Are self-reported and self-monitored adherence good proxies for reaching relevant plasma concentrations?: Experiences from a study of anti-depressants in healthy volunteers.

BACKGROUND: The use of electronic-based devices to measure and to improve adherence of subjects in clinical trials is increasing. AiCure has developed a mobile technology that is claimed to provide visual confirmation of drug ingestion. While there is evidence suggesting that including such self-monitoring device in a study increases adherence, the quality of the data produced by the device may be questionable. Can the mobile technology reliably distinguish whether a subject takes the study drug or not? METHODS: Adherence was calculated based on exposure, self-reporting and self-monitoring for subjects randomized to an anti-depressant. Levels of adherence and agreement between the three approaches were investigated based on calculation of proportions, two-way tables and receiver operating curves. RESULTS: A total of 214 subjects had measured concentrations of study drug at all three time points (end of weeks 3, 4 and 5), along with adherence data to define proportion of days adherent based on self-reporting and the self-monitoring instrument developed by AiCure. Self-reported adherence proportions were higher than self-monitored adherence proportions, although both were high (>90%). Neither self-reported and self-monitored adherence agreed with exposure-based adherence. CONCLUSION: Both self-reported and self-monitored adherence overestimated adherence. Neither the self-reported nor the self-monitored adherence measure reflected subjects' actual adherence. This prompts for cautiousness when interpreting either of them, and it underlines the need for thorough validation of electronic devices and software that claims to measure adherence. The AiCure instrument may not be able to reliably determine whether the subjects swallow the study medication.

Population pharmacokinetics of nalmefene in healthy subjects and its relation to µ-opioid receptor occupancy.

AIMS: The aims of this study were to develop a population pharmacokinetic (PK) model to describe the PK of nalmefene in healthy subjects and to relate the exposure of nalmefene to the µ-opioid receptor occupancy by simulations in the target population. METHODS: Data from nine phase I studies (243 subjects) with extensive blood sampling were pooled and used for the population PK model building. Data from four other phase I studies (85 subjects) were pooled and used as an external validation dataset. Eight subjects from an imaging study contributed occupancy data and the pharmacokinetic/pharmacodynamic (PK/PD) relationship was modelled. Combining the population PK model and the PK/PD relationship enabled simulations to predict µ-opioid occupancy. RESULTS: A two compartment model with first order absorption best described the nalmefene PK data. The typical subject in the population was estimated to have a systemic clearance of 60.4 l h(-1) and a central volume of distribution of 266 l. Absolute oral bioavailability was estimated to 41% without food intake and with food about 53%. Simulation of the µ-opioid receptor occupancy shows that the 95% confidence bound is within or above 60-90% occupancy for up to 22-24 h after a single dose of 20 mg nalmefene. CONCLUSIONS: A robust population PK model for nalmefene was developed. Based on the concentration-occupancy model the µ-opioid receptor occupancy after a single 20 mg dose of nalmefene is predicted to be above the target therapeutic occupancy for about 24 h in about 95% of the target population.

Population pharmacokinetics of eptinezumab in paediatric patients with migraine and dose selection for phase 3 paediatric migraine studies.

This population pharmacokinetics (PopPK) analysis of eptinezumab used data from a paediatric study and a prior adult PopPK model to compare eptinezumab pharmacokinetics between adult and paediatric populations to determine dose recommendations for the phase 3 paediatric studies in migraine. The data consisted of 16 adolescents and 12 children with migraine, with corresponding demographics and 278 plasma concentrations in total. PopPK analysis was performed through nonlinear mixed effect modelling and with prior knowledge taken from a previous PopPK model in adults. A two-compartment model-adjusted for body weight impact on clearances and volumes of distributions and scaled to the power of 0.75 and 1.0, respectively-was found to adequately describe the paediatric pharmacokinetic data. The simulated population showed overlap in area under the plasma concentration-time curve and maximum plasma concentration between the paediatric and adult populations, with paediatric exposures within 10%-15% above adult levels on average. To provide comparable exposure to the approved adult doses, weight-based dosing adjustments are recommended for paediatric patients weighing ≤40 kg, while no adjustments are needed for patients weighing >40 kg. These results support the dosing strategy being used in the ongoing efficacy and safety studies with eptinezumab in children and adolescents with migraine.

