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Gurbel PA, Bliden KP, Butler K, Tantry US, Gesheff T, Wei C, Teng R, Antonino MJ, Patil SB, Karunakaran A, Kereiakes DJ, Parris C, Purdy D, Wilson V, Ledley GS, Storey RF. Randomized double-blind assessment of the ONSET and OFFSET of the antiplatelet effects of ticagrelor versus clopidogrel in patients with stable coronary artery disease: the ONSET/OFFSET study. Circulation 2009; 120:2577-85. [PMID: 19923168 DOI: 10.1161/circulationaha.109.912550] [Citation(s) in RCA: 898] [Impact Index Per Article: 56.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Ticagrelor is the first reversibly binding oral P2Y(12) receptor antagonist. This is the first study to compare the onset and offset of platelet inhibition (IPA) with ticagrelor using the PLATO (PLATelet inhibition and patient Outcomes) trial loading dose (180 mg) with a high loading dose (600 mg) of clopidogrel. METHODS AND RESULTS In a multicenter, randomized, double-blind study, 123 patients with stable coronary artery disease who were taking aspirin therapy (75 to 100 mg/d) received ticagrelor (180-mg load, 90-mg BID maintenance dose [n=57]), clopidogrel (600-mg load, 75-mg/d maintenance dose [n=54]), or placebo (n=12) for 6 weeks. Greater IPA (20 micromol/L ADP, final extent) occurred with ticagrelor than with clopidogrel at 0.5, 1, 2, 4, 8, and 24 hours after loading and at 6 weeks (P<0.0001 for all); by 2 hours after loading, a greater proportion of patients achieved >50% IPA (98% versus 31%, P<0.0001) and >70% IPA (90% versus 16%, P<0.0001) in the ticagrelor group than in the clopidogrel group, respectively. A faster offset occurred with ticagrelor than with clopidogrel (4-to-72-hour slope [% IPA/h] -1.04 versus -0.48, P<0.0001). At 24 hours after the last dose, mean IPA was 58% for ticagrelor versus 52% for clopidogrel (P=NS). IPA for ticagrelor on day 3 after the last dose was comparable to clopidogrel at day 5; IPA on day 5 for ticagrelor was similar to clopidogrel on day 7 and did not differ from placebo (P=NS). CONCLUSIONS Ticagrelor achieved more rapid and greater platelet inhibition than high-loading-dose clopidogrel; this was sustained during the maintenance phase and was faster in offset after drug discontinuation.
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Research Support, Non-U.S. Gov't |
16 |
898 |
2
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Gurbel PA, Bliden KP, Butler K, Antonino MJ, Wei C, Teng R, Rasmussen L, Storey RF, Nielsen T, Eikelboom JW, Sabe-Affaki G, Husted S, Kereiakes DJ, Henderson D, Patel DV, Tantry US. Response to ticagrelor in clopidogrel nonresponders and responders and effect of switching therapies: the RESPOND study. Circulation 2010; 121:1188-99. [PMID: 20194878 DOI: 10.1161/circulationaha.109.919456] [Citation(s) in RCA: 354] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The antiplatelet effects of the Platelet Inhibition and Patient Outcomes (PLATO) trial dose of ticagrelor in patients nonresponsive to clopidogrel and after they switch agents are unknown. METHODS AND RESULTS Patients with stable coronary artery disease on aspirin therapy received a 300-mg clopidogrel load; nonresponders were identified by light transmittance aggregometry. In a 2-way crossover design, nonresponders (n=41) and responders (n=57) randomly received clopidogrel (600 mg/75 mg once daily) or ticagrelor (180 mg/90 mg twice daily) for 14 days during period 1. In period 2, all nonresponders switched treatment; half of the responders continued the same treatment, whereas the others switched treatment. Inhibition of platelet aggregation was higher in nonresponders treated with ticagrelor compared with clopidogrel (P<0.05). Treatment with ticagrelor among nonresponders resulted in a >10%, >30%, and >50% decrease in platelet aggregation from baseline in 100%, 75%, and 13% of patients, respectively. Platelet aggregation fell from 59+/-9% to 35+/-11% in patients switched from clopidogrel to ticagrelor and increased from 36+/-14% to 56+/-9% in patients switched from ticagrelor to clopidogrel (P<0.0001 for both). Platelet reactivity was below the cut points previously associated with ischemic risk measured by light transmittance aggregometry, VerifyNow P2Y(12) assay, and vasodilator-stimulated phosphoprotein phosphorylation in 98% to 100% of patients after ticagrelor therapy versus 44% to 76% of patients after clopidogrel therapy. CONCLUSIONS Ticagrelor therapy overcomes nonresponsiveness to clopidogrel, and its antiplatelet effect is the same in responders and nonresponders. Nearly all clopidogrel nonresponders and responders treated with ticagrelor will have platelet reactivity below the cut points associated with ischemic risk. Clinical Trial Registration- http://www.clinicaltrials.gov. Unique Identifier: NCT00642811.
