Need For Therapeutic Drug Monitoring Research Articles

Daptomycin Dosage Optimization in Renal Impairment Using Model-Informed Precision Dosing.

Daptomycin's efficacy and toxicity are closely related to its exposure, which can vary widely among individuals. The patient, a 59-year-old male with an estimated glomerular filtration rate (eGFR) of 12 mL/min/1.73 m² and a weight of 64 kg, was treated with 850 mg of daptomycin every other day for infective endocarditis caused by methicillin-resistant Staphylococcus aureus (MRSA). For patients with an estimated glomerular filtration rate of less than 30 mL/min/1.73 m², the dosing recommendations are not explicitly defined in the endocarditis guidelines. Subsequently, the pharmacology department was contacted to adjust the dosage. A population pharmacokinetic model developed by Dvorchik et al. was used for Bayesian estimation of the patient's pharmacokinetic parameters. The 24-hour area under the curve (AUC24) of daptomycin was calculated at steady state using peak and trough plasma samples. The minimum inhibitory concentration (MIC) of the MRSA strain was 0.25 mg/L. An AUC24/MIC ratio below 666 is associated with higher mortality risk, while an AUC24 above 939 h·mg/L correlates with increased risk of muscular toxicity. Initial AUC24 estimation was 1091 h·mg/L. Following a dosage reduction to 700 mg every other day, the AUC24 increased to 1600 h·mg/L. Further reduction to 500 mg every other day brought the AUC24 down to 750 h mg/L, with two subsequent measurements showing consistent AUC24 values of 500 h·mg/L, which is within the target range. Daptomycin ended 6 weeks after the initial negative blood culture, with no adverse effects or recurrence of MRSA infection. This case underscores the need for therapeutic drug monitoring and a multidisciplinary approach to adjust daptomycin doses in patients with renal impairment.

Pharmacokinetic variability of everolimus and impact of concomitant antiseizure medications in patients with tuberous sclerosis complex: A retrospective study of therapeutic drug monitoring data in Denmark and Norway.

The mTOR-inhibitor everolimus is a precision drug with antiepileptogenic properties approved for treatment of epilepsy in persons with tuberous sclerosis complex (TSC) in combination with other antiseizure medications (ASMs). However, the pharmacokinetic variability of everolimus is scarcely described, and the available information on pharmacokinetic interactions is scarce. The purpose of this study was to investigate pharmacokinetic variability of everolimus in patients with TSC, and the impact of age, sex and comedication. In this retrospective observational study we used anonymized data from medical records of patients with TSC using everolimus in Norway and Denmark, 2012 to 2020. Long-term therapeutic drug monitoring (TDM) identified inter-patient and intra-patient variability. The study included 59 patients, (36 females (61%)), median age 22 (range 3-59 years). Polytherapy was used in 50 patients (85%). The most frequently used ASMs were lamotrigine (n = 21), valproate (n = 17), and levetiracetam (n = 13). Blood concentrations of everolimus were measured in all patients. Pharmacokinetic variability of everolimus between patients was extensive, as demonstrated by a 24-fold variability from minimum-maximum concentration/dose (C/D)-ratios. The coefficient of variation (CV) for intra-patient (n = 59) and inter-patient variability (n = 47, ≥3 measurements) was 40% and 43%, respectively. The C/D-ratio of everolimus was 50% lower in 13 patients (22%) using enzyme-inducing ASMs compared to the 30 patients who did not (0.7 vs 1.4 ng/mL mg, P < .05). Age and sex were not significantly associated with changes in C/D-ratios of everolimus. Long-term TDM identified extensive variability in concentrations over time for everolimus both within and between patients, where comedication with enzyme-inducing ASMs was an important contributing factor. The findings suggest a need for TDM in patients with TSC treated with everolimus.