Clinical benefits and bioequivalence of vortioxetine oral drop solution versus oral tablets.

BACKGROUND: Vortioxetine is efficacious and well tolerated in patients with major depressive disorder (MDD) and is available as an immediate-release tablet and oral drop solution. The oral drop solution may offer clinical benefits versus a tablet, such as the reduced risk of nausea, personalised dosing and ease of administration. AIMS: To investigate the bioequivalence of vortioxetine 20 mg/mL oral drop solution versus a 20 mg immediate-release tablet. METHODS: Healthy adults were randomised 1:1 to receive vortioxetine 20 mg oral drop solution or immediate-release 20 mg tablet after fasting on days 1 and 29 in an open-label, single-centre, single-dose crossover study. The area under the plasma concentration-time curve from 0 to 72 h (AUC0-72h) and maximum plasma concentration (Cmax) were analysed. Bioequivalence was concluded if the 90% CI for the oral drop solution-to-immediate-release tablet ratio for AUC0-72h and Cmax were contained within a range of 0.80-1.25. RESULTS: Vortioxetine oral drop solution was bioequivalent to the tablet (n = 26; estimated AUC0-72h ratio 1.06 (90% CI: 1.03-1.10); Cmax ratio 1.01 (90% CI: 0.97-1.05)). A similar proportion of participants reported adverse events in each study arm but more headache events (7 vs 1) were reported with the oral drop solution versus tablet. The most common adverse event was nausea (16-23% of participants; all mild intensity). CONCLUSIONS: Vortioxetine oral drop solution is bioequivalent to immediate-release tablets. Oral drop solution provides an alternative to tablets and facilitates clinical benefit through individualised treatment, including gradual dose up-titration, for patients with MDD.

Stress-free blood sampling in minipigs: A novel method for assessing 24-h cortisol profiles and drug effects on diurnal and ultradian rhythms.

We developed a novel, stress-free blood sampling method for minipigs, allowing continuous cortisol monitoring over 24 h. Baseline cortisol levels exhibited both ultradian and diurnal rhythms. During nighttime, smaller ultradian rhythms overlaid a lower baseline cortisol, which increased in sleeping pigs before lights were turned on. Additionally, we developed an analytical tool based on the R package "pracma" to quantify ultradian peak and circadian components of the cortisol profiles. To validate our model, we investigated the effects of Verucerfont, a CRH receptor antagonist, and Venlafaxine, a serotonin-norepinephrine reuptake inhibitor. Verucerfont reduced cortisol levels during the first 9 h without affecting diurnal rhythm. Cortisol peak parameters decreased, with a 31% reduction in overall area under the curve (AUC) and a 38% reduction in ultradian average AUC. Ultradian peaks decreased from 7 to 4.5, with 34% lower amplitude. Venlafaxine maintained plasma concentrations within the targeted human effective range. This method enables us to enhance our understanding of cortisol regulation and provide valuable insights for the impact of investigation drugs on the diurnal and ultradian rhythms of cortisol.

Does ethnicity impact CYP2D6 genotype-phenotype relationships?

Polymorphism of the CYP2D6 gene leads to substantial interindividual variability in CYP2D6 enzyme activity. Despite improvements in prediction of CYP2D6 activity based on genotype information, large interindividual variability within CYP2D6 genotypes remains and ethnicity could be a contributing factor. The aim of this study was to investigate interethnic differences in CYP2D6 activity using clinical datasets of three CYP2D6 substrates: (i) brexpiprazole (N = 476), (ii) tedatioxetine (N = 500), and (iii) vortioxetine (N = 1073). The CYP2D6 activity of all individuals in the dataset was estimated through population pharmacokinetic analyses as previously reported. Individuals were assigned a CYP2D6 phenotype and CYP2D6 genotype group based on their CYP2D6 genotype and interethnic differences were investigated within each group. Among individuals categorized as CYP2D6 normal metabolizers, African Americans had a lower CYP2D6 activity compared to Asians (p < 0.01) and in the tedatioxetine and vortioxetine analyses also compared to Whites (p < 0.01). Among CYP2D6 intermediate metabolizers, interethnic differences were also observed, but the findings were not consistent across the substrates. Asian carriers of CYP2D6 decreased function alleles tended to exhibit higher CYP2D6 activity compared to Whites and African Americans. The observed interethnic differences within the CYP2D6 phenotype and genotype groups appeared to be driven by differences in CYP2D6 allele frequencies across ethnicities rather than interethnic differences in enzyme activity for individuals carrying identical CYP2D6 genotypes.

