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PTEN acts as a potent tumor suppressor within the PI3K/AKT/mTOR pathway. Germline mutations in the PTEN gene are a hallmark of PTEN hamartoma tumor syndrome, which includes Cowden syndrome, where they appear to elevate lifetime risk of cancer. Targeted AKT directed therapy has been proposed as an effective approach in cancer patients having germline PTEN mutations. The mechanism of action, safety and dosing regimen for the novel allosteric AKT inhibitor TAS-117 have been explored in a phase I study in Japan in which activity was observed against certain tumor types. Here we describe the study protocol of an international, two-part phase II study evaluating the safety, tolerability, pharmacokinetics, pharmacodynamics and antitumor activity of TAS-117 in patients with advanced solid tumors harboring germline PTEN-inactivating mutations.

PDF - 278K, Supplementary Methods and Materials, QTc prolongation results. Supplementary Figure 1 - QTc prolongation compared with serum U3-1287 concentration. Supplementary Figure 2 - U3-1287-mediated pancreatic xenograft growth inhibition)

Purpose: HER3 is a key dimerization partner for other HER family members, and its expression is associated with poor prognosis. This first-in-human study of U3-1287 (NCT00730470), a fully human anti-HER3 monoclonal antibody, evaluated its safety, tolerability, and pharmacokinetics in patients with advanced solid tumor.Experimental Design: The study was conducted in 2 parts: part 1—sequential cohorts received escalating doses (0.3–20 mg/kg) of U3-1287 every 2 weeks, starting 3 weeks after the first dose; part 2—additional patients received 9, 14, or 20 mg/kg U3-1287 every 2 weeks, based on observed tolerability and pharmacokinetics from part 1. Recommended phase II dose, adverse event rates, pharmacokinetics, and tumor response were determined.Results: Fifty-seven patients (part 1: 26; part 2: 31) received U3-1287. As no dose-limiting toxicities were reported, the maximum-tolerated dose was not reached. The maximum-administered dose was 20 mg/kg every 2 weeks. The most frequent adverse events related to U3-1287 were fatigue (21.1%), diarrhea (12.3%), nausea (10.5%), decreased appetite (7.0%), and dysgeusia (5.3%). No patient developed anti-U3-1287 antibodies. In these heavily pretreated patients, stable disease was maintained 9 weeks or more in 19.2% in part 1 and 10 weeks or more in 25.8% in part 2.Conclusion: U3-1287 treatment was well tolerated, and some evidence of disease stabilization was observed. Pharmacokinetic data support U3-1287 dosing of 9 to 20 mg/kg every 2 to 3 weeks. Combination studies of U3-1287 are ongoing. Clin Cancer Res; 19(11); 3078–87. ©2013 AACR.

Background: Alterations in fibroblast growth factor receptor 2 (FGFR2) have emerged as promising drug targets for intrahepatic cholangiocarcinoma, a rare cancer with a poor prognosis. Futibatinib, a next-generation, covalently binding FGFR1-4 inhibitor, has been shown to have both antitumor activity in patients with FGFR-altered tumors and strong preclinical activity against acquired resistance mutations associated with ATP-competitive FGFR inhibitors. Methods: In this multinational, open-label, single-group, phase 2 study, we enrolled patients with unresectable or metastatic FGFR2 fusion-positive or FGFR2 rearrangement-positive intrahepatic cholangiocarcinoma and disease progression after one or more previous lines of systemic therapy (excluding FGFR inhibitors). The patients received oral futibatinib at a dose of 20 mg once daily in a continuous regimen. The primary end point was objective response (partial or complete response), as assessed by independent central review. Secondary end points included the response duration, progression-free and overall survival, safety, and patient-reported outcomes. Results: Between April 16, 2018, and November 29, 2019, a total of 103 patients were enrolled and received futibatinib. A total of 43 of 103 patients (42%; 95% confidence interval, 32 to 52) had a response, and the median duration of response was 9.7 months. Responses were consistent across patient subgroups, including patients with heavily pretreated disease, older adults, and patients who had co-occurring TP53 mutations. At a median follow-up of 17.1 months, the median progression-free survival was 9.0 months and overall survival was 21.7 months. Common treatment-related grade 3 adverse events were hyperphosphatemia (in 30% of the patients), an increased aspartate aminotransferase level (in 7%), stomatitis (in 6%), and fatigue (in 6%). Treatment-related adverse events led to permanent discontinuation of futibatinib in 2% of the patients. No treatment-related deaths occurred. Quality of life was maintained throughout treatment. Conclusions: In previously treated patients with FGFR2 fusion or rearrangement-positive intrahepatic cholangiocarcinoma, the use of futibatinib, a covalent FGFR inhibitor, led to measurable clinical benefit.

