| 1. |
- Ahn, Jae Eun, et al.
(författare)
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Modeling longitudinal daily seizure frequency data from pregabalin add-on treatment
- 2012
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 52:6, s. 880-892
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to describe longitudinal daily seizure count data with respect to the effects of time and pregabalin add-on therapy. Models were developed in step-wise manner: base model, time effect model, and time and drug effect (final) model, using a negative binomial distribution with Markovian features. Mean daily seizure count (λ) was estimated to be 0.385 (RSE 3.09%) and was further increased depending on the seizure count on the previous day. An overdispersion parameter (OVDP), representing extra-Poisson variation, was estimated to be 0.330 (RSE 11.7%). Inter-individual variances on λ and OVDP were 84.7% and 210%, respectively. Over time, λ tended to increase exponentially with a rate constant of 0.272 year-1 (RSE 26.8%). A mixture model was applied to classify responders/non-responders to pregabalin treatment. Within the responders, λ decreased exponentially with respect to dose with a constant of 0.00108 mg-1 (RSE 11.9%). The estimated responder rate was 66% (RSE 27.6%). Simulation-based diagnostics showed the model reasonably reproduced the characteristics of observed data. Highly variable daily seizure frequency was successfully characterized incorporating baseline characteristics, time effect, and the effect of pregabalin with classification of responders/non-responders, all of which are necessary to adequately assess the efficacy of antiepileptic drugs.
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| 2. |
- Alskär, Oskar, et al.
(författare)
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Semi-mechanistic model describing gastric emptying and glucose absorption in healthy subjects and patients with type 2 diabetes
- 2016
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 56:3, s. 340-348
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Tidskriftsartikel (refereegranskat)abstract
- The integrated glucose-insulin (IGI) model is a previously published semi-mechanistic model, which describes plasma glucose and insulin concentrations after glucose challenges. The aim of this work was to use knowledge of physiology to improve the IGI model's description of glucose absorption and gastric emptying after tests with varying glucose doses. The developed model's performance was compared to empirical models. To develop our model, data from oral and intravenous glucose challenges in patients with type 2 diabetes and healthy control subjects were used together with present knowledge of small intestinal transit time, glucose inhibition of gastric emptying and saturable absorption of glucose over the epithelium to improve the description of gastric emptying and glucose absorption in the IGI model. Duodenal glucose was found to inhibit gastric emptying. The performance of the saturable glucose absorption was superior to linear absorption regardless of the gastric emptying model applied. The semi-physiological model developed performed better than previously published empirical models and allows for better understanding of the mechanisms underlying glucose absorption. In conclusion, our new model provides a better description and improves the understanding of dynamic glucose tests involving oral glucose.
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| 3. |
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| 4. |
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| 5. |
- Bergman, Ebba, 1977-, et al.
(författare)
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Effect of a Single Gemfibrozil Dose on the Pharmacokinetics of Rosuvastatin in Bile and Plasma in Healthy Volunteers
- 2010
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 50:9, s. 1039-1049
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Tidskriftsartikel (refereegranskat)abstract
- The effect of a single intrajejunal dose of gemfibrozil (600 mg) on the plasma pharmacokinetics and biliary excretion of a single intrajejunal dose of rosuvastatin (20 mg) was investigated by using a multichannel catheter positioned in the distal duodenum/proximal jejunum in eight healthy volunteers. Bile and plasma samples were collected every 20 min for 200 min, with additional plasma samples being withdrawn for up to 48 hrs. Gemfibrozil did not affect the bioavailability of rosuvastatin, although it increased the apparent absorption phase during the initial 200 minutes (AUC0-200) by 1.56-fold (95%CI: 1.14-2.15). The interaction was less pronounced in this single dose study than in a previous report when gemfibrozil was administered repeatedly, nevertheless, the interaction coincided with the highest exposure to gemfibrozil. The plausible reason why the interaction in this investigation was only minor is the low exposure to gemfibrozil (and its metabolites), suggesting that the total plasma concentration of gemfibrozil needs to be above 20 µM in order to affect the disposition of rosuvastatin. This study demonstrates the value of monitoring the plasma pharmacokinetics of the inhibitor, and not only the drug under investigation, to improve the mechanistic interpretation.
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| 6. |
- Buesker, Soeren, et al.