Estimating the In Vivo Function of CYP2D6 Alleles through Population Pharmacokinetic Modeling of Brexpiprazole.

Accurate prediction of CYP2D6 phenotype from genotype information is important to support safe and efficacious pharmacotherapy with CYP2D6 substrates. To facilitate accurate CYP2D6 genotype-phenotype translation, there remains a need to investigate the enzyme activity associated with individual CYP2D6 alleles using large clinical data sets. This study aimed to quantify and compare the in vivo function of different CYP2D6 alleles through population pharmacokinetic (PopPK) modeling of brexpiprazole using data from 13 clinical studies. A PopPK model of brexpiprazole and its two metabolites, DM-3411 and DM-3412, was developed based on plasma concentration samples from 826 individuals. As the minor metabolite, DM-3412, is formed via CYP2D6, the metabolic ratio of DM-3412:brexpiprazole calculated from the PopPK parameter estimates was used as a surrogate measure of CYP2D6 activity. A CYP2D6 genotype-phenotype analysis based on 496 subjects showed that the CYP2D6*2 allele (n = 183) was associated with only 10% enzyme activity relative to the wild-type allele (CYP2D6*1) and a low enzyme activity was consistently observed across genotypes containing CYP2D6*2. Among the decreased function alleles, the following enzyme activities relative to CYP2D6*1 were estimated: 23% for CYP2D6*9 (n = 20), 32% for CYP2D6*10 (n = 62), 64% for CYP2D6*14 (n = 1), 4% for CYP2D6*17 (n = 37), 4% for CYP2D6*29 (n = 13), and 9% for CYP2D6*41 (n = 64). These findings imply that a lower functional value would more accurately reflect the in vivo function of many reduced function CYP2D6 alleles in the metabolism of brexpiprazole. The low enzyme activity observed for CYP2D6*2, which has also been reported by others, suggests that the allele exhibits substrate-specific enzyme activity.

Cytochrome P450 2D6 genotype-phenotype characterization through population pharmacokinetic modeling of tedatioxetine.

The cytochrome P450 (CYP) 2D6 enzyme exhibits large interindividual differences in metabolic activity. Patients are commonly assigned a CYP2D6 phenotype based on their CYP2D6 genotype, but there is a lack of consensus on how to translate genotypes into phenotypes, causing inconsistency in genotype-based dose recommendations. The aim of this study was to quantify and compare the impact of different CYP2D6 genotypes and alleles on CYP2D6 metabolism using a large clinical data set. A population pharmacokinetic (popPK) model of tedatioxetine and its CYP2D6-dependent metabolite was developed based on pharmacokinetic data from 578 subjects. The CYP2D6-mediated metabolism was quantified for each subject based on estimates from the final popPK model, and CYP2D6 activity scores were calculated for each allele using multiple linear regression. The activity scores estimated for the decreased function alleles were 0.46 (CYP2D6*9), 0.34 (CYP2D6*10), 0.01 (CYP2D6*17), 0.65 (CYP2D6*29), and 0.21 (CYP2D6*41). The CYP2D6*17 and CYP2D6*41 alleles were thus associated with the lowest CYP2D6 activity, although only the difference to the CYP2D6*9 allele was shown to be statistically significant (p = 0.02 and p = 0.05, respectively). The study provides new in vivo evidence of the enzyme function of different CYP2D6 genotypes and alleles. Our findings suggest that the activity score assigned to CYP2D6*41 should be revisited, whereas CYP2D6*17 appears to exhibit substrate-specific behavior. Further studies are needed to confirm the findings and to improve the understanding of CYP2D6 genotype-phenotype relationships across substrates.