Busulfan Exposure Target Attainment in Adults Undergoing Allogeneic Hematopoietic Cell Transplantation: A Single Day Versus a Multiple Day Therapeutic Drug Monitoring Regimen

Busulfan exposure has previously been linked to clinical outcomes, hence the need for therapeutic drug monitoring (TDM). Study objective was to evaluate the effect of day 1 TDM-guided dosing (regimen d1) versus days 1 + 2 TDM-guided dosing (regimen d1 + 2) on attaining adequate busulfan exposure. In this observational study, we included all adults who received an allogeneic HCT with intravenous once daily busulfan over 4 days as part of the conditioning regimen at the University Medical Centre Utrecht or between July 31, 2014 and November 12, 2021. The primary outcome was attainment of the therapeutic busulfan target (cumulative area under the curve [AUCcum] 80-100 mg*h/L). Dose adjustment was based on the estimated AUC of the preceding dosing day(s). Additional TDM was performed in the event of large dose adjustments (≥25%). The choice of TDM regimen was solely based on the first day the busulfan dose was administered (regimen d1 + 2 occurred when conditioning started on a Saturday). In all patients, blood sampling was performed on day 4 for evaluation. The AUCcum was estimated using a validated population pharmacokinetic model. Busulfan target exposure was compared between both TDM regimen groups using a propensity score adjusted logistic regression model. The variance in the AUCcum between the TDM regimens was compared using the F-test. Patients were stratified for age (categorical). In regimen d1, 87.6% (n = 113/129) attained a therapeutic busulfan exposure, while in regimen d1 + 2 a proportion of 97.4% was found (n = 74/76, adjusted odds ratio for non-therapeutic AUC = 0.19, 95% confidence interval [95% CI]: 0.04-0.89). Variance of busulfan exposure in the regimen d1 group (SD = 6.8 mg*h/L) differed significantly from the variance in the regimen d1 + 2 group (SD = 3.6 mg*h/L, F-test, P < .001). Performing busulfan TDM on both day 1 and day 2, rather than only on day 1, improves busulfan target exposure attainment in adults undergoing HCT, provided that subsequent TDM is carried out if required.

Success of Combination Therapy with Isavuconazole in a Pediatric Patient with Breakthrough Invasive Aspergillosis

AbstractThe increasing incidence of invasive fungal infections, coupled with the growing population of immunocompromised patients, has led to an increased need for antifungal agents. The newest azole, isavuconazole, plays an important role in the treatment of invasive aspergillosis in adults due to its broad spectrum, tolerability, and no need for therapeutic drug monitoring. This agent, which has not yet been approved for use in children, has significant problems with drug supply in Türkiye. We present the treatment response to isavuconazole combination therapy used in salvage treatment in a patient with breakthrough invasive aspergillosis, who had treatment failure with different antifungal combination treatment options and surgical resection.

Lithium, the gold standard drug for bipolar disorder: analysis of current clinical studies.

Lithium is the gold standard drug in the treatment of bipolar disorder. Despite increasing scientific interest, relatively few patients with bipolar disorder receive lithium therapy. Lithium is the only drug that is effective in the prophylaxis of manic, depressive, and suicidal symptoms. Lithium therapy is also associated with a variety of adverse drug reactions and the need for therapeutic drug monitoring. Numerous studies have focussed on the efficacy and safety of both lithium-monotherapy and lithium-add-on therapy. The aim of this study is to provide a systematic overview of clinicalstudies on lithium therapy for bipolar disorder from the last 7 years and to present a critical analysis of these studies. The results provide an up-to-date overview of the efficacy, tolerability, and safety of lithium therapy for bipolar disorder and thus improve the pharmacotherapy of bipolar disorder. A total of 59 studies were analysed using various analysis parameters. The studies were also categorised into different subgroups. These are lithium-monotherapy, lithium vs. placebo/drug, and lithium + adjunctive therapy. The majority of the studies (N = 20) had a duration of only 3-8 weeks. Only 13 studies lasted for > 40 weeks. Lithium was superior to aripiprazole, valproic acid, and quetiapine in terms of improving manic symptoms. Lithium therapy resulted in a lower relapse rate compared to valproic acid therapy. Lithium was more neuroprotectively effective than quetiapine. Fourteen of the 22 add-on therapies to lithium showed a predominantly positive effect on the treatment outcome compared to lithium-monotherapy. Only the add-on therapy with sertraline led to a higher rate of study discontinuations than lithium-monotherapy. Lithium is a safe and effective treatment option for children. However, risperidone and quetiapine were superior to lithium in some aspects, which is why these drugs should be considered as an alternative treatment option for children. Collectively, current clinical studies highlight the relevance of lithium in the treatment of bipolar disorder.

Анти-Ха активность у пациентов с неклапанной фибрилляцией предсердий на фоне приема апиксабана и ривароксабана

Direct oral anticoagulants (DOAC) are widely used for prevention of stroke in patients with atrial fibrillation. The need for therapeutic drug monitoring of DOACs remains unclear. Measurement of anti-Xa activity that directly correlates with serum drug concentration seems to be a promising approach for monitoring of Xa inhibitors.