Breast cancer; Cancer Càncer de mama; Càncer Cáncer de mama; Cáncer The METRIC study (NCT#0199733) explored a novel antibody–drug conjugate, glembatumumab vedotin (GV), targeting gpNMB that is overexpressed in ~40% of patients with triple-negative breast cancer (TNBC) and associated with poor prognosis. The study was a randomized, open-label, phase 2b study that evaluated progression-free survival (PFS) of GV compared with capecitabine in gpNMB-overexpressing TNBC. Patients who had previously received anthracycline and taxane-based therapy were randomized 2:1 to receive, GV (1.88 mg/kg IV q21 days) or capecitabine (2500 mg/m2 PO daily d1–14 q21 days). The primary endpoint was RECIST 1.1 PFS per independent, blinded central review. In all, 327 patients were randomized to GV (213 treated) or capecitabine (92 treated). Median PFS was 2.9 months for GV vs. 2.8 months for capecitabine. The most common grade ≥3 toxicities for GV were neutropenia, rash, and leukopenia, and for capecitabine were fatigue, diarrhea, and palmar-plantar erythrodysesthesia. The study did not meet the primary endpoint of improved PFS over capecitabine or demonstrate a relative risk/benefit improvement over capecitabine. Funding provided by Celldex Therapeutics, Inc.

An incredibly high failure rate in the pharmaceutical industry has positioned personalized medicine with its prerequisite drug-diagnostic codevelopment, commonly known as companion diagnostics (CDx), in the frontline as an potential rescuer. This hopefulness is potentiated by the recent major advances and competitiveness in molecular diagnostics, making laboratory tests widely accessible at affordable prices. If executed correctly, biomarkers and CDx can potentially help the drug industry by enhancing the probability of success and possibly accelerating time to market; help the diagnostics industry develop tests utilizing precious, clinically annotated human samples; and, more importantly, benefit patients by supporting accurate diagnosis and selection of the most efficacious and least toxic therapies. However, this spectacular road is not yet paved, and it faces an enormous number of challenges. This paper will list these challenges and highlight some critical problems with representative examples of imminent but still overlooked preanalytical and analytical variables that can defeat the whole purpose of biomarkers and CDx and mislead drug developers and clinicians. The paper will provide some suggestions for mitigation.

Edoxaban is an oral, once-daily, direct factor Xa (FXa) inhibitor that has been evaluated for the prevention of stroke in patients with atrial fibrillation (AF) and for the treatment and prevention of venous thromboembolism (VTE) recurrence. Pharmacokinetic (PK) and pharmacodynamic (PD) modeling and logistic regression analyses were used to explore the clinical data from phase 1 and 2 studies to determine the relationship among PK exposure, PD response, and bleeding risk. Population PK/PD modeling was performed using plasma edoxaban concentration data from combined phase 1 and 2 studies and using intrinsic FXa data from a phase 2 AF study. A 2-compartment PK model adequately described the combined PK data, and a dynamic binding model characterized the dynamics of the intrinsic factor X activity (iFXa) data. Logistic regression analysis then identified the relationship between the iFXa and the observed bleeding risk. The more protracted suppression of FXa over the dosing interval for a 30-mg twice-daily dose compared with a 60-mg once-daily dose offers an explanation for the significantly higher bleeding rate at the former dose.

Purpose: HER3 is a key dimerization partner for other HER family members, and its expression is associated with poor prognosis. This first-in-human study of U3-1287 (NCT00730470), a fully human anti-HER3 monoclonal antibody, evaluated its safety, tolerability, and pharmacokinetics in patients with advanced solid tumor. Experimental Design: The study was conducted in 2 parts: part 1—sequential cohorts received escalating doses (0.3–20 mg/kg) of U3-1287 every 2 weeks, starting 3 weeks after the first dose; part 2—additional patients received 9, 14, or 20 mg/kg U3-1287 every 2 weeks, based on observed tolerability and pharmacokinetics from part 1. Recommended phase II dose, adverse event rates, pharmacokinetics, and tumor response were determined. Results: Fifty-seven patients (part 1: 26; part 2: 31) received U3-1287. As no dose-limiting toxicities were reported, the maximum-tolerated dose was not reached. The maximum-administered dose was 20 mg/kg every 2 weeks. The most frequent adverse events related to U3-1287 were fatigue (21.1%), diarrhea (12.3%), nausea (10.5%), decreased appetite (7.0%), and dysgeusia (5.3%). No patient developed anti-U3-1287 antibodies. In these heavily pretreated patients, stable disease was maintained 9 weeks or more in 19.2% in part 1 and 10 weeks or more in 25.8% in part 2. Conclusion: U3-1287 treatment was well tolerated, and some evidence of disease stabilization was observed. Pharmacokinetic data support U3-1287 dosing of 9 to 20 mg/kg every 2 to 3 weeks. Combination studies of U3-1287 are ongoing. Clin Cancer Res; 19(11); 3078–87. ©2013 AACR.

