ALLIANCE A022104/NRG-GI010: The Janus Rectal Cancer Trial: a randomized phase II/III trial testing the efficacy of triplet versus doublet chemotherapy regarding clinical complete response and disease-free survival in patients with locally advanced rectal cancer

Background

Recent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients with clinical complete response (cCR) after neoadjuvant therapy may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated cCR as a primary endpoint. Collaborating with a multidisciplinary oncology team and patient groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation, improve quality of life for patients and improve survival outcomes.

Methods

In this NCI-sponsored multi-group randomized, seamless phase II/III trial (1:1), up to 760 patients with LARC, T4N0, any T with node positive disease (any T, N+) or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N+ vs N0) and distance from anal verge (0-4; 4-8; 8-12 cm). Patients will be randomized to receive neoadjuvant long course chemoradiation (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 3-4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Patients will undergo assessment 8-12 (+/- 4) weeks post-TNT completion. The primary endpoint for the phase II portion will compare cCR between treatment arms. A total number of 296 evaluable patients (148 per arm) will provide statistical power of 90.5% to detect an 17% increase in cCR rate, at a one-sided alpha=0.048. The primary endpoint for the phase III portion will compare disease-free survival (DFS) between treatment arms. A total of 285 DFS events will provide 85% power to detect an effect size of hazard ratio 0.70 at a one-sided alpha of 0.025, requiring enrollment of 760 patients (380 per arm). Secondary objectives include time-to event outcomes (overall survival, organ preservation time and time to distant metastasis) and adverse effects. Biospecimens including archival tumor tissue, plasma and buffy coat in EDTA tubes, and serial rectal MRIs will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and has a current accrual of 312. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org .

Discussion

Building off of data from modern day rectal cancer trials and patient input from national advocacy groups, we have designed the current trial studying chemotherapy intensification via a consolidation chemotherapy approach with the intent to enhance cCR and DFS rates, increase organ preservation rates, and improve quality of life for patients with rectal cancer.

Trial Registration

Clinicaltrials.gov ID: NCT05610163 ; Support includes U10CA180868 (NRG) and U10CA180888 (SWOG).

The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Abstract A005: Genomic profiling identifies differences in the distribution of APC mutations in non-Hispanic black and non-Hispanic white patients with colorectal cancer

Intro: We compared molecular profiles of a large cohort of colorectal cancer patients treated at a single tertiary center to better understand the role of genomic factors for explaining differences in clinical outcomes of non-Hispanic black (NHB) vs. non-Hispanic white (NHW) patients. Methods: We analyzed targeted DNA sequencing data from 4,322 colorectal adenocarcinoma patients treated at Memorial Sloan Kettering Cancer Center, including 366 patients self-identified as NHB and 3,956 patients who self-identified as NHW. Tumors were sequenced using the MSK-IMPACT assay, a targeted sequencing platform that identifies somatic mutations, copy number changes, and gene fusions in a selected panel of 341-505 genes in tumor tissue compared to a matched normal blood sample. Genetic ancestry was estimated using reference populations from the 1000 Genomes Project, including European (EUR), African (AFR), East Asian (EAS), South Asian (SAS), and Native American (NAM). Patients were assigned specific ancestry labels when the corresponding ancestry fraction was above 80%. Results: Self-reported race and genetic ancestry were highly concordant, with 225/235, 95.7% of AFR patients self-reporting as NHB and 3215/3216, 99.96% of EUR patients self-reporting as NHW. While tumors from AFR patients were more often located in the right colon (43.27% vs. 30.56%, p<0.001), they were also found to be less frequently microsatellite-instable (MSI) when compared to tumors from EUR patients (5.96% vs. 11.1%, p=0.026). Among right-sided cases, MSI tumors accounted only for 7.8% of AFR patients vs. 26.4% in EUR cases (p<0.0001). Among MSS cases, tumors from AFR patients had a higher frequency of KRAS (59.1% vs. 44.7%, p<0.0001) and SMAD2 (7.72% vs. 3.59%, p=0.006) mutations, as well as a lower frequency of BRAF mutations (3.18% vs. 7.22%, p=0.019). While the frequency of APC mutations was similar in both groups (77.45% vs. 72.98%, p=0.147), APC mutations in tumors from AFR patients were more frequently located within the C-terminal part of the protein (i.e., beyond the first 1400 amino acids), both when all tumors were analyzed together (50.0% vs. 38.5%, p=0.003) and when the analysis was restricted to non-hypermutated, microsatellite-stable (MSS) cases (48.0% vs. 35.5%, p=0.001). This higher frequency of C-terminal side mutations was also seen in self-reported Black/African American MSS colorectal cancer patients from AACR Project GENIE (58.9% vs 41.3%, p < 0.001) and The Cancer Genome Atlas (61.1% vs 40%, p = 0.026). This type of distal APC mutations, which are considered “weak activators” of Wnt signaling, have been linked to more aggressive tumors due to concurrent activation of alternative mitogenic pathways such as ERK or PI3K. Conclusion: Some of the genomic differences between NHB and NHW patients that we had previously identified based on self-reported race were confirmed using analyses of genetic ancestry. We also present preliminary data demonstrating racial differences in the distribution of inactivating somatic mutations within the APC gene.

Citation Format: Henry Walch, Anisha Luthra, Walid Chatila, Kanika Arora, Samantha Chin, Michele Waters, Jesse J. Smith, Nikolaus Schultz, Michael F. Berger, Karuna Ganesh, Julio Garcia-Aguilar, Rona Yaeger, Francisco Sanchez-Vega. Genomic profiling identifies differences in the distribution of APC mutations in non-Hispanic black and non-Hispanic white patients with colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr A005.

Minimum standards of pelvic exenterative practice: PelvEx Collaborative guideline

This document outlines the important aspects of caring for patients who have been diagnosed with advanced pelvic cancer. It is primarily aimed at those who are establishing a service that adequately caters to this patient group. The relevant literature has been summarized and an attempt made to simplify the approach to management of these complex cases.

P-147 LAPAROSCOPIC SURGERY IS SUITABLE FOR MOST PATIENTS FOR INGUINAL HERNIA REPAIR AND IS AN EXCELLENT OPTION IN EXPERT HANDS

Introduction

This study reviews the practice of a high-volume surgeon, comparing laparoscopic and open surgery for inguinal hernia. In suitable patients the default was laparoscopic Totally Extra Peritoneal (TEP) approach.

Materials & Methods

Data from patients referred over 5 years with inguinal hernias was collated prospectively and analysed retrospectively. Short and long-term outcomes of laparoscopic and open repairs were compared.

Results

205 patients underwent repair of 288 hernias (90.7% laparoscopic, 9.3% open). 83 patients underwent bilateral repair (95.2% laparoscopic). 22 patients underwent repair of 27 recurrent hernias (68% laparoscopic).

1 case (0.5%), started laparoscopically was converted to open. Complication rates were 13.4% vs 36.8% in the laparoscopic and open arms respectively (p<0.01): superficial infection (1.6% vs 0%, p=0.58); haematoma (6.3% vs 15.8%, p=0.14); seroma (4.8% vs 5.3%, p=0.94); persisting numbness (0% vs 5.3%, p<0.01) and chronic pain (1.1% vs 0%, p=0.65). No patients suffered mesh infections or explantation.

Mean stay was significantly longer in open group (p=0.03), median stay was 0 nights in both groups. At median follow up 1.8 years (Interquartile-range 0.9–3.6 years) recurrence rate was 1.1% (0 female, 2 male) and 15.8% (1 female, 2 male) in the laparoscopic and open arms respectively (p<0.01). Open surgery was associated with significantly higher risk of recurrence (HR: 16.3, 95% CI: 2.7–97.8, p<0.01).

Conclusions

This series demonstrates the vast majority of inguinal hernias, both primary and recurrent can be treated with laparoscopic TEP repair. Higher recurrence and complication rates were associated with open repair, with a caveat of strong selection bias.

OC-029 LAPAROSCOPIC INGUINAL HERNIA REPAIR IS FEASIBLE IN PATIENTS WHO HAVE HAD PREVIOUS ABDOMINO-PELVIC SURGERY WITH NO INCREASED RISK OF COMPLICATIONS COMPARED TO OPEN REPAIR

Introduction

This study aims to understand whether previous abdomino-pelvic (AP) surgery is a predictor of peri-operative complication in inguinal hernia surgery and if there are discrepancies between laparoscopic or open repairs.

Material & Methods

All patients operated on within a 5-year period were audited and subcategorised based upon history of AP surgery. Patients were also categorised into laparoscopic and open groups. Data collected included complication rates, recurrence rates and readmission within 30 days.

Results

205 patients underwent repair of 288 hernias. 80 (39%) patients had a history of AP surgery. 32 patients suffered a complication (15.6%). 85% of the repairs were laparoscopic in the AP group vs 96.4% in the non-AP group (p=0.02). Complication rates were 17.5% and 14.4% in the AP group and non-AP group respectively (p=0.55). These included superficial infection (0% vs 2.4%, p=0.16), haematoma (11.3% vs 4.8%, p=0.08), seroma (5.0% vs 4.8%, p=0.95), persisting numbness (0% vs 0.8%, p=0.42), and chronic pain (1.3% vs 0.8%, p=0.75). There were no mesh infections or explantation in either arm. A greater proportion of patients in AP group required overnight stays (32.5% vs 21%, p=0.08). At median follow up 1.8 years, recurrence rates were 3.8% vs 1.6%, p=0.33 in AP and non-AP groups respectively.

Conclusions

Laparoscopic inguinal hernia is feasible in most patients with a history of AP surgery. Compared to open repair, there were no significant differences in recurrence or complication rates in patients with previous AP surgery. Therefore, previous AP surgery should not be a contraindication for laparoscopic repair.

P-048 DOES BILATERAL REPAIR INCREASE COMPLICATION RATES COMPARED TO UNILATERAL REPAIR IN PATIENTS UNDERGOING LAPAROSCOPIC TOTALLY EXTRAPERITONEAL INGUINAL HERNIA SURGERY?