Quantification of In Vivo Metabolic Activity of CYP2D6 Genotypes and Alleles Through Population Pharmacokinetic Analysis of Vortioxetine.

Assignment of CYP2D6 phenotype from genotype data can be challenging and despite efforts to standardize translation, there is currently no universally accepted method. To facilitate standardization, there remains a need to precisely quantify the in vivo function of different CYP2D6 genotypes. Vortioxetine is metabolized to its major metabolite, Lu AA34443, primarily via CYP2D6. The aim of this study was to quantify the in vivo CYP2D6 activity of different CYP2D6 alleles and genotypes through population pharmacokinetic (PopPK) modeling of vortioxetine and Lu AA34443. Plasma concentration data of vortioxetine and Lu AA34443 from 1,140 subjects originating from 29 clinical pharmacology studies were pooled for the analysis. A joint PopPK model described the pharmacokinetics of vortioxetine and Lu AA34443 simultaneously and provided estimates of the CYP2D6-mediated metabolism for each subject. Subjects normally classified as CYP2D6 intermediate metabolizers (IMs) showed different levels of CYP2D6 activity with carriers of one fully functional allele and one null function allele having 77% higher CYP2D6 activity compared with carriers of two decreased function alleles (P < 0.0001). The decreased function alleles were associated with different levels of reduction of CYP2D6 activity. Fixing the activity of fully functional alleles to 1.0, the relative activities of CYP2D6*9, CYP2D6*10, CYP2D6*17, and CYP2D6*41 were 0.22, 0.37, 0.17, and 0.21, respectively. The activity of CYP2D6*10 was shown to be significantly greater than that of CYP2D6*17 (P = 0.01) and CYP2D6*41 (P = 0.02). These results warrant further discussion of current CYP2D6 genotype-phenotype classification systems particularly regarding decreased function alleles and the IM phenotype.

Validation of a Population Pharmacokinetic Model of Vortioxetine Using Therapeutic Drug Monitoring Data.

INTRODUCTION: Vortioxetine is an antidepressant primarily metabolized by the polymorphic enzyme cytochrome P450 (CYP) 2D6. A population pharmacokinetic (popPK) model of vortioxetine and its CYP2D6-dependent metabolite was recently published. OBJECTIVE: The aim of the current study was to assess the predictive performance of the popPK model using vortioxetine concentration measurements from a clinical setting. Furthermore, the study aimed to evaluate the ability of different CYP2D6 phenotype classification systems to provide accurate concentration predictions. METHODS: Overall, 1388 patients receiving vortioxetine treatment were identified from a therapeutic drug monitoring (TDM) database in Oslo, Norway; 334 CYP2D6-genotyped patients with 502 serum concentrations of vortioxetine, analysed by a validated ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) method, were retrospectively included. The performance of the vortioxetine popPK model was tested on the clinical data from the TDM database. RESULTS: Overall, the model had a good ability to predict vortioxetine concentrations measured in clinical practice, with a slight tendency to overpredict concentrations. Using simulation-based diagnostics, 76% of the prediction-corrected TDM concentrations were within the 90% prediction interval based on 1000 simulated data sets. Prediction-based diagnostics showed the best performance for CYP2D6 poor and ultrarapid metabolizers, with a median prediction error (MDPE) of 12% and 23%, respectively, while the poorest performance was observed for normal metabolizers, with an MDPE of 66%. In the comparison of different CYP2D6 phenotype classification systems, the use of differentiated activity scores for decreased function alleles did not improve the concentration predictions. Grouping the CYP2D6 genotypes into the four conventional phenotype groups provided predictions closest to the TDM measured concentrations. CONCLUSION: TDM data provide a unique insight into real-world clinical practice with vortioxetine. The tendency of the popPK model to overpredict vortioxetine concentrations measured in TDM may be attributed to several factors, including poor treatment compliance for some patients and, to a lesser extent, lack of information on patient characteristics and misspecified CYP2D6 alleles. To optimize personalized therapy with vortioxetine, real-world clinical data sets originating from different ethnicities need to be studied in the future.

