1.5-2.1) but not with DNR or WLST, and central nervous system injury was associated with DNR (1.6, 1.3-1.9) and WLST (4.8, 3.7-6.2). Black race was associated with decreased odds of WLST (0.7, 0.6-0.8). Between centers, practices varied widely at different gestational ages, race, and causes of death.

CONCLUSIONS

From the available data on end-of-life care practices for regional NICU patients, variability appears to be either individualized or without consistency.

Opioid Use Following Bariatric Surgery: Results of a Prospective Survey

BACKGROUND

Opioid use after bariatric surgery is not clearly understood. Few guidelines exist to inform opioid-prescribing practices after bariatric surgery.

OBJECTIVE

To understand opioid use following bariatric surgery.

SETTING

University hospital.

METHODS

Bariatric surgery patients at a single center were prospectively surveyed at the time of their post-operative visit (January-May 2018). Patients were asked about their opioid use following surgery, whether they received education about opioid use and what they did with leftover medications. Demographic and operative details were obtained from the medical record.

RESULTS

Among 33 patients, the majority (n = 29, 88%) were female with a median age of 40 (20-68) and body mass index of 44.8 (33-78.5). Most patients had leftover narcotics (n = 25, 73%). The median number of pills used was 15 (0-48). Only 12 patients (36%) thought that they had been prescribed "too much" pain medication. Most patients reported receiving education about expectations for post-operative pain (n = 22, 69%); few recalled education about reducing or stopping opioids (n = 13, 40%). More than half of patients (n = 17, 53%) kept their leftover opioids rather than disposing of them or bringing them to an approved turn in location.

CONCLUSIONS

Despite most patients having leftover opioids following surgery, few patients recognized possible overprescription. Education regarding opioid use following surgery is inconsistent, potentially contributing to the amount of retained opioids currently available. Future guidelines should focus on determining the appropriate amount of opioids to be prescribed following surgery and standardizing and improving education given to patients.

Abstract 4489: IL-10 blockade reactivates antitumor immunity in human colorectal cancer liver metastases

Background: Colorectal cancer (CRC) is the 4th most common cancer in the US, and the liver is the most common site of metastatic disease. Immune checkpoint inhibitor therapy has not been successful in achieving a clinical response in most patients with CRC liver metastases (CRCLM). The liver is known to induce tolerance to foreign antigens as a result of immunosuppressive cytokines including IL-10. We hypothesized that blockade of IL-10 signaling in CRCLM would potentiate tumor infiltrating lymphocyte (TIL)-mediated tumor cell death.

Methods: We performed single-cell RNA sequencing (scRNAseq) of CRCLM using the 10x platform to evaluate for expression of IL-10 or IL-10 receptor (IL-10R) RNA within the tumor (n=8). To confirm if the IL-10R protein was present within the tumor microenvironment (TME), we also performed immunohistochemistry (IHC) (n=3). In order to study the functional effects of IL-10 blockade, we utilized a tumor slice culture (TSC) model, which allows for the study of cancers with their intact TME including immune cells. For TSCs, cores (6 mm diameter) were taken from freshly resected sterile human CRCLM and cut to 250 µm thick slices using a vibratome (n=3). Duplicate slices were treated with either IgG control or anti-IL-10 monoclonal antibodies and cultured for up to 6 days. To evaluate for histological evidence of necrosis and cell apoptosis within the tumor slice, we stained slides with either hematoxylin and eosin (H&E) or cleaved-Caspase-3 (CC3). To gain insight into the activation state of TIL after treatment, we measured levels of cytokines within the culture supernatants.

Results: We found by scRNAseq that that IL-10 was expressed by a subset of tumor-associated macrophages, and IL-10R was expressed by both CD4+ and CD8+ T cells as well as macrophages. We confirmed that IL-10R protein was present within the CRCLM TME by IHC, and IL-10R expression was distributed throughout the stroma in non-tumor cells. In TSC treated with anti-IL-10 antibody, CC3+ cells were found to be 82.8% of total cells, compared to 36.1% of control (p = 1 x 10-6) at day 6. These findings were consistent across all human tumor samples treated with IL-10 blockade versus control at all time points examined. Furthermore, IL-10 blockade led to histologic evidence of generalized necrosis compared to an intact TME seen in the control group. Analysis of cytokines released into the media confirmed that IL-10 was present in controls, but absent in slices blocked with anti-IL-10 antibody. We also found increased levels of granzyme B, IL-2, GM-CSF, and IL-18, as well as a reduction in the immune checkpoint receptor TIM3, after one day of IL-10 blockade in culture.