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Research Support, Non-U.S. Gov't |
15 |
354 |
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Teng R, Oliver S, Hayes MA, Butler K. Absorption, distribution, metabolism, and excretion of ticagrelor in healthy subjects. Drug Metab Dispos 2010; 38:1514-21. [PMID: 20551239 DOI: 10.1124/dmd.110.032250] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ticagrelor [(1S,2S,3R,5S)-3-[7-[[(1R,2S)-2-(3,4-difluorophenyl) cyclopropyl]amino]-5-(propylthio)-3H-1,2,3-triazolo[4,5-d]pyrimidin-3-yl]-5-(2-hydroxyethoxy)-1,2-cyclopentanediol)] is a reversibly binding oral P2Y(12) receptor antagonist in development for the prevention of thrombotic events in patients with acute coronary syndromes. The pharmacokinetics, metabolism, and excretion of ticagrelor were investigated over 168 h in six healthy male subjects receiving a single oral suspension dose of 200 mg of [(14)C]ticagrelor. Ticagrelor was rapidly absorbed with a maximum plasma concentration at 1.5 h. The major active metabolite, AR-C124910XX, is formed by O-deethylation. Exposure to AR-C124910XX was 29% of peak and 40% of overall exposure to ticagrelor. In most subjects, radioactivity was undetectable in plasma after 20 h and whole blood after 12 h (half-life values of 6.3 and 4.6 h, respectively). The ratio of radioactivity in plasma to whole blood was 1.69, suggesting that ticagrelor and its metabolites are largely restricted to the plasma space. Mean radioactivity recovery was 26.5% in urine and 57.8% in feces. Major circulating components in the plasma and feces were identified as ticagrelor and AR-C124910XX, whereas in urine the major components were metabolite M5 (AR-C133913XX) and its glucuronide conjugate M4. Levels of unchanged ticagrelor and AR-C124910XX were <0.05% in the urine, indicating that renal clearance of ticagrelor and AR-C124910XX is of minor importance. Interindividual variability was small in both urine and fecal extracts with only small quantitative differences. All 10 of the metabolites were fully or partially characterized and a full biotransformation pathway was proposed for ticagrelor, in which oxidative loss of the hydroxyethyl side chain from ticagrelor forms AR-C124910XX and a second oxidative pathway leads to N-dealkylation of ticagrelor, forming AR-C133913XX.
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Clinical Trial |
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204 |
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Storey RF, Bliden KP, Patil SB, Karunakaran A, Ecob R, Butler K, Teng R, Wei C, Tantry US, Gurbel PA. Incidence of Dyspnea and Assessment of Cardiac and Pulmonary Function in Patients With Stable Coronary Artery Disease Receiving Ticagrelor, Clopidogrel, or Placebo in the ONSET/OFFSET Study. J Am Coll Cardiol 2010; 56:185-93. [DOI: 10.1016/j.jacc.2010.01.062] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/12/2010] [Accepted: 01/18/2010] [Indexed: 11/27/2022]
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133 |
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Williams-Herman D, Johnson J, Teng R, Golm G, Kaufman KD, Goldstein BJ, Amatruda JM. Efficacy and safety of sitagliptin and metformin as initial combination therapy and as monotherapy over 2 years in patients with type 2 diabetes. Diabetes Obes Metab 2010; 12:442-51. [PMID: 20415693 DOI: 10.1111/j.1463-1326.2010.01204.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AIM To assess the 104-week efficacy and safety of sitagliptin and metformin as initial combination therapy and as monotherapy in patients with type 2 diabetes and inadequate glycaemic control (HbA(1c) 7.5-11%) on diet and exercise. METHODS This study was a 50-week, double-blind extension of a 54-week, randomized, double-blind, factorial study of the initial combination of sitagliptin and metformin, metformin monotherapy and sitagliptin monotherapy (104 weeks total duration). Patients assigned to active therapy in the 54-week base study remained on those treatments in the extension study: sitagliptin 50 mg b.i.d. + metformin 1000 mg b.i.d. (higher dose combination), sitagliptin 50 mg b.i.d. + metformin 500 mg b.i.d. (lower dose combination), metformin 1000 mg b.i.d. (higher dose), metformin 500 mg b.i.d. (lower dose) and sitagliptin 100 mg q.d. Patients randomized to receive the sequence of placebo/metformin were switched, in a blinded manner, from placebo to metformin monotherapy uptitrated to 1000 mg b.i.d. beginning at week 24 and remained on higher dose metformin through the extension. RESULTS Amongst patients who entered the extension study without having initiated glycaemic rescue therapy, least-squares mean changes in HbA(1c) from baseline at week 104 were -1.7% (higher dose combination), -1.4% (lower dose combination), -1.3% (higher dose), -1.1% (lower dose) and -1.2% (sitagliptin). The proportions of patients with an HbA(1c) <7% at week 104 were 60% (higher dose combination), 45% (lower dose combination), 45% (higher dose), 28% (lower dose) and 32% (sitagliptin). Fasting and postmeal measures of glycaemic control and beta-cell function improved in all groups, with glycaemic responses generally maintained over the 104-week treatment period. The incidence of hypoglycaemia was low across all groups. The incidences of gastrointestinal adverse experiences were generally lower in the sitagliptin group and similar between the metformin monotherapy and combination groups. CONCLUSIONS Initial combination therapy with sitagliptin and metformin and monotherapy with either drug alone provided substantial and sustained glycaemic improvements and were well tolerated over 104 weeks in patients with type 2 diabetes.