Background Tivantinib is a selective, small-molecule inhibitor of the MET receptor tyrosine kinase. Preclinical and phase 1 data suggested a possible role for MET in the pathophysiology of germ cell tumors (GCTs) and a potential clinical benefit from tivantinib in patients with these tumors. Methods Men (≥16 years) with relapsed or refractory, histologically confirmed, non-central nervous system GCTs received oral tivantinib 360 mg twice daily in 28-day cycles until progressive disease or unacceptable toxicity. The primary endpoint was objective response rate in the first 4 cycles, with study termination for

Although discrepant laboratory results still pose considerable risk to patients and to pharmaceutical development, overall clinical laboratory performance has improved with time due to significant efforts from lab professionals, diagnostic partners, and regulatory and accrediting agencies. These efforts include multiple internal and external laboratory quality control and quality assurance (QC/QA) measures. Proficiency testing (PT), provided by multiple agencies and led by the College of American Pathologists (CAP), currently serves as the main external QC/QA tool. In addition to its regulatory and educational aspects and its value as an efficient tool to monitor overall laboratory performance, this article will highlight the potential and crucial uses of PT. These uses include raising awareness among health care professionals about the serious problem of discrepancies in lab results between different methodologies or platforms, monitoring improvements in global lab performance, and expansion of the educational capacity of PT to end users in patient management and clinical trials, helping laboratorians and other health care professionals to correctly interpret biomarker data from different platforms. * QC : quality control IVD : in vitro diagnostic PT : proficiency testing CLIA : Clinical Laboratory Improvement Amendments CMS : Centers for Medicare & Medicaid Services CAP : College of American Pathologists HbA1c : hemoglobin A1c Hb : total hemoglobin ALP : alkaline phosphatase LDH : lactate dehydrogenase HDL-C : high-density lipoprotein–cholesterol LDL-C : low-density lipoprotein–cholesterol SD : standard deviation CV : coefficient of variation HI : hospital and independent laboratories AOT : all other testing NCEP : National Cholesterol Education Program NGSP : National Glycohemoglobin Standardization Program CDC-LSP : Centers for Disease Control and Prevention–Lipid Standardization Programs max : maximum min : minimum

Despite improvements achieved in laboratory medicine over the years, discrepant results from different clinical laboratories are still a source of imminent risk to patients and the pharmaceutical industry. The problem is aggravated by a disconnect between the in vitro diagnostic community and clinicians or drug developers. This is the sequel to a previous report where data from proficiency testing, originally established as a tool for good laboratory practice, were used to highlight the size of the problem, and its possible impact on patients and pharmaceutical trials. Results from three laboratory tests commonly used as tools to monitor patients undergoing therapy with heparin or antithrombin agents, activated partial thromboplastin time, anti-factor Xa and thrombin time, were investigated. Unfortunately, data show that, owing to an absence of standardization approaches or a reasonable technique to harmonize results from different laboratories, results for the same sample, if analyzed by different laboratories or even by one laboratory employing different platforms or reagents, can be extremely different and misleading.

Aims: Despite improvements achieved in laboratory medicine over the years, discrepant results from different clinical laboratories are still a source of imminent risk to patients and the pharmaceutical industry. The problem is aggravated by a disconnection between laboratorians and clinicians or drug developers. Materials & methods: In this report, results from proficiency testing, originally established as a tool for good laboratory practice, were used to highlight the size of the problem and its impact on patients and pharmaceutical trials. Results from three laboratory tests, believed to be standardized and commonly requested as tools in the management of patients, and decision-making biomarkers in drug development were used: prothrombin time expressed as international normalization ratio, digoxin and low-density lipoprotein-cholesterol. Results: Unfortunately, data demonstrate that results for the same sample or batch of samples, if analyzed by different laboratories or even by one laboratory that employs different platforms or reagents, can be extremely different. Conclusion: In the absence of an effective laboratory-to-laboratory, method-to-method or platform-to-platform standardization, or at lowest harmonization of test results, laboratory results could be misleading to clinicians and the drug industry. Drug developers need to understand the current challenge before any attempt to use biomarker data to make decisions, compile data for a biomarker from different studies or use biomarkers to bridge between different drug candidates belonging to a particular class of compounds.

Background. Culturing human islets in Memphis serum-free media (M-SFM) is associated with excellent postculture recovery, in vitro function, and in vivo survival. The authors investigate the possibility of preserving islet function for extended periods (6 months) in culture and describe the in vitro and in vivo functional outcomes associated with these extended culture times. Methods. Human islets isolated from three cadaveric donor organs were cultured in M-SFM for 1, 3, or 6 months before transplantation under the kidney capsule of nonobese diabetic (NOD)-severe combined immunodeficiency (SCID) mice. In vitro function was measured by static incubation at the time of transplantation. In vivo function was assessed by measuring human insulin and C-peptide production, and by the ability of 6-month cultured islets to cure streptozotocin-induced diabetes in this mouse model. Results. Islet recovery ratios after 1 month in culture ranged from 85% to 88% and declined to 28% to 53% after 6 months of culture (P

