Camptothesome-based combination nanotherapeutic regimen for improved colorectal cancer immunochemotherapy

Camptothesome is a sphingomyelin-conjugated camptothecin (SM-CSS-CPT) nanovesicle that fortified the therapeutic delivery of CPT in diverse cancer types. To mitigate the Camptothesome-induced IDO1 negative feedback mechanism, we had co-encapsulated, indoximod (IND, IDO1 inhibitor) into Camptothesome using doxorubicin-derived IND (DOX-IND). To maximize the therapeutic potential of DOX-IND/Camptothesome, herein, we first dissected the synergistic drug ratio (DOX-IND/SM-CSS-CPT) via systematical in vitro screening. DOX-IND/Camptothesome with optimal drug ratio synchronized in vivo drug delivery with significantly higher tumor uptake compared to free drugs. This optimum DOX-IND/Camptothesome outperformed the combination of Camptothesome, Doxil and IND or other IDO1 inhibitors (BMS-986205 or epacadostat) in treating mice bearing late-stage MC38 tumors, and combination with immune checkpoint blockade (ICB) enabled it to eradicate 60 % of large tumors. Further, this optimized co-delivery Camptothesome beat Folfox and Folfiri, two first-line combination chemotherapies for colorectal cancer in antitumor efficacy and exhibited no side effects as compared to the severe systemic toxicities associated with Folfox and Folfiri. Finally, we demonstrated that the synergistic DOX-IND/Camptothesome was superior to the combined use of Onivyde + Doxil + IND in curbing the advanced orthotopic CT26-Luc tumors and eliminated 40 % tumors with complete metastasis remission when cooperated with ICB, eliciting stronger anti-CRC immune responses and greater reversal of immunosuppression. These results corroborated that with precise optimal synergistic drug ratio, the therapeutic potential of DOX-IND/Camptothesome can be fully unleased, which warrants further clinical investigation to benefit the cancer patients.

Predictive value of CDC37 gene expression for targeted therapy in metastatic colorectal cancer

BACKGROUND

CDC37 is a key determinant of client kinase recruitment to the HSP90 chaperoning system. We hypothesized that kinase-specific dependency on CDC37 alters the efficacy of targeted therapies for metastatic colorectal cancer (mCRC).

MATERIAL AND METHODS

Two independent mCRC cohorts were analyzed to compare the survival outcomes between CDC37-high and CDC37-low patients (stratified by the median cutoff values): the CALGB/SWOG 80405 trial (226 and 207 patients receiving first-line bevacizumab- and cetuximab-containing chemotherapies, respectively) and Japanese retrospective (50 refractory patients receiving regorafenib) cohorts. A dataset of specimens submitted to a commercial CLIA-certified laboratory was utilized to characterize molecular profiles of CDC37-high (top quartile, N = 5055) and CDC37-low (bottom quartile, N = 5055) CRCs.

RESULTS

In the bevacizumab-treated group, CDC37-high patients showed significantly better progression-free survival (PFS) (median 13.3 vs 9.6 months, hazard ratio [HR] 0.59, 95% confidence interval [CI] 0.44-0.79, p < 0.01) than CDC37-low patients. In the cetuximab-treated group, CDC37-high and CDC37-low patients had similar outcomes. In the regorafenib-treated group, CDC37-high patients showed significantly better overall survival (median 11.3 vs 6.0 months, HR 0.24, 95% CI 0.11-0.54, p < 0.01) and PFS (median 3.5 vs 1.9 months, HR 0.51, 95% CI 0.28-0.94, p = 0.03). Comprehensive molecular profiling revealed that CDC37-high CRCs were associated with higher VEGFA, FLT1, and KDR expressions and activated hypoxia signature.

CONCLUSIONS

CDC37-high mCRC patients derived more benefit from anti-VEGF therapies, including bevacizumab and regorafenib, but not from cetuximab. Molecular profiles suggested that such tumors were dependent on angiogenesis-relating pathways.

Trial in progress: A phase II study (with safety run-in) of evorpacept (ALX148), cetuximab, and pembrolizumab in patients with refractory microsatellite-stable metastatic colorectal cancer (AGICC-ALX148 21CRC01)

TPS257

Background: Refractory microsatellite stable colorectal cancer (MSS CRC) is immunologically cold and single-agent anti-PD-1/PD-L1 drugs are ineffective; novel immune-based approaches are needed. Evorpacept (E, ALX148) is an engineered protein (high-affinity CD47-blocker fused to an inactive IgG Fc region), which blocks the CD47/SIRPα innate immune inhibitory phagocytosis checkpoint expressed on CRC and phagocytes, respectively. The Fc region of E does not bind to Fcγ receptors, thereby limiting hematologic toxicity, and is intended to be given in combination. In CT26 CRC syngeneic models, E ± anti-PD-1 monoclonal antibody decreases tumor growth, reduces myeloid immunosuppression, increases dendritic cell activation, and increases T cell activation (Kauder, 2018); E enhances the antibody-dependent cellular phagocytosis activity of cetuximab (C) in vitro (Kauder, 2018); and E + pembrolizumab (P) was well-tolerated in the first-in-human trial (Lakhani, 2021). Methods: AGICC-ALX148 21CRC01 (NCT05167409) is a phase 2, single-arm, multicenter, investigator-initiated trial of E (15 mg/kg weekly), C (400 mg/m2 then 250 mg/m2 weekly), and P (200 mg every 3 weeks) in 21-day cycles for patients with unresectable MSS/proficient mismatch repair CRC refractory to oxaliplatin, irinotecan, and a fluoropyrimidine, regardless of tumor sidedness and RAS/BRAF status. Additional key eligibility criteria include ECOG performance status 0-1, evaluable disease per RECIST v1.1, adequate hematologic and end organ function, absence of prior checkpoint inhibitor use, and absence of significant autoimmune disease. Six patients will be enrolled in Stage 1 (safety run-in) and treated with ECP. The study will proceed to Stage 2 (dose expansion, N = 42, and all treated with ECP) if less than 33% of patients in Stage 1 experience a dose-limiting toxicity. Otherwise, additional patients will be enrolled in Stage 1 at lower dose level(s). The co-primary objectives are to determine 1) the recommended dose of E with CP, and 2) objective response rate by RECIST v1.1 (by one-sided exact test with α = 0.05, H0 p ≤ 3% [historical controls], HA p ≥ 15%; power is 87%). The study will close for futility if there are no responses (partial or complete) in the first 24 evaluable patients (by MinMax design with α = 0.025 [1-sided]; power is 87%). Secondary and exploratory aims include determination of progression-free survival, overall survival, safety, response assessment by iRECIST, and blood- and tumor-based immune modulation and baseline tumor expression (PD-L1, EGFR, and CD47) for association with tumor response. The study is open through the Academic GI Cancer Consortium and 5 patients have been enrolled at time of submission. Clinical trial information: NCT05167409 .

Phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer: NRG-GI005 (COBRA)

TPS259

Background: Detection of circulating tumor DNA (ctDNA) shed into the bloodstream represents a highly specific and sensitive approach for identifying microscopic or residual tumor cells after surgical resection. For patients (pts) with colon cancer (CC), the detection of ctDNA is associated with persistent disease after resection and outperforms traditional clinical and pathological features in prognosticating risk for recurrence. However, for pts with stage II CC, there are currently no validated biomarkers predicting benefit in identifying pts whose residual disease cancer be cleared by adjuvant chemotherapy. We hypothesize that for pts whose stage II colon cancer has been resected and who have no traditional high-risk features, a positive ctDNA status may identify those who will benefit from adjuvant chemotherapy. Methods: In this prospective phase II/III clinical trial, pts (N=1,408) with resected stage II CC without traditional high-risk features and whom the evaluating oncologist deems suitable for active surveillance (i.e., not needing adjuvant chemotherapy) will be randomized 1:1 into 2 arms: standard-of-care/observation (Arm A), or prospective testing for ctDNA (Arm B). Postoperative blood will be analyzed for ctDNA with the Guardant Reveal assay, covering CC-relevant mutations and CC-specific methylation profiling. Pts in Arm B with ctDNA detected will be treated with 6 months of adjuvant (FOLFOX) chemotherapy. For all pts in Arm A, ctDNA status will be analyzed retrospectively at the time of endpoint analysis. The primary endpoints are clearance of ctDNA with adjuvant chemotherapy (phase II) and recurrence-free survival (RFS) for “ctDNA-detected” pts treated with or without adjuvant chemotherapy (phase III). Secondary endpoints will include time-to-event outcomes (OS, RFS, TTR) by ctDNA marker status and treatment, prevalence of detectable ctDNA in stage II CC, and rates of compliance with assigned intervention. Archived normal and matched tumor and blood samples will be collected for exploratory correlative research. Enrollment continues across North America to the 540-patient phase II endpoint. Support: U10CA180868, -180822; UG1CA189867; GuardantHealth. Clinical trial information: NCT04068103 .

The role of gene expression of CD47 in colorectal cancer (CRC)

240

Background: CD47 belongs to the immunoglobulin superfamily and is overexpressed in many tumor types. CD47 plays an important role in suppressing phagocytosis through binding to transmembrane protein SIRP-alpha on macrophages. Targeting CD47 is a novel strategy for cancer immunotherapy and is being evaluated in ongoing clinical trials. However, molecular characteristics of CD47-overexpressed colorectal cancer (CRC) are largely unknown. Methods: We retrospectively reviewed CRC patient samples (n = 14786) submitted to a commercial CLIA-certified laboratory (Caris Life Sciences, Phoenix AZ). Next-generation sequencing of DNA and RNA (whole-transcriptome sequencing) and immunohistochemistry were performed. Correlation of CD47 expression with danger-associated molecular pattern (DAMP)-related genes ( HMGB1, CALR, ANXA1, HSP90AA1, HSPA1A, and CXCL10) expressions was tested. DAMP signature calculated as composite z-score of the DAMP related genes was compared between CD47-high and -low patients classified according to the median level of CD47 expression. Distributions of KRAS and BRAF mutations, consensus molecular subtype (CMS), and signatures of oncogenic signaling pathways were compared between CD47-high and -low patients. In addition, overall survival (OS) was compared between CD47-high and -low patients available for survival data. Results: CD47 expression level was significantly higher in metastatic compared to primary lesions (1.07-fold, q < 0.05) and microsatellite instability high tumors compared to microsatellite stable tumors (1.15-fold, q < 0.05). CD47 expression was positively correlated with DAMP genes expression except for HSPA1A, and the DAMP signature (median score [MS]: 2.66 vs -2.29, q < 0.05) was significantly increased in CD47-high patients. KRAS mutations were less prevalent (45.87% vs 50.05%) and CMS1(17.72% vs 14.42%) and CMS4 (40.33% vs 27.28%) were more prevalent in CD47-high patients, while no difference was observed in the prevalence of BRAF mutations between CD47-high and -low patients. Signatures of EMT (MS:2.91 vs -3.19), TGF-beta (MS:3.72 vs -3.52), angiogenesis (MS:2.95 vs -2.78), MAPK (MS:4.99 vs -4.12), PI3K (MS:2.41 vs -2.03), and immune-related signaling pathways (MS:1.20 vs -2.51) were significantly enriched in CD47-high patients (all q < 0.05). CD47-high patients (n = 4873) showed significantly worse OS than CD47-low patients (n = 4898) (median OS, 32.4 vs 37.6 months; hazard ratio = 1.158, p< 0.01). Conclusions: Highly CD47-expressed CRC harbored activation of DAMPs and oncogenic signaling pathways that linked to aberrant tumor microenvironment and worse prognosis. Our results support intensive treatment strategies using CD47 inhibitors combined with cytotoxic agents and molecular targeted agents (such as anti-VEGF agents) in CD47-overexpressed CRC.