Conclusion: Treatment of human CRCLM TSCs with anti-IL-10 antibody leads to a marked increase in immune-mediated cell death within the tumor. Our data suggest that IL-10 serves as a critical regulator of anti-tumor immunity in the CRCLM TME and may serve as an important immunotherapeutic target.

Citation Format: Kevin M. Sullivan, Xiuyun Jiang, Yongwoo David Seo, Heidi L. Kenerson, Xiaowei Yan, Chris Lausted, Changting Meng, Neda Jabbari, Kevin P. Labadie, Sara K. Daniel, Qiang Tian, Teresa S. Kim, Raymond S. Yeung, Venu G. Pillarisetty. IL-10 blockade reactivates antitumor immunity in human colorectal cancer liver metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4489.

Effect of concurrent TP53 mutation in EGFR/ALK/ROS1 positive non-small cell lung cancer treated with first-line TKI therapy: A Single Institution Retrospective Study

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Background: Tyrosine Kinase Inhibitors (TKI) are the mainstay of therapy for patients (pts) with EGFR/ALK/ROS1 positive (pos) non-small cell lung cancer (NSCLC), however resistance to these drugs is inevitable and remains a clinical challenge. The cause for early resistance leading to progression has not been fully understood, but several mechanisms have been reported. We conducted a retrospective study to determine the impact of concurrent TP53 mutation (TP53m) in this population. Methods: NSCLC pts treated with first line TKI from 01/2014 to 06/2017 were studied. Descriptive statistics were computed. Progression was equated with TKI resistance (TKIr). We compared time to TKIr among pts with TP53m to those without. Standard survival analysis methods (i.e., Kaplan-Meier curves and multivariable Cox proportional hazards regression) were used. Results: Forty-two subjects on first line treatment TKI were included. The mean (SD) age was 67.2 (14.7) years. 37 (88%) were EGFR, 4 (10%) were ALK and 1 (2%) were ROS pos. 76% were female, 50% White, 74% non-smokers and 50% had a TP53m. The estimated median time to TKIr was 19.4 months. At 24 months from start of therapy, the predicted probability of not reaching TKIr was 46% (95% CI: 26-64%). The estimated median time to TKIr among those without TP53m is 19.4 months vs 14.4 months in those with TP53m (p = 0.13). The predicted probability of no TKIr at 12 months from start of therapy among those with and without TP53m were 59% and 80%, respectively. In multivariable analysis, TP53 status remained nonsignificant (p = 0.08) after adjusting for line of therapy. Conclusions: TP53m has been associated with worse prognosis in various cancers. The results from the studies looking at association between TP53m and NSCLC with targetable mutation have been mixed, with few studies demonstrating the association of TP53m with poor survival and earlier treatment resistance. In our study, although there was a tendency towards improved survival and delayed TKIr in the cohort without TP53m, it was not statistically significant, which may be due to small sample size. Further studies looking at concurrent TP53m and targetable mutation are required, which may help clinicians deciding how to direct therapy in this population.

Predictive value of baseline clinicopathological factors in non-small cell lung cancer (NSCLC) patients on checkpoint inhibitors (CPI)

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Background: Tumor PD-L1 expression and tumor mutational burden currently serve as primary predictive markers for CPI efficacy in NSCLC. However, these markers are imperfect due to tumor heterogeneity, changes over time, and lab variations. These challenges highlight importance of developing dynamic, readily available predictive biomarkers. We evaluated predictive value of pre-treatment Neutrophil-to-Lymphocyte Ratio (NLR), smoking history (SH), body mass index (BMI) and smoking intensity (SI) in NSCLC patients (pts) on CPIs. Methods: Retrospective analysis of NSCLC pts treated with CPIs July 2015 to November 2017. Pt demographics, tumor PD-L1 status positive (pos) or negative (neg) (PD-L1 > 0% or 0% respectively), SH, SI (heavy smokers (HS) or non-heavy smokers (NHS) [ = / > 20 pack-year (PY) and < 20 PY respectively], NLR and BMI high or low based on cutoffs of 5 and 25, respectively were captured. Disease Control Rate (DCR) was defined as objective response or stable disease per RECIST 1.1 at 3 months (m). Median overall survival (OS) and time to progression (TTP) were calculated. Fisher’s exact test and chi-square test were used to compare DCR for each group. Kaplan-Meier curves were used to estimate OS and TTP for each factor. Results: 140 pts were included. NLR was associated with DCR, OS, and TTP. 62/90 (68.9%) pts in the low NLR group and 18/47 (38.3%) in the high NLR group had DCR (p < 0.0006). Median OS for low NLR was 15 m (95% CI: 11.75, 22.25) vs. 5.25 m for high NLR (95% CI: 2.75, 9.75) (p < 0.0005). Median TTP for low NLR was 8 m (95% CI: 6.00, 11.25) vs 3 m for the high (95% CI, 2.00, 4.00) (p < 0.0001). SH was not associated with DCR or survival, but was predictive of TTP. SI was predictive of DCR, but not OS or TTP. 65/100 (65.0%) HS and 15/34 (44.1%) NHS had DCR (p < 0.0320). BMI and PD-L1 (n = 55) were not associated with any outcome. There was association between high BMI and low NLR (P < 0.0381). There were no other associations between factors. Conclusions: NLR < 5 was associated with improvement in all measures of outcome while smoking was associated with some. Neither BMI nor PD-L1 were predictive of any outcome. A score incorporating NLR and smoking status may be beneficial in choosing patients for CPIs.

