Increase In Trough Concentration Research Articles

Trough Concentration Response in Infliximab and Adalimumab Treated Children With Inflammatory Bowel Disease Following Treatment Adjustment: A Pharmacokinetic Model.

In patients with inflammatory bowel diseases (IBD), data on trough concentration (TC) response to adjustments of anti-tumor necrosis factor (TNFα) are scarce. We included pediatric patients with IBD who were treated with anti-TNFα agents and had sequential monitoring of TC pre- and post-adjustment. Patients with positive anti-drug-antibodies or with concomitant change in immunomodulatory treatment were excluded. For the entire cohort (86 patients), median age at diagnosis was 13.2 (interquartile range, 10.7-14.9) years [females, 48%; Crohn disease (CD), 72%]. For infliximab, 58 patients had 201 interval changes and 26 had dose increase. Increase in TC following dose increase could not be predicted due to significant variability (P = 0.9). For every 10% decrease in interval, TC was increased by 1.6 µg/mL or by 57.2% (P = 0.014). Perianal disease was associated with attenuated response. For every 10% increase in interval, TC was decreased by 0.66 µg/mL or by 4.2%. The diagnosis of CD was associated with reduced response to interval increase. For adalimumab, 28 patients had 31 and 12 events of interval decrease or increase, respectively. Interval decrease resulted in increased median TC from 4.5 (3.5-5.3) µg/mL to 8.1 (6.5-10.5) µg/mL (X1.8) while interval increase resulted in TC change from 15.5 (12.8-18.6) µg/mL to 9.7 (6.5-14.6) µg/mL (:1.6) (P < 0.001 for both). Increase in delta TC was associated with younger age, and with absence of perianal disease (P = 0.001). Changes in TC following treatment adjustment can be almost linearly predicted for adalimumab while response to infliximab adjustment are more variable.

Evaluation of Vancomycin Accumulation in Patients With Obesity

BackgroundCurrent vancomycin guidelines recommend early and frequent area-under-the-curve monitoring in patients with obesity. Vancomycin's volume of distribution is likely altered in patients with obesity, which may result in lower serum concentrations initially but lead to accumulation with continued use. The objective of this study was to evaluate the incidence of vancomycin accumulation in patients with obesity and identify potential factors associated with accumulation.MethodsThis was a single-center, retrospective, observational study at a tertiary academic medical center. Adult patients with a body mass index (BMI) ≥ 30 kg/m2 and ≥ 2 vancomycin serum trough concentrations drawn in 2019 were screened for inclusion. The major endpoint was the incidence of vancomycin accumulation defined as ≥ 20% increase in trough concentration within the first 10 days of therapy. Key minor endpoints included incidence of acute kidney injury (AKI) and factors associated with accumulation.ResultsOf the 443 patients screened, 162 were included. The median age was 56.5 years (interquartile range [IQR], 43–65.3), and 62.3% were male. The median weight was 112.7 kg (IQR, 99.8–122.6) and the median BMI was 36.8 kg/m2 (IQR, 33.1–41). The total daily dose median at initiation was 28.7 mg/kg per day (IQR, 25.4–31.2). Accumulation occurred in 99 of 162 patients (61.1%) and AKI occurred in 20 of 140 patients (14.3%). No specific factors were found to be associated with accumulation.ConclusionsPatients with obesity are likely to experience vancomycin accumulation within the first 10 days of therapy. Clinicians should use frequent monitoring of vancomycin and use caution when interpreting early concentrations in patients with obesity.

P443 Trough concentration response in infliximab and adalimumab treated children with IBD following treatment adjustment: A pharmacokinetic model