The role of gene expression of CDC37 in colorectal cancer (CRC)

237

Background: CDC37-HSP90 axis is an essential chaperoning system for stabilization of kinases. CDC37 determines selectivity of client kinases recognized by HSP90. We previously showed patients with CDC37-dependent ( CDC37 high expression) colorectal cancer (CRC) derived more benefit from regorafenib and bevacizumab both of which target HSP90 client kinases or signaling pathway, but not from cetuximab which targets HSP90 non-client kinase. However, molecular characteristics and interaction with relevant signaling pathways in CDC37-dependent CRC are largely unknown. Methods: We retrospectively reviewed CRC patient samples submitted to a commercial CLIA-certified laboratory (Caris Life Sciences, Phoenix AZ). Next-generation sequencing of DNA and RNA (whole-transcriptome sequencing) and immunohistochemistry were performed. Molecular profiles between top quartile transcripts per million for CDC37 expression (Q4, CDC37-high: n = 5056) and bottom quartile (Q1, CDC37-low: n = 5056) were compared for gene mutations, microsatellite instability (MSI) status, PD-L1 expression, co-expression of HSP90 genes ( HSP90AA1 and HSP90AB1), MAPK pathway activity score (MPAS), T-cell inflamed signature, and cell infiltration in the tumor microenvironment (TME) assessed by QuantiSEQ. Gene set enrichment analysis (GSEA) was performed between CDC37-high (Q4) and CDC37-low (Q1) tumors. Results: KRAS mutations trended higher in CDC37-high tumors compared to CDC37-low tumors (49.5% vs 47.1%) while APC (76.9% vs 72.3%), TP53 (75.5% vs 71.8%) and TCF7L2 (5.0% vs 3.5%) mutations were significantly higher in CDC37-high tumors compared to CDC37-low tumors (q < 0.05). No significance in expression quartiles were observed for dMMR/MSI-H or PD-L1 expression. HSP90AA1 and HSP90AB1 expression levels were significantly higher in CDC37-high tumors (2.9-fold and 2.6-fold in median, respectively; both q< 0.05). Both MPAS and T-cell inflamed signatures were significantly higher in CDC37-high tumors ( q< 0.05). Infiltration of NK cells, Tregs, neutrophils, M1 macrophages, and B-cells were greater in CDC37-high tumors (q < 0.05). GSEA showed several signaling pathways, such as KRAS, TGF-beta, hypoxia, WNT-beta catenin, and PI3K-AKT-MTOR, were enriched in CDC37-high tumors. Conclusions: Highly CDC37-expressed (CDC37-dependent) CRC was associated with aberrant TME where abundance of immune cell infiltrate and broad activation of kinase-related signaling pathways were evident. Our results support the kinase-stabilizing function of CDC37 in CRC. Further investigations combined with survival data are warranted to address the prognostic and predictive values of CDC37 expression in targeted therapies of CRC.

Camptothesome elicits immunogenic cell death to boost colorectal cancer immune checkpoint blockade

Camptothesome is an innovative nanovesicle therapeutic comprising the sphingomyelin-derived camptothecin (CPT) lipid bilayer. In this work, we deciphered that Camptothesome was taken up by colorectal cancer (CRC) cells through primarily the clathrin-mediated endocytotic pathway and displayed the potential of eliciting robust immunogenic cancer cell death (ICD) via upregulating calreticulin, high mobility group box 1 protein (HMGB-1), and adenosine triphosphate (ATP), three hallmarks involved in the induction of ICD. In addition, use of dying MC38 tumor cells treated with Camptothesome as vaccine prevented tumor growth in 60% mice that received subsequent injection of live MC38 cells on the contralateral flank, validating Camptothesome was a legitimate ICD inducer in vivo. Camptothesome markedly reduced the acute bone marrow toxicity and gastrointestinal mucositis associated with free CPT and beat free CPT and Onivyde on anti-CRC efficacy and immune responses in a partially interferon gamma (IFN-γ)-dependent manner. Furthermore, Camptothesome enhanced the efficacy of immune checkpoint inhibitors to shrink late-stage orthotopic MC38 CRC tumors with diminished tumor metastasis and markedly prolonged mice survival.

Landscape of endocytosis pathway in colorectal cancer (CRC)

3148

Background: Recent proteogenomic analyses of CRC revealed that driver gene alterations are enriched in the endocytosis pathway (Vasaikar S, et al. Cell 2019;177:1035-49). Endocytosis is a cellular system involving post-translational modification of plasma membrane proteins through internalization, intracellular trafficking, degradation, and recycling. Clathrin-mediated endocytosis (CME) is the main endocytic portal, and endosomal sorting complexes required for transport (ESCRT) play a critical role in the lysosomal degradation pathway. Besides the well-known function of endocytosis attenuating signaling pathways through receptor clearance from the cell surface, the opposite function contributing to signal maintenance has also been reported. However, the clinical implications of the endocytosis pathway alterations in CRC are largely unclear. Methods: We retrospectively reviewed CRC patient samples (n = 15025) submitted to a commercial CLIA-certified laboratory (Caris Life Sciences, Phoenix AZ). Next-generation sequencing of DNA and RNA (whole-transcriptome sequencing) and immunohistochemistry (IHC) were performed. CME-related (47 genes) and ESCRT-related (35 genes) expression signatures were calculated as composite z-scores and compared between subgroups stratified by RAS/ BRAF mutation status, MSS/MSI status, tumor sidedness, and consensus molecular subtype (CMS). VPS4A/ VPS4B expression correlation with major oncogenic pathway signatures (composite z-scores) and CMTM6/ CMTM4/ HIP1R expression association with PD-L1+ IHC were also assessed. Results: Among 17 endocytosis-related genes, no pathogenic/likely pathogenic mutations were identified. The CME-related signature was increased in RAS/ BRAF wild type vs. mutant (0.93 z-score difference, p= 0.04) and MSS vs. MSI-high (6.0 z-score difference, p< 0.01), while the ESCRT-related signature was higher in MSS compared to MSI-high (2.7 z-score difference; p< 0.01). No differences between tumor sidedness were observed in both CME- and ESCRT-related signatures (0.81 and 1.17 z-score differences, respectively). CMS4 had the highest expression of both signatures, while CMS3 had the lowest, of both CME- and ESCRT-related genes (each > 20 z-score difference, p< 0.01). VPS4A and VPS4B expression had a strong positive correlation with WNT, EGFR/MAPK, TGF-beta, and Notch pathway signatures (0.65-0.83 Spearman, all p< 0.01). CMTM6 expression was positively associated with PD-L1+ IHC (1.2-fold increase vs PD-L1-negative, p< 0.01), while CMTM4 and HIP1R expression showed a negative association (0.7- and 0.9-fold decrease, respectively, p< 0.01). Conclusions: This large study indicates endocytosis pathway expression is positively associated with oncogenic pathway signaling in CRC. Further analysis of RAS/ BRAF wild type, MSS, and CMS4 patient subgroups are warranted to determine the efficacy of targeting endocytosis pathways in CRC.

Phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer: NRG-GI005 (COBRA)

TPS233

Background: There are currently no validated predictive biomarkers for stage II resected colon cancer (CC) after adjuvant chemotherapy. However, circulating tumor DNA (ctDNA) shed into the bloodstream represents a highly specific and sensitive approach for identifying microscopic or residual tumor cells. For patients (pts) with CC, the detection of ctDNA is associated with persistent disease after resection and may outperform traditional clinical and pathological features in prognosticating risk for recurrence. We hypothesize that for pts whose stage II colon cancer has been resected and who have no traditional high-risk features, a positive ctDNA status may identify those who will benefit from adjuvant chemotherapy. Methods: In this prospective phase II/III clinical trial, pts (N = 1,408) with resected stage II CC without traditional high-risk features and whom the evaluating oncologist deems suitable for active surveillance (i.e., not needing adjuvant chemotherapy) will be randomized 1:1 into 2 arms: standard-of-care/observation (Arm A), or prospective testing for ctDNA (Arm B). Postoperative blood will be analyzed for ctDNA with the Guardant Reveal assay, covering CC-relevant mutations and CC-specific methylation profiling. Pts in Arm B with ctDNA detected will be treated with 6 months of adjuvant (FOLFOX) chemotherapy. For all pts in Arm A, ctDNA status will be analyzed retrospectively at the time of endpoint analysis. The primary endpoints are clearance of ctDNA with adjuvant chemotherapy (phase II) and recurrence-free survival (RFS) for “ctDNA-detected” pts treated with or without adjuvant chemotherapy (phase III). Secondary endpoints will include time-to-event outcomes (OS, RFS, TTR) by ctDNA marker status and treatment, prevalence of detectable ctDNA in stage II CC, and rates of compliance with assigned intervention. Archived normal and matched tumor and blood samples will be collected for exploratory correlative research. Enrollment continues across North America to the 540-patient phase II endpoint. Support: U10-CA-180868, -180822; UG1CA-189867; GuardantHealth. Clinical trial information: NCT04068103.

Mentorship during undergraduate surgical training: comparing perceptions of medical students and faculty at two institutions in South Africa and Sweden

BACKGROUND

Having a mentor during undergraduate surgical training has been shown to positively influence medical students by increasing interest in surgery, improving confidence, and assisting in career planning. This study aimed to evaluate and compare medical student and faculty perceptions of mentorship during undergraduate surgical training and compare results between two teaching institutions in South Africa and Sweden.