Introduction

There is ongoing debate over whether to fix asymptomatic contralateral inguinal hernias during repair of the presenting hernia. This study reviewed the practice of one high-volume hernia surgeon, comparing unilateral and bilateral laparoscopic repairs, to establish if bilateral repair is associated with an increased risk of post-operative complications compared to unilateral repair.

Material & Methods

All patients operated on within a 5-year period were audited and subcategorised depending on whether they underwent unilateral or bilateral repair. Data was collected on complication rates, rates of recurrence, readmission within 30 days and duration of operation.

Results

186 patients underwent repair of 265 hernias. 79 patients underwent bilateral repair. 25 patients suffered a complication (13.4%). Complication rates were 11.2% and 16.5% in the unilateral group and bilateral group respectively (p=0.50). These included superficial infection (1.9% vs 1.3%, p=0.75), haematoma (5.6% vs 7.6%, p=0.59), seroma (2.8 vs 7.6%, p=0.13), and chronic pain (0% vs 2.5%, p=0.01). There were no mesh infections, persisting numbness or explantation in either arm. In both groups, median nights stayed was 0. At median length of follow-up of 1.8 years, recurrence rates were 1.9% vs 0% in the unilateral and bilateral arms respectively (p=0.22).

Conclusions

There was no significant difference in rates of complications between the bilateral and unilateral arms. Opportunistic repair may reduce risk of future surgeries and morbidity and does not appear to be associated with increased complications. Surgeons may wish to consider this when consenting patients.

Abstract 3634: Integrative analysis of the contribution of genomic and clinical factors to worse clinical outcomes in non-Hispanic Black patients with colorectal cancer

Non-Hispanic Black (NHB) patients have higher incidence and higher mortality from colorectal cancer (CRC) than non-Hispanic white (NHW) patients. The extent to which this aggressive behavior in NHB patients is driven by differences in cancer genomics is presently unknown.

We analyzed clinical and genomic data from 3,963 CRC patients treated at Memorial Sloan Kettering, including 336 (8%) NHB and 3,627 (92%) NHW patients. Tumors were sequenced using the clinical MSK-IMPACT test, a targeted next-generation DNA sequencing assay that identifies mutations, copy number changes and structural rearrangements in 341-505 genes using solid tissue and matched blood.

No significant differences by race were observed for stage at diagnosis or sex. While the difference in median age at diagnosis was small (53.4 for NHB vs. 55 years for NHW patients, p=0.012), significantly fewer NHB patients were diagnosed after 65 years of age (17% vs. 27%, p=0.001). Right-sided colon tumors were more common among NHB patients (37% vs. 25%, p=0.02); the proportion of rectal tumors was similar in both racial groups (31% in NHB vs. 34% in NHW patients, n.s.). Hypermutated tumors, including tumors with microsatellite instability (MSI) and POLE hypermutants, were more frequent among NHW patients (12% vs. 8%, p=0.02). Right-sided tumors were more frequently MSI/hypermutated in the NHW patients (27% vs. 13%, p=0.008), whereas no differences by race were observed for left-sided colon (5% vs. 1%, n.s.) or rectal primaries (4% vs. 5%, n.s.).

Genomic analysis of the non-hypermutated tumors revealed no significant differences in tumor mutational burden or fraction of genome altered between racial groups. Tumors in NHB patients were enriched in KRAS mutations (60% vs. 45%, p<0.001), but G12C mutations accounted only for 3% of all driver KRAS mutations in NHB patients vs. 8% of all driver mutations in NHW patients (p=0.01). BRAF mutations were more frequent in non-hypermutated NHW patients (7% vs. 3%, p=0.006), but the overall frequency of RTK/RAS pathway alterations was higher in the NHB group (74% vs. 66%, p=0.004).

Even though all patients were treated at the same single institution during the study, NHB patients had shorter overall survival (OS) from the time of sequencing (median 28 months [95% CI 25-38] vs. 50 months [95% CI 47-53], p<0.001). NHB patients also had worse OS [HR 1.64, CI 1.3 - 2.1, p<0.001] in a multivariate analysis using Cox Proportional-Hazards and accounting for age at diagnosis, stage at diagnosis, body mass index, primary tumor location, MSI status and oncogenic alterations in APC, TP53, KRAS, SMAD4, and BRAF.

Our data confirms that NHB patients with CRC have worse clinical outcomes than NHW patients. Clinically relevant differences in the frequency of alterations in cancer driver genes are observed based on racial origin, but they do not fully explain the difference in survival.

Citation Format: Henry Walch, Anisha Luthra, Walid K. Chatila, Fan Wu, Debyani Chakravarty, Chin-Tung Chen, Rupa Sood, Dana M. Omer, Jesse J. Smith, Nikolaus Schultz, Karuna Ganesh, Julio Garcia-Aguilar, Rona Yaeger, Francisco Sanchez-Vega. Integrative analysis of the contribution of genomic and clinical factors to worse clinical outcomes in non-Hispanic Black patients with colorectal cancer [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 3634.

Partial Ribosomal Nontranscribed Spacer Sequences Distinguish Rhagoletis zephyria (Diptera: Tephritidae) From the Apple Maggot, R. pomonella

The apple maggot, Rhagoletis pomonella (Walsh), was introduced into the apple-growing regions of the Pacific Northwest in the U.S.A. during the past 60-100 yr. Apple maggot (larvae, puparia, and adults) is difficult to distinguish from its morphologically similar sister species, Rhagoletis zephyria Snow, which is native and abundant in the Pacific Northwest. While morphological identifications are common practice, a simple, inexpensive assay based on genetic differences would be very useful when morphological traits are unclear. Here we report nucleotide substitution and insertion-deletion mutations in the nontranscribed spacer (NTS) of the ribosomal RNA gene cistron of R. pomonella and R. zephyria that appear to be diagnostic for these two fly species. Insertion-deletion variation is substantial and results in a 49 base-pair difference in PCR amplicon size between R. zephyria and R. pomonella that can be scored using agarose gel electrophoresis. PCR amplification and DNA sequencing of 766 bp of the NTS region from 38 R. pomonella individuals and 35 R. zephyria individuals from across their geographic ranges led to the expected PCR fragments of approx. 840 bp and 790 bp, respectively, as did amplification and sequencing of a smaller set of 26 R. pomonella and 16 R. zephyria flies from a sympatric site in Washington State. Conversely, 633 bp mitochondrial COI barcode sequences from this set of flies were polyphyletic with respect to R. pomonella and R. zephyria. Thus, differences in NTS PCR products on agarose gels potentially provide a simple way to distinguish between R. pomonella and R. zephyria.

Postoperative chemotherapy improves survival in patients with resected high-risk Stage II colorectal cancer: results of a systematic review and meta-analysis

AIM

The aim was to assess the benefit of adjuvant chemotherapy in high-risk Stage II colorectal cancer.

METHOD

A systematic literature review and meta-analysis was performed comparing survival in patients with resected Stage II colorectal cancer and high-risk features having postoperative chemotherapy vs no chemotherapy.

RESULTS

Of 1031 articles screened, 29 were included, reporting on 183 749 participants. Adjuvant chemotherapy significantly improved overall survival [hazard ratio (HR) 0.61, P < 0.0001], disease-specific survival (HR = 0.73, P = 0.05) and disease-free survival (HR = 0.59, P < 0.0001) compared to no chemotherapy. Adjuvant chemotherapy significantly increased 5-year overall survival (OR = 0.53, P = 0.0008) and 5-year disease-free survival (OR = 0.50, P = 0.001). Overall survival and disease-free survival remained significantly prolonged during subgroup analysis of studies published from 2015 onwards (HR = 0.60, P < 0.0001; HR = 0.65, P = 0.0001; respectively), in patients with two or more high-risk features (HR = 0.59, P = 0.0001; HR = 0.70, P = 0.03; respectively) and in colon cancer (HR = 0.61, P < 0.0001; HR = 0.51, P = 0.0001; respectively). Overall survival, disease-specific survival and disease-free survival during subgroup analysis of individual high-risk features were T4 tumour (HR = 0.58, P < 0.0001; HR = 0.50, P = 0.003; HR = 0.75, P = 0.05), < 12 lymph nodes harvested (HR = 0.67, P = 0.0002; HR = 0.80, P = 0.17; HR = 0.72, P = 0.02), poor differentiation (HR = 0.84, P = 0.35; HR = 0.85, P = 0.23; HR = 0.61, P = 0.41), lymphovascular or perineural invasion (HR = 0.55, P = 0.05; HR = 0.59, P = 0.11; HR = 0.76, P = 0.05) and emergency surgery (HR = 0.60, P = 0.02; HR = 0.68, P = 0.19).

CONCLUSION

Adjuvant chemotherapy in high-risk Stage II colorectal cancer results in a modest survival improvement and should be considered on an individual patient basis. Due to potential heterogeneity and selection bias of the included studies, and lack of separate rectal cancer data, further large randomized trials with predefined inclusion criteria and standardized chemotherapy regimens are required.

Identification of immune and non-immune cells in regenerating axolotl limbs by single-cell sequencing

Immune cells are known to be critical for successful limb regeneration in the axolotl (Ambystoma mexicanum), but many details regarding their identity, behavior, and function are yet to be resolved. We isolated peripheral leukocytes from the blood of adult axolotls and then created two samples for single-cell sequencing: 1) peripheral leukocytes (N = 7889) and 2) peripheral leukocytes with presumptive macrophages from the intraperitoneal cavity (N = 4998). Using k-means clustering, we identified 6 cell populations from each sample that presented gene expression patterns indicative of erythrocyte, thrombocyte, neutrophil, B-cell, T-cell, and myeloid cell populations. A seventh, presumptive macrophage cell population was identified uniquely from sample 2. We then isolated cells from amputated axolotl limbs at 1 and 6 days post-amputation (DPA) and performed single cell sequencing (N = 8272 and 9906 cells respectively) to identify immune and non-immune cell populations. Using k-means clustering, we identified 8 cell populations overall, with the majority of cells expressing erythrocyte-specific genes. Even though erythrocytes predominated, we used an unbiased approach to identify infiltrating neutrophil, macrophage, and lymphocyte populations at both time points. Additionally, populations expressing genes for epidermal cells, fibroblast-like cells, and endothelial cells were also identified. Consistent with results from previous experimental studies, neutrophils were more abundant at 1 DPA than 6 DPA, while macrophages and non-immune cells exhibited inverse abundance patterns. Of note, we identified a small population of fibroblast-like cells at 1 DPA that was represented by considerably more cells at 6 DPA. We hypothesize that these are early progenitor cells that give rise to the blastema. The enriched gene sets from our work will aid future single-cell investigations of immune cell diversity and function during axolotl limb regeneration.