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Randomized Controlled Trial |
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132 |
6
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Butler K, Teng R. Pharmacokinetics, pharmacodynamics, safety and tolerability of multiple ascending doses of ticagrelor in healthy volunteers. Br J Clin Pharmacol 2011; 70:65-77. [PMID: 20642549 DOI: 10.1111/j.1365-2125.2010.03669.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT The antiplatelet agent clopidogrel is currently the recommended treatment for acute coronary syndrome (ACS). Inhibition of platelet aggregation (IPA) with clopidogrel is insufficient, which increases the risk for recurrent ischaemic events. Therefore, there is a need for antiplatelet agents with improved IPA. Ticagrelor (AZD6140) is a new antiplatelet agent in clinical development for reduction of thrombotic events in patients with ACS. WHAT THIS STUDY ADDS This study assesses the optimal dosing schedule for ticagrelor in healthy volunteers and compares the degree of IPA with clopidogrel. Our findings illustrate that the pharmacokinetics of ticagrelor are predictable and are associated with consistent inhibition of platelet activity. IPA with ticagrelor was greater and better sustained at high levels with twice daily ticagrelor than once daily regimens. AIM To determine the pharmacokinetics, pharmacodynamics, safety and tolerability of multiple oral doses of ticagrelor, a P2Y(12) receptor antagonist, in healthy volunteers. METHODS This was a randomized, single-blind, placebo-controlled, ascending dose study. Thirty-two subjects received ticagrelor 50-600 mg once daily or 50-300 mg twice daily or placebo for 5 days at three dose levels in two parallel groups. Another group of 16 subjects received a clopidogrel 300 mg loading dose then 75 mg day(-1), or placebo for 14 days. RESULTS Ticagrelor was absorbed with median t(max) 1.5-3 h, exhibiting predictable pharmacokinetics over the 50-600 mg dose range. Mean C(max) and AUC for ticagrelor and its main metabolite, AR-C124910XX, increased approximately dose-proportionately (approximately 2.2- to 2.4-fold with a twofold dose increase) over the dose range. Inhibition of platelet aggregation (IPA) with ticagrelor was greater and better sustained at high levels with ticagrelor twice daily vs. once daily regimens. Throughout dosing, more consistent IPA was observed at doses > or = 300 mg once daily and > or = 100 mg twice daily compared with clopidogrel. Mean IPA with ticagrelor > or = 100 mg twice daily was greater and less variable (93-100%, range 65-100%) than with clopidogrel (77%, range 11-100%) at trough concentrations. No safety or tolerability issues were identified. CONCLUSIONS Multiple dosing provided predictable pharmacokinetics of ticagrelor and its metabolite over the dose range of 50-600 mg once daily and 50-300 mg twice daily with C(max) and AUC(0,t) increasing approximately dose-proportionally. Greater and more consistent IPA with ticagrelor at doses > or = 100 mg twice daily and > or = 300 mg once daily were observed than with clopidogrel. Ticagrelor at doses up to 600 mg day(-1) was well tolerated.
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Randomized Controlled Trial |
14 |
111 |
7
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Abstract
Despite advancements in treatments for acute coronary syndromes over the last 10 years, they continue to be life-threatening disorders. Currently, the standard of treatment includes dual antiplatelet therapy consisting of aspirin plus a P2Y12 receptor antagonist. The thienopyridine class of P2Y12 receptor antagonists, clopidogrel and prasugrel, have demonstrated efficacy. However, their use is associated with several limitations, including the need for metabolic activation and irreversible P2Y12 receptor binding causing prolonged recovery of platelet function. In addition, response to clopidogrel is variable and efficacy is reduced in patients with certain genotypes. Although prasugrel is a more consistent inhibitor of platelet aggregation than clopidogrel, it is associated with an increased risk of life-threatening and fatal bleeding. Ticagrelor is an oral antiplatelet agent of the cyclopentyltriazolopyrimidine class and also acts through the P2Y12 receptor. In contrast to clopidogrel and prasugrel, ticagrelor does not require metabolic activation and binds rapidly and reversibly to the P2Y12 receptor. In light of new data, this review provides an update on the pharmacokinetic, pharmacodynamic and pharmacogenetic profiles of ticagrelor in different study populations. Recent studies report that no dose adjustment for ticagrelor is required on the basis of age, gender, ethnicity, severe renal impairment or mild hepatic impairment. The non-P2Y12 actions of ticagrelor are reviewed, showing indirect positive effects on cellular adenosine concentration and biological activity, by inhibition of equilibrative nucleoside transporter-1 independently of the P2Y12 receptor. CYP2C19 and ABCB1 genotypes do not appear to influence ticagrelor pharmacodynamics. A summary of drug interactions is also presented.
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Review |
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98 |
8
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Varenhorst C, Eriksson N, Johansson Å, Barratt BJ, Hagström E, Åkerblom A, Syvänen AC, Becker RC, James SK, Katus HA, Husted S, Steg PG, Siegbahn A, Voora D, Teng R, Storey RF, Wallentin L. Effect of genetic variations on ticagrelor plasma levels and clinical outcomes. Eur Heart J 2015; 36:1901-12. [DOI: 10.1093/eurheartj/ehv116] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/19/2015] [Indexed: 11/15/2022] Open
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10 |
82 |
9
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Teng R, Harris SC, Nix DE, Schentag JJ, Foulds G, Liston TE. Pharmacokinetics and safety of trovafloxacin (CP-99,219), a new quinolone antibiotic, following administration of single oral doses to healthy male volunteers. J Antimicrob Chemother 1995; 36:385-94. [PMID: 8522468 DOI: 10.1093/jac/36.2.385] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Trovafloxacin (CP-99,219) is a new fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and Gram-negative bacteria. The pharmacokinetics and safety of trovafloxacin were characterised in healthy male volunteers after administration of single oral doses of 30, 100, 300, 600 and 1000 mg. trovafloxacin was rapidly absorbed and serum concentrations reached a maximum approximately 1 h after dosing. The corresponding mean Cmax values (mean +/- SD) were 0.3 +/- 0.0, 1.5 +/- 0.5, 4.4 +/- 1.1, 6.6 +/- 1.4 and 10.1 +/- 0.5 mg/L. Terminal-phase half-life was independent of dose, with an overall mean of 9.9 +/- 2.5 h. Generally, Cmax and AUC0-infinity increased linearly with dose. Less than 10% of the administered dose was recovered unchanged in urine. Over the dosing range, trovafloxacin renal clearance was fairly constant, averaging 0.67 +/- 0.36 L/h. Trovafloxacin binding to serum proteins was moderate (70%). Trovafloxacin was well tolerated at doses of 300 mg or below. There were no significant changes in the clinical chemistry or haematology parameters evaluated over the entire dosing range.