Abstract Background In patients with IBD, data on trough concentration (TC) response to adjustments in anti-TNFα treatment are scarce. Methods We included pediatric patients with IBD who were treated with anti-TNFα agents from, 2015 to, 2020 and had sequential monitoring of TC. Treatment adjustments were detected and subsequent changes in TC were recorded (next infusion for infliximab and up to, 8 weeks TC measurement for adalimumab). Patients with positive anti-drug-antibodies or with concomitant change in immunomodulatory treatment were excluded. Results For the entire cohort (86 patients), median age at diagnosis was, 13.2 (10.7–14.9) years (Females, 48%; Crohn’s disease, 72%). For infliximab, 58 patients had, 201 interval changes (98 decrease and, 103 increase) and, 26 had dose increase. Dose increase resulted in TC change in the same direction but TC changes could not be predicted due to significant variability (p=0.9). This variability could not be attributed to any specific variable. Interval decrease: Median TC pre adjustment was, 4.3 mcg/ml (IQR, 3.1–6.9 mcg/ml). For every, 10% decrease in interval, TC was increased by, 1.6 mcg/ml (B=, 1.6, 95% CI;, 0.9–2.4; p&amp;lt;0.001) or by, 57.2% (B=57.2, 95% CI;12.8–124.6; p=0.014). The presence of perianal disease was associated with attenuated response to interval decrease (diminished TC increase), p=0.001. Interval increase: Median TC pre change was, 12.6 mcg/ml (IQR, 9.5–12.1 mcg/ml). For every, 10% increase in interval, TC was decreased by, 0.66 mcg/ml (B=, 0.66, 95% CI;, 0.2–1.2; p=0.01) or by, 4.2% (B=, 4.2, 95% CI;, 2.0–6.4; p&amp;lt;0.001). The diagnosis of Crohn’s disease (VS. diagnosis of UC) was associated with reduced response to interval increase (diminished TC decrease), p=0.012. For adalimumab, 28 patients had, 31 events of interval decrease from every, 2 weeks to every week and, 12 events of interval increase back to every, 2 weeks. Interval decrease resulted in increased median TC from, 4.5 (3.5–5.3) mcg/ml to, 8.1 (6.5–10.5) mcg/ml (X1.8) while interval increase resulted in TC change from, 15.5 (12.8–18.6) mcg/ml to, 9.7 (6.5–14.6) mcg/ml (:1.6). Changes in adalimumab TC were consistently significant (p&amp;lt;0.001). Increase in delta TC was associated with younger age (p=0.018), lower body surface area (p&amp;lt;0.001) and with the absence of perianal disease (p=0.001). Laboratory measures (CRP, albumin- mostly within normal limits) were not associated with TC response for both agents. Conclusion Changes in TC following treatment adjustment can be almost linearly predicted for adalimumab but not for infliximab. Thus, following infliximab adjustment, TC should be measured in-order to assess adequate TC response.

1102. Evaluation of Vancomycin Accumulation in Patients with Obesity

BackgroundCurrent vancomycin guidelines recommend using actual body weight for dosing. However, in patients with obesity, this may result in lower initial vancomycin concentrations that can accumulate with continued doses due to differences in volume of distribution. The objective of this study is to evaluate the incidence of vancomycin accumulation in patients with obesity and identify potential factors associated with accumulation.MethodsThis is a single-center, retrospective, observational study at a tertiary academic medical center. Adult patients with a BMI ≥ 30 kg/m2 and with ≥ 2 vancomycin serum trough concentrations within the same encounter in 2019 were screened. Patients were excluded if they were pregnant, had unstable renal function or severe renal impairment, received < 3 doses before a concentration was drawn, or had inconsistent dosing prior to a concentration draw. Linear kinetics were used to correct for differences in timing of concentration or dose changes. The major endpoint was the incidence of vancomycin accumulation, defined as a 20% increase in trough concentration between the first and any subsequent trough concentrations within the first 10 days of therapy. Minor endpoints included the percentage of supratherapeutic concentrations and the incidence of acute kidney injury (AKI). Descriptive statistics were used to evaluate endpoints and multivariable logistic regression was used to evaluate factors associated with accumulation.ResultsWe screened 543 patients, and 162 were included in our analysis. The median age was 56.5 years (interquartile range [IQR] 43 - 65.3), and 62.3% were male. The median weight was 112.7 kg (IQR 99.8 - 122.6) and the median BMI was 36.8 kg/m2 (IQR 33.1 - 41). The median total daily vancomycin dose at initiation was 28.7 mg/kg/day (IQR 25.4 - 31.2). Vancomycin accumulation occurred in 99 patients (61.1%) within the first 10 days of therapy and AKI occurred in 21 patients (14.9%). No factors studied, including age, gender, obesity class, initial dose, SCr, or frequency were associated with accumulation.ConclusionMost patients with obesity experienced vancomycin accumulation within the first 10 days of therapy. Providers should be cautious when assessing a vancomycin concentration early in the treatment course.Disclosures All Authors: No reported disclosures

Clinical outcomes of linezolid and vancomycin in patients with nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus stratified by baseline renal function: a retrospective, cohort analysis

BackgroundThe primary objective of this study is to assess whether baseline renal function impacts treatment outcomes of linezolid and vancomycin (with a dose-optimized regimen) for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia.MethodsWe conducted a retrospective cohort analysis of data generated from a prospective, randomized, controlled clinical trial (NCT 00084266). The analysis included 405 patients with culture-proven MRSA pneumonia. Baseline renal function was stratified based on creatinine clearance.Clinical and microbiological success rates and presence of nephrotoxicity were assessed at the end of treatment (EOT) and end of study (EOS). Multivariate logistic regression analyses of baseline patient characteristics, including treatment, were performed to identify independent predictors of efficacy. Vancomycin concentrations were analyzed using a nonlinear mixed-effects modeling approach. The relationships between vancomycin exposures, pharmacokinetic-pharmacodynamic index (trough concentration, area under the curve over a 24-h interval [AUC0–24], and AUC0–24/MIC) and efficacy/nephrotoxicity were assessed in MRSA pneumonia patients using univariate logistic regression or Cox proportional hazards regression analysis approach.ResultsAfter controlling for use of vasoactive agents, choice of antibiotic therapy and bacteremia, baseline renal function was not correlated with clinical and microbiological successes in MRSA pneumonia at either end of treatment or at end of study for both treatment groups. No positive association was identified between vancomycin exposures and efficacy in these patients. Higher vancomycin exposures were correlated with an increased risk of nephrotoxicity (e.g., hazards ratio [95% confidence interval] for a 5 μg/ml increase in trough concentration: 1.42 [1.10, 1.82]).ConclusionsIn non-dialysis patients, baseline renal function did not impact the differences in efficacy or nephrotoxicity with treatment of linezolid versus vancomycin in MRSA pneumonia.