IntroductionEdoxaban is an oral, once-daily direct factor Xa (FXa) inhibitor. Although rapidly cleared, strategies to reverse edoxaban-mediated effects on anticoagulation are needed in cases of excessive bleeding or emergency. This study evaluated the effect of two prohemostatic agents, recombinant factor VIIa (rFVIIa) and factor VIII inhibitor bypass activity (FEIBA), on the anticoagulatory effects of supratherapeutic concentrations of edoxaban in human whole blood ex vivo.Materials and MethodsBlood samples were collected from six healthy volunteers. Edoxaban (500 or 1000ng/mL), alone or followed by rFVIIa (0.8 or 1.8μg/mL) or FEIBA (0.75 or 1.5 U/mL), was added to an aliquot of each sample. Biomarkers, including prothrombin time (PT), activated partial thromboplastin time (aPTT), extrinsic FXa activity (anti-FXa), intrinsic factor X activity, and D-dimer, were assessed at 0.25, 0.5, 1, 2, and 4hours after adding rFVIIa or FEIBA.ResultsDecreases in measures of PT (p

The metabolism of S-adenosylmethionine (AdoMet), a key molecule in regulating T cell differentiation and proliferation, is different in normal and leukemic T cells. To delineate the basis for these differences we studied the transcriptional regulation of human methionine adenosyltransferase II (MAT II), which catalyzes AdoMet synthesis in these cells. Recently, we identified an Sp1 site in the proximal promoter of the MAT2A gene, which encodes the α2 catalytic subunit of MAT II, that is essential for the in vitro and in vivo promoter activity in Jurkat leukemic T cells, and that involves binding of the nuclear factors Sp2 and Sp3, but not Sp1. Here, the in vitro and in vivo activity of the proximal MAT2A promoter in normal resting, PHA-stimulated, and leukemic human T cells was compared. Significantly different patterns of protein factor interaction in the proximal region of the MAT2A promoter were found. Normal resting and activated T cells produced complexes of significantly lower molecular weight than those formed in leukemic T cells. Supershift studies coupled with analysis of proteins bound to the proximal promoter suggest that low levels of expression of Sp2 and Sp3 in normal T cells may be responsible for the difference in the in vitro promoter activity between normal and leukemic cells. Mutation of the key Sp1 site equally reduced the in vivo promoter activity in normal and malignant T cells; by contrast, it had significantly different effects on protein–DNA interactions in normal and leukemic T cells. Together, the data support the idea that differences in protein–DNA interactions may contribute to significant differences in MAT2A regulation in normal and malignant cells.

Mammalian methionine adenosyltransferase II (MAT II) consists of a catalytic alpha2/alpha2' and a regulatory beta subunit. Up-regulation of alpha2 subunit expression is associated with increased intracellular levels of S-adenosylmethionine, the major methyl group donor and a key compound in cell metabolism and polyamine synthesis. Previous studies have shown that expression of the alpha2 subunit is differentially regulated in normal and malignant cells. To delineate the molecular basis for the differential regulation of alpha2 subunit expression, we cloned and characterized the human MAT2A gene and its promoter and defined regions that contain enhancer and repressor elements. Detailed functional characterization of the proximal promoter of the MAT2A gene revealed the formation of three major protein-DNA complexes with probes containing three Sp1 sites (Sp1-1 at -14, Sp1-2 at -47, and Sp1-3 at -69). Competition with a probe copying sequence between -76 and -54, which contains the Sp1-3 site only, or mutation of this site, abolished complex formation. Furthermore, mutation of the Sp1-3 site, but not the Sp1-1 or Sp1-2 sites, inhibited the in vivo promoter activity by approximately 85%. Supershift assays showed that the transcription factors Sp2 and Sp3 are part of the complexes formed at the Sp1-3 site, and that Sp1 does not appear to be directly involved. The data indicate that complex formation is initiated at site Sp1-3, which appears to be essential for promoter activity. However, other regions of the proximal promoter may also contribute to the regulation of MAT2A gene expression. These studies may lead to the delineation of the molecular basis for the differential regulation of MAT2A expression in normal and leukemic T cells.

Low productivity in the pharmaceutical industry positions personalized medicine and companion diagnostics as an attractive approach. The oncology community is enthusiastic and optimistic that advances in molecular diagnostics have the potential to materialize the dream of personalized cancer therapy with the aim to: help the drug industry enhance the probability of success and, probably, accelerate time to market; help the diagnostics industry develop diagnostic tests utilizing precious human samples; and support accurate diagnosis and selection of the most efficacious and least toxic therapies. However, this spectacular road is not yet paved and remains facing the following biggest challenges: the need for better understanding of biology and limitations of preclinical models; pre-analytical variables that are likely to alter results; analytical discrepancies; and the wide gap between clinical/pharmaceutical and diagnostic understandings. This article explores these challenges, their possible impacts, and provides some suggestions for mitigation.