Intravenous vortioxetine to accelerate onset of effect in major depressive disorder: a 7-day randomized, double-blind, placebo-controlled exploratory study.

This 7-day randomized, double-blind, placebo-controlled fixed-dose study (NCT03766867) explored the potential for accelerating the onset of antidepressant efficacy of single-dose intravenous (IV) vortioxetine at oral vortioxetine treatment initiation. Patients (ages 18-65 years) hospitalized per standard-of-care with major depressive disorder, who were currently treated with a selective serotonin reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor for a major depressive episode [Montgomery-Åsberg Depression Rating Scale (MADRS) total score ≥ 30], received one dose of single-blind IV placebo (1-day placebo lead-in period) before being randomly switched to either single-dose IV vortioxetine 25 mg plus daily oral vortioxetine 10 mg (n = 39), or IV placebo plus daily oral placebo (n = 41). In the placebo lead-in period, patients improved slightly by 0.6 MADRS-6 point; however, at day 1 after randomization, both treatment groups had improved by approximately 3 MADRS-6 points (mean difference = -0.8; P = 0.263), the study thus not meeting its primary endpoint. Similar results were seen for other outcomes except a numerically larger improvement in anxiety symptoms with vortioxetine vs placebo. Pharmacokinetic data confirmed that IV vortioxetine facilitated reaching steady-state plasma concentration within 24 h. IV plus oral vortioxetine was well tolerated, with low levels of nausea as the most common adverse event.

Intravenous vortioxetine to accelerate onset of effect in major depressive disorder: a 2-week, randomized, double-blind, placebo-controlled study.

This 2-week randomized, double-blind, placebo-controlled fixed-dose study (NCT02919501) explored the potential of accelerating onset of antidepressant efficacy and plasma exposure with single-dose intravenous vortioxetine at oral vortioxetine treatment initiation. Outpatients (ages 18-65 years) with major depressive disorder and a current depressive episode (Montgomery Åsberg Depression Rating Scale total score ≥30) were randomized to an initial single dose of either intravenous vortioxetine 17 mg (n = 27) or intravenous placebo (n = 28), both treatments followed by 2 weeks of oral vortioxetine (10 mg/day). From baseline to day 7, both groups exhibited fast and substantial improvements by approximately 14 Montgomery Åsberg Depression Rating Scale points, with no statistically significant treatment difference for this primary endpoint. Improvements were substantial already within 24 hours, with numerical treatment differences of 1.3 and 1.6 points at days 1 and 3, respectively, in favour of intravenous vortioxetine + oral vortioxetine. Pharmacokinetic data confirmed that intravenous vortioxetine facilitated reaching steady-state plasma concentration within 24 hours. Intravenous vortioxetine + oral vortioxetine was safe and well-tolerated, with nausea as the most common adverse event. This study supported intravenous vortioxetine as a means of rapidly reaching therapeutic vortioxetine blood levels.

Pharmacokinetics and Safety of Vortioxetine in the Chinese Population.

INTRODUCTION: Major depressive disorder (MDD) is associated with a significant burden of disease in China. Awareness and better access to treatments could help alleviate the burden associated with MDD. Because variations have been observed in the pharmacokinetics (PK) of antidepressants across different races and ethnicities, evaluation of the clinical pharmacology of vortioxetine in diverse populations remains important to assess the potential need for dose adjustments. METHODS: Data were pooled from two phase I open-label PK studies in healthy Chinese subjects, and one phase III double-blind noninferiority study in Chinese patients with MDD to describe the PK and safety data for vortioxetine. Doses in these studies ranged from 10 mg (single dose) to 10 and 20 mg (multiple daily doses). A population PK analysis of vortioxetine in the Chinese population was conducted using nonlinear mixed-effect modeling. RESULTS: In total, 186 individuals were included in the PK analysis: 79 healthy Chinese subjects and 107 Chinese patients with MDD. No clinically significant differences in the PK of vortioxetine were observed between the Chinese population and the previous data in non-Chinese populations. Because of a generally lower weight in the Chinese population compared with the non-Chinese population, exposures were 19% and 18% higher in the Chinese population than in the non-Chinese population (for maximum observed plasma concentration and area under the plasma concentration-time curve, respectively), which is not considered clinically relevant. A high prevalence of pruritus was observed in one phase I PK study (56% overall); however, this was not reflected in the phase III study in Chinese patients with MDD (0.8%). CONCLUSIONS: The PK parameters of vortioxetine in Chinese subjects were comparable to previous data in non-Chinese subjects. Overall, no new safety concerns were raised among the Chinese population. On the basis of this analysis, the tolerability profile of vortioxetine in Chinese healthy subjects and in patients with MDD is expected to be comparable to that in the non-Chinese population. FUNDING: H. Lundbeck A/S, Valby, Denmark. TRIAL REGISTRATION: NCT01676571.

