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116 result(s) for "Valine - pharmacokinetics"
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Clinical Pharmacokinetics and Safety of ALZ-801, a Novel Prodrug of Tramiprosate in Development for the Treatment of Alzheimer’s Disease
Background ALZ-801 is an orally available, valine-conjugated prodrug of tramiprosate. Tramiprosate, the active agent, is a small-molecule β-amyloid (Aβ) anti-oligomer and aggregation inhibitor that was evaluated extensively in preclinical and clinical investigations for the treatment of Alzheimer’s disease (AD). Tramiprosate has been found to inhibit β-amyloid oligomer formation by a multi-ligand enveloping mechanism of action that stabilizes Aβ42 monomers, resulting in the inhibition of formation of oligomers and subsequent aggregation. Although promising as an AD treatment, tramiprosate exhibited two limiting deficiencies: high intersubject pharmacokinetic (PK) variability likely due to extensive gastrointestinal metabolism, and mild-to-moderate incidence of nausea and vomiting. To address these, we developed an optimized prodrug, ALZ-801, which retains the favorable efficacy attributes of tramiprosate while improving oral PK variability and gastrointestinal tolerability. In this study, we summarize the phase I bridging program to evaluate the safety, tolerability and PK for ALZ-801 after single and multiple rising dose administration in healthy volunteers. Methods Randomized, placebo-controlled, phase I studies in 127 healthy male and female adult and elderly volunteers included [ 1 ] a single ascending dose (SAD) study; [ 2 ] a 14-day multiple ascending dose (MAD) study; and [ 3 ] a single-dose tablet food-effect study. This program was conducted with both a loose-filled capsule and an immediate-release tablet formulation, under both fasted and fed conditions. Safety and tolerability were assessed, and plasma and urine were collected for liquid chromatography-mass spectrometry (LC-MS) determination and non-compartmental PK analysis. In addition, we defined the target dose of ALZ-801 that delivers a steady-state plasma area under the curve (AUC) exposure of tramiprosate equivalent to that studied in the tramiprosate phase III study. Results ALZ-801 was well tolerated and there were no severe or serious adverse events (AEs) or laboratory findings. The most common AEs were transient mild nausea and some instances of vomiting, which were not dose-related and showed development of tolerance after continued use. ALZ-801 produced dose-dependent maximum plasma concentration ( C max ) and AUC exposures of tramiprosate, which were equivalent to that after oral tramiprosate, but with a substantially reduced intersubject variability and a longer elimination half-life. Administration of ALZ-801 with food markedly reduced the incidence of gastrointestinal symptoms compared with the fasted state, without affecting plasma tramiprosate exposure. An immediate-release tablet formulation of ALZ-801 displayed plasma exposure and low variability similar to the loose-filled capsule. ALZ-801 also showed excellent dose-proportionality without accumulation or decrease in plasma exposure of tramiprosate over 14 days. Based on these data, 265 mg of ALZ-801 twice daily was found to achieve a steady-state AUC exposure of tramiprosate equivalent to 150 mg twice daily of oral tramiprosate in the previous phase III trials. Conclusions ALZ-801, when administered in capsule and tablet forms, showed excellent oral safety and tolerability in healthy adults and elderly volunteers, with significantly improved PK characteristics over oral tramiprosate. A clinical dose of ALZ-801 (265 mg twice daily) was established that achieves the AUC exposure of 150 mg of tramiprosate twice daily, which showed positive cognitive and functional improvements in apolipoprotein E4/4 homozygous AD patients. These bridging data support the phase III development of ALZ-801in patients with AD.
