Safety and Pharmacokinetics of DS-1040 Drug-Drug Interactions With Aspirin, Clopidogrel, and Enoxaparin.

DS-1040, a novel low-molecular-weight inhibitor of activated thrombin-activatable fibrinolysis inhibitor, is under development for the treatment of thromboembolic diseases including venous thromboembolism and acute ischemic stroke. Here we describe the results of 3 studies that evaluated the safety and tolerability of DS-1040 along with the effect on DS-1040 pharmacokinetic (PK) parameters, when dosed alone or when coadministered with aspirin (NCT02071004), clopidogrel (NCT02560688), or enoxaparin in healthy subjects. Concomitant administration of single-dose DS-1040 with multiple-dose aspirin, multiple-dose clopidogrel, or single-dose enoxaparin, consistent with clinically relevant dose regimens, was safe and well tolerated with no serious treatment-emergent adverse events (TEAEs), TEAEs leading to discontinuation, bleeding-related TEAEs, and no significant changes in coagulation parameters. DS-1040 did not prolong bleeding time when administered concomitantly with aspirin or clopidogrel. In the aspirin study, DS-1040 PK was evaluated following the concomitant administration with multiple-dose aspirin, where the plasma DS-1040 exposure (peak plasma concentration [Cmax ] and area under the concentration-time curve [AUCinf ]) was to be similar to the data previously published in the first-in-human study of DS-1040 in healthy subjects. The PK parameters of DS-1040 coadministered with clopidogrel were similar to those of DS-1040 alone, with small increases in geometric means for Cmax (7%) and AUClast (9%). When coadministered with enoxaparin, the PK parameters of DS-1040 were not affected (1.1% and 1.5% decreases in geometric means for Cmax and AUClast , respectively). Therefore, concomitant administration of DS-1040 and clopidogrel or enoxaparin did not demonstrate PK drug-drug interactions.

First-in-Human Study to Assess the Safety, Pharmacokinetics, and Pharmacodynamics of an Oral Formulation of DS-1040, an Inhibitor of the Activated Form of Thrombin-Activatable Fibrinolysis Inhibitor, in Healthy Subjects.

DS-1040, a low-molecular-weight imidazole derivative, inhibits the enzymatic activity of thrombin-activatable fibrinolysis inhibitor (TAFIa), enhancing endogenous tissue plasminogen activator-triggered fibrinolysis. This first-in-human, randomized, placebo-controlled, phase 1 study evaluated the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of an oral formulation of DS-1040. Healthy adults (aged 20-45 years; N = 56) were randomized 3:1 to receive DS-1040 orally administered as single ascending doses (50, 100, 200, or 400 mg) or placebo, or DS-1040 multiple ascending doses (100 mg once daily, 200 mg once daily, or 150 mg twice daily) or placebo for 14 days. Safety, PK, and PD parameters were assessed. All doses of DS-1040 were well tolerated; no serious/severe adverse events (AEs) or discontinuations due to AEs occurred. DS-1040 had no effect on coagulation parameters, and no treatment-related trends in the bleeding time were observed. DS-1040 exposure (peak concentration and area under the concentration-time curve) increased in a dose-proportional manner across the single-dose range. With multiple doses, steady state was achieved by day 7 with minimal accumulation (mean accumulation ratio 1.15-1.25), and the PK was time-independent. After 72 hours, approximately 10% of the DS-1040 400-mg single dose was recovered in urine as intact parent drug. The mean terminal half-life ranged from 17.2 to 24.9 hours, which was similar to previous intravenous administration data. Dose-dependent inhibition of total TAFIa activity was observed following single and multiple doses of oral DS-1040. The safety and PK/PD profiles of oral DS-1040 in healthy subjects support further clinical development.

Determination of edoxaban equivalent concentrations in human plasma by an automated anti-factor Xa chromogenic assay.