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Clinical Trial |
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68 |
10
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Fehn U, Teng R, Elmore D, Kubik PW. Isotopic composition of osmium in terrestrial samples determined by accelerator mass spectrometry. Nature 1986. [DOI: 10.1038/323707a0] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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54 |
11
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Teng R, Liston TE, Harris SC. Multiple-dose pharmacokinetics and safety of trovafloxacin in healthy volunteers. J Antimicrob Chemother 1996; 37:955-63. [PMID: 8737145 DOI: 10.1093/jac/37.5.955] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The multiple-dose pharmacokinetics and safety of trovafloxacin (CP-99,219), a new fluoroquinolone antibacterial agent, were evaluated in healthy male volunteers. Trovafloxacin was administered orally at 100 or 300 mg as a single dose followed by a 3 day washout period, and then was dosed once-daily for 14 consecutive days. Multiple serum and urine samples were collected on days 1 and 17 and were analysed for trovafloxacin concentrations by HPLC-UV. Following single doses, the mean Cmax values (mean +/- S.D.) were 1.0 +/- 0.3 and 2.9 +/- 0.4 mg/L for the 100 and 300 mg, respectively; those after 14-day consecutive daily dosing (day 17) were 1.1 +/- 0.2 and 3.3 +/- 0.5 mg/L, respectively. Trovafloxacin was rapidly absorbed and reached Cmax approximately 1 h after dosing. The mean values of T1/2 associated with the 100 and 300 mg doses were 9.2 +/- 1.2 on day 1 and 10.5 +/- 0.7 h on day 17; those after the 300 mg doses were 10.5 +/- 1.4 and 12.2 +/- 1.9 h, respectively. The cumulative urinary recovery of unchanged drug averaged 5.3% of the administered dose. Trovafloxacin renal clearance was 0.43 +/- 0.09 L/h. The free fraction of the drug in plasma was 23.8 +/- 6.1%. The renal clearance, half-life and unbound fraction did not change over the course of 2 weeks of multiple dosing. Steady-state serum concentrations were attained by the third daily dose, with approximately 1.3-fold accumulation. Both doses of trovafloxacin were well tolerated, and no significant changes in any laboratory safety parameters were detected. This study shows that the pharmacokinetics of trovafloxacin are linear and stationary and that steady-state serum concentrations above the MICs for most susceptible pathogens attained.
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Clinical Trial |
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12
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Vincent J, Venitz J, Teng R, Baris BA, Willavize SA, Polzer RJ, Friedman HL. Pharmacokinetics and safety of trovafloxacin in healthy male volunteers following administration of single intravenous doses of the prodrug, alatrofloxacin. J Antimicrob Chemother 1997; 39 Suppl B:75-80. [PMID: 9222074 DOI: 10.1093/jac/39.suppl_2.75] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Fifteen healthy male volunteers (in four groups) received single 1 h i.v. infusions of alatrofloxacin (CP-116,517) equivalent to 30, 100, 200 or 300 mg of its active metabolite, trovafloxacin (CP-99,219). Blood and urine were sampled over 73 and 72 h, respectively, and plasma levels of alatrofloxacin and serum concentrations of trovafloxacin were determined by HPLC with UV detection. Alatrofloxacin was not detectable in plasma samples collected after the end of infusion, indicating rapid conversion to trovafloxacin. Maximum serum concentrations of trovafloxacin were achieved at the end of the infusions. Mean maximum plasma trovafloxacin concentrations for the four alatrofloxacin doses were 0.4, 1.8, 2.3 and 4.3 mg/L. The mean area under the concentration-time curve increased proportionally with the dose. The elimination half-life (T(1/2)) for trovafloxacin was independent of the dose and the mean T(1/2)s for the 100, 200 and 300 mg equivalent doses of alatrofloxacin were 10.4, 12.3 and 10.8 h. Approximately 10% of the equivalent dose was recovered as unchanged trovafloxacin in the urine. No clinical adverse or laboratory reactions were associated with i.v. administration of alatrofloxacin and its conversion to trovafloxacin. These results indicate that alatrofloxacin is rapidly converted to trovafloxacin and that the pharmacokinetic parameters for this new fluoroquinolone after i.v. administration of its parent compound are similar to those reported after oral administration of equivalent trovafloxacin doses.
