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An experimental investigation of a novel iron chelating protoporphyrin IX prodrug for the enhancement of photodynamic therapy.
Anayo, L, Magnussen, A, Perry, A, Wood, M, Curnow, A
Lasers in surgery and medicine. 2018;(5):552-565
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Abstract
OBJECTIVES Non-melanoma skin cancers are the most frequently occurring type of cancer worldwide. They can be effectively treated using topical dermatological photodynamic therapy (PDT) employing protoporphyrin IX (PpIX) as the active photosensitising agent as long as the disease remains superficial. Novel iron chelating agents are being investigated to enhance the effectiveness and extend the applications of this treatment modality, as limiting free iron increases the accumulation of PpIX available for light activation and thus cell kill. METHODS Human lung fibroblasts (MRC-5) and epithelial squamous carcinoma (A431) cells were treated with PpIX precursors (aminolaevulinic acid [ALA] or methyl-aminolevulinate [MAL]) with or without the separate hydroxypyridinone iron chelating agent (CP94) or alternatively, the new combined iron chelator and PpIX producing agent, AP2-18. PpIX fluorescence was monitored hourly for 6 hours prior to irradiation. PDT effectiveness was then assessed the following day using the lactate dehydrogenase and neutral red assays. RESULTS Generally, iron chelation achieved via CP94 or AP2-18 administration significantly increased PpIX fluorescence. ALA was more effective as a PpIX-prodrug than MAL in A431 cells, corresponding with the lower PpIX accumulation observed with the latter congener in this cell type. Addition of either iron chelating agent consistently increased PpIX accumulation but did not always convey an extra beneficial effect on PpIX-PDT cell kill when using the already highly effective higher dose of ALA. However, these adjuvants were highly beneficial in the skin cancer cells when compared with MAL administration alone. AP2-18 was also at least as effective as CP94 + ALA/MAL co-administration throughout and significantly better than CP94 supplementation at increasing PpIX fluorescence in MRC5 cells as well as at lower doses where PpIX accumulation was observed to be more limited. CONCLUSIONS PpIX fluorescence levels, as well as PDT cell kill effects on irradiation can be significantly increased by pyridinone iron chelation, either via the addition of CP94 to the administration of a PpIX precursor or alternatively via the newly synthesized combined PpIX prodrug and siderophore, AP2-18. The effect of the latter compound appears to be at least equivalent to, if not better than, the separate administration of its constituent parts, particularly when employing MAL to destroy skin cancer cells. AP2-18 therefore warrants further detailed analysis, as it may have the potential to improve dermatological PDT outcomes in applications currently requiring enhancement. Lasers Surg. Med. 50:552-565, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.
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Effectiveness and Safety of Apixaban versus Warfarin as Outpatient Treatment of Venous Thromboembolism in U.S. Clinical Practice.
Weycker, D, Li, X, Wygant, GD, Lee, T, Hamilton, M, Luo, X, Vo, L, Mardekian, J, Pan, X, Burns, L, et al
Thrombosis and haemostasis. 2018;(11):1951-1961
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Abstract
In the AMPLIFY clinical trial, apixaban was non-inferior to warfarin plus subcutaneous enoxaparin bridge therapy in the treatment of acute venous thromboembolism (VTE) and was associated with significantly less bleeding. This study evaluated their comparative effectiveness and safety in routine clinical practice. A matched-cohort design and data from four U.S. private health care claims databases were employed. Study population comprised patients who initiated outpatient treatment with apixaban versus warfarin (plus parenteral anticoagulant bridge therapy) within 30 days of their initial VTE episode; apixaban and warfarin patients were matched on age, characteristics of VTE episode, study database and propensity score. Major bleeding, clinically relevant non-major (CRNM) bleeding and recurrent VTE during the 180-day (maximum) follow-up period were compared using shared frailty models. During mean follow-up of 143 days among apixaban patients (n = 17,878) and 152 days among warfarin patients (n = 17,878), incidence proportions for apixaban versus warfarin, respectively, were 1.7% versus 2.3% for major bleeding, 7.0% versus 9.4% for CRNM bleeding and 2.3% versus 2.9% for recurrent VTE. In shared frailty models, risks of major bleeding (hazard ratio [HR] = 0.75, 95% confidence interval [CI] = 0.64-0.87), CRNM bleeding (HR = 0.77, 95% CI = 0.71-0.83) and recurrent VTE (HR = 0.80, 95% CI = 0.70-0.91) were lower for apixaban versus warfarin. In this large-scale evaluation of VTE patients receiving outpatient treatment with apixaban or warfarin in U.S. clinical practice, risks of major bleeding, CRNM bleeding and recurrent VTE were significantly lower among patients who received apixaban.