(författare)
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Population Pharmacokinetics as a Tool to Reevaluate the Complex Disposition of Ethanol in the Fed and Fasted States
- 2023
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Ingår i: Journal of clinical pharmacology. - : WILEY. - 0091-2700 .- 1552-4604. ; 63, s. 681-694
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Tidskriftsartikel (refereegranskat)abstract
- The pharmacokinetics (PK) of ethanol are important in pharmacology and therapeutics because of potential drug-alcohol interactions as well as in forensic science when alcohol-related crimes are investigated. The PK of ethanol have been extensively studied since the 1930s, although some issues remain unresolved, such as the significance of first-pass metabolism, whether zero-order kinetics apply, and the effects of food on bioavailability. We took advantage of nonlinear mixed-effects modeling to describe blood-alcohol concentration (BAC) profiles derived from 3 published clinical studies involving oral, intraduodenal, and intravenous administration of ethanol with and without food. The overall data set included 1510 BACs derived from 72 healthy subjects (60 men, 12 women) aged between 20 and 60 years. Two-compartment models with first-order absorption and Michaelis-Menten elimination kinetics adequately described the BAC profiles. Food intake had 2 separate effects: It reduced the absorption rate constant and accelerated the maximum elimination rate. Estimates of the maximum elimination rate (fasted) and the food effect (as a factor) were 6.31 g/h (95%CI, 6.04-6.59 g/h) and 1.39-fold (95%CI, 1.33-1.46-fold), respectively. Simulations showed that the area under the BAC-time curve (AUC) was smaller with lower input rate of ethanol, irrespective of any first-pass metabolism. The AUC from time 0 to 10 hours for a 75-kg subject was 2.34 g center dot h/L (fed) and 3.83 g center dot h/L (fasted) after an oral dose of 45 g ethanol. This difference was mainly attributable to the food effect on ethanol elimination and depended less on the absorption rate. Our new approach to explain the complex human PK of ethanol may help when BAC predictions are made in clinical pharmacology and forensic medicine.
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| 7. |
- Chaurasia, Chandra S., et al.
(författare)
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AAPS-FDA Workshop White Paper : microdialysis principles, application, and regulatory perspectives
- 2007
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 47:5, s. 589-603
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Tidskriftsartikel (refereegranskat)abstract
- Many decisions in drug development and medical practice are based on measuring blood concentrations of endogenous and exogenous molecules. Yet most biochemical and pharmacological events take place in the tissues. Also, most drugs with few notable exceptions exert their effects not within the bloodstream, but in defined target tissues into which drugs have to distribute from the central compartment. Assessing tissue drug chemistry has, thus, for long been viewed as a more rational way to provide clinically meaningful data rather than gaining information from blood samples. More specifically, it is often the extracellular (interstitial) tissue space that is most closely related to the site of action (biophase) of the drug. Currently microdialysis (μD) is the only tool available that explicitly provides data on the extracellular space. Although μD as a preclinical and clinical tool has been available for two decades, there is still uncertainty about the use of μD in drug research and development, both from a methodological and a regulatory point of view. In an attempt to reduce this uncertainty and to provide an overview of the principles and applications of μD in preclinical and clinical settings, an AAPS-FDA workshop took place in November 2005 in Nashville, TN, USA. Stakeholders from academia, industry and regulatory agencies presented their views on μD as a tool in drug research and development.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Fanta, Samuel, et al.
(författare)
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Long-Term Changes in Cyclosporine Pharmacokinetics After Renal Transplantation in Children : Evidence for Saturable Presystemic Metabolism and Effect of NR1I2 Polymorphism
- 2010
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 50:5, s. 581-597
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Tidskriftsartikel (refereegranskat)abstract
- To improve cyclosporine dose individualization, the authors carried out a comprehensive analysis of the effects of clinical and genetic factors on cyclosporine pharmacokinetics in 176 children before and up to 16 years after renal transplantation. Pretransplantation test doses of cyclosporine were given intravenously and orally, followed by blood sampling for 24 hours. After transplantation, cyclosporine was quantified at trough, 2 hours postdose, or with dose-interval curves. A 3-compartment population pharmacokinetic model was used to describe the data. Cyclosporine oral bioavailability increased more than 1.5-fold in the first month after transplantation, returning thereafter gradually to its initial value in 1 to 1.5 years. Moreover, older children receiving cyclosporine twice daily as the gelatin capsule microemulsion formulation had an about 1.25 to 1.3 times higher bioavailability than did the younger children receiving the liquid formulation thrice daily. In 91 children with genetic data after transplantation, patients carrying the NR1I2 g.-25385C-g.-24381A-g.205_-200GAGAAG-g.7635G-g.8055C haplotype had about one-tenth lower bioavailability, per allele, than did non-carriers (P = .039). The significance of the NR1I2 genotype warrants further study. In conclusion, by accounting for the effects of developmental factors (body weight), time after transplantation, and cyclosporine dosing frequency/formulation, it may be possible to improve individualization of cyclosporine dosing in children.
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| 14. |
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| 15. |
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| 16. |
- Gupta, Pankaj, et al.
(författare)
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A Semi-Mechanistic Model of CP-690,550-Induced Reduction in Neutrophil Counts in Patients With Rheumatoid Arthritis
- 2010
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 50:6, s. 679-687
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Tidskriftsartikel (refereegranskat)abstract
- CP-690,550, a selective inhibitor of the Janus kinase family, is being developed as an oral disease-modifying antirheumatic drug for the treatment of rheumatoid arthritis (RA). A semi-mechanistic model was developed to characterize the time course of drug-induced absolute neutrophil count (ANC) reduction in a phase 2a study. Data from 264 RA patients receiving 6-week treatment (placebo, 5, 15, 30 mg bid) followed by a 6-week off-treatment period were analyzed. The model included a progenitor cell pool, a maturation chain comprising transit compartments, a circulation pool, and a feedback mechanism. The model was adequately described by system parameters (BASEh, ktrh, gamma, and kcirc), disease effect parameters (DIS), and drug effect parameters (koff and kD). The disease manifested as an increase in baseline ANC and reduced maturation time due to increased demand from the inflammation site. The drug restored the perturbed system parameters to their normal values via an indirect mechanism. ANC reduction due to a direct myelosuppressive drug effect was not supported. The final model successfully described the dose- and time-dependent changes in ANC and predicted the incidence of neutropenia at different doses reasonably well.
