First-in-human phase I study of the OX40 agonist GSK3174998 with or without pembrolizumab in patients with selected advanced solid tumors (ENGAGE-1).

BACKGROUND: The phase I first-in-human study ENGAGE-1 evaluated the humanized IgG1 OX40 agonistic monoclonal antibody GSK3174998 alone (Part 1 (P1)) or in combination with pembrolizumab (Part 2 (P2)) in patients with advanced solid tumors. METHODS: GSK3174998 (0.003-10 mg/kg) ± pembrolizumab (200 mg) was administered intravenously every 3 weeks using a continuous reassessment method for dose escalation. Primary objectives were safety and tolerability; secondary objectives included pharmacokinetics, immunogenicity, pharmacodynamics, and clinical activity. RESULTS: 138 patients were enrolled (45 (P1) and 96 (P2, including 3 crossovers)). Treatment-related adverse events occurred in 51% (P1) and 64% (P2) of patients, fatigue being the most common (11% and 24%, respectively). No dose-toxicity relationship was observed, and maximum-tolerated dose was not reached. Dose-limiting toxicities (P2) included Grade 3 (G3) pleural effusion and G1 myocarditis with G3 increased troponin. GSK3174998 ≥0.3 mg/kg demonstrated pharmacokinetic linearity and >80% receptor occupancy on circulating T cells; 0.3 mg/kg was selected for further evaluation. Limited clinical activity was observed for GSK3174998 (P1: disease control rate (DCR) ≥24 weeks 9%) and was not greater than that expected for pembrolizumab alone (P2: overall response rate 8%, DCR ≥24 weeks 28%). Multiplexed immunofluorescence data from paired biopsies suggested that increased infiltration of natural killer (NK)/natural killer T (NKT) cells and decreased regulatory T cells (Tregs) in the tumor microenvironment may contribute to clinical responses: CD16+CD56-CD134+ NK /NKT cells and CD3+CD4+FOXP3+CD134+ Tregs exhibited the largest magnitude of change on treatment, whereas CD3+CD8+granzyme B+PD-1+CD134+ cytotoxic T cells were the least variable. Tumor gene expression profiling revealed an upregulation of inflammatory responses, T-cell proliferation, and NK cell function on treatment with some inflammatory cytokines upregulated in peripheral blood. However, target engagement, evidenced by pharmacologic activity in peripheral blood and tumor tissue, did not correlate with clinical efficacy. The low number of responses precluded identifying a robust biomarker signature predictive of response. CONCLUSIONS: GSK3174998±pembrolizumab was well tolerated over the dose range tested and demonstrated target engagement. Limited clinical activity does not support further development of GSK3174998±pembrolizumab in advanced cancers. TRIAL REGISTRATION NUMBER: NCT02528357.

LC-MS/MS quantification of asymmetric dimethyl arginine and symmetric dimethyl arginine in plasma using surrogate matrix and derivatization with fluorescamine.

Aim: A novel LC-MS/MS method using a surrogate matrix and derivatization with fluorescamine was developed and validated for simultaneous quantification of asymmetric dimethyl arginine and symmetric dimethyl arginine. Methods & results: Asymmetric dimethyl arginine, symmetric dimethyl arginine and corresponding internal standards were extracted using protein precipitation and derivatization with fluorescamine followed by SPE. Derivatives were analyzed by turbo ion spray LC-MS/MS in the positive ion mode. Methodology was successfully transferred across multiple preclinical species and utilized in the support of several investigative studies. Conclusion: A new LC-MS/MS analytical methodology that utilizes a surrogate matrix and derivatization with fluorescamine was successfully developed and validated.

"Z4" Complex Member Fusions in NUT Carcinoma: Implications for a Novel Oncogenic Mechanism.