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Deferiprone increases endothelial nitric oxide synthase phosphorylation and nitric oxide production.
Sriwantana, T, Vivithanaporn, P, Paiboonsukwong, K, Rattanawonsakul, K, Srihirun, S, Sibmooh, N
Canadian journal of physiology and pharmacology. 2018;(9):879-885
Abstract
Iron chelation can improve endothelial function. However, effect on endothelial function of deferiprone has not been reported. We hypothesized deferiprone could promote nitric oxide (NO) production in endothelial cells. We studied effects of deferiprone on blood nitrite and blood pressure after single oral dose (25 mg/kg) in healthy subjects and hemoglobin E/β-thalassemia patients. Further, effects of deferiprone on NO production and endothelial NO synthase (eNOS) phosphorylation in primary human pulmonary artery endothelial cells (HPAEC) were investigated in vitro. Blood nitrite levels were higher in patients with deferiprone therapy than those without deferiprone (P = 0.023, n = 16 each). Deferiprone increased nitrite in plasma and whole blood of healthy subjects (P = 0.002 and 0.044) and thalassemia patients (P = 0.003 and 0.046) at time 180 min (n = 20 each). Asymptomatic reduction in diastolic blood pressure (P = 0.005) and increase in heart rate (P = 0.009) were observed in healthy subjects, but not in thalassemia patients. In HPAEC, deferiprone increased cellular nitrite and phospho-eNOS (Ser1177) (P = 0.012 and 0.035, n = 6) without alteration in total eNOS protein and mRNA. We conclude that deferiprone can induce NO production by enhancing eNOS phosphorylation in endothelial cells.
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Direct Oral Anticoagulants in End-Stage Renal Disease.
Klil-Drori, AJ, Tagalakis, V
Seminars in thrombosis and hemostasis. 2018;(4):353-363
Abstract
Patients with end-stage renal disease (ESRD) were excluded from pivotal clinical trials with oral anticoagulants. While such patients are at an increased risk of venous and arterial thromboembolism, their risk of bleeding is also elevated. It is thus of little surprise that stroke prevention with vitamin K antagonists (VKAs) in ESRD patients with atrial fibrillation is controversial, with observational evidence ranging from beneficial to harmful. This uncertainty extends to the less studied use of VKAs for venous thromboembolism in ESRD. The direct oral anticoagulants (DOACs) apixaban and rivaroxaban have now permissive labeling in the United States for atrial fibrillation in patients with ESRD; this expanded labeling has not yet occurred either in Europe or for venous thromboembolism. This review summarizes the current evidence for the pharmacology of DOACs in ESRD as well as their utilization and safety in patients with ESRD and atrial fibrillation.
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Doravirine versus ritonavir-boosted darunavir in antiretroviral-naive adults with HIV-1 (DRIVE-FORWARD): 48-week results of a randomised, double-blind, phase 3, non-inferiority trial.