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| 17. |
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| 18. |
- Hamrén, Bengt, et al.
(författare)
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Pharmacokinetic-Pharmacodynamic Assessment of the Interrelationships Between Tesaglitazar Exposure and Renal Function in Patients With Type 2 Diabetes Mellitus
- 2012
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 52:9, s. 1317-1327
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Tidskriftsartikel (refereegranskat)abstract
- The effects of tesaglitazar on renal function (assessed as urinary clearance of 125I-sodium iothalamate or estimated by the modification of diet in renal disease formula) were studied in a 24-week open-label trial in type 2 diabetes mellitus patients randomized to daily doses of either tesaglitazar 2 mg or pioglitazone 45 mg. The aim of the analysis was to develop a population pharmacokinetic-pharmacodynamic model that could simultaneously describe the interrelationship between tesaglitazar exposure and reduction in renal function over time in patients with type 2 diabetes mellitus. The pharmacokinetic-pharmacodynamic model could adequately describe the interplay between tesaglitazar and glomerular filtration rate. A one-compartment model in which the apparent clearance was influenced by glomerular filtration rate characterized the pharmacokinetics of tesaglitazar. An indirect-response model was used for the slow time course of change in glomerular filtration rate, which decreased from 100 to 78 mL/min/1.73m2 after 12 weeks of treatment. All tesaglitazar-treated patients had a reduction in glomerular filtration rate, and available demographic variables could not explain differences in response. Patients treated with an angiotensin converting enzyme inhibitor were more sensitive to tesaglitazar and had larger glomerular filtration rate decrease compared to nontreated patients. Approximately 8 weeks after discontinuing treatment, mean glomerular filtration rate had returned towards baseline. The model and data give valuable insights into the dynamic changes in glomerular filtration rate over time.
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| 19. |
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| 20. |
- Hennig, Stefanie, et al.
(författare)
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Application of the Optimal Design Approach to Improve a Pretransplant Drug Dose Finding Design for Ciclosporin
- 2012
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 52:3, s. 347-360
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Tidskriftsartikel (refereegranskat)abstract
- A time and sampling intensive pretransplant test dose design was to be reduced, but at the same time optimized so that there was no loss in the precision of predicting the individual pharmacokinetic (PK) estimates of posttransplant dosing. The following variables were optimized simultaneously: sampling times, ciclosporin dose, time of second dose, infusion duration, and administration order, using a published ciclosporin population PK model as prior information. The original design was reduced from 22 samples to 6 samples/patient and both doses (intravenous oral) were administered within 8 hours. Compared with the prior information given by the published ciclosporin population PK model, the expected standard deviations (SDs) of the individual parameters for clearance and bioavailability could be reduced by, on average, 40% under the optimized sparse designs. The gain of performing the original rich design compared with the optimal reduced design, considering the standard errors of the parameter estimates, was found to be minimal. This application demonstrates, in a practical clinical scenario, how optimal design techniques may be used to improve diagnostic procedures given available software and methods.
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| 21. |
- Hennig, Stefanie, et al.
(författare)
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Trial treatment length optimization with an emphasis on disease progression studies
- 2009
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 49:3, s. 323-335
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Tidskriftsartikel (refereegranskat)abstract
- Optimal design has been used in the past mainly to optimize sampling schedules for clinical trials. Optimization on design variables other than sampling times has been published in the literature only once before. This study shows, as an example, optimization on the length of treatment periods to obtain reliable estimates of drug effects on longterm disease progression studies. Disease progression studies are high in cost, effort, and time; therefore, optimization of treatment length is highly recommended to avoid failure or loss of information. Results are provided for different drug effects (eg, protective and symptomatic) and for different lengths of studies and sampling schedules. The merits of extending the total study length versus inclusion of more samples per participants are investigated. The authors demonstrate that if no observations are taken during the washout period, a trial can lose up to 40% of its efficiency. Furthermore, when optimization of treatment length is performed using multiple possible drug effect models simultaneously, these studies show high power in discriminating between different drug effect models.
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| 22. |
- Huledal, Gunilla, et al.