METHODS

An electronic, online questionnaire was anonymously distributed to medical students and general surgical faculty at the University of Cape Town (UCT), South Africa, and Karolinska Institutet (KI), Stockholm, Sweden. The questionnaire consisted of multiple choice, true or false, and five-point Likert scale questions, exploring perceptions of mentorship and role models, as well as rating the most important mentor characteristics.

RESULTS

Approximately one third (34.2%) of students stated they had a mentor during their surgical training, with significant differences found between student cohorts (p < 0.001). The 'registrar' was most commonly reported as the best role model for medical students by faculty from both UCT (50.0%) and KI (69.4%), as well as UCT students (36.6%). Students rated the following mentor qualities significantly higher compared to faculty: student encouragement (p = 0.037), adequate supervision (p = 0.007), setting of fair expectations (p = 0.002), and teaching skills (p = 0.010).

CONCLUSION

With significant differences existing in the perceptions of medical students and faculty regarding mentorship and role models during undergraduate surgical training in both South African and Swedish institutions, reconciling and harmonising these differences will be crucial in fostering constructive mentoring relationships.

Evaluation of febrile neutropenia and myelosuppression in patients receiving FOLFOX/FOLFIRI in gastrointestinal cancer treated with same-day (SD) pegfilgrastim/pegfilgrastim-CBQV (PFG)

311

Background: The National Comprehensive Cancer Network (NCCN) guidelines and the manufacturers of PFG recommend administration at least 24 hours after chemotherapy (CTX). Administering SD PFG carries the potential risk for exacerbation of neutropenia based on analyses in lymphoma and breast cancer regimens; however, little data exists on infusional fluorouracil and SD PFG administration. The availability of biosimilar PFG and increased utilization of growth factors during the COVID-19 pandemic has led to changes in practice for SD PFG administration. This study explored the incidence of febrile neutropenia (FN) and myelosuppression with FOLFOX and FOLFIRI regimens in Gastrointestinal malignancies (GI) to address the safety of SD utilization of PFG. Methods: Patient data was extracted through electronic health records search of ICD-9 and ICD-10 codes for GI malignancies and treated with FOLFOX or FOLFIRI-based regimens from November 2013 to May 2021. SD administration was defined as administration of PFG within 15 minutes after fluorouracil pump disconnect. The primary endpoint of our study was to evaluate the incidence of FN across all CTX cycles for up to four cycles, in SD PFG administration. Secondary outcomes included chemotherapy induced neutropenia (CIN), hospitalizations, and CTX dose reduction or delay. Results: Three hundred and thirty-nine patient charts were reviewed with 55 patients meeting the inclusion criteria. In our study cohort, 72.7% received FOLFOX and 27.2% received FOLFIRI-based regimens. Out of all 194 CTX cycles, 136 (70.1%) cycles received pegfilgrastim and 58 cycles received pegfilgrastim-cbqv (29.9%). Two patients had grade 3/4 CIN (1%), with both cases resulting in FN (1%). Both FN cases resulted in hospitalizations, and dose delays or reductions. Investigation of FN incidences revealed that both patients received CTX with active infections, one case with a urinary tract infection and the other with a chronic gangrene infection. Conclusions: Our study results suggest that SD administration of PFG can be as a safe and effective alternative to 24-hour post-chemotherapy administration in patients receiving FOLFOX or FOLFIRI-based regimens. The incidence of FN was noted to be minimal in our study. Furthermore, no noted increase in myelosuppression was seen in our analysis, as compared to previous studies in breast cancer and lymphoma-based regimens. SD administration not only minimizes travel burdens on long-distance patients but also has allowed for reduction in infusion appointments and therefore possible exposure to the SARS-COV2 virus during the 2020-2021 pandemic. Future prospective studies are warranted in order to elucidate the risk of FN and myelosuppression in patients undergoing chemotherapy for GI malignancies with SD PFG administration.

Immunogenic camptothesome nanovesicles comprising sphingomyelin-derived camptothecin bilayers for safe and synergistic cancer immunochemotherapy

Despite the enormous therapeutic potential of immune checkpoint blockade (ICB), it benefits only a small subset of patients. Some chemotherapeutics can switch 'immune-cold' tumours to 'immune-hot' to synergize with ICB. However, safe and universal therapeutic platforms implementing such immune effects remain scarce. We demonstrate that sphingomyelin-derived camptothecin nanovesicles (camptothesomes) elicit potent granzyme-B- and perforin-mediated cytotoxic T lymphocyte (CTL) responses, potentiating PD-L1/PD-1 co-blockade to eradicate subcutaneous MC38 adenocarcinoma with developed memory immunity. In addition, camptothesomes improve the pharmacokinetics and lactone stability of camptothecin, avoid systemic toxicities, penetrate deeply into the tumour and outperform the antitumour efficacy of Onivyde. Camptothesome co-load the indoleamine 2,3-dioxygenase inhibitor indoximod into its interior using the lipid-bilayer-crossing capability of the immunogenic cell death inducer doxorubicin, eliminating clinically relevant advanced orthotopic CT26-Luc tumours and late-stage B16-F10-Luc2 melanoma, and achieving complete metastasis remission when combined with ICB and folate targeting. The sphingomyelin-derived nanotherapeutic platform and doxorubicin-enabled transmembrane transporting technology are generalizable to various therapeutics, paving the way for transformation of the cancer immunochemotherapy paradigm.

Phase II/III study of Circulating tumOr DNA as a predictive BiomaRker in Adjuvant chemotherapy in patients with stage II colon cancer: NRG-GI005 (COBRA)

TPS3622

Background: There are currently no validated predictive biomarkers for stage II resected colon cancer (CC) after adjuvant chemotherapy. However, circulating tumor DNA (ctDNA) that is shed into the bloodstream represents a highly specific and sensitive approach for identifying microscopic or residual tumor cells. For patients (pts) with CC, the detection of ctDNA is associated with persistent disease after resection and may outperform traditional clinical and pathological features as a prognostic factor to assess risk for recurrence. We hypothesize that for pts whose stage II colon cancer has been resected and who have no traditional high-risk features, a positive ctDNA status may identify those who will benefit from adjuvant chemotherapy. Methods: In this prospective phase II/III clinical trial, pts (N = 1,408) with resected stage II CC without traditional high-risk features and whom the evaluating oncologist deems suitable for no adjuvant chemotherapy will be randomized 1:1 into 2 arms: standard-of-care/observation (Arm A), or prospective testing for ctDNA (Arm B). Postoperative blood will be analyzed for ctDNA with the GuardantHealth LUNAR panel, covering CC-relevant mutations and CC-specific methylation profiling. Pts in Arm B with ctDNA detected will be treated with 6 months of adjuvant (FOLFOX) chemotherapy. For all pts in Arm A, ctDNA status will be analyzed retrospectively at the time of endpoint analysis. The primary endpoints are clearance of ctDNA with adjuvant chemotherapy (phase II) and recurrence-free survival (RFS) for “ctDNA-detected” pts treated with or without adjuvant chemotherapy (phase III). Secondary endpoints will include time-to-event outcomes (OS, RFS, TTR) by ctDNA marker status and treatment, prevalence of detectable ctDNA in stage II CC, and rates of compliance with assigned intervention. Archived normal and matched tumor and blood samples will be collected for exploratory correlative research. The trial is actively accruing towards the phase II endpoint in North America. NCT#: 04068103. Support: U10-CA-180868, -180822; UG1CA-189867; GuardantHealth. Clinical trial information: NCT04068103.

Phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer:NRG-GI005 (COBRA)

TPS148

Background: There are currently no validated predictive biomarkers for stage II resected colon cancer (CC) after adjuvant chemotherapy. However, circulating tumor DNA (ctDNA) that is shed into the bloodstream represents a highly specific and sensitive approach for identifying microscopic or residual tumor cells. For patients (pts) with CC, the detection of ctDNA is associated with persistent disease after resection and may outperform traditional clinical and pathological features as a prognostic factor to assess risk for recurrence. We hypothesize that for pts whose stage II colon cancer has been resected and who have no traditional high-risk features, a positive ctDNA status may identify those who will benefit from adjuvant chemotherapy. Methods: In this prospective phase II/III clinical trial, pts (N=1,408) with resected stage II CC without traditional high-risk features and whom the evaluating oncologist deems suitable for no adjuvant chemotherapy will be randomized 1:1 into 2 arms:standard-of-care/observation (Arm A), or prospective testing for ctDNA (Arm B). Postoperative blood will be analyzed for ctDNA with the GuardantHealth LUNAR panel, covering CC-relevant mutations and CC-specific methylation profiling. Pts in Arm B with ctDNA detected will be treated with 6 months of adjuvant (FOLFOX) chemotherapy. For all pts in Arm A, ctDNA status will be analyzed retrospectively at the time of endpoint analysis. The primary endpoints are clearance of ctDNA with adjuvant chemotherapy (phase II) and recurrence-free survival (RFS) for “ctDNA-detected” pts treated with or without adjuvant chemotherapy (phase III). Secondary endpoints will include time-to-event outcomes (OS, RFS, TTR) by ctDNA marker status and treatment, prevalence of detectable ctDNA in stage II CC, and rates of compliance with assigned intervention. Archived normal and matched tumor and blood samples will be collected for exploratory correlative research. The trial is actively accruing towards the phase II endpoint across all US and Canadian cooperative groups. Support:U10-CA-180868, -180822; UG1CA-189867; GuardantHealth. Clinical trial information: NCT04068103.