Molina, JM, Squires, K, Sax, PE, Cahn, P, Lombaard, J, DeJesus, E, Lai, MT, Xu, X, Rodgers, A, Lupinacci, L, et al
The lancet. HIV. 2018;(5):e211-e220
Abstract
BACKGROUND Doravirine is a novel non-nucleoside reverse transcriptase inhibitor (NNRTI) with a pharmacokinetic profile supporting once-daily dosing, and potent in-vitro activity against the most common NNRTI-resistant HIV-1 variants. We compared doravirine with ritonavir-boosted darunavir, when both were given with two nucleoside reverse transcriptase inhibitors (NRTIs), in adults with previously untreated HIV-1 infection. METHODS In this randomised, controlled, double-blind, multicentre, non-inferiority trial, adults with HIV-1 infection were screened and enrolled at 125 clinical centres in 15 countries. Eligible participants (aged ≥18 years) were naive to antiretroviral therapy with plasma HIV-1 RNA of at least 1000 copies per mL at screening. Participants who had previously been treated for a viral infection other than HIV-1, those taking immunosuppressive drugs, and individuals with active acute hepatitis were excluded. Participants were randomly assigned (1:1) via an interactive voice and web response system to receive oral doravirine 100 mg or darunavir 800 mg plus ritonavir 100 mg once daily, with two investigator-selected NRTIs (tenofovir and emtricitabine or abacavir and lamivudine) for up to 96 weeks. Randomisation was stratified by HIV-1 RNA measurements at screening (≤100 000 vs >100 000 copies per mL) and the NRTI pair. Study participants, funding institution staff, investigators, and study site personnel were masked to treatment group assignment. The primary efficacy endpoint was the proportion of participants achieving HIV-1 RNA of less than 50 copies per mL at week 48 defined by the US Food and Drug Administration snapshot algorithm, with non-inferiority established if the lower bound of the two-sided 95% CI for the treatment difference (doravirine minus darunavir) was greater than -10 percentage points. All participants who received at least one dose of study drug were included in the primary efficacy and safety analyses. This trial is active, but not recruiting, and is registered with ClinicalTrials.gov, number NCT02275780. FINDINGS Between Dec 1, 2014, and Oct 20, 2015, 1027 participants were screened for eligibility, of whom 769 participants were randomly assigned to treatment (385 with doravirine and 384 with ritonavir-boosted darunavir). 56 participants discontinued treatment in the doravirine group compared with 71 in the darunavir group, mostly due to loss to follow-up. 383 participants who received doravirine and 383 who received darunavir were included in the primary efficacy analyses. At week 48, 321 (84%) participants in the doravirine group and 306 (80%) in the darunavir group achieved plasma HIV-1 RNA of less than 50 copies per mL (difference 3·9%, 95% CI -1·6 to 9·4), indicating non-inferiority of the doravirine regimen. The most common study drug-related adverse events were diarrhoea (21 [5%] of 383 participants in the doravirine group and 49 [13%] of 383 participants in the darunavir group), nausea (25 [7%] vs 29 [8%]), and headache (23 [6%] vs ten [3%]). 18 participants (six [2%] of 383 participants in the doravirine group vs 12 [3%] of 383 participants in the darunavir group) discontinued treatment due to adverse events, which were considered drug-related in four (1%) participants in the doravirine group and 8 (2%) participants in the darunavir group. Serious adverse events occurred in 19 (5%) of 383 participants in the doravirine group and 23 (6%) of 383 in the darunavir roup, and were considered study-drug related in one (<1%) participant of each group. INTERPRETATION In treatment-naive adults with HIV-1 infection, doravirine combined with two NRTIs might offer a valuable treatment option for adults with previously untreated HIV-1 infection. FUNDING Merck & Co.
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Clinical Pharmacokinetics and Drug Interactions of Doravirine.
Wilby, KJ, Eissa, NA
European journal of drug metabolism and pharmacokinetics. 2018;(6):637-644
Abstract
Doravirine is a new HIV-1 non-nucleoside reverse transcriptase inhibitor that has demonstrated a good efficacy and safety profile in clinical trials. It has a therapeutic profile that makes it an attractive option for treatment of HIV-1 infection. As such, there has been an increase in the published literature regarding the pharmacokinetics of doravirine and potential for drug-drug interactions. This review aimed to identify pharmacokinetic literature pertaining to doravirine, used findings from the literature to summarize its pharmacokinetic profile, and finally evaluated literature describing actual and potential drug interactions. Review findings show doravirine is well-absorbed, exhibits moderate protein binding activity, and is extensively metabolized by cytochrome P450 enzymes (specifically CYP3A). It has an elimination half-life of 12-21 h. Gender, age, moderate hepatic impairment, and co-administration with food did not greatly alter doravirine's pharmacokinetic profile. Drug interaction studies have shown doravirine does not affect the pharmacokinetics of dolutegravir or atorvastatin but may have its pharmacokinetics altered by rifampicin (rifampin) and other rifamycins (CYP3A inducers) and ritonavir (CYP3A inhibitor). No clinically significant interactions were noted between doravirine and an antacid (aluminum-magnesium), pantoprazole, ledipasvir/sofosbuvir, or elbasvir/grazoprevir. Further study is needed to better understand doravirine's efficacy and safety profile when co-administered with other agents known to be CYP inducers or inhibitors.