(författare)
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Pharmacokinetics and Metabolism of Melflufen, an Alkylating Peptide-Drug Conjugate, in Patients with Relapsed Refractory Multiple Myeloma
- 2024
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Ingår i: Journal of clinical pharmacology. - : John Wiley & Sons. - 0091-2700 .- 1552-4604. ; 64:2, s. 240-252
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Tidskriftsartikel (refereegranskat)abstract
- Melphalan flufenamide (melflufen) is a novel lipophilic peptide-drug conjugate recently approved in the European Union and the United Kingdom for the treatment of relapsed refractory multiple myeloma. Melflufen rapidly crosses the cell membrane, and inside tumor cells, melflufen utilizes peptidases and esterases to release entrapped hydrophilic metabolites with alkylating activity. In vitro, in whole blood, melflufen was rapidly distributed into blood cells and quickly converted to its main metabolite melphalan, with maximum cellular concentrations of noncovalently bound melflufen and melphalan after 1 and 6 minutes, respectively. Melphalan outflow from blood cells was slow, with peak concentrations in plasma after 25 minutes. The pharmacokinetics of melflufen was best described by a 2-compartment model. Following a 30-minutes intravenous infusion of 40 mg in 27 patients with relapsed refactory multiple myeloma, mean half-life in the alpha phase of the curve was 1.24 minutes, half-life in the beta phase of the curve 26.7 minutes, and clearance 13.4 L/min. Desethyl-melflufen exposure was below 20% compared to melflufen. Based on population analysis (298 patients with relapsed refactory multiple myeloma), the melphalan pharmacokinetics were well characterized by a 3-compartment model with melflufen dosing into a peripheral compartment, assuming instantaneous distribution of melflufen into cells and subsequent rapid metabolism to melphalan. Mean clearance and central and deep peripheral volumes of distribution were 22.4 L/h, 2.70 L, and 51.3 L, respectively. Clearance increased and maximum concentration decreased with increasing body weight and estimated glomerular filtration rate. In conclusion, melflufen administration differs from melphalan administration by a more rapid distribution into cells, which, in conjunction with a rapid intracellular metabolism, allows for higher maximum concentrations of alkylating agents, and by a more extensive distribution of melphalan to peripheral tissues.
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| 23. |
- Ibrahim, Moustafa M. A., et al.
(författare)
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Optimal Designs for Model-Based Assessment of Insulin Sensitivity and Glucose Effectiveness.
- 2021
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Ingår i: Journal of clinical pharmacology. - : John Wiley & Sons. - 0091-2700 .- 1552-4604. ; 61:1, s. 116-124
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Tidskriftsartikel (refereegranskat)abstract
- The integrated minimal model allows assessment of clinical diagnosis indices, for example, insulin sensitivity (SI ) and glucose effectiveness (SG ), from data of the insulin-modified intravenous glucose tolerance test (IVGTT), which is laborious with an intense sampling schedule, up to 32 samples. The aim of this study was to propose a more informative, although less laborious, IVGTT design to be used for model-based assessment of SI and SG . The IVGTT design was optimized simultaneously for all design variables: glucose and insulin infusion doses, time of glucose dose and start of insulin infusion, insulin infusion duration, sampling times, and number of samples. Design efficiency was used to compare among different designs. The simultaneously optimized designs showed a profound higher efficiency than both standard rich (32 samples) and sparse (10 samples) designs. The optimized designs, after removing replicate sample times, were 1.9 and 7.1 times more efficient than the standard rich and sparse designs, respectively. After including practical aspects of the designs, for example, sufficient duration between samples and avoidance of prolonged hypoglycemia, we propose 2 practical designs with fewer sampling times and lower input of glucose and insulin than standard designs, constrained to prevent hypoglycemia. The optimized practical rich design is equally efficient in assessing SI and SG as the rich standard design, but with half the number of the samples, while the optimized practical sparse design has 1 less sample and requires 4.6 times fewer individuals for equal certainty when assessing SI and SG than the sparse standard design.
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| 24. |
- Jauslin, Petra, et al.
(författare)
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Identification of the Mechanism of Action of a Glucokinase Activator From Oral Glucose Tolerance Test Data in Type 2 Diabetic Patients Based on an Integrated Glucose-Insulin Model
- 2012
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 52:12, s. 1861-1871
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Tidskriftsartikel (refereegranskat)abstract
- A mechanistic drug-disease model was developed on the basis of a previously published integrated glucose-insulin model by Jauslin et al. A glucokinase activator was used as a test compound to evaluate the model’s ability to identify a drug’s mechanism of action and estimate its effects on glucose and insulin profiles following oral glucose tolerance tests. A kinetic-pharmacodynamic approach was chosen to describe the drug’s pharmacodynamic effects in a dose-response-time model. Four possible mechanisms of action of antidiabetic drugs were evaluated, and the corresponding affected model parameters were identified: insulin secretion, glucose production, insulin effect on glucose elimination, and insulin-independent glucose elimination. Inclusion of drug effects in the model at these sites of action was first tested one-by-one and then in combination. The results demonstrate the ability of this model to identify the dual mechanism of action of a glucokinase activator and describe and predict its effects: Estimating a stimulating drug effect on insulin secretion and an inhibiting effect on glucose output resulted in a significantly better model fit than any other combination of effect sites. The model may be used for dose finding in early clinical drug development and for gaining more insight into a drug candidate’s mechanism of action.
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| 25. |
- Jauslin, Petra M, et al.
(författare)
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An integrated glucose-insulin model to describe oral glucose tolerance test data in type 2 diabetics
- 2007
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 47:10, s. 1244-1255
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Tidskriftsartikel (refereegranskat)abstract
- An integrated model for the glucose-insulin system describing oral glucose tolerance test data was developed, extending on a previously introduced model for intravenous glucose provocations. Model extensions comprised the description of glucose absorption by a chain of transit compartments with a mean transit time of 35 minutes, a bioavailability of 80%, and a representation of the incretin effect, expressed as a direct effect of the glucose absorption rate on insulin secretion. The ability of the model to predict the incretin effect was assessed by simulating the observed difference in insulin response following an oral glucose tolerance test compared with an isoglycemic glucose infusion mimicking an oral glucose tolerance test profile. The extension of the integrated glucose-insulin model to gain information from oral glucose tolerance test data considerably expands its range of applications because the oral glucose tolerance test is one of the most common glucose challenge experiments for assessing the efficacy of hypoglycemic agents in clinical drug development.