A fully validated LC‑MS/MS method for quantifyingbevacizumab in plasma samples from patients with NSCLC and its implications in therapeutic drug monitoring.

Given the increasing use of bevacizumab in combinatorial drug therapy for a multitude of different cancer types, there is a need for therapeutic drug monitoring to analyze the possible correlation between drug trough concentration, and therapeutic effect and adverse reactions. An ultra-performance liquid chromatography tandem-mass spectrometry method was then developed and validated to determine bevacizumab levels in human plasma samples. Chromatographic separation was achieved on a Shimadzu InertSustainBio C18 HP column, whereas subsequent mass spectrometric analysis was performed using a Shimadzu 8050CL triple quadrupole mass spectrometer equipped with an electro-spray ionization source in the positive ion mode. In total, three multiple reaction monitoring transitions of each of the surrogate peptides were chosen with 'FTFSLDTSK' applied as the quantification peptide whereas 'VLIYFTSSLHSGVPSR' and 'STAYLQMNSLR' were designated as the verification peptides using the Skyline software. This analytical method was then fully validated, with specificity, linearity, lower limit of quantitation, accuracy, precision, stability, matrix effect and recovery calculated. The linearity of this method was developed to be within the concentration range 5-400 µg/ml for bevacizumab in human plasma. Subsequently, eight patients with non-small cell lung cancer (NSCLC) were recruited and injected with bevacizumab over three periods of treatment to analyze their steady-state trough concentration and differences. To conclude, the results of the present study suggest that bevacizumab can be monitored in a therapeutic setting in patients with NSCLC.

Simultaneous post-neurosurgical ventriculitis and bacteraemia by two different strains of KPC-producing K. pneumoniae successfully treated with meropenem/vaborbactam and high dose of fosfomycin

ObjectiveA case of post-neurosurgical ventriculitis caused by a KPC-producing Klebsiella pneumoniae (KPC-Kp) with a ceftazidime/avibactam-resistant, meropenem-susceptible phenotype is reported. Methods and resultsThe patient had a concomitant bloodstream infection with a wild-type KPC-Kp with a ceftazidime/avibactam-susceptible, meropenem-resistant phenotype. Prolonged treatment with intravenous fosfomycin and meropenem/vaborbactam achieved clinical success.Therapeutic drug monitoring performed during the first days of treatment showed for the first time that vaborbactam efficiently penetrates cerebrospinal fluid. In contrast, meropenem was undetectable in cerebrospinal fluid at each sampling, suggesting that additional doses of meropenem may be required to appropriately prescribe meropenem/vaborbactam for central nervous system infections. Plasma and cerebrospinal fluid levels of fosfomycin were adequate, confirming the potential of this agent possibly even in the fight against multidrug-resistant organisms. ConclusionsThis case highlights the need for therapeutic drug monitoring as a crucial tool for optimizing treatment in complicated cases where the pharmacokinetic behaviour of antibiotics is difficult to predict.

Lower blood levels of isavuconazole in critically ill patients compared with other populations: possible need for therapeutic drug monitoring.

Isavuconazole is first-line treatment of invasive aspergillosis. Therapeutic drug monitoring (TDM) is deemed not necessary, since most patients reached therapeutic levels (>1 mg/L) in large studies. Low levels were reported in some critically ill patients admitted to the ICU. The aim was to compare isavuconazole levels between critically ill and non-critically ill patients. Retrospective analysis of data from all patients treated with standard-dose isavuconazole between 1 January 2019 and 26 October 2022 was performed. The following data were collected: TDM results from the first 30 days of therapy; ward of admission; demographic and clinical characteristics; continuous renal replacement therapy; extracorporeal membrane oxygenation; and co-administered drugs. Seventy-two patients (median age 65 years) and 188 TDM measurements (mean number of samples per patient 2.6 ± 1.7) were included; 33 (45.8%) were ICU patients (3 also had haematological disorders); 39 (54.2%) were non-ICU patients, of whom 31 had haematological disorders. In all patients, the mean isavuconazole blood level was 3.33 ± 2.26 mg/L. Significantly lower levels were observed in the ICU versus the non-ICU population: mean 2.02 ± 1.22 versus 4.15 ± 2.31 mg/L (P < 0.001). Significantly higher rates of subtherapeutic levels were observed in ICU patients compared with the non-ICU population: all determinations <2 mg/L in 33.3% versus 7.7%, and all determinations <1 mg/L in 12.1% versus 0%, respectively. Predictors of lower isavuconazole levels were admission to the ICU, BMI > 25 kg/m2, bilirubin > 1.2 mg/dL and the absence of haematological disorder. ICU patients had significantly lower isavuconazole blood levels compared to non-ICU population. The TDM of isavuconazole for efficacy should be performed in ICU.