Vortioxetine: Clinical Pharmacokinetics and Drug Interactions.

Vortioxetine is a novel antidepressant with multimodal activity currently approved for the treatment of major depressive disorder. Vortioxetine is orally administered once daily at 5- to 20-mg doses. The pharmacokinetics of vortioxetine are linear and dose proportional, with a mean terminal half-life of approximately 66 h and steady-state plasma concentrations generally achieved within 2 weeks of dosing. The mean absolute oral bioavailability of vortioxetine is 75%. No food effect on pharmacokinetics was observed. Vortioxetine is metabolized by cytochrome P450 enzymes and subsequently by uridine diphosphate glucuronosyltransferase. The major metabolite is pharmacologically inactive, and the minor pharmacologically active metabolite is not expected to cross the blood-brain barrier, making the parent compound primarily responsible for in-vivo activity. No clinically relevant differences were observed in vortioxetine exposure by sex, age, race, body size, and renal or hepatic function. Dose adjustment is only recommended for cytochrome P450 2D6 poor metabolizers based on polymorphism of the cytochrome P450 enzymes involved. Similarly, except for bupropion, a strong cytochrome P450 2D6 inhibitor, and rifampin, a broad cytochrome P450 inducer, co-administration of other drugs evaluated did not affect the vortioxetine exposure or safety profile in any clinically meaningful way. Pharmacodynamic studies demonstrated that vortioxetine achieved high levels of serotonin transporter occupancy in relevant brain areas, affected neurotransmitter levels in the cerebrospinal fluid, and modified abnormal resting state networks in the brain over the therapeutic dose range. Overall, vortioxetine can be administered in most populations studied to date without major dose adjustments; however, dose adjustments should be considered on a patient-by-patient basis.

Pharmacokinetics and Safety of Vortioxetine in Pediatric Patients.

OBJECTIVE: The primary objectives of this study were to evaluate the pharmacokinetics (PK) and tolerability of single and multiple doses of vortioxetine in children and adolescents with a depressive or anxiety disorder and to provide supportive information for appropriate dosing regimens for pediatric clinical trials. METHODS: This prospective, open-label, multinational, multisite, multiple-dose trial enrolled 48 patients (children and adolescents; 1:1 ratio) divided into 8 cohorts (4 adolescent and 4 child), with each cohort including 6 patients. The cohorts in each age group were assigned to receive one of four dosing regimens: vortioxetine 5, 10, 15, or 20 mg q.d. for 14 days. The total treatment period lasted 14-20 days with patients in the higher dose cohorts uptitrated over 2-6 days. Plasma samples for PK analysis were obtained on the first and last days of dosing. RESULTS: Among children and adolescents, respectively, 62% and 92% had depression and 58% and 33% had anxiety disorder. Comorbid attention-deficit/hyperactivity disorder (ADHD) was present in 50% of children and 38% of adolescents. After 14 days q.d. at the target dose, the PK of vortioxetine concentrations was generally proportional to the dose in both age groups. Exposure, as assessed by maximum plasma concentrations and area under the plasma concentration-time curve from time 0 to 24 hours, was 30%-40% lower in adolescents than in children. There was no significant relationship between sex, height, or ADHD diagnosis and PK parameters. Most adverse events were mild in severity and consistent with those seen in adults. CONCLUSION: The results suggest that the dosages of vortioxetine evaluated (5-20 mg q.d.; approved for treatment in adults) and the uptitration schedule used are appropriate for pediatric efficacy and safety trials.