INTRODUCTION: This phase I, open-label, multiple-dose, two-treatment study assessed the relationship between edoxaban equivalent concentration derived from an anti-FXa assay with the summed concentration of edoxaban and its active metabolite, M-4, as assessed by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). This study also assessed the relationship between edoxaban plasma concentrations assessed by LC/MS/MS in sodium citrate and lithium heparin tubes. MATERIALS AND METHODS: Healthy volunteers were randomized to receive once-daily edoxaban 60mg or 90mg for 5days (15 participants per treatment group). Serial blood samples were collected for analysis by LC/MS/MS and by the anti-FXa assay. Edoxaban equivalent levels were assessed using a commercially available anti-FXa activity assay with an edoxaban-specific setup. RESULTS AND CONCLUSIONS: The day 5 concentration estimates were significantly correlated between the 2 assays (P<0.0001 for both edoxaban doses). The geometric least squares mean (GLSM) ratio (90% confidence interval) for edoxaban equivalent concentrations vs edoxaban + M-4 concentrations was 114.3% (108.2-120.8) for edoxaban 60mg (P<0.0001) and 113.0% (107.1-119.2) for edoxaban 90mg (P=0.0002). The GLSM ratio for edoxaban concentrations in sodium citrate vs lithium heparin tubes for 60-mg and 90-mg edoxaban doses were 82.8% (78.5-87.3) and 83.9% (79.1-89.0), respectively. In this study, an anti-FXa chromogenic assay with edoxaban-specific calibrators and controls demonstrated good accuracy in estimating edoxaban concentrations across a wide range of concentrations relative to LC/MS/MS at steady state following the administration of once-daily edoxaban for 5days.

Pharmacokinetics and Pharmacodynamics of the Nonvitamin K Antagonist Oral Anticoagulant Edoxaban When Administered Alone or After Switching from Rivaroxaban or Dabigatran Etexilate in Healthy Subjects.

BACKGROUND AND OBJECTIVES: Edoxaban is an oral, once-daily direct factor Xa inhibitor. To support the possibility that patients may choose to switch treatment from another nonvitamin K antagonist oral anticoagulant to edoxaban, this clinical study was conducted to evaluate the pharmacokinetic and pharmacodynamic effects of edoxaban after switching from rivaroxaban or dabigatran etexilate to edoxaban. METHODS: In this open-label, three-period, crossover study, healthy subjects received 3 days of edoxaban 60 mg daily, rivaroxaban 20 mg daily, or dabigatran etexilate 150 mg twice daily, followed by edoxaban 60 mg on day 4. RESULTS: Day 4 edoxaban pharmacokinetic parameters were similar for all treatments. The peak effect of edoxaban on prothrombin time (PT) after 4 days of edoxaban only was 21.8 ± 2.46 s; after switching from rivaroxaban to edoxaban, peak effect on PT was similar at 21.8 ± 2.88 s. After switching from dabigatran etexilate to edoxaban, least squares mean activated partial thromboplastin time (aPTT) at 2 h after administration was 47.6 vs 35.0 s for edoxaban alone. The treatment difference was 12.8 s (95% confidence interval 10.5-15.1; p < 0.0001). Post hoc analysis revealed that predose aPTT was elevated on day 3 of dabigatran etexilate administration, and on day 4, indicating a carryover effect from dabigatran. All treatments were well tolerated and there were no safety concerns upon switching, with no increased risk of bleeding. CONCLUSIONS: The study results suggest that switching to edoxaban from either rivaroxaban or dabigatran etexilate at the time of the next dose is well tolerated and maintains coagulation status.

The impact of a three-factor prothrombin complex concentrate on the anticoagulatory effects of the factor Xa inhibitor edoxaban.

BACKGROUND: Edoxaban, a direct factor Xa inhibitor, is a once-daily, non-vitamin K antagonist oral anticoagulant. There is no established method to reverse the activity of non-vitamin K oral anticoagulants in cases of hemorrhage or urgent surgery. This study evaluated the ability of a 3-factor prothrombin complex concentrate (3F-PCC) to reverse the anticoagulatory effects of edoxaban. METHODS: In this phase 1 study, 24 healthy subjects were randomly assigned to receive a single dose of 60 or 180mg edoxaban, followed by placebo, 25IU/kg 3F-PCC, or 50IU/kg 3F-PCC. Edoxaban pharmacokinetics and pharmacodynamics, including the primary endpoint of prothrombin time (PT) and endogenous thrombin potential (ETP), were assessed. D-dimer and prothrombin fragment 1 and 2 (F1+2) were also measured. RESULTS: Overall, there were no apparent consistent effects of 3F-PCC on edoxaban pharmacokinetics. Administration of 3F-PCC 25 or 50IU/kg with edoxaban 60 or 180mg did not substantially accelerate the return of PT to baseline levels. However, infusion of 3F-PCC 25 and 50IU/kg did substantially accelerate return to baseline of ETP compared with placebo. D-dimer and F1+2 data did not indicate any lasting procoagulant effects of 3F-PCC infusion, although a transient increase in F1+2 was noted during and after 3F-PCC infusion. Edoxaban and 3F-PCC co-administration was well tolerated in normal healthy subjects. CONCLUSIONS: There was no apparent reversal of PT prolongation with 3F-PCC following edoxaban infusion, but ETP was completely reversed. Co-administration of 3F-PCC was well tolerated, but a dose-dependent increase in F1+2 may reflect a procoagulant risk.