Maternal Valacyclovir and Infant Cytomegalovirus Acquisition: A Randomized Controlled Trial among HIV-Infected Women
Studies in HIV-1-infected infants and HIV-1-exposed, uninfected infants link early cytomegalovirus (CMV) acquisition with growth delay and cognitive impairment. We investigated maternal valacyclovir to delay infant acquisition of CMV. Pregnant women with HIV-1, HSV-2 and CD4 count >250 cells/µl were randomized at 34 weeks gestation to 500 mg twice-daily valacyclovir or placebo for 12 months. Maternal CMV DNA was measured in plasma at 34 weeks gestation, in cervical secretions at 34 and 38 weeks gestation, and in breast milk at 7 postpartum timepoints; infant CMV DNA was measured in dried blood spots at 8 timepoints including birth. Among 148 women, 141 infants were compared in intent-to-treat analyses. Maternal and infant characteristics were similar between study arms. Infant CMV acquisition did not differ between study arms, with 46/70 infants (66%) in placebo arm and 47/71 infants (66%) in the valacyclovir arm acquiring CMV; median time to CMV detection did not differ. CMV DNA was detected in 92% of 542 breast milk specimens with no difference in CMV level between study arms. Change in cervical shedding of CMV DNA between baseline and 38 weeks was 0.40-log greater in the placebo arm than the valacyclovir arm (p = 0.05). In this cohort of HIV-1-seropositive mothers, two-thirds of infants acquired CMV by one year. Maternal valacyclovir had no effect on timing of infant CMV acquisition or breast milk CMV viral loads, although it modestly reduced cervical CMV shedding. Maternal prophylaxis to reduce infant CMV acquisition warrants further evaluation in trials with antiviral agents. ClinicalTrials.gov NCT00530777.
Efficacy, safety and pharmacokinetics of simeprevir and TMC647055/ritonavir with or without ribavirin and JNJ-56914845 in HCV genotype 1 infection
Background A Phase 2a, open-label study (NCT01724086) was conducted to assess the efficacy and safety of a once-daily, 2-direct-acting-antiviral-agent (2-DAA) combination of simeprevir + TMC647055/ritonavir ± ribavirin and of the 3-DAA combination of simeprevir + TMC647055/ritonavir + JNJ-56914845 in chronic hepatitis C virus genotype (GT)1-infected treatment-naïve and prior-relapse patients. Methods The study comprised four 12-week treatment panels: Panel 1 ( n  = 10; GT1a) and Panel 2-Arm 1 ( n  = 12; GT1b): simeprevir 75 mg once daily + TMC647055 450 mg once daily/ritonavir 30 mg once daily + ribavirin 1000–1200 mg/day; Panel 2-Arm 2 ( n  = 9; GT1b): simeprevir 75 mg + TMC647055 450 mg/ritonavir 30 mg without ribavirin; Panel 3: simeprevir 75 mg + TMC647055 600 mg/ritonavir 50 mg with (Arm 1: GT1a; n  = 7) or without (Arm 2: GT1b; n  = 8) ribavirin; Panel 4: simeprevir 75 mg + TMC647055 450 mg/ritonavir 30 mg + JNJ-56914845 30 mg once daily (Arm 1: n  = 22; GT1a/GT1b) or 60 mg once daily (Arm 2: n  = 22; GT1a/GT1b). Primary endpoint was sustained virologic response 12 weeks after end of treatment (12 weeks of combination treatment; SVR12). Results In Panel 1 and Panel 2-Arm 1, 5/10 and 6/12 (50%) GT1a/GT1b + ribavirin patients achieved SVR12, versus 3/9 (33%) GT1b without ribavirin patients in Panel 2-Arm 2. In Panel 3-Arm 1 and Panel 3-Arm 2, 6/7 (86%) GT1a + ribavirin and 4/8 (50%) GT1b without ribavirin patients, respectively, achieved SVR12. In Panel 4, 10/14 (71%) and 14/15 (93%) GT1a patients in Arms 1 and 2 achieved SVR12 compared with 8/8 and 7/7 (100%) GT1b patients in each arm, respectively. No deaths, serious adverse events (AEs), Grade 4 AEs or AEs leading to treatment discontinuation occurred. Conclusions The 2- and 3-DAA combinations were well tolerated. High SVR rates of 93% and 100% in GT1a- and GT1b-infected patients, respectively, were achieved in this study by combining simeprevir with JNJ-56914845 60 mg and TMC647055/ritonavir. Trial registration NCT01724086 (date of registration: September 26, 2012)
Pharmacokinetic Comparison of 2 Fixed-Dose Combination Tablets of Amlodipine and Valsartan in Healthy Male Korean Volunteers: A Randomized, Open-Label, 2-Period, Single-Dose, Crossover Study