Comparative renal, hepatic, and bone marrow toxicity of Cisplatin and radioactive Cisplatin (191Pt) in Wistar rats.

The aim of the study was to investigate the possibility to increase the therapeutic gain of the cytotoxic agent, cisplatin, by incorporation of radioactive platinum. In this study, we investigated how organs at risk (i.e., kidneys, bone marrow, and liver) are affected by treatment with 191Pt-cisplatin, compared to treatment with conventional cisplatin. Rats (total, n = 69) were divided into three groups and given 5 mg/kg 191Pt-cisplatin and 5 mg/kg nonradioactive cisplatin or saline. The weight of the animals and blood samples, including analysis of creatinine, bilirubin, alanine and aspartate aminotransferases and platelet count, was followed for 6 weeks after treatment. Histopathology examinations of kidney and liver tissues were performed. An initial decrease in weight gain was seen from 3 days after treatment with cisplatin and 191Pt-cisplatin and for 1 week onward; thereafter, the weight gain continued, following the same pattern as for the control group. Concentration of plasma creatinine was increased for both cisplatin groups but with no significant difference between treatment groups. No other significant differences in effect parameters were found. There was no increase in toxicity for radioactive cisplatin on liver, kidneys, and bone marrow, compared to conventional cisplatin. Further experimental and clinical studies on preparations of this type are thus warranted.

A Population Pharmacokinetic-Pharmacodynamic Meta-Analysis of Vortioxetine in Patients with Major Depressive Disorder.

Vortioxetine is approved for the treatment of major depressive disorder (MDD). This analysis aimed to develop pharmacokinetic (PK) and PK/Efficacy models to evaluate the exposure-response relationship for vortioxetine in patients with MDD. PK data from 10 MDD and two generalized anxiety disorder studies of vortioxetine (3160 patients), and efficacy data [Montgomery-Åsberg Depression Rating Scale (MADRS)] from seven MDD studies (2537 patients), were used for the development of PK and PK/Efficacy models. One- and two-compartment models were evaluated as structural PK models, and linear and nonlinear (Emax) models were used to describe the relationship between average vortioxetine concentration at steady-state (Cav) and change in MADRS score from baseline (ΔMADRS). The impact of selected covariates on the PK and efficacy parameters of vortioxetine was also investigated. PK of vortioxetine was best characterized by a two-compartment model with first-order absorption and elimination. Mean estimates for oral clearance (CL/F) and volume of distribution for the central compartment of vortioxetine were 42 L/hr and 2920 L. Creatinine clearance, height and geographic region had statistically significant effects on vortioxetine CL/F, but the effect of each of these covariates was not considered clinically relevant, as they lead to ±26% change in area under the curve or Cmax of vortioxetine. An Emax model best described the relationship between ΔMADRS and Cav. Half-maximal effective concentration (EC50) and Emax estimates were 24.9 ng/mL and 7.0. No identified covariates, except region, had clinically meaningful effects on vortioxetine efficacy. These PK/Efficacy models adequately characterized the vortioxetine exposure-response relationship.

Population biokinetic modeling of thyroid uptake and retention of radioiodine.

The aim of this study was to build a population biokinetic model for the uptake and retention of radioiodine in the thyroid of hyperthyroid patients. At Malmö University Hospital (Malmö, Sweden), a database with detailed information from (131)I-iodide therapies has been created. The database consisted of uptake measurement from 422 patients with the diagnoses of diffuse goiter, multinodular goiter, adenoma, and undefined. In total, 2013 uptake measurements, performed from 3 hours to 9 days after intake of a test activity of (131)I, were included. Nonlinear mixed effect modeling (NLME) was used to model the population biokinetics of (131)I. The structural model was parameterized in terms of the level of uptake (A), the rate constant for the absorption to the thyroid (k(a)) and the rate constant for the output from the thyroid (k(e)). Interindividual and interoccasion variabilities were added to all three structural parameters. The following covariates were found to significantly affect the structural model parameters: Diagnosis on A, k(a) and K(e), volume of the thyroid on A and k(a), and age on k(a) and k(e). The interindividual and interoccasion variabilities were in the range of 8%-28%. The variance of the residual error, modeled as an additive, was low. This type of modeling is a powerful tool for biokinetic studies and should be used in other biokinetic areas of radioiodine therapy, such as radiation dosimetry.