The role of low dose aspirin, vitamin D, or metformin in EGFR, ALK, and ROS positive non-small cell lung cancer: A single institution retrospective analysis

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Background: Tyrosine kinase inhibitor (TKI) is the backbone therapy for EGFR, ALK and ROS positive (pos) non-small cell lung cancer (NSCLC). Metformin has shown to sensitize EGFR resistant lung cancer cells in vitro through IL-6/STAT pathways. COX-2 overexpression triggers activation of a transcription factor that binds to EGFR that activates MAPK signaling pathway. Vitamin D receptor (VDR) has shown to directly inhibit EGFR transcriptional activity. Some studies have shown that adding metformin, aspirin and vitamin D (MAD) to chemotherapy may improve progression free survival (PFS) and overall survival (OS) in lung cancer. However, data supporting use of MAD is unknown in EGFR, ALK and ROS pos NSCLC. Methods: Patients (pts) with EGFR, ALK, ROS pos NSCLC treated with first line TKI from January 2014 to June 2017 were included. Information on concurrent use of MAD was obtained. Patients were dichotomized based on use of these individual supportive medications. Two sample t-test was used to compare mean PFS and chi-square test to compare proportions of disease control rate (DCR) at 3 months between groups. Results: 74 patients were included. Vitamin D supplementation (n = 38, 51.3%) prolonged PFS by 16 m vs 11 m (p = 0.04; 95%CI 0.23 to 9.34). For those on aspirin (n = 23, 35%), mean PFS was 16m vs 12.5 m (p = 0.72; 95% CI -5.58to 3.88). Mean PFS for pts on metformin (n = 8, 10%) was 14 months (m) vs 13.5 m for those who were not (p = 0.93, 95% CI -7.27 to 7.87). DCR for metformin use was 26.5% vs 89% (p = 0.0001); for aspirin was 50% vs 65% (p = 0.17) and for vitamin D 48.6% vs 43.7% (p = 0.69). Conclusions: To our knowledge, no data has been published regarding use of MAD in NSCLC with driver mutations. In our study, concurrent use of vitamin D with TKI prolonged PFS in these pts. However, this effect was not seen with metformin or aspirin. Our study was limited by retrospective design, possible under-reporting of medication use by patients and small patient population. Further prospective studies using these medications is important to evaluate the synergistic benefit with the approved targeted therapy.

An acquired scaffolding function of the DNAJ-PKAc fusion contributes to oncogenic signaling in fibrolamellar carcinoma

Fibrolamellar carcinoma (FLC) is a rare liver cancer. FLCs uniquely produce DNAJ-PKAc, a chimeric enzyme consisting of a chaperonin-binding domain fused to the Cα subunit of protein kinase A. Biochemical analyses of clinical samples reveal that a unique property of this fusion enzyme is the ability to recruit heat shock protein 70 (Hsp70). This cellular chaperonin is frequently up-regulated in cancers. Gene-editing of mouse hepatocytes generated disease-relevant AML12^DNAJ-PKAc cell lines. Further analyses indicate that the proto-oncogene A-kinase anchoring protein-Lbc is up-regulated in FLC and functions to cluster DNAJ-PKAc/Hsp70 sub-complexes with a RAF-MEK-ERK kinase module. Drug screening reveals Hsp70 and MEK inhibitor combinations that selectively block proliferation of AML12^DNAJ-PKAc cells. Phosphoproteomic profiling demonstrates that DNAJ-PKAc biases the signaling landscape toward ERK activation and engages downstream kinase cascades. Thus, the oncogenic action of DNAJ-PKAc involves an acquired scaffolding function that permits recruitment of Hsp70 and mobilization of local ERK signaling.

Fibrolamellar carcinoma (or FLC for short) is a rare type of liver cancer that affects teenagers and young adults. FLC tumors are often resistant to standard radiotherapy or chemotherapy treatments. The only way to treat FLC is to remove tumors by surgery. However, often the tumors come back after initial treatment and spread to other locations. Therefore, there is a genuine need to improve the treatment options available to FLC patients.