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Clinical Trial |
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13
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Sarich TC, Teng R, Peters GR, Wollbratt M, Homolka R, Svensson M, Eriksson UG. No influence of obesity on the pharmacokinetics and pharmacodynamics of melagatran, the active form of the oral direct thrombin inhibitor ximelagatran. Clin Pharmacokinet 2003; 42:485-92. [PMID: 12739986 DOI: 10.2165/00003088-200342050-00006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND Ximelagatran, an oral direct thrombin inhibitor, is currently in clinical development for the prevention and treatment of thromboembolic disease. Following oral administration, ximelagatran undergoes rapid bioconversion to its active form, melagatran, via two minor intermediates. Obesity, defined as body mass index (BMI) >30 kg/m(2), is a recognised risk factor for thrombosis. There is potential for differences in the pharmacokinetics and pharmacodynamics of drugs administered to obese versus non-obese patients, and some drugs may require alternative administration strategies in obese patients. OBJECTIVE To investigate the effect of obesity on the pharmacokinetics and pharmacodynamics of melagatran after oral administration of ximelagatran. DESIGN AND PARTICIPANTS This was an open-label, single-dose, group-matched study in which obese subjects (BMI 32-39 kg/m(2); six male and six female; age 21-40 years) were matched by sex and age (+/-2 years) with non-obese subjects (BMI 21-26 kg/m(2); six male and six female; aged 21-39 years). Each subject received a single oral dose of ximelagatran 24mg. Blood samples for determination of plasma concentrations of melagatran and activated partial thromboplastin times (APTT; a marker of melagatran pharmacodynamics) were collected up to 12 hours after administration. RESULTS There were no statistically significant differences in the pharmacokinetic properties of melagatran between obese and non-obese subjects. Values of area under the melagatran plasma concentration-time curve, maximum plasma concentration (C(max)), time at which C(max) occurred and terminal elimination half-life were approximately 1 micromol. h/L, 0.2 micromol/L, 2 hours and 3 hours in both obese and non-obese subjects, respectively. In addition, there was no statistically significant difference between the obese and non-obese subjects in the amount of ximelagatran, melagatran or the minor intermediates ethyl-melagatran and melagatran hydroxyamidine excreted in urine. When relating the prolongation of APTT ratio to the square root of plasma concentration of melagatran and obesity status (no/yes), no statistically significant interaction between plasma concentration and obesity status was observed. Ximelagatran was well tolerated in both obese and non-obese subjects, and no bleeding events or serious adverse events occurred. CONCLUSIONS No differences in the pharmacokinetics or pharmacodynamics of melagatran were detected between obese and non-obese subjects after oral administration of ximelagatran, suggesting that dose adjustment of ximelagatran in obesity (BMI up to 39 kg/m(2)) is not necessary.
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Clinical Trial |
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14
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Teng R, Mitchell PD, Butler KA. Pharmacokinetic interaction studies of co-administration of ticagrelor and atorvastatin or simvastatin in healthy volunteers. Eur J Clin Pharmacol 2012; 69:477-87. [PMID: 22922682 DOI: 10.1007/s00228-012-1369-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Interactions between ticagrelor and atorvastatin or simvastatin were investigated in two-way crossover studies. METHODS Both studies were open-label for statin; the atorvastatin study was placebo-controlled for ticagrelor. For atorvastatin, volunteers (n = 24) received ticagrelor (loading dose 270 mg; 90 mg twice daily, 7 days) or placebo, plus atorvastatin calcium (80 mg; day 5). For simvastatin, volunteers (n = 24) received simvastatin 80 mg, or ticagrelor (loading dose 270 mg; 180 mg twice daily, 7 days) plus simvastatin (80 mg; day 5). In each study, volunteers received the alternate treatment after washout (≥ 7 days). RESULTS Ticagrelor increased mean atorvastatin maximum plasma concentration (C(max)) and area under the plasma concentration-time curve from zero to infinity (AUC) by 23 % and 36 %, respectively. Simvastatin C(max) and AUC were increased by 81 % and 56 % with ticagrelor. Ticagrelor also increased C(max) and AUC of analysed atorvastatin metabolites by 13-55 % and 32-67 %, respectively, and simvastatin acid by 64 % and 52 %, respectively. Co-administration of ticagrelor with each statin was well tolerated. CONCLUSIONS Exposure to ticagrelor and its active metabolite, AR-C124910XX, was generally unchanged by a single dose of either statin, except for a minor increase in ticagrelor C(max) in the presence of simvastatin. Effects of ticagrelor on atorvastatin pharmacokinetics were modest and unlikely clinically relevant, while with simvastatin, changes were slightly larger, and simvastatin doses >40 mg with ticagrelor should be avoided.
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Research Support, Non-U.S. Gov't |
13 |
48 |
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Trachtman H, Hainer JW, Sugg J, Teng R, Sorof JM, Radcliffe J. Efficacy, safety, and pharmacokinetics of candesartan cilexetil in hypertensive children aged 6 to 17 years. J Clin Hypertens (Greenwich) 2009; 10:743-50. [PMID: 19090875 DOI: 10.1111/j.1751-7176.2008.00022.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This 4-week randomized, double blind, placebo-controlled study (N=240), 1-year open label trial (N=233), and single-dose pharmacokinetic study (N=22) evaluated candesartan cilexetil (3 doses) in hypertensive children aged 6 to 17 years. Seventy-one percent were 12 years of age or older, 71% were male, and 47% were black. Systolic (SBP)/diastolic (DBP) blood pressure declined 8.6/4.8-11.2/8.0 mm Hg with candesartan and 3.7/1.8 mm Hg with placebo (P<.01 compared to placebo for SBP and for the mid and high doses for DBP; placebo-corrected 4.9/3.0-7.5/6.2 mm Hg). The slopes for dose were not, however, different from zero (P>.05). The response rate (SBP and DBP <95th percentile) after 1 year was 53%. The pharmacokinetic profiles in 6- to 12- and 12- to 17-year-olds were similar and were comparable to adults. Eight candesartan patients discontinued treatment because of an adverse event. Candesartan is an effective, well-tolerated antihypertensive agent for children aged 6 to 17 years and has a pharmacokinetic profile that is similar to that in adults.