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| 26. |
- Jauslin, Petra, et al.
(författare)
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Modeling of 24-Hour Glucose and Insulin Profiles of Patients With Type 2 Diabetes
- 2011
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 51:2, s. 153-164
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Tidskriftsartikel (refereegranskat)abstract
- A model able to simultaneously characterize and simulate 24-hour glucose and insulin profiles following multiple meal tests was developed, extending an integrated glucose-insulin model for oral glucose tolerance tests that was previously published. The analysis was based on glucose and insulin measurements from 59 placebo-treated patients with type 2 diabetes. Circadian variations in glucose homeostasis were assessed on relevant parameters based on literature review. They were best described by a nighttime dip in insulin secretion between approximately 9 p.m. and 5 a.m. using a modulator function. The integrated glucose-insulin model has thus been shown to be applicable to real-life situations determined by multiple meals over the course of a day. This provides the basis for the analysis and simulation of long-term glucose and insulin data. The model may also prove useful for understanding antidiabetic drug actions and requirements in the context of circadian changes in glucose-insulin regulation.
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| 27. |
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| 28. |
- Jönsson, Siv, et al.
(författare)
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Population pharmacokinetics of edoxaban and its main metabolite in a dedicated renal impairment study
- 2015
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 55:11, s. 1268-1279
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Tidskriftsartikel (refereegranskat)abstract
- A model characterizing the population pharmacokinetics (PK) of edoxaban and its major metabolite, M4, following a single oral dose of 15mg administered to subjects with varying kidney function was developed. Thirty-two subjects contributed with edoxaban plasma, edoxaban urine, and M4 plasma concentrations. Edoxaban urine concentrations allowed estimation of renal clearance, and high contribution of renal to total clearance enabled estimation of absolute oral bioavailability. A 2-compartment model with delayed absorption and elimination parameterized as renal clearance linearly related to creatinine clearance (CLcr) and nonrenal clearance forming M4 described edoxaban PK. The PK of M4 was described with a 1-compartment model. For a typical subject (70kg; CLcr, 100mL/min) bioavailability, clearance, and central and peripheral volume of distribution for edoxaban was estimated to 72.3%, 21.0 L/h, 95.4 L, and 54.3 L, respectively. For both edoxaban and M4, the model predicted systemic exposure to increase 57.0%, 35.0%, and 11.6% in a subject having CLcr of 30, 50, and 80mL/min, respectively, compared with a subject having a CLcr of 100mL/min. Concentration ratios (M4 over edoxaban) were predicted to vary with time after dose, but with minor influence of kidney function and body weight. Results were in agreement with previous analyses.
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| 29. |
- Kjellsson, Maria C., et al.
(författare)
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A Model-Based Approach to Predict Longitudinal HbA1c, Using Early Phase Glucose Data From Type 2 Diabetes Mellitus Patients After Anti-Diabetic Treatment
- 2013
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 53:6, s. 589-600
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Tidskriftsartikel (refereegranskat)abstract
- Predicting late phase outcomes from early-phase findings can help inform decisions in drug development. If the measurements in early-phase differ from those in late phase, forecasting is more challenging. In this paper, we present a model-based approach for predicting glycosylated hemoglobin (HbA1c) in late phase using glucose and insulin concentrations from an early-phase study, investigating an anti-diabetic treatment. Two previously published models were used; an integrated glucose and insulin (IGI) model for meal tolerance tests and an integrated glucose-red blood cell-HbA1c (IGRH) model predicting the formation of HbA1c from the average glucose concentration (Cg,av). Output from the IGI model was used as input to the IGRH model. Parameters of the IGI model and drug effects were estimated using data from a phase1 study in 59 diabetic patients receiving various doses of a glucokinase activator. Cg,av values were simulated according to a Phase 2 study design and used in the IGRH model for predictions of HbA1c. The performance of the model-based approach was assessed by comparing the predicted to the actual outcome of the Phase 2 study. We have shown that this approach well predicts the longitudinal HbA1c response in a 12-week study using only information from a 1-week study where glucose and insulin concentrations were measured.
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| 30. |
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| 31. |
- Kotani, Naoki, et al.