Antibiotic safety among neonates and paediatrics in a public hospital: KwaZulu-Natal.

The World Health Organization (WHO) guidelines recommend the empiric treatment of infections before definitive treatment begins. However, ethical concerns limit the availability of clinical trials in neonates and paediatrics to fully ascertain the safety profile of antibiotics in these populations. This study aimed to quantify the use of antibiotics among neonates and paediatrics and commented on the use, rationale and appropriateness of antibiotics prescribed. A secondary level public sector hospital located in Durban, KwaZulu-Natal. Demographic and treatment information of neonates and paediatrics were collected retrospectively from January 2022 to June 2022. Data were obtained from patient files and extracted for analysis using Microsoft Excel®. Analytical and descriptive statistics were used to analyse patient demographics and treatment variables. A total of 568 antibiotics, issued to 389 patients, were reviewed. Penicillins (40.1%), aminoglycosides (24.3%) and combination penicillin-beta-lactam inhibitors (23.3%) were identified as the most frequently prescribed antibiotics for inpatients. Most antibiotics prescribed to inpatients were for complications associated with pre-term birth (66.9%). Combination penicillin-beta-lactam inhibitors (34.7%), penicillins (29.5%) and cephalosporins (29.5%) were the most frequently prescribed antibiotics to outpatients. A correlation was found between the route of administration and the duration of therapy; the intravenous route (63.6%) was preferred over the oral route (36.4%) for administration. Many broad-spectrum antibiotics were prescribed, thus increasing the risk of resistance. Antibiotics were being prescribed according to the guidelines; however, there is still a need for therapeutic drug monitoring to ensure the continuation of rational drug use. There was evidence of rational use of antibiotics in the public hospital (KwaZulu-Natal), in keeping with economic and availability factors.

Validation of Liquid Chromatography Coupled with Tandem Mass Spectrometry for the Determination of 12 Tyrosine Kinase Inhibitors (TKIs) and Their Application to Therapeutic Drug Monitoring in Adult and Pediatric Populations.

Tyrosine kinase inhibitors (TKIs) are used as targeted cancer therapies in adults and have an off-label pediatric application for the treatment of Langerhans cell histiocytosis. A multitarget LC-MS/MS method was developed and validated for the determination of alectinib, alectinib-M4, binimetinib, cobimetinib, crizotinib, dabrafenib, encorafenib, imatinib, lorlatinib, osimertinib, AZ5104, and trametinib. A total of 150 µL of internal standard methanolic solution was added to 50 µL of plasma sample to precipitate proteins. After centrifugation, 10 µL of the supernatant was injected into the chromatographic system. The chromatographic separation was conducted on a Kinetex C18 Polar column with a gradient of 2 mM ammonium formate in 0.1% formic acid and acetonitrile over 5 min. Limits of detection and quantification, linearity, accuracy, precision, selectivity, carryover, matrix effect, recovery, and stability were evaluated and satisfied EMA guidelines on bioanalytical methods. This method has been successfully applied to the therapeutic drug monitoring (TDM) of adults with melanoma and lung cancer, as well as children with histiocytosis, to improve the pharmacokinetic data for these drugs, with the aim of enhancing the therapeutic management and follow-up of patients. Blood concentrations of trametinib and binimetinib were different in the two groups, highlighting the age-related inter-individual variability of these molecules and the need for TDM.

Liquid Chromatography-Tandem Mass Spectrometry-Based Therapeutic Monitoring of Plasma Atovaquone Concentrations in Pediatric Patients.