Differentiated effects of the multimodal antidepressant vortioxetine on sleep architecture: Part 1, a pharmacokinetic/pharmacodynamic comparison with paroxetine in healthy men.

We compared the effect of vortioxetine, paroxetine and placebo after three days of dosing on sleep architecture. This was a randomised, double-blind, four-way crossover, placebo-controlled, multiple-dose study in 24 healthy young men. Subjects received 20mg vortioxetine, 40 mg vortioxetine, 20mg paroxetine or placebo for three consecutive days in four different periods with at least three weeks between them. Polysomnography and blood sampling for pharmacokinetic analysis were performed on the pre-dose night and nights 1 and 3 of dosing in each period. Plasma concentrations of vortioxetine and paroxetine during the polysomnography measurement were used to estimate SERT occupancies using published relationships in healthy subjects.All three active treatments significantly increased REM onset latency and decreased time spent in REM sleep. In the pharmacokinetic/pharmacodynamics analysis significant relationships were found between REM onset latency and time spent in REM sleep and vortioxetine/paroxetine exposure. The relation between REM suppression parameters and SERT occupancy was significantly different between vortioxetine and paroxetine, despite the same SERT occupancy. This indicates that vortioxetine has a different clinical pharmacological profile from paroxetine, which may explain the differences in adverse effect profile of the two drugs, for instance the lower incidence of nausea, weight gain and sexual dysfunction with vortioxetine.

Nutritional status and muscle strength in patients with emphysema and severe alpha(1)-antitrypsin deficiency.

BACKGROUND: The association between emphysema and weight loss is well known. Severe alpha(1)-antitrypsin deficiency is an important risk factor for the development of emphysema. STUDY OBJECTIVE: To study nutritional status and muscle strength in patients with severe alpha(1)-antitrypsin deficiency and emphysema. METHODS: Fifteen alpha(1)-antitrypsin-deficient patients with emphysema (7 men) and 18 healthy control subjects (9 men) were included in the study. Total body protein (TBP) was measured by in vivo neutron activation analysis of nitrogen. Lean body mass (LBM) was estimated from measurement of total body potassium. In analogy with body mass index (BMI), TBP index and LBM index were calculated as TBP/height squared and LBM/height squared, respectively. Respiratory muscle strength was studied by maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax), and skeletal muscle strength by handgrip test. Plasma albumin, transthyretin, and retinol-binding protein concentrations were analyzed as biochemical markers of nutritional status. RESULTS: In the alpha(1)-antitrypsin-deficient individuals, lung function test results were consistent with severe chronic airway obstruction, whereas the healthy control subjects had normal lung function. No significant differences were found in age, body weight, or BMI between the groups. TBP (p < 0.05), TBP index (p < 0.001), LBM index (p < 0.05), and plasma concentration of transthyretin (p < 0.01) were significantly lower in the patients than in the control subjects. There was a significant correlation between TBP and LBM (p < 0.001), and between TBP and body weight (p < 0.001). In the male subgroup, PImax (p < 0.05) and PEmax (p < 0.05) were significantly lower in the patients than in the control subjects. In the female subgroup, handgrip strength was significantly lower in the patients than in the control subjects (p < 0.05). Body weight was significantly correlated with handgrip test (p < 0.05) in the male patients. In the female patients, body weight was significantly correlated with PImax (p < 0.05), LBM with PEmax (p < 0.05), and LBM with handgrip test (p < 0.01). CONCLUSION: Reduced TBP and plasma transthyretin concentration in alpha(1)-antitrypsin-deficient patients with emphysema may indicate early signs of malnutrition.