Mentorship during undergraduate surgical training: comparing perceptions of medical students and faculty at two institutions in South Africa and Sweden

ABSTRACT BACKGROUND: Having a mentor during undergraduate surgical training has been shown to positively influence medical students by increasing interest in surgery, improving confidence, and assisting in career planning. This study aimed to evaluate and compare medical student and faculty perceptions of mentorship during undergraduate surgical training and compare results between two teaching institutions in South Africa and Sweden METHODS: An electronic, online questionnaire was anonymously distributed to medical students and general surgical faculty at the University of Cape Town (UCT), South Africa, and Karolinska Institutet (KI), Stockholm, Sweden. The questionnaire consisted of multiple choice, true or false, and five-point Likert scale questions, exploring perceptions of mentorship and role models, as well as rating the most important mentor characteristics RESULTS: Approximately one third (34.2%) of students stated they had a mentor during their surgical training, with significant differences found between student cohorts (p < 0.001). The 'registrar' was most commonly reported as the best role model for medical students by faculty from both UCT (50.0%) and KI (69.4%), as well as UCT students (36.6%). Students rated the following mentor qualities significantly higher compared to faculty: student encouragement (p = 0.037), adequate supervision (p = 0.007), setting of fair expectations (p = 0.002), and teaching skills (p = 0.010 CONCLUSION: With significant differences existing in the perceptions of medical students and faculty regarding mentorship and role models during undergraduate surgical training in both South African and Swedish institutions, reconciling and harmonising these differences will be crucial in fostering constructive mentoring relationships Keywords: mentorship, role model, perception, surgical education

Phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer: NRG-GI005 (COBRA)

TPS4121

Background: There are currently no validated predictive biomarkers for stage II resected colon cancer (CC) after adjuvant chemotherapy. However, circulating tumor DNA (ctDNA) that is shed into the bloodstream represents a highly specific and sensitive approach for identifying microscopic or residual tumor cells. For patients (pts) with CC, the detection of ctDNA is associated with persistent disease after resection and may outperform traditional clinical and pathological features as a prognostic factor to assess risk for recurrence. We hypothesize that for pts whose stage II colon cancer has been resected and who have no traditional high-risk features, a positive ctDNA status may identify those who will benefit from adjuvant chemotherapy. Methods: In this prospective phase II/III clinical trial, pts (N=1,408) with resected stage II CC without traditional high-risk features and whom the evaluating oncologist deems suitable for no adjuvant chemotherapy will be randomized 1:1 into 2 arms: standard-of-care/observation (Arm A), or prospective testing for ctDNA (Arm B). Postoperative blood will be analyzed for ctDNA with the GuardantHealth LUNAR panel, covering CC-relevant mutations and CC-specific methylation profiling. Pts in Arm B with ctDNA detected will be treated with 6 months of adjuvant (FOLFOX) chemotherapy. For all pts in Arm A, ctDNA status will be analyzed retrospectively at the time of endpoint analysis. The primary endpoints are clearance of ctDNA with adjuvant chemotherapy (phase II) and recurrence-free survival (RFS) for “ctDNA-detected” pts treated with or without adjuvant chemotherapy (phase III). Secondary endpoints will include time-to-event outcomes (OS, RFS, TTR) by ctDNA marker status and treatment, prevalence of detectable ctDNA in stage II CC, and rates of compliance with assigned intervention. Archived normal and matched tumor and blood samples will be collected for exploratory correlative research. The trial is actively accruing towards the phase II endpoint across all US and Canadian cooperative groups. Support: U10-CA-180868, -180822; UG1CA-189867; GuardantHealth. Clinical trial information: NCT04068103 .

The landscape of MAP3K1/MAP2K4 alterations in gastrointestinal (GI) malignancies

4113

Background: Inactivating alterations in MAP3K1/MAP2K4 occur in various solid tumors, sensitize cancer models to MEK inhibitors, and have co-mutation partners which may enable therapeutic targeting. Methods: We retrospectively reviewed 20290 GI malignancy patients (pts), comprised of 9986 colorectal carcinoma (CRC) and 10304 non-CRC, whose tumors were profiled with Caris Life Sciences from 2015-2019. Profiling included immunohistochemistry (IHC) with programmed death ligand-1 (PD-L1), next-generation sequencing (NGS), tumor mutational burden (TMB) and deficient mismatch repair or microsatellite instability-high status (dMMR/MSI-H). Results: MAP3K1/MAP2K4-alteration ( MAP3K1/MAP2K4-MT) was more frequent in CRC than non-CRC pts (2.0% v. 1.2%, p<0.0001), with truncating mutations representing the majority of lesions along both genes. While MAP3K1/MAP2K4-MT CRC pts were similar in age and gender to wild-type (WT), mutated non-CRC pts were older (median age 69 v. 65 years) and more likely female (51% v. 42%) compared to WT (both p<0.05). MAP3K1/MAP2K4-MT CRC (25% v. 7%) and non-CRC (30% v. 3%) were more frequently dMMR/MSI-H than WT pts (both p<0.0001). MAP3K1/MAP2K4-MT CRC cases were affiliated with higher TMB and similar rate of PD-L1 expression compared to WT. A higher rate of MAP3K1/MAP2K4-MT CRC pts were right-sided (36% v. 22%, p<0.0001) and transverse (8% v. 4%, p<0.05) compared to WT, whereas a higher frequency of WT cases were left-sided (20% v. 28%, p<0.05) and rectal (15% v 23%, p<0.05). Of microsatellite stable (MSS) CRC pts, those with MAP3K1/MAP2K4-MT were more likely PIK3CA (26% v. 17%) and APC (85% v. 78%) and less-likely TP53 (64% v. 77%) co-mutated versus WT MSS pts (all p<0.05); no difference was seen in BRAF V600E, ERBB2/ ERBB3 or KRAS co-mutation rate in MSS pts. In both all-comers and MSS CRC, MAP3K1/MAP2K4-MT pts were more frequently co-mutated than WT with ARID1A, POLE, ATM, BRCA2 and PIK3R1 (all ≥7% of MAP3K1/MAP2K4-MT pts, p<0.0001). A higher frequency of all-comer non-CRC GI malignancy pts with MAP3K1/MAP2K4-MT were co-mutated with PIK3CA (13% v. 6%), ERBB2/ERBB3 (8% v. 3%) or APC (13% v. 5%) compared to WT (all p<0.01). For MSS non-CRC GI cases, ARID1A (50% v. 30%) and SMAD4 (21% v. 12%) were more frequently co-mutated in MAP3K1/MAP2K4-MT versus WT pts (all p<0.05). Conclusions: Truncating MAP3K1/MAP2K4 alterations occur in nearly 2% of GI malignancy pts and are more commonly associated with dMMR/MSI-H than WT. Potentially targetable co-mutation partners implicated in MAPK and PI3K pathways as well as POLE, BRCA2 and ATM warrant further evaluation.

Somatic alterations of NF1 in colorectal cancer

4066

Background: NF1 encodes neurofibromin, which is a key GTPase-activating protein that downregulates RAS activation. Inactivating mutations in NF1 result in sustained activation of RAS signaling, a key driver for development of colorectal cancer (CRC), and have been suggested to be a potential mechanism of resistance to EGFR inhibition in RAS-wild type (WT) CRC. Little is known about molecular characteristics of NF1-mutated (MT) CRC. Methods: Tumor profiles from 8150 CRC patients (pts) with available NF1 mutation status were retrospectively reviewed. NextGen sequencing by a customized 592-gene panel was performed. Microsatellite instability (MSI) / mismatch repair (MMR) status, tumor mutational burden (TMB) and PD-L1 expression were tested. Molecular profiles between NF1-MT and NF1-WT pts were compared. Results: Out of 8150 pts, 176 (2.2%) had somatic NF1 mutations with pathogenic or presumed pathogenic function. A higher NF1-MT frequency was observed in MSI-H/dMMR vs MSS/pMMR (13.5% vs 1.4%, p < 0.0001), in right-sided vs left sided (2.9% vs 1.8%, p < 0.01), and in RAS-WT vs RAS-MT (3.0% vs 1.4%, p < 0.0001). In MSS/pMMR tumors, no association with sidedness was observed (right: 1.3% vs left: 1.2%, NS). The most prevalent co-mutations with NF-1 were APC (63.2%), ARID1A (57.5%), TP53 (51.5%), KMT2D (32.9%) and KRAS (32.4%) in all cases, and APC (76.2%), TP53 (69.5%), KRAS (38.8%), ARID1A (34.4%) and FBXW7 (21.5%) in MSS/pMMR cases. POLE mutation was observed in 18.4% of NF1-MT/MSS/pMMR pts. Compared to NF1-WT pts, NF1-MT pts had more frequent mutations in ARID1A (All: 57.5% vs 23.3%, p < 0.0001; MSS/pMMR: 34.4% vs 15.2%, p < 0.05), and less frequent mutations in KRAS (All: 32.4% vs 49.0%, p < 0.0001; MSS/pMMR: 38.8% vs 50.3%, p < 0.05). Also, NF1-MT pts had more frequent alterations in homologous recombination pathway compared to NF1-WT pts (All: 39.8% vs 7.5%, p < 0.0001; MSS/pMMR: 17.5% vs 4.4%, p < 0.0001). Mean TMB was significantly greater in NF1-MT than NF1-WT (All: 48.9/Mb vs 10.0/Mb, p < 0.0001; MSS/pMMR: 48.3/Mb vs 8.2/Mb, p < 0.0001). Also, PD-L1 positivity was higher in NF1-MT compared to NF1-WT (All: 12.9% vs 3.6%, p < 0.0001; MSS/pMMR: 7.1% vs 2.6%, p < 0.05). Conclusions: While more frequent than in RAS-MT pts, NF1-MT CRC was a small subset in RAS-WT pts. NF1-MT was associated with alterations in chromatin remodeling and DNA damage response pathways, as well as elevated TMB and PD-L1 expression, which may provide alternative therapeutic strategies beyond EGFR inhibition.

The landscape of DNA damage response (DDR) pathway in colorectal cancer (CRC)

4064

Background: Abnormal DDR is a hallmark of cancer, relating to genome instability, anti-tumor immunity, and sensitivity to chemotherapeutic agents and radiation. We conducted a large-scale investigation to clarify the alteration of DDR pathway in CRC. Methods: Tumor samples from 9321 CRC patients were retrospectively reviewed. Next-Generation Sequencing (NGS) on a custom-designed panel enriching 592 gene targets was performed. Samples with mutations detected in any of 29 DDR-related genes were deemed DDR-mutant (DDR-MT); the rest DDR-wild type (DDR-WT). Microsatellite instability (MSI) status was tested with a combination of immunohistochemistry (IHC), fragment analysis and NGS. Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mutations. PD-L1 was tested by IHC (SP142). Consensus molecular subtype (CMS) was developed using RNA sequencing data. Results: Of 9321 cases, 1290 (13.8%) were DDR-MT. DDR-MT frequency was higher in right vs. left sided (20.9% vs 10.8%, p < 0.001) and MSI-H vs. MSS (76.4% vs 9.5%, p < 0.001) cases. In the MSS cases, right-sided had marginally higher frequency of DDR-MT than left-sided (10.6% vs 9.1%, p = 0.055), with much higher frequency of Fanconi anemia pathway alteration in right-sided (1.5% vs 0.7%, p < 0.01). CMS1 subtype had the highest frequency of DDR-MT (34.8%); CMS2 had the lowest (7.1%). DDR-MT cases (vs. DDR-WT) had higher mutation rate of ARID1A (55.0% vs 19.1%, p < 0.0001), PIK3CA (22.6% vs 15.8%, p < 0.0001) and BRAF (20.4% vs 7.3%, p < 0.0001), and lower mutation rate of TP53 (48.2% vs 76.1%, p < 0.0001), APC (60.5% vs 74.5%, p < 0.0001) and KRAS (44.0% vs 49.8%, p < 0.001). Mean TMB was much greater in DDR-MT than DDR-WT (All: 20.9/Mb vs 7.7/Mb, p < 0.0001; MSS: 13.7/Mb vs 7.6/Mb, p < 0.05). PD-L1 positivity was also higher in DDR-MT compared to DDR-WT (All: 10.1% vs 2.7%, p < 0.0001; MSS: 4.8% vs 2.4%, p < 0.0001). Conclusions: Alteration of the DDR pathway was strongly associated with MSI status in CRC. The primary tumor sidedness might also be related, as DDR-MT was more prevalent in right-sided tumors. Elevated TMB and PD-L1 expression in DDR-MT CRC indicate more activated anti-tumor immune profiles compared to DDR-WT, regardless of MSI status, suggesting possible therapeutic benefit from immune checkpoint inhibitors in DDR-MT CRC.