Discovery of 1-arylcarbonyl-6,7-dimethoxyisoquinoline derivatives as glutamine fructose-6-phosphate amidotransferase (GFAT) inhibitors.

Through high throughput screening and subsequent hit identification and optimization, we synthesized a series of 1-arylcarbonyl-6,7-dimethoxyisoquinoline derivatives as the first reported potent and reversible GFAT inhibitors. SAR studies of this class of compounds indicated significant impact on GFAT inhibition potency by substitutions on the A-ring and C-ring. The ketone group was found to be necessary for high potency. Compound 28 (RO0509347) demonstrated potent GFAT inhibition (IC(50)=1µM) with a desirable pharmacokinetic profile in rats, and showed significant efficacy in reducing the glucose excursion in an OGTT test in ob/ob mice.

Characterization of FcepsilonRI-bearing CD123 blood dendritic cell antigen-2 plasmacytoid dendritic cells in atopic dermatitis.

BACKGROUND: The high-affinity receptor for IgE (FcepsilonRI) on myeloid dendritic cells has been shown to play a major role in atopic dermatitis (AD). Plasmacytoid dendritic cells (pDCs), which are instrumental in the defense of viral infections, are present in reduced amounts in the skin of patients with AD, which is characterized by a high susceptibility to viral infections. OBJECTIVE: We explored phenotypical and functional characteristics of pDC in the peripheral blood of patients with AD and healthy individuals. METHODS: Blood dendritic cell antigen-2+CD123+ pDCs were enriched from the peripheral blood of patients with AD and studied in functional assays. RESULTS: Skin-homing molecules such as cutaneous lymphocyte antigen and L-selectin CD62L were expressed in lower levels on pDCs of patients with AD. pDCs expressed high amounts of IgE-occupied FcepsilonRI. Further, FcepsilonRI aggregation on pDCs impaired the surface expression of MHC I and II, induced the production of IL-10, and enhanced the apoptosis of pDCs. Importantly, FcepsilonRI preactivated pDC produced less IFN-alpha and IFN-beta after stimulation with CpG motifs and enhanced the outcome of immune responses of the TH2 type. CONCLUSION: From these data, we conclude that FcepsilonRI-bearing pDCs from patients with AD (1) are different from pDCs of healthy individuals, (2) might be important in the pathophysiology of AD, and (3) contribute to the enhanced susceptibility of patients with AD to viral infections.

Surface expression of Fc epsilon RI on Langerhans' cells of clinically uninvolved skin is associated with disease activity in atopic dermatitis, allergic asthma, and rhinitis.

BACKGROUND: Fc epsilon RI expressed on the surface of human epidermal Langerhans' cells facilitates uptake of IgE-associated allergens and plays a pivotal role in the pathogenesis of atopic dermatitis. Seminal results from studies investigating Langerhans' cell Fc epsilon RI in skin biopsy sections or epidermal cell suspensions demonstrate the highest receptor expression in lesional skin of patients with active atopic dermatitis. OBJECTIVE: We sought to investigate and localize Fc epsilon RI expression on Langerhans' cells within a minimally disturbed tissue environment in clinically uninvolved skin and to compare receptor expression between healthy donors and patients with atopic dermatitis or other allergic diseases. METHODS: Intact epidermal sheets from skin suction blisters, immunofluorescently stained with Langerhans' cell markers and anti-Fc epsilon RI alpha (mAbs 15E5 and 22E7) or anti-IgE, were examined by means of confocal microscopy. Samples incubated with anti-Fc epsilon RI alpha before or after cell fixation-permeabilization were compared to discriminate between cytoplasmic and membrane localization. RESULTS: Cytoplasmic Fc epsilon RI alpha chain was found in Langerhans' cells from all donors, irrespective of atopic status. Surface Fc epsilon RI-bound IgE was detected in the skin of individuals with active atopic dermatitis and in the skin of those with active asthma or rhinitis. No surface Fc epsilon RI was expressed in the skin of patients with a clinical history of atopic dermatitis, asthma, or rhinitis whose disease was in remission or in the skin of nonatopic individuals. CONCLUSION: In clinically uninvolved skin, Langerhans' cell-surface Fc epsilon RI expression is not only linked to atopic dermatitis but is also generally associated with allergic disease. This supports the concept of a systemic regulatory mechanism associated with active allergic disease, which is further aggravated by local inflammation in atopic skin lesions.