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Research Support, Non-U.S. Gov't |
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Husted SE, Storey RF, Bliden K, Tantry US, Høimark L, Butler K, Wei C, Teng R, Gurbel PA. Pharmacokinetics and pharmacodynamics of ticagrelor in patients with stable coronary artery disease: results from the ONSET-OFFSET and RESPOND studies. Clin Pharmacokinet 2012; 51:397-409. [PMID: 22515556 DOI: 10.2165/11599830-000000000-00000] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND AND OBJECTIVES Ticagrelor, the first reversibly binding oral P2Y(12) receptor antagonist, improves outcomes in patients with acute coronary syndromes (ACS) compared with clopidogrel. In the ONSET-OFFSET study (parallel group trial) and the RESPOND study (crossover trial), the pharmacodynamic effects of ticagrelor were compared with clopidogrel in patients with coronary artery disease (CAD). We now report the pharmacokinetic analyses of ticagrelor, and the exposure-inhibition of platelet aggregation (IPA) relationships from these studies. PATIENTS AND METHODS Patients were treated with ticagrelor (180 mg loading dose, 90 mg twice daily maintenance dose) or clopidogrel (600 mg loading dose, 75 mg once daily maintenance dose) in addition to aspirin (acetylsalicylic acid) [75-100 mg once daily]. Ticagrelor administration was for 6 weeks in ONSET-OFFSET. In RESPOND, ticagrelor was given for 14 days before or after 2 weeks of clopidogrel in patients classified as clopidogrel responders or non-responders. Pharmacokinetics and IPA were evaluated following the loading and last maintenance doses. Exposure-IPA relationships were evaluated using a sigmoid maximum effect (E(max)) model. OUTCOME MEASURES The outcome measures were ticagrelor and AR-C124910XX (active metabolite) pharmacokinetics and exposure-IPA relationships in both trials, including the effect of prior clopidogrel exposure, and effects in clopidogrel responders and non-responders in RESPOND. RESULTS In ONSET-OFFSET, maximum (peak) plasma concentration (C(max)), time to C(max) (t(max)) and area under the plasma concentration-time curve from time 0 to 8 hours (AUC(8)) for ticagrelor were 733 ng/mL, 2.0 hours and 4130 ng · h/mL, respectively; and for AR-C124910XX were 210 ng/mL, 2.1 hours and 1325 ng · h/mL, respectively. E(max) estimates were IPA >97%. Trough plasma ticagrelor (305 ng/mL) and AR-C124910XX (121 ng/mL) concentrations were 5.2 and 7.7 times higher than respective concentration producing 50% of maximum effect (EC(50)) estimates. In RESPOND, ticagrelor mean C(max) and AUC(8) following 2-week dosing were comparable between clopidogrel responders (724 ng/mL and 3983 ng · h/mL, respectively) and non-responders (764 ng/mL and 3986 ng · h/mL, respectively). Pharmacokinetics of ticagrelor were unaffected by prior clopidogrel dosing. E(max) estimates were IPA >96% for both responders and non-responders. Trough plasma concentrations were sufficient to achieve high IPA. CONCLUSIONS Ticagrelor pharmacokinetics in stable CAD patients were comparable to previous findings in stable atherosclerotic and ACS patients, and were not affected by prior clopidogrel exposure or clopidogrel responsiveness. Ticagrelor effectively inhibited platelet aggregation, and trough plasma concentrations of ticagrelor and AR-C124910XX were sufficient to result in high IPA in stable CAD patients.
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Research Support, Non-U.S. Gov't |
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Yoon KH, Shockey GR, Teng R, Golm GT, Thakkar PR, Meehan AG, Williams-Herman DE, Kaufman KD, Amatruda JM, Steinberg H. Effect of initial combination therapy with sitagliptin, a dipeptidyl peptidase-4 inhibitor, and pioglitazone on glycemic control and measures of β-cell function in patients with type 2 diabetes. Int J Clin Pract 2011; 65:154-64. [PMID: 21235696 DOI: 10.1111/j.1742-1241.2010.02589.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM/HYPOTHESIS To assess the safety and efficacy of initial combination therapy with sitagliptin and pioglitazone compared with pioglitazone monotherapy in drug-naïve patients with type 2 diabetes. METHODS A total of 520 patients were randomised to initial combination therapy with sitagliptin 100 mg q.d. and pioglitazone 30 mg q.d. or pioglitazone 30 mg q.d. monotherapy for 24 weeks. RESULTS Initial combination therapy with sitagliptin and pioglitazone led to a mean reduction from baseline in A1C of -2.4% compared with -1.5% for pioglitazone monotherapy (p<0.001). Mean reductions from baseline were greater in patients with a baseline A1C≥10% (-3.0% with combination therapy vs. -2.1% with pioglitazone monotherapy) compared with patients with a baseline A1C<10% (-2.0% with combination therapy vs. -1.1% with pioglitazone monotherapy). Sixty percent of patients in the combination therapy group vs. 28% in the pioglitazone monotherapy group had an A1C of <7% at week 24 (p<0.001). Fasting plasma glucose decreased by -63.0 mg/dl (-3.5 mmol/l) in the combination therapy group compared with -40.2 mg/dl (-2.2 mmol/l) for pioglitazone monotherapy (p<0.001), and 2-h post meal glucose decreased by -113.6 mg/dl (-6.3 mmol/l) with combination therapy compared with -68.9 mg/dl (-3.8 mmol/l) for pioglitazone monotherapy (p<0.001). Measures related to β-cell function also improved significantly with combination therapy compared with pioglitazone monotherapy. Combination therapy was generally well-tolerated compared with pioglitazone monotherapy, with similar incidences of hypoglycemia (1.1% and 0.8%, respectively), gastrointestinal adverse events (5.7% and 6.9%, respectively), and oedema (2.7% and 3.5%, respectively). CONCLUSION/INTERPRETATION Initial combination therapy with sitagliptin and pioglitazone substantially improved glycemic control and was generally well-tolerated compared with pioglitazone monotherapy.