The tumor cells of FLC patients contain a genetic defect that fuses together two genes, which produce proteins called DNAJ and PKAc. Normally, DNAJ helps other proteins in the cell to fold into their correct shapes, while PKAc is an enzyme that can control how cells communicate. However, it is not clear what the abnormal DNAJ-PKAc fusion protein does, or how it causes FLC.

Turnham, Smith et al. have now used gene editing to make mouse liver cells that mimic the human FLC mutation. Biochemical experiments on these cells showed that the DNAJ-PKAc protein brings together unique combinations of enzymes that drive uncontrolled cell growth. Analyzing cells taken from tumors in FLC patients confirmed that these enzymes are also activated in the human disease. Turnham, Smith et al. also found that combinations of drugs that simultaneously target the DNAJ-PKAc protein and the recruited enzymes slowed down the growth of FLC cells. More experiments are now needed to test these drug combinations on human FLC cells or in mice.

Necrotizing enterocolitis totalis: High mortality in the absence of an aggressive surgical approach

BACKGROUND

Necrotizing enterocolitis is the leading case of gastrointestinal-related morbidity in premature infants. Necrotizing enterocolitis totalis is an aggressive form of necrotizing enterocolitis, which has traditionally been managed with comfort care. Recent advances in management of short bowel syndrome have resulted in some reported long-term survival.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, studies that reported outcomes in children with necrotizing enterocolitis totalis were identified. The definition of necrotizing enterocolitis totalis was captured along with length of follow-up, patient demographics, and outcomes.

RESULTS

A total of 766 articles were screened, of which 166 were selected for full article review. Of these, 32 articles included data on 414 patients with necrotizing enterocolitis totalis. In the majority of studies (52%), necrotizing enterocolitis totalis was not defined. Aggressive surgical therapy (defined as bowel resection or fecal diversion) was undertaken in 32 patients (7.7%), with a mortality rate of 68.8%. In contrast, nonaggressive surgical therapy was undertaken in 382 patients (92.3%), and the mortality in these patients was 95%. Long-term outcomes for necrotizing enterocolitis totalis survivors, such as length of time on parenteral nutrition, progression to liver and/or small bowel transplant, and quality of life, were not reported.

CONCLUSION

We found that there is no accepted definition of necrotizing enterocolitis totalis. Aggressive surgical therapy is rarely pursued, which likely drives the overall high mortality rate. This study underscores the importance of standardizing the definition of necrotizing enterocolitis totalis and capturing short and long-term outcomes prospectively. With more aggressive surgical therapy, more infants are likely to survive this abdominal catastrophe, which was once thought to be uniformly fatal.

Mobilization of CD8+ T Cells via CXCR4 Blockade Facilitates PD-1 Checkpoint Therapy in Human Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDA) is rarely cured, and single-agent immune checkpoint inhibition has not demonstrated clinical benefit despite the presence of large numbers of CD8⁺ T cells. We hypothesized that tumor-infiltrating CD8⁺ T cells harbor latent antitumor activity that can be reactivated using combination immunotherapy.

EXPERIMENTAL DESIGN

Preserved human PDA specimens were analyzed using multiplex IHC (mIHC) and T-cell receptor (TCR) sequencing. Fresh tumor was treated in organotypic slice culture to test the effects of combination PD-1 and CXCR4 blockade. Slices were analyzed using IHC, flow cytometry, and live fluorescent microscopy to assess tumor kill, in addition to T-cell expansion and mobilization.

RESULTS

mIHC demonstrated fewer CD8⁺ T cells in juxtatumoral stroma containing carcinoma cells than in stroma devoid of them. Using TCR sequencing, we found clonal expansion in each tumor; high-frequency clones had multiple DNA rearrangements coding for the same amino acid binding sequence, which suggests response to common tumor antigens. Treatment of fresh human PDA slices with combination PD-1 and CXCR4 blockade led to increased tumor cell death concomitant with lymphocyte expansion. Live microscopy after combination therapy demonstrated CD8⁺ T-cell migration into the juxtatumoral compartment and rapid increase in tumor cell apoptosis.

CONCLUSIONS

Endogenous tumor-reactive T cells are present within the human PDA tumor microenvironment and can be reactivated by combined blockade of PD-1 and CXCR4. This provides a new basis for the rational selection of combination immunotherapy for PDA.See related commentary by Medina and Miller, p. 3747.