(författare)
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Population Pharmacokinetics and Exposure-Response Relationships of Astegolimab in Patients With Severe Asthma
- 2022
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Ingår i: Journal of clinical pharmacology. - : John Wiley & Sons. - 0091-2700 .- 1552-4604. ; 62:7, s. 905-917
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Tidskriftsartikel (refereegranskat)abstract
- Astegolimab is a fully human immunoglobulin G2 monoclonal antibody that binds to the ST2 receptor and blocks the interleukin-33 signaling. It was evaluated in patients with uncontrolled severe asthma in the phase 2b study (Zenyatta) at doses of 70, 210, and 490 mg subcutaneously every 4 weeks for 52 weeks. This work aimed to characterize astegolimab pharmacokinetics, identify influential covariates contributing to its interindividual variability, and make a descriptive assessment of the exposure-response relationships. A population pharmacokinetic model was developed using data from 368 patients in the Zenyatta study. Predicted average steady-state concentration was used in the subsequent exposure-response analyses, which evaluated efficacy (asthma exacerbation rate) and biomarker end points including forced expiratory volume in 1 second, fraction exhaled nitric oxide, blood eosinophils, and soluble ST2. A 2-compartment disposition model with first-order elimination and first-order absorption best described the astegolimab pharmacokinetics. The relative bioavailability for the 70-mg dose was 15.3% lower. Baseline body weight, estimated glomerular filtration rate, and eosinophils were statistically correlated with pharmacokinetic parameters, but only body weight had a clinically meaningful influence on the steady-state exposure (ratios exceeding 0.8-1.25). The exposure-response of efficacy and biomarkers were generally flat with a weak trend in favor of the highest dose/exposure. This study characterized astegolimab pharmacokinetics in patients with asthma and showed typical pharmacokinetic behavior as a monoclonal antibody-based drug. The exposure-response analyses suggested the highest dose tested in the Zenyatta study (490 mg every 4 weeks) performed close to the maximum effect, and no additional response may be expected above it.
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| 32. |
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| 33. |
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| 34. |
- Litjens, Carlijn H. C., et al.
(författare)
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Prediction of Moxifloxacin Concentrations in Tuberculosis Patient Populations by Physiologically Based Pharmacokinetic Modeling
- 2022
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Ingår i: Journal of clinical pharmacology. - : John Wiley & Sons. - 0091-2700 .- 1552-4604. ; 62:3, s. 385-396
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Tidskriftsartikel (refereegranskat)abstract
- Moxifloxacin has an important role in the treatment of tuberculosis (TB). Unfortunately, coadministration with the cornerstone TB drug rifampicin results in suboptimal plasma exposure. We aimed to gain insight into the moxifloxacin pharmacokinetics and the interaction with rifampicin. Moreover, we provided a mechanistic framework to understand moxifloxacin pharmacokinetics. We developed a physiologically based pharmacokinetic model in Simcyp version 19, with available and newly generated in vitro and in vivo data, to estimate pharmacokinetic parameters of moxifloxacin alone and when administered with rifampicin. By combining these strategies, we illustrate that the role of P-glycoprotein in moxifloxacin transport is limited and implicate MRP2 as transporter of moxifloxacin-glucuronide followed by rapid hydrolysis in the gut. Simulations of multiple dose area under the plasma concentration-time curve (AUC) of moxifloxacin (400 mg once daily) with and without rifampicin (600 mg once daily) were in accordance with clinically observed data (predicted/observed [P/O] ratio of 0.87 and 0.80, respectively). Importantly, increasing the moxifloxacin dose to 600 mg restored the plasma exposure both in actual patients with TB as well as in our simulations. Furthermore, we extrapolated the single dose model to pediatric populations (P/O AUC ratios, 1.04-1.52) and the multiple dose model to children with TB (P/O AUC ratio, 1.51). In conclusion, our combined approach resulted in new insights into moxifloxacin pharmacokinetics and accurate simulations of moxifloxacin exposure with and without rifampicin. Finally, various knowledge gaps were identified, which may be considered as avenues for further physiologically based pharmacokinetic refinement.
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| 35. |
- Lledó-García, Rocío, et al.
(författare)
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Ethically Attractive Dose-Finding Designs for Drugs With a Narrow Therapeutic Index
- 2012
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 52:1, s. 29-38
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Tidskriftsartikel (refereegranskat)abstract
- A simulation-based comparison study on the relative merits of dose-control trials (DCTs) with exposure-response analysis versus concentration-control trials (CCTs) for drugs with narrow therapeutic index showed that DCT designs are more informative about the exposure-response relationship. The authors revisit the question employing optimal design methodology and propose strategies for designing ethically attractive trials for these drugs, balancing between individual-collective risk and informativeness. An optimal study was performed considering a hypothetical immunosuppressant agent with 2 clinical end points. Different scenarios were optimized applying cost-based designs (unwanted events vs number of sub-jects/trial or maximal individual risk). Dose/exposure targets and number of subjects per trial/arm were optimized. Prior information inclusion on baseline risks was evaluated. DCTs were more informative, needing smaller studies to provide the same information as CCTs. Using the number of unwanted events-rather than subjects-as cost resulted in ethically more attractive designs. Including prior baseline risk information reduced the number of subject/events and allowed the use of targets closer to the optimal. Designing dose-finding trials for some narrow therapeutic index drugs may be improved by using DCTs with exposure-response analysis, cost-based designs, prior information, and optimal design analysis providing information on the ethical trade-off between individual risk and information gain.
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| 36. |
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| 37. |
- Maloney, Alan, et al.