Amlodipine and valsartan have different mechanisms of action, and it is known that the combination therapy with the 2 drugs increases treatment effects compared with the monotherapy with each drug. A fixed-dose combination (FDC) drug is a formulation including fixed amounts of active drug ingredients combined in a single dosage form that is expected to improve medication compliance. The goal of this study was to compare the pharmacokinetic profiles of single administration of a newly developed FDC tablet containing amlodipine orotate 10 mg and valsartan 160 mg (test formulation) with the conventional FDC tablet of amlodipine besylate 10 mg and valsartan 160 mg (reference formulation) in healthy male Korean volunteers. This was a randomized, open-label, single-dose, 2-way crossover study. Eligible subjects were between the ages of 20 and 50 years and within 20% of their ideal weight. Each subject received a single dose of the reference and the test formulations, with a 14-day washout period between formulations. Blood samples were collected up to 144 hours after the dose, and pharmacokinetic parameters were determined for amlodipine and valsartan. Adverse events were evaluated based on subject interviews and physical examinations. Forty-eight of the 50 enrolled subjects completed the study. For both amlodipine and valsartan, the primary pharmacokinetic parameters were included in the range for assumed bioequivalence, yielding 90% CI ratios of 0.9277 to 0.9903 for AUC0–last and 0.9357 to 1.0068 for Cmax in amlodipine, and 0.9784 to 1.1817 for AUC0–last and 0.9738 to 1.2145 for Cmax in valsartan. Dizziness was the most frequently noted adverse event, occurring in 4 subjects with the test formulation, followed by oropharyngeal pain occurring in 1 subject with the test formulation and 3 subjects with the reference formulation. All other adverse events occurred in <3 subjects. These findings suggest that the pharmacokinetics of the newly developed FDC tablet of amlodipine and valsartan did not differ significantly from the conventional FDC tablet in these healthy Korean male subjects. Both formulations were well tolerated, with no serious adverse events observed. ClinicalTrials.gov identifier: NCT01823913.
Pharmacokinetic Interactions of Valsartan and Hydrochlorothiazide: An Open-Label, Randomized, 4-Period Crossover Study in Healthy Egyptian Male Volunteers
Co-administration of valsartan (VAL) and hydrochlorothiazide (HCT) has been used to regulate blood pressure. Compliance with a multiple medication regimen can be difficult for some patients; therefore, a combination of VAL + HCT tablets may be a suitable alternative. This study was conducted to compare the rate and extent of absorption of VAL and HCT after oral administration as a fixed-dose combination (FDC) tablet and concomitant administration of the individual drugs under fasting conditions in healthy Egyptian subjects. The study was extended to investigate any potential interaction between VAL and HCT. This study was conducted as an open-label, randomized study with 2 parts (parts I and II), with each part consisting of 4 single-dose treatment periods with a crossover design and 2-week washout periods. Blood samples were collected up to 48 hours postdose, and plasma was analyzed for VAL and HCT concentrations by using HPLC. The pharmacokinetic properties of each drug after co-administration of VAL and HCT were compared with those of each drug administered alone. Tolerability was assessed by physical examination and verbally questioning subjects regarding their well-being and any feelings of discomfort. All events reported by the subjects were recorded in adverse-event forms. Forty-eight healthy subjects were enrolled (24 in each part), and all subjects completed the study. None of the participants showed any sign of adverse drug reactions during or after the completion of the study. Statistical analysis confirmed that the 90% CIs for AUC and Cmax of VAL/HCT FDC and VAL + HCT were within the commonly accepted bioequivalence range of 0.8 to 1.25. As a result, from an in vivo pharmacokinetic perspective, 1 FDC tablet could be considered interchangeable in medical practice with the 2 individual reference tablets. However, the 90% CIs between VAL alone and when administered with HCT, either as FDC or concomitantly, indicated the presence of an interaction between VAL and HCT, which would significantly decrease the systemic exposure and intensity of VAL absorption. The co-administration of HCT with VAL decreased the AUC and Cmax of HCT nonsignificantly compared with administration of HCT alone. Both VAL/HCT FDC and VAL + HCT were well tolerated. The safety/efficacy profile of VAL + HCT co-administration therapy could be extended to the VAL/HCT FDC tablet. The interaction of HCT with other angiotensin-receptor blockers should be investigated to determine whether this interaction is limited to VAL or if other angiotensin-receptor blockers have the same pharmacokinetic interactions. Further studies are necessary to determine the role of efflux and influx transporters on VAL and HCT disposition and pharmacokinetics.