Nuclear protein in testis (NUT) carcinoma (NC) is a rare, distinctly aggressive subtype of squamous carcinoma defined by the presence of NUT-fusion oncogenes resulting from chromosomal translocation. In most cases, the NUT gene (NUTM1) is fused to bromodomain containing 4 (BRD4) forming the BRD4-NUT oncogene. Here, a novel fusion partner to NUT was discovered using next-generation sequencing and FISH from a young patient with an undifferentiated malignant round cell tumor. Interestingly, the NUT fusion identified involved ZNF592, a zinc finger containing protein, which was previously identified as a component of the BRD4-NUT complex. In BRD4-NUT-expressing NC cells, wild-type ZNF592 and other associated "Z4" complex proteins, including ZNF532 and ZMYND8, colocalize with BRD4-NUT in characteristic nuclear foci. Furthermore, ectopic expression of BRD4-NUT in a non-NC cell line induces sequestration of Z4 factors to BRD4-NUT foci. Finally, the data demonstrate the specific dependency of NC cells on Z4 modules, ZNF532 and ZNF592. IMPLICATIONS: This study establishes the oncogenic role of Z4 factors in NC, offering potential new targeted therapeutic strategies in this incurable cancer.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/16/12/1826/F1.large.jpg.

Efficacy and safety of trametinib in Japanese patients with advanced biliary tract cancers refractory to gemcitabine.

Gemcitabine-based therapy remains the mainstay of treatment for patients with biliary tract cancers (BTCs) with no second-line treatment(s) established yet. Aberrant activation of the MAPK pathway in patients with BTC indicates its importance in BTC. Trametinib is a potent, highly selective, allosteric non-competitive inhibitor of MEK1/MEK2. In this phase IIa open-label, single-arm study, we investigated the efficacy and safety of trametinib in Japanese patients with advanced BTC refractory to gemcitabine-based therapy. All patients received oral trametinib 2 mg once daily until progressive disease (PD), death, or unacceptable toxicity. The primary objective was to determine the 12-week non-PD rate. Secondary assessments included safety, progression-free survival (PFS), overall survival, and overall response rate. Targeted exome sequencing was used to identify biomarkers for sensitivity or resistance to trametinib monotherapy. Twenty patients (median age, 61.5 years) with carcinoma of gall bladder (40%), intrahepatic (25%) or extrahepatic (30%) bile duct, and ampulla of Vater (5%) were enrolled. The non-PD rate at week 12 was 10% (95% confidence interval, 1.2-31.7); it did not reach the threshold rate of 25%. Median PFS was 10.6 weeks (95% confidence interval, 4.6-12.1) and 1-year overall survival was 20.0%. Stable disease and PD were observed in 13 (65%) and seven (35%) patients, respectively. No new safety signals were reported. Although the primary end-point was not met, prolonged PFS was observed in one patient having six somatic variants including synonymous NF1 exon 12 splice variant and a loss-of-function variant in ARID1A. Efforts to understand responsive mutations and sensitivity to targeted therapies are warranted. This trial was registered with ClinicalTrials.gov: NCT01943864.

A DNA Hypomethylation Signature Predicts Antitumor Activity of LSD1 Inhibitors in SCLC.

Epigenetic dysregulation has emerged as an important mechanism in cancer. Alterations in epigenetic machinery have become a major focus for targeted therapies. The current report describes the discovery and biological activity of a cyclopropylamine containing inhibitor of Lysine Demethylase 1 (LSD1), GSK2879552. This small molecule is a potent, selective, orally bioavailable, mechanism-based irreversible inactivator of LSD1. A proliferation screen of cell lines representing a number of tumor types indicated that small cell lung carcinoma (SCLC) is sensitive to LSD1 inhibition. The subset of SCLC lines and primary samples that undergo growth inhibition in response to GSK2879552 exhibit DNA hypomethylation of a signature set of probes, suggesting this may be used as a predictive biomarker of activity.

Gene expression profiling in whole blood identifies distinct biological pathways associated with obesity.