MAT II, the extrahepatic form of methionine adenosyltransferase (MAT), consists of catalytic alpha(2)/alpha(2') subunits and a noncatalytic beta subunit, believed to have a regulatory function. The full-length cDNA that encodes the beta subunit of human MAT II was cloned and found to encode for a 334-amino acid protein with a calculated molecular weight of 37,552. Analysis of sequence homology showed similarity with bacterial enzymes that catalyze the reduction of TDP-linked sugars. The beta subunit cDNA was cloned into the pQE-30 expression vector, and the recombinant His tagged protein, which was expressed in Escherichia coli, was recognized by antibodies to the human MAT II, to synthetic peptides copying the sequence of native beta subunit protein, and to the rbeta protein. There is no cross-reactivity between the MAT II alpha(2) or beta subunits. None of the anti-beta subunit antibodies reacted with protein extracts of E. coli host cells, suggesting that these bacteria have no beta subunit protein. Interestingly, the rbeta subunit associated with E. coli as well as human MAT alpha subunits. This association changed the kinetic properties of both enzymes and lowered the K(m) of MAT for L-methionine. Together, the data show that we have cloned and expressed the human MAT II beta subunit and confirmed its long suspected regulatory function. This knowledge affords a molecular means by which MAT activity and consequently the levels of AdoMet may be modulated in mammalian cells.

Infection with hepatitis C virus (HCV) has become the most important public health problem in Egypt. In Egypt, viral hepatitis along with infection with Schistosoma mansoni is the major cause of chronic liver disease and liver cirrhosis. Although HCV infection is highly prevalent in Egypt, very little information is available on the distribution of the different genotypes of HCV. Our aims in this study were first to determine the prevalence of viral and parasite infections in patients with chronic liver disease and then to assess the distribution of HCV genotypes in these patients. In the present study, 151 individuals (50 with chronic liver disease, 51 with chronic diseases of organs other than the liver, and 50 apparently healthy persons) were investigated. The last 2 groups served as control groups. These individuals were subjected to routine liver function tests and detection of serum antibodies to bilharziasis, hepatitis B surface antigen (HBsAg), and HCV. Furthermore, the presence of hepatitis G virus (HGV) and HCV in the serum samples were tested for by a reverse transcription polymerase chain reaction (RT-PCR). Prevalence of different genotypes of HCV in patients positive for HCV were determined by RT-PCR using type-specific primers. Results of the study revealed that 84, 74, 12, and 20% of patients with chronic liver disease were positive for Schistosoma mansoni, HCV, HBsAg, and HGV, respectively, as compared to 51, 43.1, 2, and 4% of patients with other chronic diseases and 22, 6, 0, and 0% of apparently healthy individuals. One hundred percent of patients with chronic liver disease, 72.5% of those with other diseases, and 26% of normal controls were shown to have at least one of the studied infectious agents. Two or more of the agents were highly coincident in patients with chronic liver disease. In Egypt, HCV genotype 4a is highly prevalent, where it contributed 85% of the tested samples in comparison to 10, 2.5, and 2.5% for subtypes 1b, 2a, and 3a, respectively. In conclusion, these results suggest that in Egypt, HCV along with schistosomal parasite infection is the major risk factor for chronic liver disease. In most Egyptian patients, HCV genotype 4 is highly prevalent.

The high costs incurred when drugs fail during clinical trials has prompted interest in biomarkers as biological indicators for progress of disease, effect of therapeutic interventions, and/or drug-induced toxicity. One of the goals is to reduce attrition of drugs during the clinical, and probably preclinical, phases of drug development, and hence, the overall cost of drug development. The role of biomarkers has been exponentially increasing in guiding decisions in every phase of drug development, from drug discovery and preclinical evaluations through each phase of clinical trials and into post-marketing studies. In early phases of drug development, biomarkers are used to evaluate activity in animal models, prove mechanism of action and concept of an investigational entity, bridge pre-clinical and clinical pharmacology, and evaluate safety in animal models and humans. In late stages of drug development, biomarkers can be used to make decisions in the evaluation of dose-response and optimal regimen for desired pharmacologic effect and safety, and some biomarkers can be used as a surrogate endpoint for efficacy and/or toxicity. Also, biomarkers can predict patients’ response to compound-enabling patient enrichment strategies by identifying certain patient populations that are more likely to respond to the drug therapy or to avoid specific adverse events. This shift toward “personalized medicine,” in which the patient receives a treatment based on his/her genetic makeup as well as medical profile, is helping the drug industry achieve the goal of quick and cost-effective research, especially in poorly served areas such as neurodegenerative disorders and cancer. Biomarker assays range from exploratory type of assays performed on a fit-for-purpose basis to rigorously validated assays when a biomarker is used as a surrogate end point, for patient selection, or for randomization into different arms. Validation of biomarker assays should be considered a continuous and evolving process. It is imperative that biomarker development be accelerated along with therapeutics. Assay validation is essential, but of equal or even greater importance is the monitoring of assay performance and level of quality during production. Despite all of the potential benefits of using biomarkers to advance pharmaceutical research and development, discrepant results can pose a threat to development programs by triggering false decisions.