Prediction of pharmacokinetic profile of valsartan in human based on in vitro uptake transport data
The aim of this study was to evaluate a strategy based on a physiologically based pharmacokinetic (PBPK) model for the prediction of PK profiles in human using in vitro data when elimination of compounds relies on active transport processes. The strategy was first applied to rat in vivo and in vitro data in order to refine the PBPK model. The model could then be applied to human in vitro uptake transport data using valsartan as a probe substrate. Plated rat and human hepatocytes, and cell lines overexpressing human OATP1B1 and OATP1B3 were used for in vitro uptake experiments. The uptake rate of valsartan was higher for rat hepatocytes ( K m,u  = 28.4 ± 3.7 μM, V max  = 1318 ± 176 pmol/mg/min and P dif  = 1.21 ± 0.42 μl/mg/min) compared to human hepatocytes ( K m,u  = 44.4 ± 14.6 μM, V max  = 304 ± 85 pmol/mg/min and P dif  = 0.724 ± 0.271 μl/mg/min). OATP1B1 and 1B3 parameters were correlated to human hepatocyte data using experimentally established relative activity factors (RAF). Resulting PBPK simulations using those in vitro data were compared for plasma (human and rat) and bile (rat) concentration–time profiles following i.v. bolus administration of valsartan. An uncertainty analysis indicated that the scaled in vitro uptake clearance had to be adjusted with an additional empirical scaling factor of 5 to match the plasma concentrations and biliary excretion profiles. Applying this model, plasma clearances (CL P ) for rat and human were predicted within two-fold relative to predictions based on respective in vitro data. The corrected hepatic uptake transport kinetic parameters enabled the prediction of valsartan in vivo PK profiles and plasma clearances, using PBPK modeling. Moreover, the interspecies difference in elimination rate observed in vivo was correctly reflected in the transport parameters determined in vitro. More data are needed to support more general applications of the proposed approach including its use for metabolized compounds.
Pharmacokinetic Properties and Bioequivalence of 2 Formulations of Valsartan 160-mg Tablets: A Randomized, Single-Dose, 2-Period Crossover Study in Healthy Korean Male Volunteers
The solubility of valsartan is dependent on pH and thus may cause patient variability in drug absorption and failure in bioequivalence studies; thus, increasing the solubility and release of valsartan at low pH has been suggested for a more favorable pharmacokinetic profile. However, due to this pH dependence, the change in the formulation process could alter the disintegration and/or dissolution profile of the drug, possibly making the results of bioequivalence studies misleading. The aim of this study was to assess the bioavailability and tolerability of a newly developed oral formulation of valsartan 160 mg (wet-granulation tablet) in healthy Korean male volunteers. This study was performed with the subjects under fasted conditions, using a randomized, single-dose, 2-period crossover design. Subjects were assigned to receive, in randomized order, a single dose of the test formulation and a reference formulation (valsartan 160-mg dry-granulation tablet), with a washout period of 7 days between the administrations. Blood samples were collected up to 24 hours after dosing, and pharmacokinetic parameters were determined after the plasma valsartan concentration was analyzed using UPLC-MS/MS. The dissolution studies of both formulations were conducted using USP apparatus 2 at 50 rpm with 1000 mL of phosphate buffer solution (pH, 6.8) at 37°C ± 0.5°C. Bioequivalence was defined per Korean Food and Drug Administration’s regulatory criteria as 90% CIs of the geometric mean test/reference ratios of AUC0–t and Cmax within the range of 0.8 to 1.25. Tolerability was assessed using physical examination and subject interviews. Sixty subjects were enrolled (mean [SD] age [range], 23.6 [2.4] years [21–31]; height, 173.7 [6.6] cm [161–190]; and weight, 68.0 [8.7] kg [54–85]). The mean AUC0–∞ values with the test and reference tablets were 31,784 (13,844) and 32,714 (14,512) ng·h/mL, respectively; Cmax, 5094 (2061) and 5064 (1864) ng/mL; Tmax, 2.92 (1.04) and 3.08 (1.01) hours. The 90% CIs for the geometric mean test/reference ratios of AUC0–t and Cmax were 0.9295 to 1.0546 and 0.9190 to 1.0848, respectively, which met the criteria for bioequivalence. The most frequently reported adverse event was dizziness after blank blood sampling, recorded in 4 subjects, 2 cases each with the test and reference formulations. In this study in healthy Korean male volunteers, the test and reference formulations of 160-mg valsartan met the Korean Food and Drug Administration’s regulatory criteria for bioequivalence despite the difference in formulation (wet granulation vs dry granulation). Both formulations were well tolerated, with no serious adverse events reported.