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Multicenter Study |
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Teng R. Pharmacokinetic, Pharmacodynamic and Pharmacogenetic Profile of the Oral Antiplatelet Agent Ticagrelor. Clin Pharmacokinet 2012; 51:305-18. [DOI: 10.2165/11630960-000000000-00000] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Teng R, Yokohata K, Utsunomiya N, Takahata S, Nabae T, Tanaka M. Endoscopic retrograde cholangiopancreatography in infants and children. J Gastroenterol 2000; 35:39-42. [PMID: 10632539 DOI: 10.1007/pl00009974] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A single institutional experience with endoscopic retrograde cholangiopancreatography (ERCP) in pediatric patients was reviewed, focusing on the method of anesthesia, choice of an endoscope, indications, and complications. The medical records of 50 ERCPs performed in 42 infants and children (14 male and 28 female) were reviewed retrospectively. The patients' ages ranged from 57 days to 15 years. Forty-four ERCPs were diagnostic and 6 were therapeutic, including incision of choledochocele, and sphincterotomy and extraction of pancreatic stones. All procedures were successful. The most common indication for ERCP was to evaluate congenital biliary dilatation, in 28 patients (67%). Mild cholangitis occurred as a complication in 1 patient, but was alleviated with medication. A conventional duodenoscope could be used in patients older than 10 years. A pediatric duodenoscope was always used in patients under 1 year of age. Either type was chosen individually for those aged 1 to 10 years depending on the purpose, diagnostic or therapeutic. It is noteworthy that ERCP and/or sphincterotomy in a 1-year-old infant and two 2-year-old children were safely performed with the conventional endoscope. General anesthesia was employed in those younger than 9 years and intravenous sedation and local anesthesia in those older than 11 years. For children aged 9 to 11 years, anesthesia was chosen individually. We concluded that ERCP is a relatively easy and safe technique even for infants and children when performed by skilled hands with an appropriate duodenoscope under suitable anesthesia. The minimum age for use of the conventional duodenoscope may be 1 year.
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Li H, Butler K, Yang L, Yang Z, Teng R. Pharmacokinetics and Tolerability of Single and Multiple Doses of Ticagrelor in Healthy Chinese Subjects. Clin Drug Investig 2012; 32:87-97. [DOI: 10.2165/11595930-000000000-00000] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Teng R, Dogolo LC, Willavize SA, Friedman HL, Vincent J. Oral bioavailability of trovafloxacin with and without food in healthy volunteers. J Antimicrob Chemother 1997; 39 Suppl B:87-92. [PMID: 9222076 DOI: 10.1093/jac/39.suppl_2.87] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two studies determined the oral bioavailability of trovafloxacin (CP-99,219) in healthy volunteers under fasted and fed conditions. In a randomized, two-way crossover study, 12 fasting subjects received two 100 mg tablets of trovafloxacin and an equivalent dose of alatrofloxacin (CP-116,517), administered by i.v. infusion over 1 h. Alatrofloxacin, the L-Ala-L-Ala prodrug of trovafloxacin, is rapidly converted in the body to trovafloxacin. After the oral dose of trovafloxacin, the mean Cmax and AUC were 2.2 mg/L and 30.4 mg x h/L, respectively. After the infusion of alatrofloxacin, the Cmax and AUC of trovafloxacin were 3.2 mg/L and 34.7 mg x h/L, respectively. The mean T(1/2) after both treatments was about 11 h. The mean Cl and Vd(ss) of trovafloxacin after the infusion of alatrofloxacin were 1.32 mL/min/kg and 1.13 L/kg, respectively. The mean oral bioavailability of trovafloxacin was estimated to be 87.6% (range 64.8-122.1%). Another randomized, open, three-way crossover study was conducted in 12 healthy male volunteers to investigate the effect of food in the gastrointestinal tract on the bioavailability of trovafloxacin. Each subject received three 100 mg tablets after fasting overnight (treatment A) or after a standard breakfast (treatment B), or 300 mg as oral aqueous suspension after fasting overnight (treatment C). Mean Tmax after treatment B occurred 2.2 h later (3.6 h vs 1.4 h) than after treatment A. Mean Cmax and AUC were 2.3 and 2.6 mg/L and 38.2 and 39.5 mg x h/L after B and A, respectively. About 5% of the administered dose was recovered unchanged in the 24 h urine sample after all three treatments. Thus, the food reduced mean Cmax by 12% but had no appreciable effect on mean AUC. The mean bioavailability of trovafloxacin administered as treatment regimen B was 96.6% relative to that of treatment A. The respective mean bioavailabilities of trovafloxacin as treatments B and A were 91.3% and 94.5% respectively of that of treatment C. The results of these studies indicate that trovafloxacin has good oral bioavailability and that the ingestion of food is unlikely to have a clinically significant effect on the bioavailability of trovafloxacin.