SummaryEdoxaban is an oral direct factor (F)Xa inhibitor in advanced stages of clinical development. The primary objective of the present study was to assess the pharmacodynamics (PD) and safety of enoxaparin 1 mg/kg followed 12 hours (h) post-dose by edoxaban 60 mg, which is the regimen being used in the phase III study of edoxaban for the treatment of venous thromboembolism (Hokusai-VTE). This was a phase I, open-label, randomised, four-period, four-treatment cross-over study. Treatments were edoxaban alone (EDOX), enoxaparin alone (ENOX), edoxaban plus enoxaparin (EDOX+ENOX), and enoxaparin followed by edox aban 12 h later (ENOX12-EDOX). Serial blood samples were collected for PD (thrombin generation, anti-FXa) and pharmacokinetic (PK) variables (edoxaban and its principal metabolite M4 by LC-MS/MS, and anti-FIIa as a surrogate of enoxaparin). The highest effect on thrombin AUC (endogenous thrombin potential, or ETP), thrombin (peak), thrombin generation lag time, and velocity index was observed for EDOX+ENOX, followed by ENOX, ENOX12-EDOX, and EDOX. The greatest effect on anti-FXa activity was observed for EDOX+ENOX, followed by ENOX12-EDOX. As expected, neither edoxaban nor enoxaparin significantly altered the PK of the other drug. There were no serious adverse events during the study. It is concluded that a 60-mg dose of edoxaban can be safely administered 12 h following enoxaparin 1 mg/ kg.

Efatutazone (CS-7017), a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist, exerts anticancer activity in preclinical models. The authors conducted a phase 1 study to determine the recommended phase 2 dose, safety, tolerability, and pharmacokinetics of efatutazone.Patients with advanced solid malignancies and no curative therapeutic options were enrolled to receive a given dose of efatutazone, administered orally (PO) twice daily for 6 weeks, in a 3 + 3 intercohort dose-escalation trial. After the third patient, patients with diabetes mellitus were excluded. Efatutazone dosing continued until disease progression or unacceptable toxicity, with measurement of efatutazone pharmacokinetics and plasma adiponectin levels.Thirty-one patients received efatutazone at doses ranging from 0.10 to 1.15 mg PO twice daily. Dose escalation stopped when maximal impact on PPARγ-related biomarkers had been reached before any protocol-defined maximum-tolerated dose level. On the basis of a population pharmacokinetic/pharmacodynamic analysis, the recommended phase 2 dose was 0.5 mg PO twice daily. A majority of patients experienced peripheral edema (53.3%), often requiring diuretics. Three episodes of dose-limiting toxicities, related to fluid retention, were noted in the 0.10-, 0.25-, and 1.15-mg cohorts. Of 31 treated patients, 27 were evaluable for response. A sustained partial response (PR; 690 days on therapy) was observed in a patient with myxoid liposarcoma. Ten additional patients had stable disease (SD) for ≥60 days. Exposures were approximately dose proportional, and adiponectin levels increased after 4 weeks of treatment at all dose levels. Immunohistochemistry of archived specimens demonstrated that PPARγ and retinoid X receptor expression levels were significantly greater in patients with SD for ≥60 days or PR (P = .0079), suggesting a predictive biomarker.Efatutazone demonstrates acceptable tolerability with evidence of disease control in patients with advanced malignancies.

Culturing human islets in Memphis serum-free media (M-SFM) is associated with excellent postculture recovery, in vitro function, and in vivo survival. The authors investigate the possibility of preserving islet function for extended periods (6 months) in culture and describe the in vitro and in vivo functional outcomes associated with these extended culture times.Human islets isolated from three cadaveric donor organs were cultured in M-SFM for 1, 3, or 6 months before transplantation under the kidney capsule of nonobese diabetic (NOD)-severe combined immunodeficiency (SCID) mice. In vitro function was measured by static incubation at the time of transplantation. In vivo function was assessed by measuring human insulin and C-peptide production, and by the ability of 6-month cultured islets to cure streptozotocin-induced diabetes in this mouse model.Islet recovery ratios after 1 month in culture ranged from 85% to 88% and declined to 28% to 53% after 6 months of culture (P0.01). Insulin stimulation indices did not differ among the fresh or the 6-month cultured preparations. All preparations cultured for 1 to 3 months functioned in the NOD-SCID mice. After 6 months of culture, two of the three preparations demonstrated in vivo function and were able to cure streptozotocin-induced diabetes.These data demonstrate that human islets can be cultured in M-SFM for extended periods and still retain in vitro and in vivo function and the ability to cure experimental diabetes. The ability to maintain islets in culture for prolonged periods is an important step toward the development of islet tissue repositories and distribution centers.