Localization of a susceptibility gene for type 2 diabetes to chromosome 5q34-q35.2.

We report a genomewide linkage study of type 2 diabetes (T2D [MIM 125853]) in the Icelandic population. A list of type 2 diabetics was cross-matched with a computerized genealogical database clustering 763 type 2 diabetics into 227 families. The diabetic patients and their relatives were genotyped with 906 microsatellite markers. A nonparametric multipoint linkage analysis yielded linkage to 5q34-q35.2 (LOD = 2.90, P=1.29 x 10(-4)) in all diabetics. Since obesity, here defined as body mass index (BMI) > or =30 kg/m(2), is a key risk factor for the development of T2D, we studied the data either independently of BMI or by stratifying the patient group as obese (BMI > or =30) or nonobese (BMI <30). A nonparametric multipoint linkage analysis yielded linkage to 5q34-q35.2 (LOD = 3.64, P=2.12 x (10)-5) in the nonobese diabetics. No linkage was observed in this region for the obese diabetics. Linkage analysis conditioning on maternal transmission to the nonobese diabetics resulted in a LOD score of 3.48 (P=3.12 x 10(-5)) in the same region, whereas conditioning on paternal transmission led to a substantial drop in the LOD score. Finally, we observed potential interactions between the 5q locus and two T2D susceptibility loci, previously mapped in other populations.

Characterization of dendritic cells from human oral mucosa: a new Langerhans' cell type with high constitutive FcepsilonRI expression.

BACKGROUND: The oral mucosa represents a unique immunologic unit with a high frequency of native allergen contact within the gastrointestinal tract in which immune tolerance is the natural outcome of allergen contact. Although Langerhans' cells (LC), known to play a crucial role in initiating allergen-dependent immune responses in the skin, have also been detected in the oral mucosa, little is known about their phenotype and exact physiologic role. OBJECTIVE: To elucidate whether LC from oral mucosa (oLC) differ from skin LC (sLC), these cells were subjected to detailed comparative analysis. METHODS: Crude epidermal and oral mucosa cell suspensions were prepared by trypsinization. oLC and sLC were compared phenotypically by flow cytometry techniques and functionally in T-cell proliferation assays. RESULTS: In contrast to sLC, freshly isolated oLC expressed significantly higher amounts of MHC class I and II, as well as costimulatory molecules CD40, CD80/B7.1, and CD86/B7.2. oLC displayed FcgammaRIII/CD16 and FcgammaRI/CD64. Most surprisingly, oLC constitutively expressed the high affinity receptor for IgE (FcepsilonRI) even in nonatopic donors. FcepsilonRI expression on oLC was further increased and correlated with the serum IgE levels in atopic individuals. oLC showed a higher allogeneic stimulatory activity than sLC, whereas the activation of autologous T cells correlated to the FcepsilonRI expression. CONCLUSION: Taken together, our results strongly indicate that oLC profoundly differ from their skin counterparts. The constitutive high expression of FcepsilonRI on oLC could point to particular skills of these cells within the regional immune system of the oral mucosa.

Mitochondrial and nucleocytoplasmic targeting of O-linked GlcNAc transferase.

O-linked GlcNAc transferase (OGT) mediates a novel glycan-dependent signaling pathway, but the intracellular targeting of OGT is poorly understood. We examined the localization of OGT by immunofluorescence microscopy, subcellular fractionation and immunoblotting using highly specific affinity-purified antisera. In addition to the expected nuclear localization, we found that OGT was highly concentrated in mitochondria. Since the mitochondrial OGT (103 kDa) was smaller than OGT found in other compartments (116 kDa) we reasoned that it was one of two predicted splice variants of OGT. The N-termini of these isoforms are unique; the shorter form contains a potential mitochondrial targeting sequence. We found that when epitope-tagged, the shorter form (mOGT; 103 kDa) concentrated in HeLa cell mitochondria, whereas the longer form (ncOGT; 116 kDa) localized to the nucleus and cytoplasm. The N-terminus of mOGT was essential for proper targeting. Although mOGT appears to be an active transferase, O-linked GlcNAc-modified substrates do not accumulate in mitochondria. Using immunoelectron microscopy and mitochondrial fractionation, we found that mOGT was tightly associated with the mitochondrial inner membrane. The differential localization of mitochondrial and nucleocytoplasmic isoforms of OGT suggests that they perform unique intracellular functions.