Hypoxia as a barrier to immunotherapy in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease with limited response to cytotoxic chemoradiotherapy, as well as newer immunotherapies. The PDA tumor microenvironment contains infiltrating immune cells including cytotoxic T cells; however, there is an overall immunosuppressive milieu. Hypoxia is a known element of the solid tumor microenvironment and may promote tumor survival. Through various mechanisms including, but not limited to, those mediated by HIF-1α, hypoxia also leads to increased tumor proliferation and metabolic changes. Furthermore, epithelial to mesenchymal transition is promoted through several pathways, including NOTCH and c-MET, regulated by hypoxia. Hypoxia-promoted changes also contribute to the immunosuppressive phenotype seen in many different cell types within the microenvironment and thereby may inhibit an effective immune system response to PDA. Pancreatic stellate cells (PSCs) and myofibroblasts appear to contribute to the recruitment of myeloid derived suppressor cells (MDSCs) and B cells in PDA via cytokines increased due to hypoxia. PSCs also increase collagen secretion in response to HIF-1α, which promotes a fibrotic stroma that alters T cell homing and migration. In hypoxic environments, B cells contribute to cytotoxic T cell exhaustion and produce chemokines to attract more immunosuppressive regulatory T cells. MDSCs inhibit T cell metabolism by hoarding key amino acids, modulate T cell homing by cleaving L-selectin, and prevent T cell activation by increasing PD-L1 expression. Immunosuppressive M2 phenotype macrophages promote T cell anergy via increased nitric oxide (NO) and decreased arginine in hypoxia. Increased numbers of regulatory T cells are seen in hypoxia which prevent effector T cell activation through cytokine production and increased CTLA-4. Effective immunotherapy for pancreatic adenocarcinoma and other solid tumors will need to help counteract the immunosuppressive nature of hypoxia-induced changes in the tumor microenvironment. Promising studies will look at combination therapies involving checkpoint inhibitors, chemokine inhibitors, and possible targeting of hypoxia. While no model is perfect, assuring that models incorporate the effects of hypoxia on cancer cells, stromal cells, and effector immune cells will be crucial in developing successful therapies.

Does the initial surgery for necrotizing enterocolitis matter? Comparative outcomes for laparotomy vs. peritoneal drain as initial surgery for necrotizing enterocolitis in infants <1000 g birth weight

PURPOSE

Quantify short-term outcomes associated with initial surgery [laparotomy (LAP) vs. peritoneal drain (PD)] for necrotizing enterocolitis (NEC) in extremely-low-birth-weight (ELBW) infants.

METHODS

Using the Children's Hospitals Neonatal Database, we identified ELBW infants <32 weeks' gestation with surgical NEC (sNEC). Unadjusted and multivariable regression analyses were used to estimate the associations between LAP (or PD) and death/short bowel syndrome (SBS) and length of stay (LOS).

RESULTS

LAP was the more common initial procedure for sNEC (n = 359/528, 68%). Infants receiving LAP were older and heavier. Initial procedure was unrelated to death/SBS in both bivariate (LAP: 43% vs PD: 46%, p = 0.573) and multivariable analyses (OR = 0.89, 95% CI = 0.57, 1.38, p = 0.6). LAP was inversely related to mortality (29% vs. 41%, p < 0.007) in bivariate analysis, but not significant in multivariable analysis accounting for markers of preoperative illness severity. However, the association between LAP and SBS (14% vs. 5%, p = 0.012) remained significant in multivariable analyses (adjusted OR = 2.25, p = 0.039). LOS among survivors was unrelated to the first surgical procedure in multivariable analysis.

CONCLUSION

ELBW infants who undergo LAP as the initial operative procedure for sNEC may be at higher risk for SBS without a clear in-hospital survival advantage or shorter hospitalization.

LEVEL OF EVIDENCE

Level II.

Abstract A156: PDA tumor cell death as following combination anti-PD-1 blockade and CXCR4 blockade is a direct effect of CD8+ T-cells