Detection of pancreatic cancer using a novel blood-based DNA methylation signature

e15546

Background: Pancreatic cancer (PC) is a high mortality malignancy typically found when curative surgery is not an option. Liquid biopsies are a minimally invasive option that may allow earlier detection of PC. Using a bioinformatic analysis of TCGA and GEO we identified a novel set of blood-based biomarkers to detect PC with high sensitivity and specificity (AUROC = 0.999) (Vrba et al, Epigenetics 2019). Here we tested the ability of this DNA methylation signature (MS) to distinguish metastatic PC from pancreatic cysts (Cy) and healthy controls (HC) through quantitative DNA methylation analysis of cell free DNA (cfDNA). Methods: A 10 gene DNA methylation marker set that identifies PC was used to evaluate the cfDNA component of the plasma of PC patients, Cy patients and HC. The ROC analysis and AUC calculations were performed using the R library pROC (Robin et al, BMC Bioinformatics 2011). Plasma samples were collected in cfDNA collection tubes from patients with benign Cy, PC, and HC. Clinical information was collected including age, gender, smoking history, CA 19-9 level, cyst size, presence of liver metastases, and survival status. After processing and cfDNA extraction, qRT-PCR methylation analysis was performed on these prospectively collected samples. The difference in median DNA MS per marker of the full 10-gene marker set between the above groups was analyzed by Wilcoxon rank sum test and ROC analysis. A Cox proportional hazard regression model was used to test the association between MS and survival. Results: A total of 66 samples were collected (PC = 10, Cy = 12, HC = 44). Clinical information was collected on all patients included in the analysis. Using liquid biopsies for cfDNA analysis and a novel set of DNA methylation biomarkers, MS was substantially stronger in PC (median, 13.2) patients than Cy (median, 3.5) patients (p = 0.0001). Importantly, while there was no clear association between MS and age, gender, smoking status, CA 19-9 levels, or presence of liver metastases, higher methylation levels were non-significantly associated with worse overall survival in PC patients (HR, 1.29; 95% CI, 0.97–1.72; p = 0.082). Conclusions: While this is a small sample size, early findings suggest that a DNA MS may reliably distinguish PC from benign Cy. The strength of signal may be a prognostic marker that could play a role in determining treatment approaches. Given its utility in predicting PC, future directions include testing this tool as a blood-based early detection mechanism as well as a predictor for recurrence or response to PC treatment.

NRG-GI005 (COBRA): Phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer

TPS261

Background: There are currently no validated predictive biomarkers for stage II resected colon cancer (CC) after adjuvant chemotherapy. However, circulating tumor DNA (ctDNA) that is shed into the bloodstream represents a highly specific and sensitive approach for identifying microscopic or residual tumor cells. For patients (pts) with CC, the detection of ctDNA is associated with persistent disease after resection and may outperform traditional clinical and pathological features as a prognostic factor to assess risk for recurrence. We hypothesize that for pts whose stage II colon cancer has been resected and who have no traditional high-risk features, a positive ctDNA status may identify those who will benefit from adjuvant chemotherapy. Methods: In this prospective phase II/III clinical trial, pts (N=1,408) with resected stage II CC without traditional high-risk features and whom the evaluating oncologist deems suitable for no adjuvant chemotherapy will be randomized 1:1 into 2 arms: standard-of-care/observation (Arm A), or prospective testing for ctDNA (Arm B). Postoperative blood will be analyzed for ctDNA with the GuardantHealth LUNAR panel, covering CC-relevant mutations and CC-specific methylation profiling. Pts in Arm B with ctDNA detected will be treated with 6 months of adjuvant (FOLFOX) chemotherapy. For all pts in Arm A, ctDNA status will be analyzed retrospectively at the time of endpoint analysis. The primary endpoints are clearance of ctDNA with adjuvant chemotherapy (phase II) and recurrence-free survival (RFS) for “ctDNA-detected” pts treated with or without adjuvant chemotherapy (phase III). Secondary endpoints will include time-to-event outcomes (OS, RFS, TTR) by ctDNA marker status and treatment, prevalence of detectable ctDNA in stage II CC, and rates of compliance with assigned intervention. Archived normal and matched tumor and blood samples will be collected for exploratory correlative research. Trial accrual is anticipated across all US and Canadian cooperative groups.NCT#: 04068103. Support: U10-CA-180868, -180822; UG1CA-189867; GuardantHealth. Clinical trial information: 04068103.

A phase II study investigating cabozantinib in patients with refractory metastatic colorectal cancer (AGICC 17CRC01)

103

Background: Therapeutic resistance to antiangiogenics in metastatic colorectal cancer (mCRC) inevitably develops via multiple mechanisms including upregulation of the MET kinase pathway. Cabozantinib, an oral multityrosine kinase inhibitor targeting MET, AXL, and VEGFR, demonstrated significant anti-tumor activity in CRC xenograft and cell line models. Methods: A single-arm, two-stage phase II study was conducted at 7 AGICC centers nationwide. 44 patients (pts) with mCRC who had progressed on or were intolerant of standard of care agents were treated with cabozantinib 60 mg daily in q3 wk cycles. The primary endpoint was 12-wk PFS rate. Based on the control arm of phase III CORRECT study, the Kaplan-Meier 12-wk PFS rate estimate was 13% and served as the null hypothesis. This study was powered at 0.906 to detect the alternative hypothesis of 12-wk PFS rate of 33% with a type I error rate of 0.044. Secondary endpoints were safety, RR, OS, and retrospective analysis of PFS and RR based on RAS, BRAF, and PIK3CA mutation status. Results: 44 pts were enrolled and 34 pts were response-evaluable as having undergone at least the first 6-wk restaging scan. 10 pts discontinued treatment prior to the first 6-wk scan due to clinical disease progression. Median number of cycles was 4 and median follow-up was 2.5 months. As of data-cutoff 8/23/2019, 55 Grade 3/4 AEs were reported with the most common being hypertension, fatigue, diarrhea, pain, HFS, nausea, vomiting, and proteinuria. 32 SAEs occurred in 18 pts. 5 Grade 5 AEs were reported: disease progression (3), disseminated intravascular coagulopathy, and bowel perforation. 15 pts (34%) achieved ≥ 12-wk PFS and 8 patients remain on treatment. Best response was 1 PR and 31 SD with a DCR at 6 wks of 72.7%. Of the pts who achieved ≥ 12-wk PFS, 12 had left-sided primary tumors, 5 had a RAS mutation, 1 had a PIK3CA mutation, and all pts were BRAF WT and MSI stable. Conclusions: Cabozantinib was deemed safe and demonstrates encouraging efficacy in a heavily pretreated mCRC pt population. These results support further investigation of cabozantinib in mCRC. Clinical trial information: NCT03542877.

Albuminuria in people at least 40 years old: effect of alcohol consumption, regular exercise, and cigarette smoking

We investigated the relation between albuminuria and life-style factors in 5670 people, ages 40 years and over, who participated in a health screening survey of a local workforce. The degree of albuminuria showed piecewise log-linear relationships with alcohol consumption and cigarette smoking, with changes in slope (and 95% confidence interval) corresponding with 5 (2, 8) g of alcohol/day and 10 (6, 14) cigarettes/day. After adjusting for age, gender, ethnicity, and other life-style variables, relative risks (95% confidence interval) of slight albuminuria for people consuming &gt; 32 g of alcohol/day compared with nondrinkers, and for cigarette smokers compared with nonsmokers, were 1.74 (1.02, 2.98) and 1.37 (1.01, 1.88), respectively. However, there was no significant effect of exercise. We conclude that slight albuminuria is significantly associated with cigarette smoking and heavy alcohol consumption, consistent with its role as an index of risk of cardiovascular disease.

Cartilage oligomeric matrix protein (COMP) promotes cell proliferation in early-onset colon cancer tumorigenesis

BACKGROUND

Colon cancer (CC) is the third most commonly diagnosed cancer in the USA. While the overall incidence is declining, it is rising alarmingly in young patients (EOCC). CC in young patients tends to be more aggressive and often diagnosed at more advanced stages and portend poorer prognosis. Our recently published data showed that EOCC is a distinct disease with unique molecular features compared to late-onset CC (LOCC). The Cartilage Oligomeric Matrix Protein (COMP) was shown to be significantly upregulated in EOCC and correlated with poor survival. However, the role of COMP in CC tumorigenesis, especially in young patients, is not well understood. Thus, the aim of this study was to elucidate the role of COMP in CC tumorigenesis by modulating COMP levels in vitro and test how it affects proliferation. Then, patient samples were evaluated by testing the levels of proliferation marker Ki67. In addition, this study investigates whether higher transcriptional mRNA levels of COMP seen in more aggressive early-onset CC correlate with protein levels compared to late-onset CC.

METHODS

COMP mRNA levels in fresh frozen colon tumors (young: n = 5; old: n = 5) were assessed by quantitative PCR (qPCR). Additionally, CC cell lines were profiled for COMP expression to choose an in vitro model to study the role of COMP in CC tumorigenesis. HT-29 (low COMP expression) and CaCo-2 (high COMP expression) cells were used for in vitro proliferation studies. Immunohistochemical (IHC) analysis was conducted to assess COMP and Ki67 protein levels in formalin-fixed paraffin-embedded (FFPE) colon tumors.