(författare)
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Optimal adaptive design in clinical drug development : a simulation example
- 2007
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 47:10, s. 1231-1243
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this article is to demonstrate optimal adaptive design as a methodology for improving the performance of phase II dose-response studies. Optimal adaptive design uses both information prior to the study and data accrued during the study to continuously update and refine the study design. Dose-response models include linear, log-linear, 4-parameter sigmoidal E-max, and exponential models. Where the response has both a placebo effect and plateau at higher doses, only the 4-parameter sigmoidal E-max model behaves acceptably and hence is used to illustrate the methodology. Across 13 hypothetical dose-response scenarios considered, it was shown that the capability of the adaptive designs to "learn" the true dose response resulted in performances up to 180% more efficient than the best fixed optimal designs, This work exposes the common misconception that adaptive designs are somehow "risky." As shown in this simple simulation example, the converse is true. Adaptive designs perform extremely well both when prior information is accurate and inaccurate. This leads to improved dose-response models and dose selection in phase III. This benefits sponsors, regulators, and subjects alike by reducing sample size, increasing information, and providing better dose guidance.
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| 38. |
- Matsson, Elin, 1979-, et al.
(författare)
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Biliary Excretion of Ximelagatran and Its Metabolites and the Influence of Erythromycin Following Intraintestinal Administration to Healthy Volunteers
- 2011
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 51:5, s. 770-783
-
Tidskriftsartikel (refereegranskat)abstract
- The biliary excretion of the oral thrombin inhibitor ximelagatran and its metabolites was investigated by using duodenal aspiration in healthy volunteers following intraintestinal dosing. In the first investigation, radiolabeled [C-14] ximelagatran was administered, enabling quantification of the biliary excretion and identification of metabolites in the bile. In the second study, the effect of erythromycin on the biliary clearance of ximelagatran and its metabolites was investigated to clarify the reported ximelagatran-erythromycin interaction. Approximately 4% of the intraintestinal dose was excreted into bile with ximelagatran and its active form, melagatran, being the most abundant compounds. Four novel ximelagatran metabolites were identified in bile (< 0.1% of dose). Erythromycin changed the pharmacokinetics of ximelagatran and its metabolites, with an elevated ximelagatran (78% increase), OH-melagatran (89% increase), and melagatran (86% increase) plasma exposure and higher peak plasma concentrations of the compounds being measured. In parallel, the biliary clearance was moderately reduced. The results suggest that inhibition of hepatobiliary transport is a likely mechanism for the interaction between erythromycin and ximelagatran. Furthermore, the study demonstrated the value of direct bile sampling in humans for the identification of primary biliary metabolites.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
- Nielsen, Elisabet I., 1973-, et al.
(författare)
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Population Pharmacokinetic Analysis of Vaginally and Intravenously Administered Oxytocin in Postmenopausal Women
- 2017
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 57:12, s. 1573-1581
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Tidskriftsartikel (refereegranskat)abstract
- Oxytocin is a neuropeptide hormone used clinically for more than 50 years due to its ability to induce uterine contractions and milk ejection. Vagitocin is a vaginal oxytocin gel developed as a potential treatment of vaginal atrophy in postmenopausal women. The aim of this study was to characterize the oxytocin pharmacokinetics following vaginal and intravenous administration in postmenopausal women. Data from 33 participants enrolled in 2 clinical studies were used in the analysis, with a total of 651 observed oxytocin plasma concentrations, of which 78 were baseline observations, 178 observations following intravenous administration (10 IU), and 395 observations following vaginal administration (100 or 400 IU). The population pharmacokinetics of oxytocin was described using a 2-compartment disposition model with a flexible parallel absorption model accounting for double-peak profiles following vaginal administration. The clearance, volume of distribution at steady state, distribution half-life, and terminal half-life were estimated to be 27 L/h, 15 L, 5.5 minutes, and 1.2 hours, respectively. The bioavailability following vaginal administration was estimated to be 2.5% for the typical patient, but with considerable variability both between individuals (interindividual variability of 374%) and between occasions (interoccasion variability of 79%). The data and the developed model add new and important information as to the clinical pharmacokinetics of oxytocin.
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| 44. |
- Nilsson, Dag, et al.
(författare)
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NXY-059 does not affect bleeding time in healthy volunteers : A randomized, double-blind, placebo-controlled, 3-period crossover phase I study
- 2007
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 47:2, s. 264-272
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Tidskriftsartikel (refereegranskat)abstract
- NXY-059 is a novel free radical-trapping neuroprotectant that reduces infarct size and preserves brain function in animal models of acute ischemic stroke. It is the first neuroprotectant to demonstrate a reduction in global disability in a phase III clinical trial, as measured by the modified Rankin Scale. Any effect of NXY-059 on hemostasis may be important when treating stroke patients. This phase I randomized, double-blind, placebo-controlled, 3-period crossover study compared the effect of NXY-059, desmopressin, and placebo on bleeding time, platelet aggregation, and adhesion in 30 healthy volunteers. NXY-059 did not prolong bleeding time compared with placebo: mean (SD) time for NXY-059, 369.5 seconds (125.0 seconds) versus placebo, 369.1 seconds (136.0 seconds). There were no significant effects on platelet aggregation or adhesion. At a mean unbound plasma concentration (Cu-ss) of 335 mu mol/L, NXY-059 was well tolerated, with no major safety concerns identified. In conclusion, NXY-059 does not appear to affect primary hemostasis.
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| 45. |
- Novakovic, Ana M., 1985-, et al.