Pharmacokinetic Interaction Between Pitavastatin and Valsartan: A Randomized, Open-Labeled Crossover Study in Healthy Male Korean Volunteers
Pitavastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, and valsartan, an angiotensin receptor blocker, are used concurrently in some patients who are both hyperlipidemic and hypertensive. However, to date, no published studies have explored whether there is an interaction between pitavastatin and valsartan. The aim of this study was to investigate the potential pharmacokinetic interaction between pitavastatin and valsartan in healthy male volunteers in Korea. A randomized, open-label crossover study was conducted in healthy male Korean volunteers. In varying sequences, each subject received pitavastatin 2 × 2 mg, valsartan 2 × 160 mg, and both treatments, once daily for 7 consecutive days, with a 7-day washout period between each treatment period. Plasma samples were obtained at steady state for the pharmacokinetic evaluation of pitavastatin and valsartan. Pharmacodynamic assessment included lipid profiles and vital sign measurements (systolic and diastolic blood pressure [SBP and DBP, respectively] and pulse rate [PR]). A safety profile assessment, which included vital sign measurements, ECG, and clinical laboratory testing, was performed in each subject. A total of 24 subjects were enrolled (mean age, 30.5 years [range, 23.0−45.0 years]; mean body weight, 71.2 kg [range, 56.1−86.0 kg]; and mean body mass index, 23.2 kg/m2 [range, 19.2−25.8 kg/m2]). The 95% CIs of the geometric mean ratios of AUCτ and Cmax,ss of pitavastatin were 0.97 to 1.11 and 0.73 to 1.09, respectively. The 95% CIs of the geometric mean ratios of AUCτ and Cmax,ss of valsartan were 0.90 to 1.27 and 0.81 to 1.29. Pitavastatin administered as monotherapy and in combination with valsartan was associated with significantly lowered total cholesterol and LDL-C compared with valsartan monotherapy (both, P < 0.05). Differences in lipid-lowering effects were not statistically significant between pitavastatin monotherapy and pitavastatin combined with valsartan. Valsartan monotherapy and valsartan combined with pitavastatin were associated with significantly lower SBP and DBP compared with baseline (both, P < 0.05), although no significant changes in PR were observed. No significant differences in BP or PR changes were noted between concurrent administration of valsartan monotherapy compared with pitavastatin + valsartan. There were no serious AEs reported, and none of the subjects discontinued the study due to AEs. The pharmacokinetic profiles of pitavastatin and valsartan administered as monotherapy were comparable to combination treatment in these healthy male Korean volunteers, suggesting that individual pharmacokinetic properties are not significantly affected by concurrent administration. The concurrent administration of pitavastatin and valsartan was generally well tolerated. The findings from the present study provide a basis for a larger study in hypertensive patients with hyperlipidemia. ClinicalTrials.gov identifier: NCT01232049.
Evaluation of the pharmacokinetic and pharmacodynamic drug interactions between cilnidipine and valsartan, in healthy volunteers
Although cilnidipine and valsartan are widely coadministered to patients with hypertension, their drug-drug interaction potential has not been investigated. This study compared the pharmacokinetic (PK), pharmacodynamic (PD), and tolerability profiles of cilnidipine and valsartan, both alone and in combination, in healthy male subjects. Fifty-four subjects, enrolled into an open-label, single-dose, three-treatment, three-period crossover study, randomly received cilnidipine (10 mg), valsartan (160 mg), or both according to one of six sequences. Blood samples were collected at baseline and up to 24 hours after drug administration in each period. Plasma concentrations of cilnidipine and valsartan were determined by liquid chromatography with tandem mass spectrometry. Maximum plasma concentration (Cmax) and area under the concentration-time curve from 0 to the last measurable time (AUC(last)) were estimated using a noncompartmental method. Tolerability was evaluated by assessing adverse events (AEs), vital signs, electrocardiograms, and clinical laboratory tests. Blood pressure was also measured for PD assessment. A total of 51 subjects completed the study. The PK profile of cilnidipine was not significantly affected by coadministered valsartan; the geometric mean ratio and 90% confidence interval (90% CI) of AUC(last) for cilnidipine with and without valsartan was 1.04 (0.98-1.10). Likewise, cilnidipine did not affect the PK of valsartan; the geometric mean ratio (90% CI) of AUC(last) for valsartan with and without cilnidipine was 0.94 (0.83-1.07). Coadministration of cilnidipine and valsartan reduced blood pressure in an additive way. No serious AEs were reported, and both cilnidipine and valsartan were well tolerated. Coadministered cilnidipine and valsartan do not cause a significant PK or PD interaction, and they are well tolerated.