RESULTS

Significantly higher COMP expression levels were observed in fresh frozen EOCC compared to LOCC tumors. This observation confirmed our previously reported results from NanoString gene expression assay using FFPE samples. Cell proliferation was significantly increased in HT-29 and CaCo-2 cells upon treatment with human recombinant COMP protein after 48 and 72 h (P < 0.05). This increase was more profound in HT-29 cells. Staining for COMP and Ki67 revealed high COMP protein levels in EOCC compared to LOCC patients.

CONCLUSION

COMP mRNA and protein levels are significantly higher in EOCC patients. Higher COMP levels correlate with increased proliferation suggesting a role in CC tumorigenesis.

An analysis of the safety and efficacy of rivaroxaban (Riv) and low molecular weight heparin (LMWH) in gastrointestinal cancer-associated venous thromboembolism (GICA-VTE)

374

Background: CAVTE has a significant morbidity and mortality burden, with higher incidence and bleeding complications of anticoagulation (AC) in GICA. Current guidelines prefer LMWH, and recently added Riv, as an alternative standard after the SELECT-D trial (S-D). There is a paucity of data comparing the safety and efficacy of other DOACs in pts with GICA. We indirectly compared the safety and efficacy of Riv vs LMWH of our pts with active GICA-VTE at the University of Arizona Cancer Center (UACC) to the S-D GI-population. Methods: Pts with biopsy proven GICA, symptomatic or incidental VTE, and 6 months or more treatment with Riv or LMWH at UACC from 11/2013 - 12/2017 were retrospectively reviewed. S-D GICA data was extracted. Primary efficacy outcome was recurrent deep vein thrombosis (DVT), nonfatal pulmonary embolism (PE), or fatal PE. Safety outcomes for major bleeding (MB) include Hg drop ≥ 2 g/dL, transfusion of ≥ 2 units PRBC, bleeding in critical site, or bleeding contributing to death. Fisher exact test was used for p-value < 0.05. Results: Our review included pts on LMWH (n = 40), and Riv (n = 37) balanced population to the S-D trial. Recurrent VTE at 6mo was noted in 7.5% and 2.7% of pts, compared to S-D trial 11% and 4%, for LMWH and Riv respectively. MB at 6mo was 5% and 21.6% [p < 0.04] of pts, compared to S-D trial 5.8% and 8.7%, for LMWH and Riv, respectively. There was a non-significant difference [p > 0.07] between Riv and LMWH efficacy and safety beyond 6mo of AC. Conclusions: VTE secondary prophylaxis in GICA pts is complicated by high rates of recurrence and bleeding risk, DOACs provide another AC option. The most recent systemic review that included the two published DOACs RCTs for CAVTE [Hokusai and SELECT-D 2018], showed a higher incidence at 6-month of MB compared to LMWH RR: 1.74 (95% CI: 1.05–2.88) [Ang Li 2018], mainly driven by GICA. Our retrospective study showed a non-significant improved efficacy outcome although worse safety profile with Riv versus LMWH in GICA pts, by indirect comparison. Future RCTs with multi-center participation, particularly focused on GICA, can further provide information to guide safe and effective AC selection.

Phase I results from the phase 1/3 FIGHT study evaluating bemarituzumab and mFOLFOX6 in advanced gastric/GEJ cancer (GC)

91

Background: GC with FGFR2b overexpression or FGFR2 amplification is associated with a poor prognosis. Bemarituzumab (bema, FPA144) is a first-in-class humanized monoclonal IgG1 antibody that selectively blocks FGFR2b and triggers antibody-dependent cell-mediated cytotoxicity. With favorable safety and activity as a single agent in 2L+ patients with FGFR2b+ GC, the global, randomized, double-blind, placebo-controlled FIGHT study (NCT03343301) is evaluating the front-line combination of bema with mFOLFOX6. We report here the results from the phase I evaluation of the combination. Methods: Patients (pts) with unresectable, locally advanced or metastatic gastrointestinal malignancy (irrespective of FGFR2b status) for whom mFOLFOX6 would be appropriate were eligible for enrollment in the phase I. Her2+ disease or prior treatment with FGF-FGFR inhibitors was not allowed. All pts in the Phase 1 received mFOLFOX6 combined with bema in Q2W cycles. Cohort 1 (3+3) began with bema 6 mg/kg and cohort 2 (Rolling-6) bema 15 mg/kg with one dose of 7.5 mg/kg on C1D8. A dose-limiting toxicity (DLT) evaluation window of 28 days was used for both cohorts. Results: Cohorts 1 and 2 treated 3 pts and 9 pts respectively with a median of 4 and 2 prior lines of therapy. As of the iDMC data-cut on July 24, 2018, the median duration of treatment was 15 wks for cohort 1 and 4 wks for cohort 2; 6/9 pts in cohort 2 continue on treatment. No DLTs were identified. No adverse events (AEs) led to treatment discontinuation. There were no newly identified bema-related toxicities and the only ≥ Gr 2 AE attributable to bema in cohort 2 was fatigue (1 pt/Gr 2). The most common AEs overall were fatigue (6 pts/50%), nausea, vomiting and diarrhea (5 pts/42% each) and were generally attributed to FOLFOX or underlying disease. The ≥ Gr 3 AEs present in ≥ 1 pt were fatigue and neutropenia (2 pts/Gr 3 each). mFOLFOX6 did not affect bema exposure and all evaluable pts in cohort 2 achieved the target ≥ 60 µg/mL trough concentration by day 15. 2/7 pts at the data-cut had FGFR2b+ GC. Conclusions: Bema in combination with mFOLFOX6 has acceptable safety to proceed with the cohort 2 dose to the phase III portion of the FIGHT trial in previously untreated patients with FGFR2b+ GC. Clinical trial information: NCT03343301.

Prospective Risk Factor Analysis for the Development of Post-operative Urinary Retention Following Ambulatory General Surgery

Aims

Post-operative urinary retention (POUR) is a common cause of unplanned admission following day-case surgery and has negative effects on both patient and surgical institution. We aimed to prospectively evaluate potential risk factors for the development of POUR following day-case general surgical procedures.

Methods

Over a 24-week period, consecutive adult patients undergoing elective day-case general surgery at a single institution were prospectively recruited. Data regarding urinary symptoms, comorbidities, drug history, surgery and perioperative anaesthetic drug use were collected. The primary outcome was the incidence of POUR, defined as an impairment of bladder voiding requiring either urethral catheterisation, unplanned overnight admission or both. Potential risk factors for the development of POUR were analysed by logistic regression.

Results

A total of 458 patients met the inclusion criteria during the study period, and data were collected on 382 (83%) patients (74.3% male). Sixteen patients (4.2%) experienced POUR. Unadjusted analysis demonstrated three significant risk factors for the development of POUR: age ≥ 56 years (OR 7.77 [2.18–27.78], p = 0.002), laparoscopic surgery (OR 3.37 [1.03–12.10], p = 0.044) and glycopyrrolate administration (OR 5.56 [2.00–15.46], p = 0.001). Male sex and lower urinary tract symptoms were not significant factors. Multivariate analysis combining type of surgery, age and glycopyrrolate use revealed that only age ≥ 56 years (OR 8.14 [2.18–30.32], p = 0.0018) and glycopyrrolate administration (OR 3.48 [1.08–11.24], p = 0.0370) were independently associated with POUR.

Conclusions

Patients aged at least 56 years and/or requiring glycopyrrolate—often administered during laparoscopic procedures—are at increased risk of POUR following ambulatory general surgery.

Electronic supplementary material

The online version of this article (10.1007/s00268-018-4697-4) contains supplementary material, which is available to authorized users.

Correlative analysis of circulating tumor (ct) DNA and tumor mutational analysis (TMA) in patients with advanced pancreatobilliary malignancies (PBM)

235

Background: Tumor archival tissue (TT) MA of PBM is challenging due to insufficient specimen acquired from fine needle aspirations. This is a barrier to analyzing specimens for targeted therapy (clinical trial enrollment). The correlation of cell free ctDNA and TMA has not been studied extensively. We hypothesize that somatic TMA correlates with ctDNA and will be a surrogate for enrollment to targeted trials. Methods: We retrospectively identified PBM patients evaluated in the Phase I Program and analyzed ctDNA and TT. ctDNA was extracted from plasma, genomic alterations were analyzed by parallel sequencing of amplified target genes (73 genes) using Illumina Hi Seq (Guardant360). Direct sequence analysis was performed on genomic DNA isolated from FFPE TT using the Illumina MiSeq platform, 592-whole gene targets (Caris MI/X). The primary objective was to correlate the mutation concordance rate (mCR, common mutations/all mutations) between ctDNA and TT. We utilized Stata 15 for descriptive analysis, Spearman correlation coefficient, and Wilcoxon Sign Rank test for statistical analysis. Results: Between 03/2016-08/2017, 28 patients (M:F 1:1) were identified, 89.2% had pancreatic adenocarcinoma, 54% were treatment naïve and age ranged from 52-83 years old. The mCR for ctDNA was 31% (21/67) and the mCR for TT was 38% (21/55). These mCRs were highly correlative with a Spearman’s Rho = 0.89, (p < 0.0001). The mCR in ctDNA was compared to mCR in TT using Wilcoxon Sign Rank Test and was found to not be statistically different (p = 0.69). Adequate TT for MA occurred in 64 % (18/28) of patients. Percentage of DNA alterations found was 89.3% (25/28) in ctDNA and 94.4% (17/18) in TT. Moreover, 61% (11/18) of patients had at least 1 shared mutation. Percentages of driver mutations identified were 92% (23/25) in ctDNA and 100% (17/17) in TT. The most common driver mutations in ctDNA were TP53, KRAS, SMAD4, and NF1. The most common driver mutations in TT were KRAS, TP53, CDKN2A, and SMAD4. Conclusions: There was a statistically significant correlation between mCR of ctDNA and TMs in PBM (p < 0.0001).