Population Pharmacokinetics of Isavuconazole in Subjects with Mild or Moderate Hepatic Impairment.

Isavuconazole, administered as the prodrug isavuconazonium sulfate, was recently approved by the U.S. Food and Drug Administration and the European Medicines Agency for the treatment of adults with invasive aspergillosis and mucormycosis. The objective of this analysis was to develop a population pharmacokinetic model using NONMEM (version 7.2) for subjects with hepatic impairment, using intravenous and oral administration data from two hepatic studies, and to simulate concentration profiles to steady state, thus evaluating the need for dose adjustment. A two-compartment model with Weibull absorption function and first-order elimination process adequately described plasma isavuconazole concentrations. The population mean clearance in healthy subjects was 2.5 liters/h (5th and 95th percentiles: 2.0 and 3.1). The mean clearance values for subjects with mild and moderate hepatic impairment decreased approximately to 1.55 liters/h (5th and 95th percentiles: 1.3 and 1.8 liters/h) and 1.32 liters/h (5th and 95th percentiles: 1.05 and 1.35), respectively. Peripheral volume of distribution increased with body mass index. Simulations of mean concentration time profiles to steady state showed less than a 2-fold increase in mean trough concentrations for subjects with mild and moderate hepatic impairment compared with healthy subjects. After administration of the single dose, safety data for subjects with mild and moderate hepatic impairment were generally comparable to those for healthy subjects in both studies. Due to the <2-fold increase in trough concentrations and the established safety margin, dose adjustment appears to be unnecessary in subjects with mild or moderate hepatic impairment.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of a long-acting release (LAR) formulation of pasireotide (SOM230) in patients with gastroenteropancreatic neuroendocrine tumors: results from a randomized, multicenter, open-label, phase I study

PurposePasireotide (SOM230), a novel multireceptor ligand somatostatin analog (SSA), binds with high affinity to four of the five somatostatin receptor subtypes (sst1–3, 5). This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics profiles of pasireotide long-acting release (LAR) formulation in patients with advanced gastroenteropancreatic neuroendocrine tumor (GEP NET) refractory to other SSAs.MethodsIn this randomized, multicenter, open-label, phase II study, patients with biopsy-proven primary or metastatic GEP NET refractory to available SSAs were randomly assigned 1:1:1 to receive pasireotide LAR by deep intragluteal injection at a dose of 20, 40, or 60 mg once every 28 days for 3 months.ResultsForty-two patients received pasireotide LAR. Adverse events were reported by 34 (81 %) patients, with the most frequently reported including diarrhea, fatigue, abdominal pain, and nausea. Mean fasting glucose levels were increased compared with baseline at all points throughout the study. After the third injection of pasireotide LAR, the median trough plasma concentrations on day 84 were 4.82, 12.0, and 19.7 ng/mL in the 20-, 40-, and 60-mg treatment groups, respectively. Drug accumulation was limited for each dose based on the increase in trough concentrations after the first to third injections (accumulation ratios were approximately 1 from all dose levels).ConclusionsThis study demonstrated that a new, once-monthly, intramuscular LAR formulation of pasireotide was well tolerated in patients with advanced GEP NET. Steady state levels of plasma pasireotide were achieved after three injections.

Pharmacokinetic Modeling of Hepatocyte Growth Factor in Experimental Animals and Humans

Hepatocyte growth factor (HGF) is under development for treatment of renal failure. This study was designed to clarify changes in HGF pharmacokinetics in renal failure and to establish a pharmacokinetic model applicable to single and repeated doses. The plasma concentration profile in mice with glycerol-induced acute renal failure was similar to that in normal mice, indicating a minimal contribution of kidney to systemic clearance of HGF. Nevertheless, accumulation of fluorescein-4-isocyanate-labeled HGF in renal tubules in both cases suggests the occurrence of efficient endocytosis of HGF in kidney. A pharmacokinetic model including plasma and liver compartments was constructed, incorporating both high- and low-affinity receptors for association and subsequent endocytosis of HGF because HGF is eliminated via specific receptor c-Met and heparin-like substance. The model well explained the plasma concentration profiles at all doses examined after bolus injection in animals and humans, and those during infusion in rodents. It includes externalization of receptors, which is negatively regulated by HGF, and can explain the gradual increase in trough concentration during repeated dosing in monkeys. Overall pharmacokinetic profiles of HGF are governed by at least two receptors and are well described by this pharmacokinetic model, which should assist in safe management of clinical trials.