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Molecular mechanism of seed dormancy release induced by fluridone compared with cod stratification in Notopterygium incisum.
Aihua, L, Shunyuan, J, Guang, Y, Ying, L, Na, G, Tong, C, Liping, K, Luqi, H
BMC plant biology. 2018;(1):116
Abstract
BACKGROUND Notopterygium incisum is an important Chinese medicinal plant. Its mature seeds have underdeveloped embryos and are physiological dormant. We found the seeds with full developed embryos can germinate after treated by fluridone (FL), an inhibitor of abscisic acid (ABA). In order to understand the molecular mechanisms underlying seed dormancy release by FL, we compared the transcriptomic changes in dormancy release induced by two different methods, FL and cold stratification (CS) in N. incisum. We further analyzed the gene expression patterns involved in seed germination and dormancy using quantitative reverse-transcription PCR. RESULTS RNA-sequence analysis revealed more dramatic changes in the transcriptomes of FL than those in CS, particularly for genes involved in the biosynthesis and regulation of gibberellins (GAs) and ABA. The down-regulation of ABA biosynthesis genes and the dramatic up-regulation of NiCYP707As, an ABA catabolic gene, contributed to the reduced ABA levels in FL. The increased GA3 levels in CS-treated seeds were due to the up-regulation of NiGA3OX. Both NiABI5 (a positive ABA regulator) and NiGAI (a negative regulator of GA) were down-regulated in FL and CS. The upregulation of strigolactones (SLs; the metabolites with the same precursor as ABA) biosynthesis and regulatory genes in both FL- and CS-treated seeds indicates that SLs contribute positively to seed dormancy release in N. incisum. CONCLUSIONS Our results indicated that FL- and CS-seed dormancy release possibly depends on two totally different mechanisms: alleviation of the effects of ABA and potentiation of the effects of GA, respectively. However, NiABI5 and NiGAI probably function as common factors integrating the effects of ABA and GA on seed dormancy release.
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Efficacy and Safety of Combined Oral Chelation With Deferiprone and Deferasirox in Children With β-Thalassemia Major: An Experience From North India.
Parakh, N, Chandra, J, Sharma, S, Dhingra, B, Jain, R, Mahto, D
Journal of pediatric hematology/oncology. 2017;(3):209-213
Abstract
OBJECTIVE A combination of desferrioxamine with either deferiprone (DFP) or deferasirox (DFX) for patients with β-thalassemia major who do not achieve negative iron balance with monotherapy has been studied widely. However, poor compliance resulting from the need for parentral administration of desferrioxamine and its cost necessicitates combining 2 oral chelators. METHODS A prospective study was conducted in patients with transfusion-dependent β-thalassemia major in a tertiary care center over 2 years. Patients on either DFP or DFX who were not improving on monotherapy over a long period and persistently maintaining serum ferritin >2500 µg/L were enrolled. Efficacy was assessed by serum ferritin levels assessed at 12 months and 2 years. Complete blood counts and liver and kidney function tests were monitored to assess the safety of the combination of drugs. RESULTS In total, 33 patients with a mean age of 12.67 years (7.5 to 17.5 y) and a mean ferritin of 4835.2394±1443.85 µg/L formed the study cohort.In total, 28 patients completed the 1-year study period; and 12 patients completed 2 years. Mean serum ferritin reduction at 1 and 2 years was 34.99%±18.13% (range, -34.36% to 56.17%) and 44.67%±13.78% (range, 22.17% to 62.74%), respectively. The combination therapy was well tolerated. CONCLUSIONS Combined oral chelation with DFP and DFX has better efficacy than either drug used alone. The combination of drugs was well tolerated and no new adverse effects were observed.
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Factors associated with non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with new-onset atrial fibrillation: Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II (ORBIT-AF II).