Risk factors associated with progression to referable retinopathy: a type 2 diabetes mellitus cohort study in the Republic of Ireland

AIM

To determine factors associated with progression to referable diabetic retinopathy in people with type 2 diabetes in the Republic of Ireland.

RESEARCH DESIGN AND METHODS

The study was conducted in a dynamic cohort of 2770 people with type 2 diabetes, recruited between April 2005 and July 2013. Systemic factors (systolic and diastolic blood pressure, HbA_1c , lipid levels, BMI) and baseline diabetic retinopathy grading results were evaluated at 4-monthly and yearly intervals, respectively. Associations between risk factors (most recently recorded value, and rate of change in value between pairs of consecutive systemic evaluations) and development of referable diabetic retinopathy were estimated using Cox proportional hazards models.

RESULTS

There was a fourfold increased risk of progression to referral when retinopathy was present at baseline vs no retinopathy at baseline (hazard ratio 4.02, 95% CI 2.80-5.78; P<0.001). Higher current values of HbA_1c (hazard ratio 1.22, 95% CI 1.11-1.34; P<0.001), systolic blood pressure (hazard ratio 1.29, 95% CI 1.15-1.45; P<0.001) and triglycerides (hazard ratio 1.10, 95% CI 1.03-1.18; P=0.004) were associated with increased risk of referral. Higher current BMI (hazard ratio 0.83, 95% CI 0.73-0.95; P=0.007) and diastolic blood pressure (hazard ratio 0.91, 95% CI 0.85-0.97; P=0.006) were associated with reduced risk of referral.

CONCLUSIONS

Presence of retinopathy at baseline was strongly associated with increased risk of referral. Modest associations between systemic factors and risk of progression to referable retinopathy were detected.

Changes in the multidisciplinary management of rectal cancer from 2009 to 2015 and associated improvements in short-term outcomes

AIM

Significant recent changes in management of locally advanced rectal cancer (LARC) include preoperative staging, use of extended neoadjuvant therapies and minimally invasive surgery (MIS). This study was aimed at characterizing these changes and associated short-term outcomes.

METHOD

We retrospectively analysed treatment and outcome data from patients with T3/4 or N+ LARC ≤ 15 cm from the anal verge who were evaluated at a comprehensive cancer centre in 2009-2015.

RESULTS

In total, 798 patients were identified and grouped into five cohorts based on treatment year: 2009-2010, 2011, 2012, 2013 and 2014-2015. Temporal changes included increased reliance on MRI staging, from 57% in 2009-2010 to 98% in 2014-2015 (P < 0.001); increased use of total neoadjuvant therapy, from 17% to 76% (P < 0.001); and increased use of MIS, from 33% to 70% (P < 0.001). Concurrently, median hospital stay decreased (from 7 to 5 days; P < 0.001), as did the rates of Grade III-V complications (from 13% to 7%; P < 0.05), surgical site infections (from 24% to 8%; P < 0.001), anastomotic leak (from 11% to 3%; P < 0.05) and positive circumferential resection margin (from 9% to 4%; P < 0.05). TNM downstaging increased from 62% to 74% (P = 0.002).

CONCLUSION

Shifts toward MRI-based staging, total neoadjuvant therapy and MIS occurred between 2009 and 2015. Over the same period, treatment responses improved, and lengths of stay and the incidence of complications decreased.

Anti-tumor Activity of the Type I PRMT Inhibitor, GSK3368715, Synergizes with PRMT5 Inhibition through MTAP Loss

Type I protein arginine methyltransferases (PRMTs) catalyze asymmetric dimethylation of arginines on proteins. Type I PRMTs and their substrates have been implicated in human cancers, suggesting inhibition of type I PRMTs may offer a therapeutic approach for oncology. The current report describes GSK3368715 (EPZ019997), a potent, reversible type I PRMT inhibitor with anti-tumor effects in human cancer models. Inhibition of PRMT5, the predominant type II PRMT, produces synergistic cancer cell growth inhibition when combined with GSK3368715. Interestingly, deletion of the methylthioadenosine phosphorylase gene (MTAP) results in accumulation of the metabolite 2-methylthioadenosine, an endogenous inhibitor of PRMT5, and correlates with sensitivity to GSK3368715 in cell lines. These data provide rationale to explore MTAP status as a biomarker strategy for patient selection.

Effectiveness of a multidisciplinary patient care bundle for reducing surgical-site infections

BACKGROUND

Surgical-site infection (SSI) is associated with significant healthcare costs. To reduce the high rate of SSI among patients undergoing colorectal surgery at a cancer centre, a comprehensive care bundle was implemented and its efficacy tested.

METHODS

A pragmatic study involving three phases (baseline, implementation and sustainability) was conducted on patients treated consecutively between 2013 and 2016. The intervention included 13 components related to: bowel preparation; oral and intravenous antibiotic selection and administration; skin preparation, disinfection and hygiene; maintenance of normothermia during surgery; and use of clean instruments for closure. SSI risk was evaluated by means of a preoperative calculator, and effectiveness was assessed using interrupted time-series regression.

RESULTS

In a population with a mean BMI of 30 kg/m² , diabetes mellitus in 17·5 per cent, and smoking history in 49·3 per cent, SSI rates declined from 11·0 to 4·1 per cent following implementation of the intervention bundle (P = 0·001). The greatest reductions in SSI rates occurred in patients at intermediate or high risk of SSI: from 10·3 to 4·7 per cent (P = 0·006) and from 19 to 2 per cent (P < 0·001) respectively. Wound care modifications were very different in the implementation phase (43·2 versus 24·9 per cent baseline), including use of an overlying surface vacuum dressing (17·2 from 1·4 per cent baseline) or leaving wounds partially open (13·2 from 6·7 per cent baseline). As a result, the biggest difference was in wound-related rather than organ-space SSI. The median length of hospital stay decreased from 7 (i.q.r. 5-10) to 6 (5-9) days (P = 0·002). The greatest reduction in hospital stay was seen in patients at high risk of SSI: from 8 to 6 days (P < 0·001). SSI rates remained low (4·5 per cent) in the sustainability phase.

CONCLUSION

Meaningful reductions in SSI can be achieved by implementing a multidisciplinary care bundle at a hospital-wide level.

Abstract 406: CRISPR pooled screening of hundreds of cancer cell lines identifies differential dependencies on epigenetic pathways and synthetic lethal relationships

Target identification is a critical step in drug discovery, but the process has many challenges including non-specific reagents, limited ability to test numerous models, and incomplete target inhibition. Pooled screening with CRISPR/Cas9 permits the quick and accurate examination of proliferation effects across many genes and many cell lines. To determine the specific dependencies of cell lines on epigenetic pathways, we designed a CRISPR/Cas9 library to target 640 epigenetic genes and screened more than 200 cell lines covering a variety of oncology indications, including breast, lung, and renal cell carcinoma (RCC). We find that CRISPR pooled screening is a highly effective approach for target identification and provides robust, highly reproducible data as long as a sufficient number of small guide RNAs are used. We identify known pan-essential genes, including in the transcription (CDK9), translation (EIF4A1 and EIF4A3) and splicing (SRSF2) machinery. We additionally identify many novel pan-essential genes across a variety of epigenetic pathways, including histone acetylases and deacetylases, chromatin remodeling factors, helicases and others. We also investigated epigenetic synthetic lethal interactions that have been previously reported. For example, it has been reported that the SWI/SNF family displays paralog synthetic lethality for SMARCA2 in the context of SMARCA4 mutations, and for ARID1B in the context of ARID1A mutations. While we do see that some of the same trends hold, the synthetic lethal relationship appears to be more complex than previously realized, including the need to examine mRNA levels in addition to mutation type. Most importantly, we identify more than 100 epigenetic genes which show selective sensitivity, i.e. where knockout shows an anti-proliferative effect in only a subset of the cell lines. These are the most promising targets for further drug discovery programs. We have used additionally CRISPR/Cas9-domain based screening to identify the functionally relevant sites for many of these genes. Furthermore, we can overlay gene expression and mutation data to identify novel synthetic lethal relationships. One gene that displays selective sensitivity is EGLN1, the prolyl hydroxylase for the hypoxia-inducible factor, HIF1α. We find that EGLN1 is required for proliferation only in RCC cell lines which retain wild-type VHL, another component of the hypoxia response pathway, which is frequently lost in RCC. As such, EGLN1 loss is synthetically lethal in the presence of wild-type VHL in RCC cells. Thus this approach not only identifies an enzymatic drug target but also a patient stratification method. Other novel synthetic lethal interactions have also been identified. Our data demonstrates that CRISPR pooled screening is a powerful technique for identification of epigenetic synthetic lethal interactions.