The streptococcal pyrogenic exotoxins (Spes) play a central role in the pathogenesis of invasive group A streptococcal (GAS) infections. The majority of recent invasive GAS infections have been caused by an M1T1 strain that harbors the genes for several streptococcal superantigens, including speA , speB , speF , speG , and smeZ . However, considerable variation in the expression of Spe proteins among clonal M1 isolates has been found, and many of the speA -positive M1 strains do not produce detectable amounts of SpeA in vitro. This study was designed to test the hypothesis that speA gene expression can be induced in vivo. A mouse infection chamber model that allows sequential sampling of GAS isolates at various time points postinfection was developed and used to monitor the kinetics of Spe production in vivo. Micropore Teflon diffusion chambers were implanted subcutaneously in BALB/c mice, and after 3 weeks the pores became sealed with connective tissue and sterile fluid containing a white blood cell infiltrate accumulated inside the infection chambers. Representative clonal M1T1 isolates expressing no detectable SpeA were inoculated into the implanted chambers, and the expression of SpeA in the aspirated aliquots of the chamber fluid was analyzed on successive days postinfection. Expression of SpeA was detected in the chamber fluid as early as days 3 to 5 postinfection in most animals, with a significant increase in expression by day 7 in all infected mice. Isolates recovered from the chamber and grown in vitro continued to produce SpeA even after 21 passages in vitro, suggesting stable switch on of the speA gene. A temporal relation between the upregulation of SpeA expression and the downregulation of SpeB expression was observed in vivo. These data suggest that in vivo host and/or environmental signals induced speA gene expression and suppressed speB gene expression. This underscores the role of the host-pathogen interaction in regulating the expression of streptococcal virulence factors in vivo. The model described here should facilitate such studies.

Methionine adenosyltransferase (MAT) catalyzes the biosynthesis of S-adenosylmethionine (AdoMet), a key molecule in transmethylation reactions and polyamine biosynthesis. The MAT II isozyme consists of a catalytic alpha2 and a regulatory beta subunit. Down-regulation of the MAT II beta subunit expression causes a 6-10-fold increase in intracellular AdoMet levels. To understand the mechanism by which the beta subunit expression is regulated, we cloned the MAT2B gene, determined its organization, characterized its 5'-flanking sequences, and elucidated the in vitro and in vivo regulation of its promoter. Transcription of the MAT2B gene initiates at position -203 relative to the translation start site. Promoter deletion analysis defined a minimal promoter between positions +52 and +93 base pairs, a GC-rich region. Inclusion of the sequences between -4 and +52 enhanced promoter activity; this was primarily because of an Sp1 recognition site at +9/+15. The inclusion of sequences up to position -115 provided full activity; this was attributed to a TATA at -32. The Sp1 site at position +9 was key for the formation of protein.DNA complexes. Mutation of both the Sp1 site at +9 and the TATA at -32 reduced promoter activity to its minimal level. Supershift assays showed no effect of the anti-Sp1 antibody on complex formation, whereas the anti-Sp3 antibody had a strong effect on protein.DNA complex formation, suggesting that Sp3 is one of the main factors binding to this Sp1 site. Chromatin immunoprecipitation assays supported the involvement of both Sp1 and Sp3 in complexes formed on the MAT2B promoter. The data show that the 5'-untranslated sequences play an important role in regulating the MAT2B gene and identifies the Sp1 site at +9 as a potential target for modulating MAT2B expression, a process that can have a major effect on intracellular AdoMet levels.

Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine (AdoMet). The mammalian MAT II isozyme consists of catalytic alpha(2) and regulatory beta subunits. The aim of this study was to investigate the interaction and kinetic behavior of the human MAT II subunit proteins in mammalian cells. COS-1 cells were transiently transfected with pTargeT vector harboring full-length cDNA that encodes for the MAT II alpha(2) or beta subunits. Expression of the His-tagged recombinant alpha(2) (ralpha(2)) subunit in COS-1 cells markedly increased MAT II activity and resulted in a shift in the K(m) for L-methionine (L-Met) from 15 microM (endogenous MAT II) to 75 microM (ralpha(2)), and with the apparent existence of two kinetic forms of MAT in the transfected COS-1 cell extracts. By contrast, expression of the recombinant beta (rbeta) subunit had no effect on the K(m) for L-Met of the endogenous MAT II, while it did cause an increase in both the V(max) and the specific activity of endogenous MAT. Co-expression of both ralpha(2) and rbeta subunits resulted in a significant increase of MAT specific activity with the appearance of a single kinetic form of MAT (K(m) = 20 microM). The recombinant MAT II alpha(2) and rbeta subunit associated spontaneously either in cell-free system or in COS-1 cells co-expressing both subunits. Analysis of nickel-agarose-purified His-tagged ralpha(2) subunit from COS-1 cell extracts showed that the beta subunit co-purified with the alpha(2) subunit. Furthermore, the alpha(2) and beta subunits co-migrated in native polyacrylamide gels. Together, the data provide evidence for alpha(2) and beta MAT subunit association. In addition, the beta subunit regulated MAT II activity by reducing its K(m) for L-Met and by rendering the enzyme more susceptible to feedback inhibition by AdoMet. We believe that the previously described differential expression of MAT II beta subunit may be an important mechanism by which MAT activity can be modulated to provide different levels of AdoMet that may be required at different stages of cell growth and differentiation.