Introduction: Pancreatic ductal adenocarcinoma (PDA) is the fourth most common cause of cancer death in the United States. Despite the fact that the human PDA microenvironment contains a mixture of infiltrating immune cells, including activated effector CD8+ T-cells, attempts to apply immune checkpoint inhibitor therapy have not yet been successful in achieving a clinical response (1). Combining blockade of the immune checkpoint receptor PD-1 with blockade of the chemokine receptor CXCR4 in a mouse model of PDA produced T-cell-mediated tumor cell killing (2). We therefore hypothesized that, in a human PDA slice culture model system that maintains the intact tumor microenvironment (3), combination of CXCR4 blockade with PD-1 blockade would lead to anti-tumor T-cell activation. Methods: Cores (6 mm) were taken from freshly resected, sterile human PDA specimens and cut into 250 µm thick slices using a vibratome. The slices were treated with either IgG antibody isotype control, AMD3100 (a CXCR4 blocking small molecule drug) plus antibody isotype control, anti-PD-1 antibody, or a combination of anti-PD-1 antibody and AMD3100 for two days. The slices were then stained with fluorescently labelled antibodies for CD8 and EpCAM, as well as with SR-FLICA, a reagent that produces a fluorescent signal when bound to activated Caspase 3 and 7 enzymes. Live slices were maintained in a humidified, temperature-controlled CO2 chamber for time-lapse confocal imaging for 1 hour. Similarly, untreated slices were imaged for 90 minutes prior to and following combined anti-PD-1 and AMD3100 drug treatment. Each slice was imaged at 3 different positions to observe CD8+ T-cells, EpCAM+ tumor cells, and SR-FLICA+ apoptotic cells throughout the slice. Each cell type was counted at each position over the entire time course imaged. Results: Compared to antibody isotype control or monotherapy, slices treated with combined PD-1 and CXCR4 blockade contained a greater fraction of EpCAM+ tumor cells that were undergoing apoptosis, indicated by SR-FLICA positivity. This treatment also increased the proportion of EpCAM+ tumor cells with a CD8+ T-cell within 20 µm, and EpCAM+ cells had increased evidence of apoptosis when a CD8+ cell was nearby. When individual slices were imaged before and after combined PD-1 and CXCR4 blockade, a greater proportion of EpCAM+ cells were found to have a CD8+ cell nearby after treatment compared to before treatment, and the tumor cells with a CD8+ cell nearby were more like to be undergoing apoptosis compared to before treatment. Conclusion: Direct visualization of live pancreatic cancer slice cultures demonstrates that combined PD-1 and CXCR4 blockade enhances both the migration of CD8+ T-cells towards epithelial tumor cells and their anti-tumor cytotoxic activity. References: 1. Shibuya KC, Goel VK, Xiong W, Sham JG, Pollack SM, Leahy AM, et al. Pancreatic ductal adenocarcinoma contains an effector and regulatory immune cell infiltrate that is altered by multimodal neoadjuvant treatment. PLoS One 2014;9(5):e96565. 2. Feig C, Jones JO, Kraman M, Wells RJ, Deonarine A, Chan DS, et al. Targeting CXCL12 from FAP-expressing carcinoma-associated fibroblasts synergizes with anti-PD-L1 immunotherapy in pancreatic cancer. Proc Natl Acad Sci U S A 2013;110(50):20212-7. 3. Jiang X, Seo YD, Chang JH, Coveler A, Nigjeh EN, Pan S, et al. Long-lived pancreatic ductal adenocarcinoma slice cultures enable precise study of the immune microenvironment. Oncoimmunology 2017;6(7).

Citation Format: Kevin M. Sullivan, Yongwoo David Seo, Xiuyun Jiang, Teresa David Kim, Raymond S.W. Yeung, Venu G. Pillarisetty. PDA tumor cell death as following combination anti-PD-1 blockade and CXCR4 blockade is a direct effect of CD8+ T-cells [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A156.

Road map for fibrolamellar carcinoma: progress and goals of a diversified approach

Fibrolamellar carcinoma is a rare liver cancer, which primarily afflicts adolescents and young adults worldwide and is frequently lethal. Given the rarity of this disease, patient recruitment for clinical trials remains a challenge. In November 2017, the Second Fibrolamellar Cancer Foundation Scientific Summit (Stamford, CT, USA) provided an opportunity for investigators to discuss recent advances in the characterization of the disease and its surrounding liver and immune context. The Fibrolamellar Cancer Foundation has thus set out a road map to identify and test therapeutic targets in the most efficient possible manner.

The Use and Availability of Anthropometry Software

This paper describes the recent availability of microcomputer software for computing paediatric anthropometry-specifically height-for-age, weight-for-height, and weight-for-age indices based on the CDC/WHO international reference population. The primary software packages discussed are CASE, Epi Info, Anthro, ISSA, and IQ.

Abstract 1005: Combination T cell receptor immunosequencing and multiplex immunohistochemistry reveal novel insights into the immune response to human pancreatic cancer

Background: Despite advancements in therapy, pancreatic ductal adenocarcinoma (PDA) remains an aggressive cancer with high mortality. It is characterized by dense inflammation, including many T cells; however, it is unclear whether these T cells signify true anti-tumor response. In the setting of disappointing results of immunotherapy in PDA, we sought to gain a deeper understanding of the intratumoral T cell response.