Atovaquone is an FDA-approved antiparasitic and antifungal therapeutic that is currently used as a prophylactic agent to prevent Pneumocystis carinii pneumonia (PCP) infections in acute myeloid leukemia (AML) patients after receiving hematopoietic stem cell transplantation (HSCT). Recent studies have shown that atovaquone has shown potential as an anticancer agent. The high variability in atovaquone bioavailability prompts the need for therapeutic drug monitoring, especially in pediatric patients. The goal of our study was to develop and validate the performance of an assay to quantify atovaquone plasma concentrations collected from pediatric cancer patients. Briefly, an organic-based solvent system is used to precipitate protein and extract the atovaquone content from each patient-derived plasma sample. After completing a second stage of sample dilution (5000-fold overall), a 2 μL volumeof the plasma extract is analyzed using the liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based bioanalytical method described.

DETERMINATION OF THE LEVEL OF VALPROIC ACID IN THE BLOOD AGAINST THE BACKGROUND OF THE COMBINED USE OF VALPROATES WITH ERTAPENEM IN PEDIATRIC PRACTICE

The article presents a clinical case of the combined use of valproic acid and an antibacterial drug from the carbapenem group – ertapenem in a 15-year-old girl with epilepsy in a pediatric hospital. Therapeutic drug monitoring with an assessment of the level of valproic acid in blood plasma against the background of joint use with carbapenem (ertapenem) allowed to revise and adjust the prescribed antibacterial therapy, and later allowed to adjust the daily dose of sodium valproate in a child with epilepsy. The change of the antibacterial drug was accompanied by an increase in the level of valpro-ic acid in the blood plasma. The transition from intravenous administration of valproic acid to enteral administration of the drug was accompanied by a decrease in the concentration of valproic acid in blood plasma. The authors of the article presented data confirming the need for therapeutic drug moni-toring in children receiving valproic acid and beta-lactam antibiotic from the carbapenem group - ertapenem, based on the known mechanisms of famacokinetic interaction, as well as in patients whose management tactics are planned to change the dosage form of valproic acid.

Isavuconazole use and TDM in real-world pediatric practice.

Isavuconazole (ISA) is approved for treating invasive aspergillosis and mucormycosis in adults, but its use in children remains off-label. We report on the use of ISA in real-world pediatric practice with 15 patients receiving ISA for treatment of invasive fungal infections. Therapeutic drug monitoring (TDM) was performed in all patients, with 52/111 (46.8%) Ctrough determinations out of range, thus supporting the need for TDM in children, especially those receiving extracorporeal membrane oxygenation (ECMO).

Dopamine agonist serum concentrations and impulse control disorders in Parkinson's disease.

Impulse control disorders (ICDs) are common among Parkinson's disease patients using dopamine agonists. We wanted to determine whether ICD patients have higher dopamine agonist serum concentrations than those without any sign of ICD. Patients who used either pramipexole or ropinirole depot once daily were screened for ICDs using the validated Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale. Those who scored above the cut-off for one or more of the four defined ICDs (gambling, compulsive sexual behavior, compulsive shopping, and binge-eating) were compared in a case-control study to patients who scored zero points (no evidence of ICD) on the same items. They were examined clinically and evaluated using relevant scales. Three blood samples were taken on the same day: before daily dose, and then 6 and 12 h later. Forty-six patients were included: 19 ICD-positive and 27 controls. Ropinirole serum concentrations 6 h after daily intake (Cmax ) were higher in the case group compared to the control group, as was the daily ropinirole dosage. No differences were observed in serum concentrations, dosage or total drug exposure for pramipexole. Disease duration and length of dopamine agonist treatment was significantly longer among ICD patients for ropinirole, but not for pramipexole. The use of pramipexole may in itself confer high ICD risk, whereas ICDs among ropinirole users depend more on serum concentration and drug exposure. The pharmacokinetic properties of ropinirole make it challenging to predict its effects on patients, which supports the need for therapeutic drug monitoring to reduce risk of ICD.

Empiric dosing strategies to predict lamotrigine concentrations during pregnancy.