Abstract 1252 Introduction: Edoxaban is an oral, direct factor Xa (FXa) inhibitor currently in phase 3 clinical development for stroke prevention in nonvalvular atrial fibrillation (AF) and the treatment and secondary prevention of venous thromboembolism (VTE). Guidance for the emergency management of serious bleeding and strategies for reversing the anticoagulant effects edoxaban are needed. Both recombinant human FVIIa (rhFVIIa; NovoSeven®) and a human plasma fraction containing nonactivated forms of FII, FIX, and FX/proteins C and S and activated FVII (FEIBA; factor eight inhibitor bypassing activity) have been identified as potential reversal agents for edoxaban. The minimum effective doses and the time course required for either rhFVIIa or FEIBA to reverse supratherapeutic concentrations of edoxaban in an anticoagulated patient have yet to be established. This ex vivo study was conducted to assess the effects and establish the time course of various concentrations of rhFVIIa and FEIBA on the reversal of edoxaban's anticoagulant effects. Methods: Edoxaban at supratherapeutic concentrations of 500 and 1000 ng/mL (therapeutic level is ∼250 ng/mL for Cmax of a 60-mg dose) was added to fresh blood drawn from healthy subjects; control samples were diluent alone. After 60 min of incubation, rhFVIIa, FEIBA, or control was added to the samples. rhFVIIa was added to produce final concentrations of 0.8 and 1.8 μg/mL, which correspond to known maximal observed human plasma concentrations at doses of 40 and 90 μg/kg. FEIBA was added to produce concentrations of 0.75 and 1.4 U/mL, which correspond to human plasma concentrations at the therapeutic doses of FEIBA of 50 to 100 U/kg. In order to determine reversal of anticoagulant effects over time, coagulation assays (PT, aPTT, anti-Xa, intrinsic FXa activity, thrombin generation assay [TGA], D-dimer, and FVIIa activity) were measured at times 0, 0.25, 0.50, 1, 2, and 4 h after incubation with rhFVIIa, FEIBA, or control. Results: In edoxaban alone and control samples, PT, aPTT, and anti-Xa results reflected previously established anticoagulant activity. Both 500 and 1000 ng/mL of edoxaban completely inhibited intrinsic FXa and thrombin generation as measured by TGA (peak). Measures of FVIIa activity indicated that the concentrations of rhFVIIa utilized were consistent with previously reported responses. With the exception of thrombin levels, reversal of edoxaban anticoagulant activity by both rhFVIIa and FEIBA was observed for PT, aPTT, and anti-Xa beginning at 0.25 h and was maintained across the experimental period. At 1000 ng/mL edoxaban, the observed decrease at 0.25 h post-reversal of anticoagulant activity was 82% for anti-Xa, 72% for PT, and 58% for aPTT. Compared with baseline, the maximum reversal of intrinsic FXa activity for edoxaban 500 ng/mL was ∼30% and for 1000 ng/mL was 15% across all concentrations of rhFVIIa and FEIBA. The TGA assay indicated both rhFVIIa and FEIBA reversed ∼45% and 20% of the effect of edoxaban at 500 ng/mL and 1000 ng/mL, respectively, 4 h after adding the reversal agents. With the exception of 1 baseline sample, levels of D-dimer did not show significant changes with the addition of edoxaban or with its subsequent reversal by either rhFVIIa or FEIBA. Conclusion: Low therapeutic concentrations of rhFVIIa and FEIBA showed significant and rapid reversal of supratherapeutic concentrations of the anticoagulant activity induced by edoxaban based on PT, aPTT, and anti-Xa activity. Disclosures: Halim: Daiichi Sankyo Pharma Development: Employment. Li:Daiichi Sankyo Pharma Development: Employment. Stein:Daiichi Sankyo: Consultancy, Research Funding; AACC: Consultancy, Honoraria, Research Funding; Abbott: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; FDA: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; ISIS: Consultancy, Honoraria, Research Funding; Merck & Co: Consultancy, Honoraria, Research Funding; National Lipid Association: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Reliant: Consultancy, Honoraria, Research Funding; Regeneron: Consultancy, Honoraria, Research Funding; SanofiAventis: Consultancy, Honoraria, Research Funding; Schering-Plough: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Wyeth: Consultancy, Honoraria, Research Funding. Mendell:Daiichi Sankyo Pharma Development: Employment.