BACKGROUND: Obesity is reaching epidemic proportions and represents a significant risk factor for cardiovascular disease, diabetes, and cancer. METHODS: To explore the relationship between increased body mass and gene expression in blood, we conducted whole-genome expression profiling of whole blood from seventeen obese and seventeen well matched lean subjects. Gene expression data was analyzed at the individual gene and pathway level and a preliminary assessment of the predictive value of blood gene expression profiles in obesity was carried out. RESULTS: Principal components analysis of whole-blood gene expression data from obese and lean subjects led to efficient separation of the two cohorts. Pathway analysis by gene-set enrichment demonstrated increased transcript levels for genes belonging to the "ribosome", "apoptosis" and "oxidative phosphorylation" pathways in the obese cohort, consistent with an altered metabolic state including increased protein synthesis, enhanced cell death from proinflammatory or lipotoxic stimuli, and increased energy demands. A subset of pathway-specific genes acted as efficient predictors of obese or lean class membership when used in Naive Bayes or logistic regression based classifiers. CONCLUSION: This study provides a comprehensive characterization of the whole blood transcriptome in obesity and demonstrates that the investigation of gene expression profiles from whole blood can inform and illustrate the biological processes related to regulation of body mass. Additionally, the ability of pathway-related gene expression to predict class membership suggests the feasibility of a similar approach for identifying clinically useful blood-based predictors of weight loss success following dietary or surgical interventions.

Distinct skeletal muscle fiber characteristics and gene expression in diet-sensitive versus diet-resistant obesity.

Inter-individual variability in weight gain and loss under energy surfeit and deficit conditions, respectively, are well recognized but poorly understood phenomena. We documented weight loss variability in an intensively supervised clinical weight loss program and assessed skeletal muscle gene expression and phenotypic characteristics related to variable response to a 900 kcal regimen. Matched pairs of healthy, diet-compliant, obese diet-sensitive (ODS) and diet-resistant (ODR) subjects were defined as those in the highest and lowest quintiles for weight loss rate. Physical activity energy expenditure was minimal and comparable. Following program completion and weight stabilization, skeletal muscle biopsies were obtained. Gene expression analysis of rectus femoris and vastus lateralis indicated upregulation of genes and gene sets involved in oxidative phosphorylation and glucose and fatty acid metabolism in ODS compared with ODR. In vastus lateralis, there was a higher proportion of oxidative (type I) fibers in ODS compared with ODR women and lean controls, fiber hypertrophy in ODS compared with ODR women and lean controls, and lower succinate dehydrogenase in oxidative and oxidative-glycolytic fibers in all obese compared with lean subjects. Intramuscular lipid content was generally higher in obese versus lean, and specifically higher in ODS vs. lean women. Altogether, our findings demonstrate differences in muscle gene expression and fiber composition related to clinical weight loss success.

Small and intermediate conductance Ca(2+)-activated K+ channels confer distinctive patterns of distribution in human tissues and differential cellular localisation in the colon and corpus cavernosum.

The SK/IK family of small and intermediate conductance calcium-activated potassium channels contains four members, SK1, SK2, SK3 and IK1, and is important for the regulation of a variety of neuronal and non-neuronal functions. In this study we have analysed the distribution of these channels in human tissues and their cellular localisation in samples of colon and corpus cavernosum. SK1 mRNA was detected almost exclusively in neuronal tissues. SK2 mRNA distribution was restricted but more widespread than SK1, and was detected in adrenal gland, brain, prostate, bladder, liver and heart. SK3 mRNA was detected in almost every tissue examined. It was highly expressed in brain and in smooth muscle-rich tissues including the clitoris and the corpus cavernosum, and expression in the corpus cavernosum was upregulated up to 5-fold in patients undergoing sex-change operations. IK1 mRNA was present in surface-rich, secretory and inflammatory cell-rich tissues, highest in the trachea, prostate, placenta and salivary glands. In detailed immunohistochemical studies of the colon and the corpus cavernosum, SK1-like immunoreactivity was observed in the enteric neurons. SK3-like immunoreactivity was observed strongly in smooth muscle and vascular endothelium. IK1-like immunoreactivity was mainly observed in inflammatory cells and enteric neurons of the colon, but absent in corpus cavernosum. These distinctive patterns of distribution suggest that these channels are likely to have different biological functions and could be specifically targeted for a number of human diseases, such as irritable bowel syndrome, hypertension and erectile dysfunction.