Maintaining seizure control with lamotrigine is complicated by altered pharmacokinetics and existence of subpopulations in whom clearance increases or remains constant during pregnancy. Our objective was to characterize the potential for particular dosing scenarios to lead to increased seizure risk or toxicity. Lamotrigine pharmacokinetic parameters obtained from our previous study were applied to a one-compartment model structure with subpopulations (75:25%) exhibiting different clearance changes. A single-patient simulation was conducted with typical pharmacokinetic parameter values from each subpopulation. Population-level simulations (N = 48,000) included six dosing scenarios and considered four preconception doses using the R package mrgsolve (Metrum Research Group). Thresholds for efficacy and toxicity were selected as drug concentration that are 65% lower than preconception concentrations and doubling of preconception concentrations, respectively. Individual simulation results demonstrated that without dose increases, concentrations fell below 0.65 at 6-8 weeks in the high clearance change (HC) subpopulation, depending on preconception clearance. While no simulated dosing regimen allowed all women in both subpopulations to maintain preconception concentrations, some regimens provided a more balanced risk profile than others. Predicted concentrations suggested potential increased seizure risk for 7%-100% of women in the HC group depending on preconception dose and subpopulation. Additionally, in 63% of dosing scenarios for women with low clearance change (LC), there was an increased risk of toxicity (34%-100% of women). A substantial percentage of simulated individuals had concentrations low enough to potentially increase seizure risk or high enough to create toxicity. Early clearance changes indicate possible subpopulation categorization if therapeutic drug monitoring is conducted in the first trimester. An arbitrary "one-size-fits-all" philosophy may not work well for lamotrigine dosing adjustments during pregnancy and reinforces the need for therapeutic drug monitoring until a patient is determined to be in the LC or HC group.

Posaconazole exposure in critically ill ICU patients: a need for action

PurposePosaconazole is an antifungal drug currently being used for prophylaxis and treatment of invasive fungal infections such as aspergillosis. To date, therapeutic drug monitoring (TDM) of posaconazole is recommended with the use of oral suspension, but the potential need of TDM with the use of IV formulations is rising. Therefore, we aimed to investigate the pharmacokinetics of IV posaconazole in critically ill patients.MethodsIn a prospective study, we analysed 168 consecutivelly collected posaconazole levels from 10 critically ill patients drawn during a 7 day curse. Posaconazole concentrations were measured using a chromatographic method. Demographic and laboratory data were collected, and the data was analysed using descriptive statistics.ResultsWe included 168 posaconazole levels, resulting in a median trough of 0.62 [0.29–1.05] mg/L with 58% not reaching the suggested target of 0.5 mg/L for fungal prophylaxis. Moreover, 74% of the trough levels were under the target of 1 mg/L which is proposed for the treatment of aspergillosis.ConclusionPosaconazole exposure is highly variable in critically ill patients resulting in potentially insufficient drug concentrations in many cases. TDM is highly recommended to identify and avoid underexposure.Trial registration numberNCT05275179, March 11, 2022.

#2989 SELECTIVE RENAL DISPOSITION OF THE CALCINEURIN INHIBITORS VOCLSOPORIN, CYCLOSPORINE, AND TACROLIMUS

Abstract Background and Aims The calcineurin inhibitors (CNI) cyclosporine (CSA) and tacrolimus (TAC) were revolutionary immunosuppressants when first introduced for solid organ transplantation in the 1980s. Voclosporin (VCS), a novel CNI, recently became the first oral therapy approved in the United States, Great Britain, and Europe for the treatment of active lupus nephritis based on positive results from Phase 2 and 3 clinical trials. Unlike CSA and TAC, VCS has demonstrated a consistent pharmacokinetic and pharmacodynamic profile, eliminating the need for therapeutic drug monitoring. Further, VCS is associated with a more favorable metabolic profile and has not been associated with electrolyte disturbances. Emerging evidence indicates small molecule therapeutics may display differential disposition within organ tissues. This suggests that CNIs may be differentially distributed and retained in the kidney, potentially explaining the difference in their efficacy and safety profiles. To evaluate renal disposition of CSA, TAC, and VCS, we assessed in mice and humans the disposition of each CNI in the kidney relative to its systemic drug exposure. Method Single 30 mg/kg doses of CSA, TAC and VCS were administered intravenously to mice. Following intravenous administration, kidneys were collected at 15 minutes, 30 minutes, 1 hour and 2 hours, flash frozen in liquid nitrogen, and stored at −20 °C until sectioning. Sections of 10 μm kidney tissue were mounted on indium tin oxide coated glass slides. Matrix of 10 mg/mL α-Cyano-4-hydroxycinnamic acid in 85% acetonitrile/13% ethanol + 2% water + 0.1% trifluoroacetic acid was sprayed on the tissue using an HTX tissue sprayer, dried for 10 minutes in the vacuum, and subjected to Matrix-assisted Laser Desorption and Ionization Mass Spectrometry Imaging (MALDI-MSI). The systemic and renal clearance in humans of CSA and TAC were obtained from the literature; pharmacokinetic data on VCS was obtained from data on file. Renal secretion of each drug was compared to its expected passive filtration based on glomerular filtration rate (GFR), fraction unbound in plasma (fu), and respective systemic drug exposure. Results MALDI-MSI demonstrated significantly higher concentrations of drug and more diffuse tissue disposition of CSA in mouse kidney compared to VCS (Figure 1). CSA was retained in all kidney tissues up to 2 hours post-administration. Higher concentrations and more diffuse disposition of TAC was also noted compared to VCS at 15 and 30 minutes; TAC was distinctively retained in the cortex and medulla. VCS had moderate distribution in the cortex and was rapidly excreted with low levels of drug present in the kidney after 1 hour. According to published data, CSA has a measured renal clearance of 1.48 mL/min in healthy human subjects, representing approximately 10% of expected passive filtration of 12.5 mL/min (Table 1). TAC has a renal clearance of 0.014 mL/min representing &amp;lt;2% of expected passive filtration of 1.25 mL/min. VCS has a renal clearance of 7.82 mL/min representing approximately 200% of its expected passive filtration rate of 3.75 mL/min. Conclusion MALDI-MSI revealed differential retention and distribution of CSA, TAC and VCS in mice, consistent with their respective renal clearances in humans. Higher drug exposure and &amp;gt;90% renal reabsorption was observed for both CSA and TAC in this study, whereas the renal handling of VCS suggested a significant component of tubular secretion. The higher rate of secretion and lower overall exposure of kidney tissue to VCS may be associated with an improved safety profile when compared to the more diffuse distribution and greater renal retention of CSA and TAC.