Methods: With IRB approval, we obtained archival resected PDA tumors in paraffin embedded blocks from 54 patients and performed T cell receptor (TCR) immunosequencing on extracted DNA. Productive clonality was defined as 1-Pielou's evenness; TCR fraction was calculated from number of observed templates versus housekeeping genes. Multiplex immunohistochemistry (IHC) was performed on slides immediately adjacent to blocks sent for TCR sequencing using the PerkinElmer Vectra system. False H&E images generated from autofluorescence signatures were analyzed by a pathologist to categorize peritumoral stroma versus lymphoid tissue. Image analysis was performed using FlowJo10, turning object fluorescence data into cytometric outputs. Correlation analysis between multiplex and TCR data was performed using Pearson's correlation.

Results: Mean TCR fraction was 0.27, and mean clonality was 0.15 (typical peripheral blood clonality is 0.08). TCR fraction was positively correlated with clonality (R2=0.23, p=0.007), but there was no survival difference between high or low TCR fraction or clonality. 3.1 million individual cells within the peritumoral stroma were phenotyped in total using multiplex IHC; within the stroma, CD4 T cells, CD8 T cells, and macrophages made up on average 4.6%, 6.8%, and 2.0% of all cells analyzed. 35.6% of CD8 T cells were positive for PD-1, while 20.8% of CD4 cells were FOXP3+ regulatory T cells (Treg). TCR fraction correlated positively with infiltration of CD8+ (R2=0.28, p=0.03) and CD68+ (R2=0.27, p=0.03) cells, but not CD4 cells. Only CD8 cells which were PD-1- correlated positively with clonality (R2=0.26, p=0.04). The presence of Treg correlated very strongly with CD8+PD-1+ cells (R2=0.44, p=0.0004).

Conclusion: Here we demonstrate a novel approach to describe the varying immunophenotypic landscape of human PDA depending on the clonal expansion of intratumoral T cells. T cell infiltration appear to be correlated mostly with CD8 T cells as well as the presence of macrophages. Patients with more clonal expansion also had more CD8 cells that lacked the exhaustion marker PD-1, and the presence of regulatory T cells accompanied environments where CD8 cells were positive for PD-1. These data suggest that cytotoxic T cell exhaustion is a phenomenon which may be regulated by Treg and have a negative impact on clonal expansion of intratumoral T cells in human PDA.

Citation Format: Yongwoo David Seo, Florencia Jalikis, Xiuyun Jiang, Kevin M. Sullivan, Marissa Vignali, Harlan Robins, Venu G. Pillarisetty. Combination T cell receptor immunosequencing and multiplex immunohistochemistry reveal novel insights into the immune response to human pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1005.

Precision oncology in liver cancer

With the widespread adoption of molecular profiling in clinical oncology practice, many physicians are faced with making therapeutic decisions based upon isolated genomic alterations. For example, epidermal growth factor receptor tyrosine kinase inhibitors (TKIs) are effective in EGFR-mutant non-small cell lung cancers (NSCLC) while anti-EGFR monoclonal antibodies are ineffective in Ras-mutant colorectal cancers. The matching of mutations with drugs aimed at their respective gene products represents the current state of "precision" oncology. Despite the great expectations of this approach, only a fraction of cancers responds to 'targeted' interventions, and many early responders will ultimately develop resistance to these agents. The underwhelming success of mutation-driven therapies across all cancer types is not due to an inability to detect genetic changes in tumors; rather a deficit in functional insight into the genomic alterations that give rise to each cancer. The Achilles heel of precision oncology thus remains the lack of a robust functional understanding of an individual cancer genome that then allows prediction of the best therapy and resultant outcome for that patient. Current practice focuses on one 'actionable' mutation at a time, while solid cancers typically possess many mutations that involve different cellular sub-populations within a tumor. No method or platform currently exists to guide the interpretation of these complex data, nor to accurately predict response to treatment. This problem is particularly germane to primary liver cancers (PLC), for which only a handful of targeted therapies have been introduced. Here, we will review strategies aimed at overcoming some of these challenges in precision oncology, using liver cancer as an example.