Analyzing the efficacy and safety of immunotherapy in pancreatic ductal adenocarcinoma (PDA): A systematic review and meta-analysis

512

Background: The tumor microenvironment in PDA is heterogeneous and immunosuppressive given the presence of regulatory T cells and exhausted effector T cells. Despite the upsurge of effective immunotherapeutic agents (IA) in other tumor types, the role in PDA remains unknown. We conducted a meta-analysis of IA in PDA. Methods: Following PRISMA guidelines, we searched PubMed/MEDLINE, Elsevier/Embase, Wiley/Cochrane Library and ClinicalTrials.gov. Articles were selected per the following criteria: (1) Study participants had a diagnosis of PDA; (2) An IA was used in the trial. Titles, abstracts and full text articles were reviewed by 2 independent reviewers; disagreements were resolved by a third. Data extraction and analysis were performed by 3 independent reviewers. Descriptive analysis, mean, median, confidence interval and forest plots were used for statistical analysis. Results: We found 20,792 studies through the database, 16,105 remained after duplicates were removed and 15,889 were excluded due to irrelevance. Strict inclusion criteria were applied to the full text of 216 articles. The most common reason for exclusion were conference abstracts (44%) and ongoing trials (16%). Fifty-four trials (39 metastatic (met), 12 adjuvant (Ad) and 3 neoadjuvant (nAd) met criteria for further analysis. Age range was 27-86 (median 61) and 52.3% were males. IA included cytokine therapy (33%), peptide vaccines (22%), dendritic cell vaccine (13%), oncolytic viruses (9%), CTLA-4 inhibitors (2%) and others. IA in met-PDA had a median overall survival (mOS) of 8.1 months (ms) and a disease control rate (DCR) of 55.4% (95% CI, 51.85-58.95). There was no statistical difference in DCR among IA subtypes (range 49-60%) (p = 0.22). The mOS of Ad-PDA trials was 25 ms (historically comparable to gemcitabine, p = 0.75) and 18 ms for nAd-PDA. The most common Gr1/2 toxicities were skin reactions, fever, and chills and Gr3/4 were cytopenias, diarrhea, and mucositis. One death occurred due to neutropenic sepsis. Conclusions: IA demonstrates modest efficacy in the treatment of met-PDA albeit exhibits a favorable toxicity profile. Many trial results are available only in abstract format and some are ongoing.

An analysis of the efficacy and safety of direct oral anticoagulants (DOACs) in gastrointestinal cancer-associated venous thromboembolism (GI-CAVTE)

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Background: Two major trials and meta-analysis of patients (pts) with active cancer and VTE suggests that apixaban (A) and rivaroxaban (R) showed similar efficacy to enoxaparin and warfarin while having less associated major bleeding. GICA is associated with a higher incidence of VTE compared to other tumors. Moreover, bleeding complications of DOACs are not well defined in GICA pts. We compared the efficacy and safety of DOACs in pts with active GICA and VTE at the University of Arizona Cancer Center (UACC). Methods: A retrospective chart review of pts receiving DOACs with GICA and VTE treated at UACC was performed (11/2013-02/2017). GICA subgroup extracted from clinical trial delineations followed: active cancer, defined as cancer diagnosed at any stage +/- 6 months of VTE diagnosis. Efficacy outcomes were recurrent DVT, nonfatal pulmonary embolism (PE), or fatal PE. Safety outcomes for major bleeding were Hg drop of ≥2 g/dL, transfusion of ≥2 units of PRBC, bleeding in a critical site, or bleeding contributing to death. Fisher exact test is used for testing the difference in categorical variables for p-value < 0.05. Results: Our review included pts on A (n = 28) and R (n = 34). Pts had similar baseline characteristics compared to AMPLIFY (n = 81) and pooled-EINSTEIN (n = 71). Recurrent VTE at 6 months were 7.1% and 2.9% for pts on A and R, respectively. VTE historical comparison to AMPLIFY (3.7%) and EINSTEIN (2.8%) showed no significant difference. Major bleeding at 6 months were 7.1% and 14.7% for A and R, respectively, compared to 2.3% AMPLIFY / 2.8% EINSTEIN. R had the one recurrent non-fatal PE event and a significantly worse safety profile with 2 fatal bleeds (hemopericardium and upper GI bleed) and 2 critical bleeding sites (subarachnoid hemorrhage and retroperitoneal) [p = 0.0348], whereas A had non-significant of the before stated. Conclusions: To our knowledge, this is the first retrospective analysis to present long-term outcome data of DOACs in pts with GICA and VTE, which showed a similar risk of recurrent VTE and worse safety profile with R versus A. This data warrants further prospective clinical analysis of the efficacy and safety of DOACs in pts with GICA and VTE.

Robust theoretical modelling of core ionisation edges for quantitative electron energy loss spectroscopy of B- and N-doped graphene

Electron energy loss spectroscopy (EELS) is a powerful tool for understanding the chemical structure of materials down to the atomic level, but challenges remain in accurately and quantitatively modelling the response. We compare comprehensive theoretical density functional theory (DFT) calculations of 1s core-level EEL K-edge spectra of pure, B-doped and N-doped graphene with and without a core-hole to previously published atomic-resolution experimental electron microscopy data. The ground state approximation is found in this specific system to perform consistently better than the frozen core-hole approximation. The impact of including or excluding a core-hole on the resultant theoretical band structures, densities of states, electron densities and EEL spectra were all thoroughly examined and compared. It is concluded that the frozen core-hole approximation exaggerates the effects of the core-hole in graphene and should be discarded in favour of the ground state approximation. These results are interpreted as an indicator of the overriding need for theorists to embrace many-body effects in the pursuit of accuracy in theoretical spectroscopy instead of a system-tailored approach whose approximations are selected empirically.

The International Association of Student Surgical Societies: A brief history from 2014-2017

The International Association of Student Surgical Societies (IASSS) was founded in 2011 to link up student surgical societies from around the world. These Societies have been formed by students with an aim to promote interest in surgical education and research amongst undergraduate medical students. Their formation has been fostered by the recent realization that adequate surgical care is a neglected component of global public health.1 The insufficient number of trained surgeons is one of the many barriers to meeting global surgical needs, especially in middle- and low-income countries. This barrier is one the IASSS aims to address.2,3 Since its inauguration, the IASSS has been active in creating opportunities for undergraduate medical students across the world to explore the full spectrum of surgery.

Factors influencing medical students in pursuing a career in surgery: a cross-sectional survey

BACKGROUND

Many factors play a role in the decision of a medical student to pursue a career in surgery. With a decline in numbers of applications into surgical programmes seen globally, the aim of this study was to determine the factors that influence medical students in pursuing a career in surgery.

METHOD

A descriptive, cross-sectional survey was distributed online to all medical students studying at a tertiary, academic institution. Survey items obtained data on demographics, surgical interest and training, as well as factors affecting a surgical career.

RESULTS

A total of 245 medical students responded, of which 56% were female. The majority (69%) stated they were interested in pursuing a career in surgery. Despite 75% of respondents stating South Africa was a good place for surgical training, females reported significantly higher levels of agreement that surgical training would be better overseas when compared to males (p = 0.027). Overall, 20% were undecided on what surgical specialty they would pursue. The largest proportion of respondents (33%) stated that 'Length of training' was the main barrier to pursuing a career in surgery. Thirtythree (13.5%) respondents reported 'Female-unfriendly' as a barrier, of whom all were female. The greatest motivator to pursuing a career in surgery was 'Hands-on work', stated by 36% of respondents.

CONCLUSION

Though length of surgical training was deemed the principal barrier, the majority of students indicated they would pursue a career in surgery. Despite continued perceptions that surgery poses a female-unfriendly environment as a career, respondents held South African surgical training in high esteem, and were motivated by a clinically hands-on approach. These factors may play an important role in determining methods of improving numbers of surgical applications worldwide.

Collective Order and Economic Coordination in Industrial Agglomerations: The Technopoles of Southern California

We begin by remarking upon the pervasiveness of nonmarket institutional arrangements in capitalist economic systems. We then sketch out some typical generalized forms of collective order and economic coordination in industrial agglomerations—quasi-integration, voluntary associations, informal business cultures, and governmental institutions. With the aid of simple statistics we describe the growth of the high-technology industrial agglomerations (technopoles) of Southern California since the 1950s. The specific regulatory tasks and institutions engendered by this growth are reviewed in detail with special reference to transactional economies, innovation and technology transfer, labor supply, land development, and lobbying and local economic growth. We conclude with a brief discussion of some of the problems and predicaments experienced by high-technology industry in Southern California and in the USA in the current (neoconservative) policy environment.

The Industrial Resurgence of Southern California? Advanced Ground Transportation Equipment Manufacturing and Local Economic Development

Southern California is in a deeply rooted process of economic restructuring. Much of the region's manufacturing base is made up of two groups of industries: A declining aerospace–defense sector, and a low-wage, low-skill sweatshop sector. What are the prospects for creating a growing manufacturing base focused on high-wage, high-skill industries? In this paper we examine the opportunities presented by the Los Angeles County Metropolitan Transportation Authority's $183 billion thirty-year capital improvement plan as the potential catalyst of a set of technological and manufacturing synergies that would reorient the regional economy towards a new advanced ground transportation equipment industry. We investigate the dynamics of agglomerated complexes of industry in general, and the institutional and infrastructural arrangements that create and sustain competitive advantage within regional economic systems. Next, we evaluate the potential for the successful development of a technologically dynamic advanced ground transportation equipment industry in Southern California. This central part of the analysis focuses on (a) the existing industrial assets of the region, (b) specific forms of institution building that need to be carried out in the interests of local economic development and high-quality job creation, and (c) the importance of building a cooperative, high-trust manufacturing system. We then offer suggestions for specific types of policy intervention that might foster new forms of local economic growth. We argue that a coordinated response by both the public and the private sectors could conceivably set the region on a successful new economic development trajectory.

Completion of hand-written surgical consent forms is frequently suboptimal and could be improved by using electronically generated, procedure-specific forms

INTRODUCTION

Completion of hand-written consent forms for surgical procedures may suffer from missing or inaccurate information, poor legibility and high variability. We audited the completion of hand-written consent forms and trialled a web-based application to generate modifiable, procedure-specific consent forms.

METHODS

The investigation comprised two phases at separate UK hospitals. In phase one, the completion of individual responses in hand-written consent forms for a variety of procedures were prospectively audited. Responses were categorised into three domains (patient details, procedure details and patient sign-off) that were considered "failed" if a contained element was not correct and legible. Phase two was confined to a breast surgical unit where hand-written consent forms were assessed as for phase one and interrogated for missing complications by two independent experts. An electronic consent platform was introduced and electronically-produced consent forms assessed.

RESULTS

In phase one, 99 hand-written consent forms were assessed and the domain failure rates were: patient details 10%; procedure details 30%; and patient sign-off 27%. Laparoscopic cholecystectomy was the most common procedure (7/99) but there was significant variability in the documentation of complications: 12 in total, a median of 6 and a range of 2-9. In phase two, 44% (27/61) of hand-written forms were missing essential complications. There were no domain failures amongst 29 electronically-produced consent forms and no variability in the documentation of potential complications.