Protective effect of the novel calcineurin inhibitor voclosporin in experimental colitis.

Acute severe steroid-refractory ulcerative colitis remains a medically challenging condition with frequent need of surgery. It can be treated with the calcineurin inhibitor cyclosporine A with the need for therapeutic drug monitoring and significant toxicity. Recently, a novel calcineurin inhibitor, voclosporin, has been approved for the treatment of lupus nephritis with no need for therapeutic drug monitoring and an improved long-term safety profile. However, the therapeutic effect of voclosporin in acute severe steroid-refractory ulcerative colitis is still uncertain. We aimed to assess the therapeutic potential of voclosporin to ameliorate inflammation in an experimental model of colitis. We used the dextran sodium sulfate-induced model of colitis in C57BL/6 J wildtype mice treated with either cyclosporine A, voclosporin or solvent control. We employed endoscopy, histochemistry, immunofluorescence, bead-based multiplex immunoassays and flow cytometry to study the therapeutic effect of calcineurin inhibitors in a preventive setting. Acute colitis was induced by dextran sodium sulfate characterized by weight loss, diarrhea, mucosal erosions and rectal bleeding. Both cyclosporine A and voclosporin strongly ameliorated the course of disease and reduced colitis severity in a similar manner. Voclosporin was identified as biologically effective in a preclinical model of colitis and may be a potential therapeutic option in treating acute severe steroid-refractory ulcerative colitis.

Pharmacokinetics of Venetoclax Co-Administered with Posaconazole in Patients with Acute Myeloid Leukemia.

The Food and Drug Administration currently approves the combination of hypomethylating agents (HMA), azacytidine or decitabine with venetoclax (VEN) for acute myeloid leukemia (AML) patients aged more than 75 years and for patients unsuitable for intensive chemotherapy. The risk of fungal infection in the early phase of treatment is not negligible; therefore, posaconazole (PCZ) is commonly administered as primary prophylaxis. A drug-drug interaction between VEN and PCZ is well known, but the trend of serum levels of venetoclax when both drugs are overlapped is not clear. In total, 165 plasma samples from 11 elderly AML patients receiving combined treatment with HMA, VEN and PCZ were analyzed by a validated analytical method (high-pressure liquid chromatography-tandem mass spectrometry). Venetoclax trough plasma concentrations were detected during the 3 days of ramp-up as well as on day 7 and day 12 of treatment when the exposure as the area under the plasma concentration-time curve and the accumulation ratio were also calculated. The results were compared with the expected data for 400 mg/dose VEN administered alone-the confirmed high inter-individual variability in pharmacokinetics suggests the need for therapeutic drug monitoring.