Citation Format: Alexandra R. Grassian, Darren Harvey, Julian Fowler, Allison E. Drew, Igor Feldman, Richard Chesworth, Robert Copeland, Jesse J. Smith, Scott Ribich. CRISPR pooled screening of hundreds of cancer cell lines identifies differential dependencies on epigenetic pathways and synthetic lethal relationships [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 406. doi:10.1158/1538-7445.AM2017-406

Abstract 3345: Selective killing of SMARCA2- and SMARCA4-deficient tumors by inhibition of EZH2: In vitro and in vivo preclinical models

The histone methyltransferase EZH2 is the enzymatic subunit of the polycomb repressive complex 2 (PRC2) that catalyzes the methylation of H3K27 thereby repressing target gene transcription. EZH2 is amplified, overexpressed, or mutated in multiple cancer types, most notably Follicular Lymphoma (FL) and germinal center Diffuse Large B-cell Lymphoma (GCB-DLBCL). We previously reported that preclinical models of malignant rhabdoid tumors, which are deficient in the SWI/SNF core component INI1 (SNF5, SMARCB1), are selectively killed by potent and selective inhibitors of EZH2. Here we report another class of SWI/SNF-altered cancers named small cell carcinoma of the ovary hypercalcemic type (SCCOHT) that is dependent on EZH2 activity. SCCOHT is a very aggressive form of cancer that responds poorly to conventional therapy with a one-year overall survival rate of only 50%. Very few novel agents have been approved for this indication; thus there is a need for targeted therapeutics in SCCOHT. SMARCA4 and SMARCA2 are co-inactivated in this tumor type that has many rhabdoid features. We demonstrate that tazemetostat, an EZH2 inhibitor currently in phase 2 clinical trials, induces potent and selective killing in SMARCA2 and SMARCA4-deficient ovarian cell lines. In addition to small molecule inhibitor data, we conducted functional genomics studies with CRISPR pooled screening, and confirmed that SCCOHT is also sensitive to CRISPR-mediated EZH2 gene ablation. Dose-dependent anti-tumor effects were observed upon tazemetostat treatment in SCCOHT xenografts deficient in both SMARCA2 and SMARCA4. We also report on additional non-ovarian tumor types with dual SMARCA2/SMARCA4 loss including NSCLC that exhibit EZH2 dependence representing additional potential therapeutic indications for tazemetostat treatment.

Citation Format: Elayne Chan-Penebre, Kelli Armstrong, Allison Drew, Alexandra R. Grassian, Igor Feldman, Maria Roche, Peter Ho, Dorothy Brach, Alejandra Raimondi, Robert A. Copeland, Richard Chesworth, Jesse J. Smith, Scott A. Ribich. Selective killing of SMARCA2- and SMARCA4-deficient tumors by inhibition of EZH2: In vitro and in vivo preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3345. doi:10.1158/1538-7445.AM2017-3345

Abstract 1944: Tazemetostat displays synergistic antiproliferative activity with backbone therapies in preclinical models of AT/RT and MRT

Malignant Rhabdoid Tumors (MRT) and Atypical Teratoid Rhabdoid Tumors (AT/RT) are typically pediatric cancers which are rare and aggressive with extremely high unmet medical need. At a molecular level MRT and AT/RT tumors are almost universally characterized by loss of the INI1 protein (also known as SNF5 or SMARCB1), a component of the Switch Sucrose Non-fermentable (SWI/SNF) multimeric chromatin modifying complex. In many cell types, the SWI/SNF complex and the PRC2 complex have an antagonistic relationship in the regulation of tumor suppressor genes, cell cycle checkpoints, hedgehog and myc pathway genes, among others [Wilson et al, Cancer Cell. 2010 Oct 19;18(4):316-28.]. This explicated the possibility of a novel treatment modality for these tumors, based on inhibition of EZH2 - the catalytic subunit of PRC2. Tazemetostat (EPZ-6438) is a potent and orally bioavailable small molecule inhibitor of EZH2 currently in phase 2 clinical trials in adult patients with non-Hodgkin lymphoma, INI1-negative tumors and mesothelioma. Dependency of INI1-negative tumors on EZH2 catalytic activity was demonstrated in preclinical models of MRT, where robust tumor regressions were induced with tazemetostat treatment [Knutson et al, Proc Natl Acad Sci USA. 2013 May 7;110(19):7922-7]. Consistent with this, tazemetostat demonstrated activity in relapsed or refractory patients with INI1-negative tumors enrolled in the adult phase 1 clinical trial. In addition, a phase 1 dose escalation study in pediatric patients with INI1-negative solid tumors is currently ongoing. Backbone therapies for MRT and AT/RT are comprised of cytotoxic chemotherapy which may or may not be administered in the context of stem cell transplant, in addition to surgical resection and radiation therapy. In support of combination clinical scenarios including EZH2 inhibition in this setting, we sought to explore the antiproliferative effects of combining tazemetostat with current small molecule treatment therapies in cell line models of AT/RT and MRT. Synergistic activity was observed when tazometostat was combined with individual components of chemotherapeutic regimens and targeted therapies such as vincristine, doxorubicin, alisertib and HDAC inhibitors.Further, we investigated the effects of ionizing radiation together with tazemetostat treatment. Application of X-ray irradiation concomitantly or after tazemetostat treatment, induced robust antiproliferative activity and reduction in clonogenic potential of both AT/RT cell lines tested.Taken together these results suggest that pharmacological inhibition of EZH2 enhances the activity of backbone therapy and may have an advantage over monotherapy in INI1-negative cancers supporting the therapeutic potential of combination regimens that include tazemetostat in these tumors.

Citation Format: Christine R. Klaus, Jeffrey A. Keats, Jesse J. Smith, Richard Chesworth, Robert A. Copeland, Scott Ribich, Alejandra Raimondi. Tazemetostat displays synergistic antiproliferative activity with backbone therapies in preclinical models of AT/RT and MRT [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1944. doi:10.1158/1538-7445.AM2017-1944

Mechanisms of Pinometostat (EPZ-5676) Treatment-Emergent Resistance in MLL-Rearranged Leukemia

DOT1L is a protein methyltransferase involved in the development and maintenance of MLL-rearranged (MLL-r) leukemia through its ectopic methylation of histones associated with well-characterized leukemic genes. Pinometostat (EPZ-5676), a selective inhibitor of DOT1L, is in clinical development in relapsed/refractory acute leukemia patients harboring rearrangements of the MLL gene. The observation of responses and subsequent relapses in the adult trial treating MLL-r patients motivated preclinical investigations into potential mechanisms of pinometostat treatment-emergent resistance (TER) in cell lines confirmed to have MLL-r. TER was achieved in five MLL-r cell lines, KOPN-8, MOLM-13, MV4-11, NOMO-1, and SEM. Two of the cell lines, KOPN-8 and NOMO-1, were thoroughly characterized to understand the mechanisms involved in pinometostat resistance. Unlike many other targeted therapies, resistance does not appear to be achieved through drug-induced selection of mutations of the target itself. Instead, we identified both drug efflux transporter dependent and independent mechanisms of resistance to pinometostat. In KOPN-8 TER cells, increased expression of the drug efflux transporter ABCB1 (P-glycoprotein, MDR1) was the primary mechanism of drug resistance. In contrast, resistance in NOMO-1 cells occurs through a mechanism other than upregulation of a specific efflux pump. RNA-seq analysis performed on both parental and resistant KOPN-8 and NOMO-1 cell lines supported two unique candidate pathway mechanisms that may explain the pinometostat resistance observed in these cell lines. These results are the first demonstration of TER models of the DOT1L inhibitor pinometostat and may provide useful tools for investigating clinical resistance. Mol Cancer Ther; 16(8); 1669-79. ©2017 AACR.

Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis

OBJECTIVE

The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions.

METHODS

A systematic search was performed to identify randomized controlled trials targeting adolescents (age: ≥10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored.

RESULTS

Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects.

CONCLUSION

Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols.

Selective Killing of SMARCA2- and SMARCA4-deficient Small Cell Carcinoma of the Ovary, Hypercalcemic Type Cells by Inhibition of EZH2: In Vitro and In Vivo Preclinical Models

The SWI/SNF complex is a major regulator of gene expression and is increasingly thought to play an important role in human cancer, as evidenced by the high frequency of subunit mutations across virtually all cancer types. We previously reported that in preclinical models, malignant rhabdoid tumors, which are deficient in the SWI/SNF core component INI1 (SMARCB1), are selectively killed by inhibitors of the H3K27 histone methyltransferase EZH2. Given the demonstrated antagonistic activities of the SWI/SNF complex and the EZH2-containing PRC2 complex, we investigated whether additional cancers with SWI/SNF mutations are sensitive to selective EZH2 inhibition. It has been recently reported that ovarian cancers with dual loss of the redundant SWI/SNF components SMARCA4 and SMARCA2 are characteristic of a rare rhabdoid-like subtype known as small-cell carcinoma of the ovary hypercalcemic type (SCCOHT). Here, we provide evidence that a subset of commonly used ovarian carcinoma cell lines were misdiagnosed and instead were derived from a SCCOHT tumor. We also demonstrate that tazemetostat, a potent and selective EZH2 inhibitor currently in phase II clinical trials, induces potent antiproliferative and antitumor effects in SCCOHT cell lines and xenografts deficient in both SMARCA2 and SMARCA4. These results exemplify an additional class of rhabdoid-like tumors that are dependent on EZH2 activity for survival. Mol Cancer Ther; 16(5); 850-60. ©2017 AACR.

Rapid, specific, simple, in-field detection of Xanthomonas campestris pathovar musacearum by loop-mediated isothermal amplification

AIMS

To develop and evaluate a loop-mediated isothermal amplification (LAMP) assay for Xanthomonas campestris pathovar musacearum (Xcm), the causal agent of banana Xanthomonas wilt, a major disease of banana in Africa.

METHODS AND RESULTS

LAMP primers were designed to the general secretion pathway protein D gene and tested against 17 isolates of Xcm encompassing the known genetic and geographic diversity of the bacterium and all isolates were detected. Seventeen other Xanthomonas isolates, including closely related Xanthomonas vasicola, other bacterial pathogens/endophytes of Musa and two healthy Musa varieties gave negative results with the LAMP assay. The assay showed good sensitivity, detecting as little as 51 fg of Xcm DNA, a greater level of sensitivity than that of an Xcm PCR assay. Amplification with the LAMP assay was very rapid, typically within 9 min from bacterial cultures. Symptomatic field samples of Musa from Uganda were tested and all produced amplification in less than 13 min.

CONCLUSIONS

The LAMP assay provides rapid, sensitive detection of the pathogen that is ideally suited for deployment in laboratories with basic facilities and in-field situations.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first LAMP assay for Xcm which provides a significant improvement compared to existing diagnostics.

Abstract 4078: KRAS mutation status is associated with stromal inactivation in colorectal cancer and predicts poor response to neoadjuvant chemoradiotherapy

Background: Treatment for locally advanced rectal cancer (LARC) consists of neoadjuvant chemoradiotherapy (NCRT) followed by radical excision. Patients with tumors carrying a mutant KRAS are less likely to respond to NCRT compared to KRAS wild type tumors. We hypothesized that an RNA-based signature differentiating KRAS mutant and wild type patients could serve as an indicator of the biological process associated with response to NCRT. We found that the RNA-based signature is enriched for stromal and immune genes. Furthermore, the stromal component of the signature is a predictor of response to NCRT.