Steinberg, BA, Shrader, P, Thomas, L, Ansell, J, Fonarow, GC, Gersh, BJ, Hylek, E, Kowey, PR, Mahaffey, KW, O'Brien, EC, et al
American heart journal. 2017;:40-47
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BACKGROUND Several non-vitamin K antagonist oral anticoagulant (NOAC) alternatives to warfarin are available for stroke prevention in atrial fibrillation (AF). We aimed to describe the factors associated with selection of NOACs versus warfarin in patients with new onset AF. METHODS The ORBIT-AF II study is a national, US, prospective, observational, cohort study of anticoagulation treatment in patients with AF receiving NOACs or warfarin in the United States from 2013 to 2016. We measured factors associated with oral anticoagulant selection in 4,670 patients recently diagnosed with AF. RESULTS At baseline, 1,169 (25%) patients were started on warfarin and 3,501 (75%) on NOACs: of these latter, 259 (6%) were started on dabigatran, 1858 (40%) on rivaroxaban, and 1384 (30%) on apixaban. Those receiving NOACs were slightly younger patients (median age 71 vs 72, P<.0001); were less likely to have prior stroke (5.3% vs 8.6%; P<.0001) or prior bleeding (2.7% vs 4.4%; P=.005); had better kidney function (mean estimated glomerular filtration rate 91 mL/min vs 80 mL/min, P<.0001); and had fewer patients at high stroke risk (CHA2DS2-VASc score [Congestive heart failure, Hypertension, Age ≥75years, Diabetes mellitus, Prior stroke, transient ischemic attack {TIA}, or thromboembolism,Vascular disease, Age 65-74years, Sex category {female}] ≥2 in 86% vs 93%; P<.0001). In multivariable analysis, factors associated with NOAC selection versus warfarin included renal function, prior stroke or valve replacement, rhythm control AF management strategy, treatment by a cardiologist, and higher patient education level. CONCLUSIONS In contemporary clinical practice, up to three-fourths of patients with new-onset AF are now initially treated with a NOAC for stroke prevention. Those selected for NOAC treatment had lower stroke and bleeding risk profiles, were more likely treated by cardiologists, and had higher socioeconomic status. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01701817.
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Adherence to Rivaroxaban, Dabigatran, and Apixaban for Stroke Prevention for Newly Diagnosed and Treatment-Naive Atrial Fibrillation Patients: An Update Using 2013-2014 Data.
Brown, JD, Shewale, AR, Talbert, JC
Journal of managed care & specialty pharmacy. 2017;(9):958-967
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BACKGROUND Few studies have assessed adherence to non-vitamin K antagonist oral anticoagulants (NOACs), especially using contemporary data now that multiple NOACs are available. OBJECTIVE To compare adherence and treatment patterns among NOACs for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). METHODS Incident and treatment-naive NVAF patients were identified during 2013-2014 from a large claims database in this retrospective cohort study. Patients were included who initiated rivaroxaban, dabigatran, or apixaban within 30 days after diagnosis. Adherence to the index medication and adherence to any oral anticoagulant was assessed using the proportion of days covered (PDC) at 3, 6, and 9 months. The number of switches and gaps in therapy were also evaluated. Analyses were stratified by stroke risk scores, and a logistic regression model was used to control for factors that may predict high adherence. RESULTS Dabigatran had lower adherence (PDC = 0.76, 0.64, 0.57) compared with rivaroxaban (PDC = 0.83, 0.73, 0.66; P < 0.001) and apixaban (PDC = 0.82, 0.72, 0.66; P < 0.001) at 3, 6, and 9 months of follow-up and twice the number of switches to either other anticoagulants or antiplatelet therapy. Adherence was higher overall as stroke risk increased, and dabigatran had consistently lower adherence compared with the other NOACs. Multivariable logistic regression predicting PDC ≥ 0.80 showed rivaroxaban users with higher odds of high adherence compared with dabigatran or rivaroxaban across all time periods. Adjusted analyses showed that increasing age and comorbid hypertension and diabetes were associated with higher adherence. CONCLUSIONS In this real-world analysis of adherence to NOACs, rivaroxaban and apixaban had favorable unadjusted adherence profiles compared with dabigatran, while rivaroxaban users had higher odds of high adherence (PDC ≥ 0.80) among the NOACs in adjusted analyses. Clinicians and managed care organizations should consider the implications of lower adherence on clinical outcomes and quality assessment. DISCLOSURES This project was supported by the National Center for Advancing Translational Sciences, National Institutes of Health, through grant number UL1TR000117. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. The authors have nothing to disclose. Study concept and design were contributed by Brown and Shewale. Brown and Talbert collected the data, and data analysis was performed primarily by Brown, along with Shewale and Talbert. The manuscript was written primarily by Brown, along with Shewale, and revised by all the authors.