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Clinical Trial |
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Butler K, Teng R. Pharmacokinetics, Pharmacodynamics, and Safety of Ticagrelor in Volunteers With Mild Hepatic Impairment. J Clin Pharmacol 2013; 51:978-87. [DOI: 10.1177/0091270010379409] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Teng R, Tensfeldt TG, Liston TE, Foulds G. Determination of trovafloxacin, a new quinolone antibiotic, in biological samples by reversed-phase high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1996; 675:53-9. [PMID: 8634768 DOI: 10.1016/0378-4347(95)00340-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A simple, accurate and precise high-performance liquid chromatographic method was developed and validated for the determination of trovafloxacin, a new quinolone antibiotic, in serum and urine. Following solid-phase extraction, chromatographic separation was accomplished using a C18 column with a mobile phase consisting of 0.04 M H3PO4-acetonitrile-tetrabutylammonium hydroxide-0.005 M dibutyl amine phosphate (D-4) reagent (83:16.85:0.05:0.1, v/v), pH 3. Trovafloxacin and the internal standard (a methyl derivative of trovafloxacin) were detected by ultraviolet absorbance at 275 nm. The lower limit of quantification for trovafloxacin was 0.1 microgram/ml and the calibration curves were linear over a concentration range of 0.1 to 20.0 micrograms/ml (r2 = 0.9997). The average recoveries were greater than 70% for both trovafloxacin and internal standard. The intra-day and inter-day coefficients of variation were generally less than 5% in urine and serum over the concentration range of 0.1 to 20.0 micrograms/ml. Human serum samples could be stored for up to 12 months at -20 degrees C and urine samples could be stored up to 18 months at -80 degrees C.
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Teng R, Mitchell PD, Butler K. The effect of desmopressin on bleeding time and platelet aggregation in healthy volunteers administered ticagrelor. J Clin Pharm Ther 2014; 39:186-91. [DOI: 10.1111/jcpt.12130] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 12/10/2013] [Indexed: 11/28/2022]
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Williams-Herman D, Xu L, Teng R, Golm GT, Johnson J, Davies MJ, Kaufman KD, Goldstein BJ. Effect of initial combination therapy with sitagliptin and metformin on β-cell function in patients with type 2 diabetes. Diabetes Obes Metab 2012; 14:67-76. [PMID: 22050786 DOI: 10.1111/j.1463-1326.2011.01492.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To examine the effect of sitagliptin and metformin, alone and in combination, on modelled parameters of β-cell function in patients with type 2 diabetes. METHODS The data used in the present analyses are from a 104-week study, which included a 24-week, placebo- and active controlled phase followed by a 30-week, active controlled, continuation phase and an additional 50-week, active controlled extension phase. Patients were randomised to one of six blinded treatments: sitagliptin 50 mg + metformin 1000 mg b.i.d., sitagliptin 50 mg + metformin 500 mg b.i.d., metformin 1000 mg b.i.d., metformin 500 mg b.i.d., sitagliptin 100 mg q.d. or placebo. Patients on placebo were switched in a blinded manner to metformin 1000 mg b.i.d. at week 24. Subsets of patients volunteered to undergo frequently sampled meal tolerance tests at baseline and at weeks 24, 54 and 104. β-cell responsivity was assessed with the C-peptide minimal model. The static component (Φ(s)) estimates the rate of insulin secretion related to above-basal glucose concentration. The dynamic component (Φ(d)) is related to the rate of change in glucose. The total index (Φ(total)) represents the overall response to a glycaemic stimulus and is calculated as a function of Φ(s) and Φ(d). Insulin sensitivity was estimated with the Matsuda index (ISI). The disposition index, which assesses insulin secretion relative to the prevailing insulin sensitivity, was calculated based on the Φ(total) and ISI. RESULTS At week 24, substantial reductions in postmeal glucose were observed with all active treatment groups relative to the placebo group. Φ(s), Φ(total) and the disposition index were significantly improved from baseline at week 24 with all active treatments relative to placebo. Generally larger effects were observed with the initial combination of sitagliptin and metformin relative to the monotherapy groups. When expressed as median percent change from baseline, Φ(s) increased from baseline by 137 and 177% in the low- and high-dose combination groups and by 85, 54, 73 and -9% in the high-dose metformin, low-dose metformin, sitagliptin monotherapy and placebo groups, respectively. At weeks 54 and 104, the combination treatment groups continued to demonstrate greater improvements in β-cell function relative to their respective monotherapy groups. CONCLUSIONS After 24 weeks of therapy, relative to placebo, initial treatment with sitagliptin or metformin monotherapy improved β-cell function; moreover, initial combination therapy demonstrated larger improvements than the individual monotherapies. Improvements in β-cell function were found with treatments for up to 2 years.
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Randomized Controlled Trial |
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