Methods: Tumors from 120 LARC patients enrolled in a multicenter phase 2 trial studying response to NCRT were tested for KRAS status by Sanger Sequencing or Memorial Sloan Kettering (MSK)-IMPACT assay and gene expression was quantified by sequencing. Colorectal cancer (CRC) patients from MSK (n = 95) and TCGA (n = 261), previously annotated for KRAS mutation status and gene expression, were used for validation. A KRAS-inducible mouse model and CRC patient-derived xenografts (PDXs) were utilized to determine the cell of origin for the gene expression signature. Stromal enrichment was assessed with the ESTIMATE stromal gene signature. Immunohistochemistry (IHC) was completed for Periostin (POSTN), a stromal marker from the RNA-signature. Variant Allele Frequency (VAF) was used to measure the abundance of KRAS, TP53 and Adenomatous Polyposis Coli (APC) mutant alleles in tumors, and was quantified by targeted exome sequencing with the MSK-IMPACT assay.

Results: Analysis of the KRAS-associated gene signature showed significant stromal inactivation in KRAS mutant patients. The signature was validated in the MSK and TCGA cohorts. The stromal signature was recapitulated in a KRAS inducible mouse model. Human CRC PDXs in mouse indicated that the signature arose from murine stroma and not human epithelium. Consistent with the stromal signature, IHC for POSTN, a stromal marker, was significantly lower in the KRAS mutant tumors compared with the KRAS wild type tumors (p&lt;0.05) and was absent from the epithelium. The stromal enrichment in mutant KRAS tumors was inversely correlated with the KRAS VAF (p&lt;0.01). This finding was not observed for TP53 or APC VAF indicating specificity for stromal inactivation in KRAS mutant tumors. Furthermore, the stromal component of the signature is associated with poor response to NCRT in LARC.

Conclusions: This study shows that a KRAS mutation in CRC is associated with a lower expression of a stromal signature and that this signature is derived from the tumor microenvironment. This study indicates that CRC KRAS mutant tumors and a stromal subtype are closely related. Understanding this relationship may play a key role in elucidating the mechanism by which a KRAS mutant tumor is resistant to standard therapy.

Citation Format: Raphael Pelossof, Moshe Elkatebts, Oliver Chow, Lauren Fairchild, Kevin O’Rourke, Jesse J. Smith, Chin-Tung Chen, Samuel Brook, Maurizio Scaltriti, Jinru Shia, Philip Paty, Christina Leslie, Scott Lowe, Jose Baselga, Julio Garcia-Aguilar. KRAS mutation status is associated with stromal inactivation in colorectal cancer and predicts poor response to neoadjuvant chemoradiotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4078.

Multiplex GPCR Assay in Reverse Transfection Cell Microarrays

G protein-coupled receptors (GPCRs) are a superfamily of proteins that include some of the most important drug targets in the pharmaceutical industry. Despite the success of this group of drugs, there remains a need to identify GPCR-targeted drugs with greater selectivity, to develop screening assays for validated targets, and to identify ligands for orphan receptors. To address these challenges, the authors have created a multiplexed GPCR assay that measures greater than 3000 receptor: ligand interactions in a single microplate. The multiplexed assay is generated by combining reverse transfection in a 96-well plate format with a calcium flux readout. This assay quantitatively measures receptor activation and inhibition and permits the determination of compound potency and selectivity for entire families of GPCRs in parallel. To expand the number of GPCR targets that may be screened in this system, receptors are cotransfected with plasmids encoding a promiscuous G protein, permitting the analysis of receptors that do not normally mobilize intracellular calcium upon activation. The authors demonstrate the utility of reverse transfection cell microarrays to GPCR-targeted drug discovery with examples of ligand selectivity screening against a panel of GPCRs as well as dose-dependent titrations of selected agonists and antagonists.

A comparison of health-related quality of life of patients with primary and recurrent varicose veins

Aim: To determine whether recurrent varicose veins affect patient quality of life. The health-related quality of life (HRQL) scores of patients with recurrent varicose veins were compared with those of patients presenting with primary varicose vein disease.

Methods: HRQL among patients attending outpatient appointments for recurrent and primary varicose veins was measured using the Aberdeen Varicose Vein Questionnaire (AVVQ) and the Short Form-36 General Health Survey (SF-36).

Results: Questionnaires were given to 211 patients (150 primary, 61 recurrent), and 194 (133 primary, 61 recurrent) completed them. For the AVVQ, patients with recurrent varicose veins had significantly worse symptom scores compared with those with primary disease (24.87 ± 12.28 vs 17.77 ± 9.68, Mann-Whitney, P <0.01). The SF-36 recorded significantly worse HRQL (Mann-Whitney, P <0.05) for patients with recurrent varicose veins compared with those with primary varicose veins in all but one of the eight domains (role limitation attributed to emotional problems, RE, P = 0.073).

Conclusion: Varicose vein recurrence is associated with a significantly worse HRQL than is found among patients with primary varicose veins.

Randomized clinical trial of varicose vein surgery with compression versus compression alone for the treatment of venous ulceration

Objectives: No randomized controlled trials exist to show whether varicose vein surgery improves healing of venous ulcers. In this study we investigated whether superficial venous surgery gave additional benefit to compression therapy in terms of healing rate, time to healing and quality of life of patients with venous ulcers.

Methods: A total of 121 consecutive patients with venous ulceration were identified, of which 45 were unfit/unwilling to be included. The remaining 76 (aged 38-89, 39 female) were randomized to receive either four-layer bandaging ( n =39) or superficial venous surgery (long and short saphenous with or without perforator surgery) and four-layer bandaging ( n =37). Ulcer healing and health-related quality of life (HRQL) were assessed.

Results: The healing rate was 64% (25/39) in the compression treatment group and 68% (25/37) in the surgical treatment group. This difference was not statistically significant (Pearson 2 P=0.75). There was no significant difference between the time to ulcer healing in the two treatment groups (log rank statistic=0.69, P value=0.41): median time 83 days for surgery vs 98 days for compression. After adjusting for duration of ulcer, size of ulcer and previous deep vein thrombosis, there was still no significant difference between time to healing for the two treatment groups (adjusted hazard ratio=0.79, 95% confidence interval 0.45-1.39). There was no difference in HRQL between the two groups, using the scores of a disease-specific questionnaire (CXVUQ).

Conclusions: This study suggests that for venous ulceration, superficial venous surgery gives no additional benefit to compression therapy from the point of view of healing rate and quality of life.

Myeloid translocation genes differentially regulate colorectal cancer programs

Myeloid translocation genes (MTGs), originally identified as chromosomal translocations in acute myelogenous leukemia, are transcriptional corepressors that regulate hematopoietic stem cell programs. Analysis of The Cancer Genome Atlas (TCGA) database revealed that MTGs were mutated in epithelial malignancy and suggested that loss of function might promote tumorigenesis. Genetic deletion of MTGR1 and MTG16 in the mouse has revealed unexpected and unique roles within the intestinal epithelium. Mtgr1^−/− mice have progressive depletion of all intestinal secretory cells, and Mtg16^−/− mice have a decrease in goblet cells. Furthermore, both Mtgr1^−/− and Mtg16^−/− mice have increased intestinal epithelial cell proliferation. We thus hypothesized that loss of MTGR1 or MTG16 would modify Apc^1638/+-dependent intestinal tumorigenesis. Mtgr1^−/− mice, but not Mtg16^−/− mice, had a 10-fold increase in tumor multiplicity. This was associated with more advanced dysplasia, including progression to invasive adenocarcinoma, and augmented intratumoral proliferation. Analysis of ChIP-seq datasets for MTGR1 and MTG16 targets indicated that MTGR1 can regulate Wnt and Notch signaling. In support of this, immunohistochemistry and gene expression analysis revealed that both Wnt and Notch signaling pathways were hyperactive in Mtgr1^−/− tumors. Furthermore, in human colorectal cancer (CRC) samples MTGR1 was downregulated at both the transcript and protein level. Overall our data indicates that MTGR1 has a context dependent effect on intestinal tumorigenesis.

Novel Oxindole Sulfonamides and Sulfamides: EPZ031686, the First Orally Bioavailable Small Molecule SMYD3 Inhibitor

SMYD3 has been implicated in a range of cancers; however, until now no potent selective small molecule inhibitors have been available for target validation studies. A novel oxindole series of SMYD3 inhibitors was identified through screening of the Epizyme proprietary histone methyltransferase-biased library. Potency optimization afforded two tool compounds, sulfonamide EPZ031686 and sulfamide EPZ030456, with cellular potency at a level sufficient to probe the in vitro biology of SMYD3 inhibition. EPZ031686 shows good bioavailability following oral dosing in mice making it a suitable tool for potential in vivo target validation studies.

Structure and Property Guided Design in the Identification of PRMT5 Tool Compound EPZ015666

The recent publication of a potent and selective inhibitor of protein methyltransferase 5 (PRMT5) provides the scientific community with in vivo-active tool compound EPZ015666 (GSK3235025) to probe the underlying pharmacology of this key enzyme. Herein, we report the design and optimization strategies employed on an initial hit compound with poor in vitro clearance to yield in vivo tool compound EPZ015666 and an additional potent in vitro tool molecule EPZ015866 (GSK3203591).

Mode instability thresholds for Tm-doped fiber amplifiers pumped at 790 nm

We use a detailed numerical model of stimulated thermal Rayleigh scattering to compute mode instability thresholds in Tm(3+)-doped fiber amplifiers. The fiber amplifies 2040 nm light using a 790 nm pump. The cross-relaxation process is strong, permitting power efficiencies of 60%. The predicted instability thresholds are compared with those in similar Yb(3+)-doped fiber amplifiers with 976 nm pump and 1060 nm signal, and are found to be higher, even though the heat load is much higher in Tm-doped amplifiers. The higher threshold in the Tm-doped fiber is attributed to its longer signal wavelength, and to stronger gain saturation, due in part to cross-relaxation heating.