CONCLUSION

Completion of hand-written consent forms suffers from wide variation and is frequently suboptimal. Electronically-produced, procedure-specific consent forms can improve the quality and consistency of consent documentation.

Apatinib: a promising oral antiangiogenic agent in the treatment of multiple solid tumors

Aberrant proangiogenic pathways have long been implicated in tumorigenesis and metastasis. Antiangiogenic therapies have shown efficacy in the treatment of a variety of solid tumors including lung, breast, colon, glioblastomas, and other solid tumor types. Apatinib, a small-molecule inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2), is an orally bioavailable agent currently being studied in multiple tumor types. Apatinib has shown a survival benefit in gastric cancer in a phase III trial and non-small cell lung cancer in a phase II trial. With a favorable side effect profile and improved outcomes, apatinib has demonstrated a substantial potential to augment therapeutic options in a variety of tumor types.

A phase II/III randomized study to compare the efficacy and safety of rigosertib plus gemcitabine versus gemcitabine alone in patients with previously untreated metastatic pancreatic cancer

BACKGROUND

Rigosertib (ON 01910.Na), a first-in-class Ras mimetic and small-molecule inhibitor of multiple signaling pathways including polo-like kinase 1 (PLK1) and phosphoinositide 3-kinase (PI3K), has shown efficacy in preclinical pancreatic cancer models. In this study, rigosertib was assessed in combination with gemcitabine in patients with treatment-naïve metastatic pancreatic adenocarcinoma.

MATERIALS AND METHODS

Patients with metastatic pancreatic adenocarcinoma were randomized in a 2:1 fashion to gemcitabine 1000 mg/m(2) weekly for 3 weeks of a 4-week cycle plus rigosertib 1800 mg/m(2) via 2-h continuous IV infusions given twice weekly for 3 weeks of a 4-week cycle (RIG + GEM) versus gemcitabine 1000 mg/m(2) weekly for 3 weeks in a 4-week cycle (GEM).

RESULTS

A total of 160 patients were enrolled globally and randomly assigned to RIG + GEM (106 patients) or GEM (54). The most common grade 3 or higher adverse events were neutropenia (8% in the RIG + GEM group versus 6% in the GEM group), hyponatremia (17% versus 4%), and anemia (8% versus 4%). The median overall survival was 6.1 months for RIG + GEM versus 6.4 months for GEM [hazard ratio (HR), 1.24; 95% confidence interval (CI) 0.85-1.81]. The median progression-free survival was 3.4 months for both groups (HR = 0.96; 95% CI 0.68-1.36). The partial response rate was 19% versus 13% for RIG + GEM versus GEM, respectively. Of 64 tumor samples sent for molecular analysis, 47 were adequate for multiplex genetic testing and 41 were positive for mutations. The majority of cases had KRAS gene mutations (40 cases). Other mutations detected included TP53 (13 cases) and PIK3CA (1 case). No correlation between mutational status and efficacy was detected.

CONCLUSIONS

The combination of RIG + GEM failed to demonstrate an improvement in survival or response compared with GEM in patients with metastatic pancreatic adenocarcinoma. Rigosertib showed a similar safety profile to that seen in previous trials using the IV formulation.

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.

A phase II/III randomized study to compare the efficacy and safety of rigosertib plus gemcitabine versus gemcitabine alone in patients with previously untreated metastatic pancreatic cancer

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Background: Rigosertib (ON 01910.Na), a dual non-ATP inhibitor of polo-like kinase 1 (Plk1) and phosphoinositide 3-kinase (PI3K) pathways, was assessed in patients with treatment-naïve metastatic pancreatic adenocarcinoma. Methods: Patients with metastatic adenocarcinoma of the pancreas were randomized in a 2:1 fashion to gemcitabine 1000 mg/m2 weekly for 3 weeks of a 4-week cycle plus rigosertib 1800mg/m2 via 2-hr CIV infusions given twice weekly for 3 weeks of a 4-week cycle versus gemcitabine 1000mg/m2 weekly for 3 weeks in a 4-week cycle. Results: A total of 160 patients were enrolled globally and randomly assigned to rigosertib plus gemcitabine (106 patients) or gemcitabine (54). The most common grade 3 or higher adverse events were neutropenia (8% in the rigosertib plus gemcitabine group vs. 6% in the gemcitabine group), hyponatremia (17% vs. 4%), and anemia (8% vs. 4%). The primary outcome of the study, median OS, was 6.1 months in the gemcitabine plus rigosertib arm versus 6.4 months with gemcitabine alone (hazard ratio (HR), 1.24; 95% confidence interval [CI], 0.85-1.81). The median PFS was 3.4 months for both groups (HR, 0.96; 95% CI, 0.68-1.36). The overall best response between arms were partial response rates of 19% versus 13% and stable disease in 50% versus 56% in the gemcitabine plus rigosertib versus gemcitabine alone, respectively. Of 64 tumor samples sent for molecular analysis, 47 were adequate for multiplex genetic testing and 41 were positive for mutations. The majority of cases had KRAS gene mutations (40/47, 85%), which included c.35G>T, p.G12V (12 cases), c.35G>A, p.G12D (21 cases), c.34G>C, p.G12R (4 cases), c.34G>T, p.G12C (1 case) and c.183C>A, p.Q61H (2 cases). Other mutations detected included TP53 (13 cases) and PIK3CA(1 case). No correlation between mutational status and efficacy was detected. Conclusions: The combination of rigosertib plus gemcitabine failed to demonstrate an improvement in survival or response compared to gemcitabine alone in metastatic pancreatic adenocarcinoma. Clinical trial information: NCT01360853.

Dielectric response of pentagonal defects in multilayer graphene nano-cones

The dielectric response of pentagonal defects in multilayer graphene nano-cones has been studied by electron energy loss spectroscopy and ab initio simulations. At the cone apex, a strong modification of the dielectric response is observed below the energy of the π plasmon resonance. This is attributed to π → π* interband transitions induced by topology-specific resonant π bonding states as well as π*-σ* hybridization. It is concluded that pentagonal defects strongly affect the local electronic structure in such a way that multi-walled graphene nano-cones should show great promise as field emitters.

Extended interplanar linking in graphite formed from vacancy aggregates

The mechanical and electrical properties of graphite and related materials such as multilayer graphene depend strongly on the presence of defects in the lattice structure, particularly those which create links between adjacent planes. We present findings which suggest the existence of a new type of defect in the graphite or graphene structure which connects adjacent planes through continuous hexagonal sp2 bonding alone and can form through the aggregation of individual vacancy defects. The energetics and kinetics of the formation of this type of defect are investigated with atomistic density functional theory calculations. The resultant structures are then employed to simulate high resolution transmission electron microscopy images, which are compared to recent experimental images of electron irradiation damaged graphite.

Weight gain and lipid-glucose profiles among patients taking antipsychotic medications: comparisons for prescriptions administered using algorithms versus usual care

The purpose of this study was to determine if treatment strategy had a significant effect on the occurrence of physiological changes consistent with metabolic syndrome and/or type 2 diabetes in patients using atypical antipsychotic medications. The four variables assessed were: weight gain, fasting blood sugar, triglycerides and cholesterol. The two strategies compared were (1) evidence-based practice, derived from the Texas Medication Algorithm Project, and (2) practitioner preference. A retrospective chart review was performed on patients diagnosed with a chronic psychiatric disorder being treated with atypical antipsychotics. The dates of the reviewed records were from 1 January 2008 to 31 December 2008. The sample of patients totaled 113. Statistical analysis included logistic regression for each of the four variables assessed. The use of evidence-based practice guidelines was found to have strong positive effects on two of the four variables assessed. Further studies need to be conducted to include medications being taken to lower lipids and blood sugar. Overall, the use of evidence-based practice guidelines has a positive effect on weight, triglycerides and cholesterol. It is important that patients be closely monitored and changes made in a timely manner to minimize adverse effects of atypical antipsychotics.

Social determinants of health among African Americans in a rural community in the Deep South: an ecological exploration

INTRODUCTION

African Americans living in rural USA experience multiple health disparities as a result of both race and rural geography. An increasing literature suggests that social determinants of health, the social contexts in which people live their lives, are key contributors to these health disparities. Ecological theory provides a valuable conceptual framework for exploring social determinants of health in communities, but few US rural health community-based studies have utilized this approach, or engaged ecological theory to explore rural contexts. This exploratory study blended a community-based, qualitative approach with ecological theory with the objective of identifying potential social determinants of health among African Americans in a rural community in the Deep South, from the perspectives of participants.

METHODS

In-depth interviews were conducted with rural, Deep South African Americans participants who were purposefully sampled to incorporate a range of perspectives. Interview guides structured around five ecological levels (individual, relational, environmental, structural, and superstructural) were used to frame interviews. Iterative content analysis of interview transcripts and field notes identified potential social determinants of health. An 'editing' approach to content analysis was used. Data and analysis quality was tested by triangulation at the level of the researcher, and by member checking with community members.

RESULTS

Potential determinants of health were identified at all five levels of the ecological framework. At the individual level, lack of engagement with personal health and health promotion was a recurring theme. Participation in preventive health activities and education was minimal, even when offered in community settings. At the relational level, lack of social capital emerged as another potential social determinant of health, with estrangement between the younger and elder generations as one source, and fractiousness among churches (key institutions in the community) representing another. At the environmental level, the community built environment was an area of concern as it lacked opportunities for physical activity and access to healthy foods. The local job environment was identified as a potential social determinant of health, given the strong ties between income and health. At the structural level, participants complained of cronyism and nepotism favoring Whites in access to jobs, including those where local policies and funding allocations were made (eg funding for the local health department). In education, school system tracking policies were perceived to discourage African Americans from university education. At the superstructural level, high rates of poverty and racism emerged as potential social determinants. Poverty directly limited many African Americans' access to quality health care, and subtle racism was perceived in some delivery of care. Persistent stress from poverty and racism was reported, which creates health risks through physiologic pathways.

CONCLUSION

This study identified potential social determinants of health, at multiple ecological levels, among African Americans in a rural community in the Deep South. The social determinants identified had the ability to impact a variety of health behaviors and health outcomes. The results demonstrate the value of this approach to conducting rural, community-based research. This descriptive and exploratory study highlights the need for quantitative exploration of these issues, as well as the development of context-appropriate, community-based health interventions that address multiple ecological levels.