New PD-L1 inhibitors in non-small cell lung cancer - impact of atezolizumab

The era of immunotherapy has changed the face of how we approach treatment for many oncologic and hematologic malignancies. Lung cancer has been in the forefront of checkpoint inhibition for the past 2 years and has paved the path for other subspecialties. While PD-1 inhibitors nivolumab and pembrolizumab have been approved for non-small cell lung cancer (NSCLC), this review focuses on atezolizumab, its landmark studies, and ongoing trials. Atezolizumab is the first programmed death ligand 1 (PD-L1) inhibitor to receive US Food and Drug Administration (FDA) approval for metastatic NSCLC patients who have progressed on frontline chemotherapy. This approval was based on two open-label Phase II multicenter trials, POPLAR (NCT01903993) and BIRCH (NCT02031458). Both studies revealed a benefit in overall survival (OS), progression-free survival, and response rate in the atezolizumab arm when compared to single-agent docetaxol. There were also fewest Grade 3–5 treatment-related adverse events (TRAEs) in the atezolizumab cohort. The open-label randomized Phase III OAK trial (NCT02008227) further established the role of atezolizumab in previously treated NSCLC. This study compared atezolizumab with docetaxel in patients with advanced NSCLC (squamous or nonsquamous histologies) who had progressed on one to two prior chemotherapy regimens. OS in the PD-L1-enriched population was superior in the atezolizumab arm (n=241) at 15.7 months compared with docetaxel (n=222) at 10.3 months (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.58–0.93; p=0.0102). Patients lacking PD-L1 also had survival benefit with atezolizumab with a median OS (mOS) of 12.6 months versus 8.9 months with chemotherapy (HR 0.75, 95% CI 0.59–0.96). Benefit was noted in both squamous and nonsquamous NSCLC subsets and regardless of PD-L1 expressivity. As seen in the POPLAR and BIRCH studies, the toxicity profile was significantly better with immunotherapy. The future is unfolding rapidly as new checkpoint inhibitors are gaining FDA approval. It is still not known if these agents will be used in combination with chemotherapy, with other immune-modulating agents, radiation therapy, or all of the above. The results of these studies investigating their use in combination with chemotherapy agents, with other immunotherapy agents such as CTLA-4 inhibitors, and with radiation therapy, are eagerly awaited.

The utilization of pre-treatment neutrophil to lymphocyte ratio as a predictive marker for response to nivolumab therapy in non small cell lung cancer

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Background:The tumor immune environment is integral in lung cancer progression. Cancer cells attract neutrophils through chemokine signaling pathyways into the tumor stroma. Neutrophils promote angiogenesis, metastasis and inhibit apoptosis whereas lymphocytes assist with tumor defense. Increased peritumoral neutrophil-to-lymphocyte ratio (NLR) has been shown to mediate T cell anergy and tumor immune evasion. In solid tumor pre-clinical models, elevated blood NLR correlates with increased tumor neutrophil infiltration and decreased CD3(+) T-cell infiltration. Immunotherapy is a promising anticancer strategy in Non-Small Cell Lung Cancer (NSCLC). We hypothesized that peripheral blood NLR could serve as a predictive marker for clinical benefit (CB) from this intervention. Methods:A single institution retrospective analysis of 81 patients with NSCLC treated with Nivolumab from July 2015 to November 2016. Each patient’s NLR was calculated prior to starting Nivolumab. A cut-off of 5 categorized NLR as high or low based on prior studies. The presence or absence of CB (objective response or stable disease per RECIST 1.1) after at least 3 months of therapy was determined. Descriptive statistics were utilized to summarize the data. Fischer exact test was used to compare proportions and student t test to compare means. Results:79 patients were included. 54 (68%) had low NLR and 25 (31.6%) had high NLR. 44 patients (81.48%) in the low NLR group and 7 (28%) in the high NLR group experienced CB (28%) at 3 months. This difference was statistically significant (P = 0.0001). The mean time to progression(TTP) for the low NLR population was 5.53 months, as compared to 2.39 months in the high NLR group( p = 0.0001) (95% confidence interval 1.59 to 4.55).The mean TTP in the CB cohort was 6.42 months in the low NLR group and 4.43 months in the high NLR group (p = 0.0052 ) (95% CI 0.61 to 3.39). Conclusions:The immune response to cancer is lymphocyte dependent. In our study, the majority of patients with low NLR experienced CB from Nivolumab whereas most of the patients with elevated NLR did not. NLR as a predictive biomarker should be further investigated in large prospective studies.

Immune checkpoint inhibitors in lung cancer: past, present and future

Inhibitory ligands on tumor cells and their corresponding receptors on T cells are collectively called immune checkpoint molecules and have emerged as druggable targets that harness endogenous immunity to fight cancer. Immune checkpoint inhibitors targeting CTLA-4, PD-1 and PD-L1 have been developed for the treatment of patients with non-small-cell lung cancer and other malignancies, with impressive clinical activity, durable responses and a favorable toxicity profile. This article reviews the development, current status and future directions for some of these agents. The efficacy and safety data for drugs such as ipilimumab, nivolumab, pembrolizumab, atezolizumab and durvalumab are reviewed, along with combination strategies and response evaluation criteria. The toxicity profiles and predictive biomarkers of response are also discussed.