Abstract IA27: Tazemetostat, an EZH2 inhibitor and potential therapeutic for non-Hodgkin lymphoma

Cell fate decisions, such as whether to self-renew or to differentiate, are regulated in large part by epigenetic mechanisms. Dysregulation of epigenetic machinery, such as histone methyltransferases, in certain progenitor cell contexts can promote increased self-renewal, decreased differentiation and ultimately oncogenesis. For example, EZH2, the histone H3K27 methyltransferase, has been implicated in a diverse set of cancer indications. As the catalytic subunit of the polycomb repressive complex 2 (PRC2), EZH2 is responsible for the initiation of gene silencing during embryonic development and in maintenance of pluripotency in certain adult stem cell settings. On the other hand, EZH2 activity is downregulated in the majority of adult somatic cells to facilitate the expression of lineage-specific gene programs, leading to differentiation. Thus, inappropriate activation of EZH2 can contribute to oncogenic signaling by potentiating “stem-like” programs in certain contexts.

For example, during B cell maturation, EZH2 activity is critical for formation of the germinal center (GC) reaction. PRC2-mediated repression of certain target sets, such as cell cycle checkpoint genes and DNA damage response genes, allows germinal center B (GCB) cells to undergo clonal expansion and somatic hypermutation. In order for GCB cells to exit the germinal center reaction, EZH2 expression and activity must be attenuated – the failure to do so may contribute to oncogenic signaling in certain B cell lymphomas. We and others have previously reported on gain-of-function mutations in EZH2, involving residues such as Y646, A682 and A692. These lesions result in increased trimethylation of H3K27 on polycomb target genes, including those required for B cell maturation and exit from the germinal center reaction. Importantly, lymphoma cell lines bearing these mutations demonstrate robust antiproliferative phenotypes, both in culture and in subcutaneous xenograft models, in response to small molecule inhibitors of EZH2. Beyond these mutant EZH2 cell lines, there is evidence that small molecule inhibitors of EZH2 also have antiproliferative activity in GCB cell and non-GCB lymphomas with wild type (wt) EZH2. These data are consistent with the idea that EZH2 is a “lineage factor” for B cell maturation, and that certain B cell lymphomas may possibly become “addicted” to EZH2 through mechanisms other than gain-of-function mutations in said gene. In addition to these preclinical findings, a recent update from ongoing clinical trials reported objective responses to single-agent tazemetostat (an EZH2 inhibitor in clinical development) in both wild-type and mutant EZH2 non-Hodgkin lymphoma (NHL) patients.

The focus of this presentation will be the emerging translational landscape for tazemetostat (EPZ-6438), a small molecule inhibitor of EZH2, currently in phase II clinical trials for multiple oncology indications, including subsets of NHL. Data to be discussed will include preclinical efforts to understand the molecular mechanisms that determine GCB and non-GCB lymphoma response to EZH2 inhibition. Additionally, preclinical investigations evaluating the combination of tazemetostat with multiple therapeutic modalities will be presented. Finally, a brief overview of the early clinical observations of tazemetostat will be discussed.

Citation Format: Jesse J. Smith. Tazemetostat, an EZH2 inhibitor and potential therapeutic for non-Hodgkin lymphoma. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Sep 24-27, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2016;76(2 Suppl):Abstract nr IA27.

Abstract C85: Identification of a novel potent selective SMYD3 inhibitor with oral bioavailability

SMYD3 (Set and Mynd Domain containing 3) is a lysine methyltransferase overexpressed in several cancer types including breast, prostrate, pancreatic, and lung, and this overexpression is associated with poor clinical prognosis. Genetic knockdown of SMYD3 by shRNA has been shown to decrease proliferation in a range of cancer cell lines suggesting that inhibition of SMYD3 may have therapeutic utility.

In this presentation we describe the discovery and optimization of a novel series of oxindole sulfonamides and sulfamides with SMYD3 inhibitory activity. One of these compounds, EPZ030456, has a SMYD3 biochemical IC50 of 4 nM and is active in cells with an IC50 of 48 nM in a trimethyl MAP3K2 (MEKK2) in-cell western (ICW) assay. The crystal structure of this compound was solved with SMYD3 and the nucleotide substrate, S-adenosylmethionine and shows the oxindole portion of the molecule extends into the SMYD3 lysine binding channel. EPZ030456 shows &lt; 30% inhibition at a 10 uM screening concentration against 17 histone methyltransferase targets tested, including SMYD2.

Further optimization within the series resulted in EPZ031686 which has similar potency to EPZ030456 with a biochemical IC50 of 3 nM and an ICW IC50 of 36 nM and in addition exhibits good bioavailability following oral dosing in mice. Hence, EPZ031686 is a suitable tool to study the role of SMYD3 in cancer and other therapeutic areas, using both in vitro and in vivo models.

Citation Format: Lorna H. Mitchell, Paula A. Boriack-Sjodin, Sherri Smith, Michael Thomenius, Nathalie Rioux, Michael Munchhof, James E. Mills, Christine Klaus, Jennifer Totman, Thomas V. Riera, Alejandra Raimondi, Suzanne L. Jacques, Megan Foley, Nigel J. Waters, Kevin W. Kuntz, Tim J. Wigle, Margaret Porter Scott, Robert A. Copeland, Jesse J. Smith, Richard Chesworth. Identification of a novel potent selective SMYD3 inhibitor with oral bioavailability. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C85.

Abstract C162: A medium-throughput single cell CRISPR-Cas9 assay to assess gene essentiality

Target selection for oncology and other indications is a critical step in the successful development of therapeutics, however it remains one of the most challenging areas of drug discovery. In fact, up to two-thirds of oncology relevant targets reported in literature have not been confirmed on follow-up studies, indicating that target validation in oncology is especially challenging. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of specific loci offers an alternative method to RNA interference and complements small molecule inhibitors for determining whether or not a cell line is dependent on a specific gene product for proliferation and/or survival. Importantly, CRISPR-Cas9 may be advantageous for some studies as it offers efficient and specific gene knock-out leading to complete loss of protein function. This may be especially useful for some target classes, including epigenetic targets, which appear to require near complete loss of protein function to observe phenotypes. In our initial studies using CRISPR-Cas9 to verify the essential nature of EZH2 (Enhancer of Zest 2) expression for the proliferation of SMARCB1/SNF5/INI1 mutant malignant rhabdoid tumor cell lines, we observed that the initial reduction in proliferation was lost over time. We hypothesized that in the few cells that retain proliferative capacity at least one allele of EZH2 remains functional, and this hypothesis suggests that carrying out CRISPR-Cas9 studies for individual target genes without analyzing single cell clones could produce misleading results. To verify this, we developed a medium throughput assay to analyze 10s-100s of single cell clones for target gene disruption using CRISPR-Cas9 gene knockout, followed by a restriction digest and fluorescent undigested fragment length analysis to successfully assess EZH2 allele status. Significantly, these data support our hypothesis that retention of one functional copy of EZH2 is required for the proliferation of EZH2-dependent cell lines and that this can be rapidly assessed by our assay. Thus, the assessment of zygosity of the gene of interest can be evaluated in a medium-throughput manner in single cell clones. The assay is thereby able to unambiguously indicate whether or not a specific gene is essential for survival and/or proliferation in a given cell line, and offers a unique approach for target validation using gene editing. Importantly, this approach should be applicable to any target of interest that is expected to affect cell proliferation or survival. Such data can aid in the development of more robust cancer therapeutics by increasing confidence in target selection.

Citation Format: Alexandra R. Grassian, Tim Scales, Sarah K. Knutson, Nicola J. McCarthy, Chris E. Lowe, Jon D. Moore, Robert A. Copeland, Heike Keilhack, Jesse J. Smith, Julie A. Wickendon, Scott Ribich. A medium-throughput single cell CRISPR-Cas9 assay to assess gene essentiality. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C162.

Abstract B78: CRISPR pooled screening identifies differential dependencies on epigenetic pathways

It has become clear in the past decade that dysregulation of epigenetic pathways is fundamental to many if not all tumors. Importantly, a number of epigenetic targeted therapies are now being tested in the clinic and are beginning to show promising efficacy. Identification of new targets for oncology therapeutics is critical, and the ideal target should: 1) be effective in a specific indication or genetically defined patient population; and 2) lead to a minimal amount of deleterious side effects in patients. Thus, target identification must be performed in a large number of cell lines to address both objectives and to ensure specific target dependence. However, it remains challenging to identify specific dependencies on epigenetic genes in preclinical models, which may result in part from the need for near complete loss of protein function for this class of enzymes to observe proliferation phenotypes, and this can be difficult to achieve with RNAi reagents. The advent of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology enables the specific and complete knockout of the target protein and allows for observation of proliferation phenotypes that RNAi studies may not uncover. Additionally, the CRISPR-Cas9 system is amenable to pooled cell line screening which permits the quick and accurate examination of proliferation effects across many genes and many cell lines.

To examine the specific dependencies of cell lines on epigenetic pathways, we have used pooled CRISPR-Cas9 screening to interrogate over 600 epigenetic-related genes in a panel of more than 60 cells lines. The performance of the screen is highly consistent and able to reproduce findings that have been previously reported. We observe that CRISPR pooled screening is highly effective at identifying targets which are known to be required for cell proliferation either in all cell lines or in a genetically-defined subset of cell lines. We also identify new epigenetic-related genes required for the proliferation of almost all the cell lines tested, and have termed these “pan-essential” epigenetic genes. Intriguingly, these pan-essential genes represent members of almost all classes of epigenetic pathways, including histone methyltransferases, histone acetylases and deacetylases, chromatin remodeling factors, regulators of mRNA splicing, DNA helicases and others. This is an important set of genes to identify, as they represent targets which are likely to induce broad clinical toxicity if inhibited in patients, yet may be identified as potential targets in pre-clinical interrogation which does not fully examine proliferation dependencies in a sufficiently broad panel of cell lines.

Importantly, we also identify a variety of epigenetic targets which induce altered proliferation in a subset of cell lines tested. These include epigenetic-related genes from many classes, including histone methyltransferases. Notably, for certain genes, trends are emerging that indicate a specific genetic marker(s) which may predict dependence on these epigenetic targets. These genes represent highly promising targets for epigenetic therapeutics in a variety of oncology indications.