(författare)
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Pharmacometric analysis of the relationship between absolute lymphocyte count, and expanded disability status scale and relapse rate, efficacy end points, in multiple sclerosis trials
- 2018
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 58:10, s. 1284-1294
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to assess the relationship between the absolute lymphocyte count (ALC), and disability (as measured by the Expanded Disability Status Scale [EDSS]) and occurrence of relapses, 2 efficacy endpoints, respectively, in patients with remitting-relasping multiple sclerosis. Data for ALC, EDSS, and relapse rate were available from 1319 patients receiving placebo and/or cladribine tablets. Pharmacodynamic models were developed to characterize the time course of the endpoints. ALC-related measures were then evaluated as predictors of the efficacy endpoints. EDSS data were best fitted by a model where the logit-linear disease progression is affected by the dynamics of ALC change from baseline. Relapse rate data were best described by the Weibull hazard function, and the ALC change from baseline was also found to be a significant predictor of time to relapse. Presented models have shown that once cladribine exposure driven ALC-derived measures are included in the model, the need for drug effect components is of less importance (EDSS) or disappears (relapse rate). This simplifies the models and theoretically makes them mechanism specific rather than drug specific. Having a reliable mechanism-specific model would allow leveraging historical data across compounds, to support decision making in drug development and possibly shorten the time to market.
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| 46. |
- Quartino, Angelica, et al.
(författare)
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Modeling of in vitro drug activity and prediction of clinical outcome in acute myeloid leukemia
- 2007
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 47:8, s. 1014-1021
-
Tidskriftsartikel (refereegranskat)abstract
- The objectives of this study were to develop a population pharmacodynamic model describing the in vitro drug sensitivity of tumor cells and to relate in vitro parameters to clinical outcome. Cell samples from 179 patients with acute myelocytic leukemia were exposed to cytosine arabinoside and daunorubicin, and cytotoxicity was analyzed using the fluorometric microculture cytotoxicity assay. A sigmoid E(max)-model for daunorubicin and an E(max)-model for cytosine arabinoside described the data. The model predicted drug potency (EC(50)) adequately from 1 concentration measurement. A logistic regression on individual in vitro parameters of 46 patients treated with the daunorubicin plus cytosine arabinoside regimen showed that the probability of complete response was significantly (P < .05) related to the product of the E(max)/EC(50) ratio of the two drugs. The findings demonstrate the value of population pharmacodynamic modeling of in vitro drug sensitivity data and a significant relationship between the in vitro parameters and clinical outcome.
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| 47. |
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| 48. |
- Rayner, Craig R., et al.
(författare)
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Population pharmacokinetics of oseltamivir when coadministered with probenecid.
- 2008
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 48:8, s. 935-947
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Tidskriftsartikel (refereegranskat)abstract
- Oseltamivir is a potent, selective, oral neuraminidase inhibitor for the treatment and prophylaxis of influenza. Plasma concentrations of the active metabolite, oseltamivir carboxylate, are increased in the presence of probenecid, suggesting that the combination could allow for the use of reduced doses of oseltamivir. To investigate this proposal, we developed a population pharmacokinetic model and simulated the pharmacokinetics of candidate combination regimens of oral oseltamivir (45 mg and 30 mg twice a day) plus oral probenecid (500 mg/6 hourly). Probenecid plus oseltamivir 45 mg achieved all the pharmacokinetic parameters expected of oseltamivir alone, but combination with oseltamivir 30 mg and dose interval extension approaches did not. An oseltamivir-probenecid combination may compromise tolerability and enhance the potential for drug interactions. In addition, increased dosing requirements may affect compliance and attainment of optimal oseltamivir exposure, potentially facilitating the emergence of viral strains with reduced susceptibility to oseltamivir. These factors, set alongside increased capacity for oseltamivir production, should be carefully considered before an oseltamivir-probenecid combination is used.
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| 49. |
- Ribbing, Jakob, et al.
(författare)
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A model for glucose, insulin, and beta-cell dynamics in subjects with insulin resistance and patients with type 2 diabetes.
- 2010
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Ingår i: Journal of clinical pharmacology. - : Wiley. - 1552-4604 .- 0091-2700. ; 50:8, s. 861-72
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 diabetes mellitus (T2DM) is a progressive, metabolic disorder characterized by reduced insulin sensitivity and loss of beta-cell mass (BCM), resulting in hyperglycemia. Population pharmacokinetic-pharmacodynamic (PKPD) modeling is a valuable method to gain insight into disease and drug action. A semi-mechanistic PKPD model incorporating fasting plasma glucose (FPG), fasting insulin, insulin sensitivity, and BCM in patients at various disease stages was developed. Data from 3 clinical trials (phase II/III) with a peroxisome proliferator-activated receptor agonist, tesaglitazar, were used to develop the model. In this, a modeling framework proposed by Topp et al was expanded to incorporate the effects of treatment and impact of disease, as well as variability between subjects. The model accurately described FPG and fasting insulin data over time. The model included a strong relation between insulin clearance and insulin sensitivity, predicted 40% to 60% lower BCM in T2DM patients, and realistic improvements of BCM and insulin sensitivity with treatment. The treatment response on insulin sensitivity occurs within the first weeks, whereas the positive effects on BCM arise over several months. The semi-mechanistic PKPD model well described the heterogeneous populations, ranging from nondiabetic, insulin-resistant subjects to long-term treated T2DM patients. This model also allows incorporation of clinical-experimental studies and actual observations of BCM.
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| 50. |
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