Citation Format: Alexandra R. Grassian, Julian Fowler, Igor Feldman, Thomas Riera, Darren Harvey, Allison E. Drew, Richard Chesworth, Robert A. Copeland, Heike Keilhack, Jesse J. Smith, Scott Ribich. CRISPR pooled screening identifies differential dependencies on epigenetic pathways. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B78.

Abstract 5383: DOT1L inhibitor EPZ-5676 synergizes with cytarabine and azacitidine in preclinical models of MLL-rearranged leukemia

EPZ-5676 is a small molecule inhibitor of the histone methyltransferase DOT1L currently in clinical development and represents a first in class novel therapeutic agent for the treatment of MLL-rearranged (MLL-r) leukemia. In preclinical studies, EPZ-5676 selectively inhibited intracellular histone H3K79 methylation, downstream target gene expression and demonstrated complete tumor regression in a MLL-r leukemia xenograft model. We previously reported synergistic and durable anti-proliferative activity when EPZ-5676 was combined with current AML standard of care drugs, cytarabine and daunorubicin in MLL-r leukemia models MOLM-13 (MLL-AF9) and MV4-11 (MLL-AF4). Combination benefit was also observed when MLL-r cells were treated with cytarabine, prior to co-treatment with EPZ-5676. Additionally, both cytarabine and the DNA methyltransferase inhibitor azacitidine, displayed synergistic anti-leukemic activity in MLL-r rearranged cells in a 7 day co-treatment model (7 days of continuous treatment with EPZ-5676 and second agent; see Klaus et al, JPET, 2014). In this report we discuss results of investigating additional treatment schedules using EPZ-5676 in combination with azacitidine in MLL-r cells. Cells were pretreated with azacitidine at nanomolar concentrations known to reverse promoter DNA-hypermethylation and alter the chromatin state (Tsai et al., Cancer Cell, 2012). We found treating MV4-11 and MOLM-13 cells once daily for three consecutive days followed by sequential treatment with EPZ-5676 elicited a synergistic anti-proliferative effect using the Chou-Talalay method (Chou, Pharmacol Rev., 2006). Results of studies to investigate the mechanism of this synergistic cell killing, including evaluation of differentiation markers and Annexin V staining will be reported. To determine if combinations of EPZ-5676 with cytarabine or azacitidine were tolerable and efficacious in vivo, nude rats implanted subcutaneously with MV4-11 tumors were treated using a range of doses and schedules. Azacitidine and cytarabine were delivered by intraperitoneal injection once daily for 14 days at their respective maximum tolerated doses of 2 and 200 mg/kg. Dosing at the established MTD, these agents inhibited the subcutaneous MV4-11 tumor growth by 50% compared to vehicle controls. Efficacy results from the EPZ-5676 combination studies with cytarabine or azacitidine will be presented. In summary, our results indicate that EPZ-5676 in combination with cytarabine or azacitidine revealed a synergistic effect, regardless of the treatment schedule used in preclinical models of MLL-r leukemia. Tolerable in vivo rat combination doses for EPZ-5676 with both cytarabine and azacitidine have been determined in support of potential future assessment of these combinations in MLL-r leukemia patients.

Citation Format: Christine R. Klaus, Scott R. Daigle, Vivek Chopra, Jeffrey A. Keats, Carly T. Campbell, Dorothy Iwanowicz, Edward J. Olhava, Margaret P. Scott, Roy M. Pollock, Robert A. Copeland, Jesse J. Smith, Jorge DiMartino, Stephen J. Blakemore, Alejandra Raimondi. DOT1L inhibitor EPZ-5676 synergizes with cytarabine and azacitidine in preclinical models of MLL-rearranged leukemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5383. doi:10.1158/1538-7445.AM2015-5383

Abstract 2701: Characterization of acquired EPZ-5676 resistance in cell line models of MLL rearranged leukemia

DOT1L inhibitor EPZ-5676 is currently under Phase 1 clinical trial investigation in relapsed/refractory patients with acute leukemia, including those with an MLL-rearrangement (MLL-r). Early clinical results, including complete remissions, support ongoing clinical development and preclinical investigation into mechanisms precipitating EPZ-5676 treatment induced resistance. MLL-r cell lines KOPN-8 (MLL-ENL) and NOMO-1 (MLL-AF9) were exposed to an EPZ-5676 concentration above the pre-determined 14 day proliferation assay IC90. Initial treatment of the cell lines led to the expected inhibition of H3K79 dimethylation (H3K79me2) and MLL-r target genes HOXA9 and MEIS1 as outlined in previous work (Daigle et al, Cancer Cell 2011). Resistance to EPZ-5676 in both cell lines emerged following three weeks of continued treatment with EPZ-5676 and was defined by increased growth rates in the presence of inhibitor. Mechanisms of resistance for both cell lines were investigated using RNASeq and ChIPSeq on parental and resistant cell line pools. Our analysis identified common characteristics between the resistant cell lines, but mechanisms by which they became resistant differed. Global H3K79me2 inhibition was maintained in both refractory cell lines, yet ChIP-seq analysis of resistant pools identified specific loci with H3K79me2 recovery in KOPN-8 cells. In resistant KOPN-8 cells recovery of H3K79me2 was concentrated at the HOXA locus and other MLL-r target genes (e.g. MEIS1 and RUNX2), with the remainder of actively transcribed genes maintaining H3K79me2 inhibition at levels observed in parental cells. In contrast, resistant NOMO-1 cells did not recover H3K79me2 at any actively transcribed genes, including those of the MLL-r signature. Only resistant KOPN-8 cells regained expression of the MLL-r target genes HOXA9 and MEIS1. Of note both resistant NOMO-1 and KOPN-8 cell lines had 8 and 40 fold upregulation of the ABCB1 (MDR1, P-gp) tranporter respectively when compared to a matched control cell line. To explore the role of drug efflux transporter ABCB1 on resistance, we treated cells with Valspodar, a known inhibitor of ABCB1. Following treatment with 1 μM Valspodar, KOPN-8 cells showed decreased cell growth similar to the naïve control cell line. Supporting the presence of an alternative resistance mechanism in NOMO-1 cells in addition to MDR1 upregulation, NOMO-1 cells remained resistant upon Valspodar treatment. Detailed gene expression and pathway analysis will be presented supporting mechanisms of treatment emergent resistance to EPZ-5676. In summary, we have identified two mechanisms of EPZ-5676 resistance in MLL-r cell lines, one mechanism dependent on and the other independent of ABCB1. Further refinement of these mechanisms will aid in providing hypotheses for testing mechanisms of EPZ-5676 treatment emergent resistance in patients and may support designing future rational clinical combinations.

Citation Format: Scott R. Daigle, Carly T. Campbell, Nigel J. Waters, Edward J. Olhava, Robert A. Copeland, Stephen J. Blakemore, Roy M. Pollock, Jesse J. Smith. Characterization of acquired EPZ-5676 resistance in cell line models of MLL rearranged leukemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2701. doi:10.1158/1538-7445.AM2015-2701

Aryl Pyrazoles as Potent Inhibitors of Arginine Methyltransferases: Identification of the First PRMT6 Tool Compound

A novel aryl pyrazole series of arginine methyltransferase inhibitors has been identified. Synthesis of analogues within this series yielded the first potent, selective, small molecule PRMT6 inhibitor tool compound, EPZ020411. PRMT6 overexpression has been reported in several cancer types suggesting that inhibition of PRMT6 activity may have therapeutic utility. Identification of EPZ020411 provides the field with the first small molecule tool compound for target validation studies. EPZ020411 shows good bioavailability following subcutaneous dosing in rats making it a suitable tool for in vivo studies.

The early management of the burned patient in the Naval service

Burns represent a perpetual threat in military combat and are a pervasive threat in the land, maritime and air arenas. Therefore, it is imperative that military clinicians are well versed in managing burns in order to ensure optimal survival and recovery. This article aims to explore the epidemiology, pathophysiology, assessment and early management of the burned patient with a focus on the austere maritime environment and current military guidance.

EPZ011989, A Potent, Orally-Available EZH2 Inhibitor with Robust in Vivo Activity

Inhibitors of the protein methyltransferase Enhancer of Zeste Homolog 2 (EZH2) may have significant therapeutic potential for the treatment of B cell lymphomas and other cancer indications. The ability of the scientific community to explore fully the spectrum of EZH2-associated pathobiology has been hampered by the lack of in vivo-active tool compounds for this enzyme. Here we report the discovery and characterization of EPZ011989, a potent, selective, orally bioavailable inhibitor of EZH2 with useful pharmacokinetic properties. EPZ011989 demonstrates significant tumor growth inhibition in a mouse xenograft model of human B cell lymphoma. Hence, this compound represents a powerful tool for the expanded exploration of EZH2 activity in biology.

ERBB4 is over-expressed in human colon cancer and enhances cellular transformation

The ERBB4 receptor tyrosine kinase promotes colonocyte survival. Herein, we tested whether ERBB4's antiapoptotic signaling promotes transformation and colorectal tumorigenesis. ERBB4 alterations in a The Cancer Genome Atlas colorectal cancer (CRC) data set stratified survival, and in a combined Moffitt Cancer Center and Vanderbilt Medical Center CRC expression data set, ERBB4 message levels were increased at all tumor stages. Similarly, western blot and immunohistochemistry on additional CRC tissue banks showed elevated ERBB4 protein in tumors. ERBB4 was highly expressed in aggressive, dedifferentiated CRC cell lines, and its knockdown in LIM2405 cells reduced anchorage-independent colony formation. In nude mouse xenograft studies, ERBB4 alone was insufficient to induce tumor establishment of non-transformed mouse colonocytes, but its over-expression in cells harboring Apc(min) and v-Ha-Ras caused a doubling of tumor size. ERBB4-expressing xenografts displayed increased activation of survival pathways, including epidermal growth factor receptor and Akt phosphorylation and COX-2 expression, and decreased apoptotic signals. Finally, ERBB4 deletion from mouse intestinal epithelium impaired stem cell replication and in vitro enteroid establishment. In summary, we report that ERBB4 is over-expressed in human CRC, and in experimental systems enhances the survival and growth of cells driven by Ras and/or WNT signaling. Chronic ERBB4 over-expression in the context of, for example, inflammation may contribute to colorectal carcinogenesis. Tumors with high receptor levels are likely to have enhanced cell survival signaling through epidermal growth factor receptor, PI3K and COX-2. These results suggest ERBB4 as a novel therapeutic target in a subset of CRC.

Risk stratification by the Appendicitis Inflammatory Response score to guide decision-making in patients with suspected appendicitis

BACKGROUND

Current management of suspected appendicitis is hampered by the overadmission of patients with non-specific abdominal pain and a significant negative exploration rate. The potential benefits of risk stratification by the Appendicitis Inflammatory Response (AIR) score to guide clinical decision-making were assessed.

METHODS

During this 50-week prospective observational study at one institution, the AIR score was calculated for all patients admitted with suspected appendicitis. Appendicitis was diagnosed by histological examination, and patients were classified as having non-appendicitis pain if histological findings were negative or surgery was not performed. The diagnostic performance of the AIR score and the potential for risk stratification to reduce admissions, optimize imaging and prevent unnecessary explorations were quantified.

RESULTS

A total of 464 patients were included, of whom 210 (63·3 per cent) with non-appendicitis pain were correctly classified as low risk. However, 13 low-risk patients had appendicitis. Low-risk patients accounted for 48·1 per cent of admissions (223 of 464), 57 per cent of negative explorations (48 of 84) and 50·7 per cent of imaging requests (149 of 294). An AIR score of 5 or more (intermediate and high risk) had high sensitivity for all severities of appendicitis (90 per cent) and also for advanced appendicitis (98 per cent). An AIR score of 9 or more (high risk) was very specific (97 per cent) for appendicitis, and the majority of patients with appendicitis in the high-risk group (21 of 30, 70 per cent) had perforation or gangrene. Ultrasound imaging could not exclude appendicitis in low-risk patients (negative likelihood ratio (LR) 1·0) but could rule-in the diagnosis in intermediate-risk patients (positive LR 10·2). CT could exclude appendicitis in low-risk patients (negative LR 0·0) and rule-in appendicitis in the intermediate group (positive LR 10·9).

CONCLUSION

Risk stratification of patients with suspected appendicitis by the AIR score could guide decision-making to reduce admissions, optimize utility of diagnostic imaging and prevent negative explorations.

The early management of the burned patient in the Naval service

Burns represent a perpetual threat in military combat and are a pervasive threat in the land, maritime and air arenas. Therefore, it is imperative that military clinicians are well versed in managing burns in order to ensure optimal survival and recovery. This article aims to explore the epidemiology, pathophysiology, assessment and early management of the burned patient with a focus on the austere maritime environment and current military guidance.

Synergistic Anti-Tumor Activity of EZH2 Inhibitors and Glucocorticoid Receptor Agonists in Models of Germinal Center Non-Hodgkin Lymphomas

Patients with non-Hodgkin lymphoma (NHL) are treated today with a cocktail of drugs referred to as CHOP (Cyclophosphamide, Hydroxyldaunorubicin, Oncovin, and Prednisone). Subsets of patients with NHL of germinal center origin bear oncogenic mutations in the EZH2 histone methyltransferase. Clinical testing of the EZH2 inhibitor EPZ-6438 has recently begun in patients. We report here that combining EPZ-6438 with CHOP in preclinical cell culture and mouse models results in dramatic synergy for cell killing in EZH2 mutant germinal center NHL cells. Surprisingly, we observe that much of this synergy is due to Prednisolone - a glucocorticoid receptor agonist (GRag) component of CHOP. Dramatic synergy was observed when EPZ-6438 is combined with Prednisolone alone, and a similar effect was observed with Dexamethasone, another GRag. Remarkably, the anti-proliferative effect of the EPZ-6438+GRag combination extends beyond EZH2 mutant-bearing cells to more generally impact germinal center NHL. These preclinical data reveal an unanticipated biological intersection between GR-mediated gene regulation and EZH2-mediated chromatin remodeling. The data also suggest the possibility of a significant and practical benefit of combining EZH2 inhibitors and GRag that warrants further investigation in a clinical setting.

Reaction coupling between wild-type and disease-associated mutant EZH2

EZH2 and EZH1 are protein methyltransferases (PMTs) responsible for histone H3, lysine 27 (H3K27) methylation. Trimethylation of H3K27 (H3K27me3) is a hallmark of many cancers, including non-Hodgkin lymphoma (NHL). Heterozygous EZH2 point mutations at Tyr641, Ala677, and Ala687 have been observed in NHL. The Tyr641 mutations enhance activity on H3K27me2 but have weak or no activity on unmethylated H3K27, whereas the Ala677 and Ala687 mutations use substrates of all methylation states effectively. It has been proposed that enzymatic coupling of the wild-type and mutant enzymes leads to the oncogenic H3K27me3 mark in mutant-bearing NHL. We show that coupling with the wild-type enzyme is needed to achieve H3K27me3 for several mutants, but that others are capable of achieving H3K27me3 on their own. All forms of PRC2 (wild-type and mutants) display kinetic signatures that are consistent with a distributive mechanism of catalysis.

DOT1L inhibitor EPZ-5676 displays synergistic antiproliferative activity in combination with standard of care drugs and hypomethylating agents in MLL-rearranged leukemia cells

EPZ-5676 [(2R,3R,4S,5R)-2-(6-amino-9H-purin-9-yl)-5-((((1r,3S)-3-(2-(5-(tert-butyl)-1H-benzo[d]imidazol-2-yl)ethyl)cyclobutyl)(isopropyl)amino)methyl)tetrahydrofuran-3,4-diol], a small-molecule inhibitor of the protein methyltransferase DOT1L, is currently under clinical investigation for acute leukemias bearing MLL-rearrangements (MLL-r). In this study, we evaluated EPZ-5676 in combination with standard of care (SOC) agents for acute leukemias as well as other chromatin-modifying drugs in cellular assays with three human acute leukemia cell lines: MOLM-13 (MLL-AF9), MV4-11 (MLL-AF4), and SKM-1 (non-MLL-r). Studies were performed to evaluate the antiproliferative effects of EPZ-5676 combinations in a cotreatment model in which the second agent was added simultaneously with EPZ-5676 at the beginning of the assay, or in a pretreatment model in which cells were incubated for several days in the presence of EPZ-5676 prior to the addition of the second agent. EPZ-5676 was found to act synergistically with the acute myeloid leukemia (AML) SOC agents cytarabine or daunorubicin in MOLM-13 and MV4-11 MLL-r cell lines. EPZ-5676 is selective for MLL-r cell lines as demonstrated by its lack of effect either alone or in combination in the nonrearranged SKM-1 cell line. In MLL-r cells, the combination benefit was observed even when EPZ-5676 was washed out prior to the addition of the chemotherapeutic agents, suggesting that EPZ-5676 sets up a durable, altered chromatin state that enhances the chemotherapeutic effects. Our evaluation of EPZ-5676 in conjunction with other chromatin-modifying drugs also revealed a consistent combination benefit, including synergy with DNA hypomethylating agents. These results indicate that EPZ-5676 is highly efficacious as a single agent and synergistically acts with other chemotherapeutics, including AML SOC drugs and DNA hypomethylating agents in MLL-r cells.

Selective inhibition of EZH2 by EPZ-6438 leads to potent antitumor activity in EZH2-mutant non-Hodgkin lymphoma

Mutations within the catalytic domain of the histone methyltransferase EZH2 have been identified in subsets of patients with non-Hodgkin lymphoma (NHL). These genetic alterations are hypothesized to confer an oncogenic dependency on EZH2 enzymatic activity in these cancers. We have previously reported the discovery of EPZ005678 and EPZ-6438, potent and selective S-adenosyl-methionine-competitive small molecule inhibitors of EZH2. Although both compounds are similar with respect to their mechanism of action and selectivity, EPZ-6438 possesses superior potency and drug-like properties, including good oral bioavailability in animals. Here, we characterize the activity of EPZ-6438 in preclinical models of NHL. EPZ-6438 selectively inhibits intracellular lysine 27 of histone H3 (H3K27) methylation in a concentration- and time-dependent manner in both EZH2 wild-type and mutant lymphoma cells. Inhibition of H3K27 trimethylation (H3K27Me3) leads to selective cell killing of human lymphoma cell lines bearing EZH2 catalytic domain point mutations. Treatment of EZH2-mutant NHL xenograft-bearing mice with EPZ-6438 causes dose-dependent tumor growth inhibition, including complete and sustained tumor regressions with correlative diminution of H3K27Me3 levels in tumors and selected normal tissues. Mice dosed orally with EPZ-6438 for 28 days remained tumor free for up to 63 days after stopping compound treatment in two EZH2-mutant xenograft models. These data confirm the dependency of EZH2-mutant NHL on EZH2 activity and portend the utility of EPZ-6438 as a potential treatment for these genetically defined cancers.

Experts reviews of the multidisciplinary consensus conference colon and rectal cancer 2012: science, opinions and experiences from the experts of surgery

The first multidisciplinary consensus conference on colon and rectal cancer was held in December 2012, achieving a majority of consensus for diagnostic and treatment decisions using the Delphi Method. This article will give a critical appraisal of the topics discussed during the meeting and in the consensus document by well-known leaders in surgery that were involved in this multidisciplinary consensus process. Scientific evidence, experience and opinions are collected to support multidisciplinary teams (MDT) with arguments for medical decision-making in diagnosis, staging and treatment strategies for patients with colon or rectal cancer. Surgery is the cornerstone of curative treatment for colon and rectal cancer. Standardizing treatment is an effective instrument to improve outcome of multidisciplinary cancer care for patients with colon and rectal cancer. In this article, a review of the following focuses; Perioperative care, age and colorectal surgery, obstructive colorectal cancer, stenting, surgical anatomical considerations, total mesorectal excision (TME) surgery and training, surgical considerations for locally advanced rectal cancer (LARC) and local recurrent rectal cancer (LRRC), surgery in stage IV colorectal cancer, definitions of quality of surgery, transanal endoscopic microsurgery (TEM), laparoscopic colon and rectal surgery, preoperative radiotherapy and chemoradiotherapy, and how about functional outcome after surgery?