Therapeutic drug monitoring of pazopanib: Using cost-neutral PK-guided interventions to optimize exposure.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3598-3598
Author(s):  
Stefanie L. Groenland ◽  
Ruben A.G. van Eerden ◽  
Stijn L.W. Koolen ◽  
Dirk Jan A.R. Moes ◽  
Alex Imholz ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Standard Dose ◽  
Daily Practice ◽  
Fixed Dose ◽  
Therapeutic Drug ◽  
Fasting State ◽  
Reduced Dose ◽  
Drug Concentrations ◽  
Clinical Trial Information

3598 Background: Pazopanib is an approved treatment for renal cell carcinoma (RCC) and soft tissue sarcoma (STS). At the currently registered fixed dose of 800 mg QD, 20% of patients (pts) do not attain the efficacy threshold of Cmin ≥ 20.5 mg/L (Suttle et al, 2014), providing a strong rationale for therapeutic drug monitoring (i.e. individualizing the dose based on measured plasma drug concentrations). Previous studies provided cost-neutral alternatives to absolute dose increments to optimize exposure (i.e. splitting intake moments or concomitant intake with food (Groenland et al, 2020; Lubberman et al, 2019)). This study aimed to investigate the feasibility, tolerability and efficacy of TDM of pazopanib, using cost-neutral interventions. Methods: Patients starting treatment with pazopanib at the standard dose of 800 mg QD in modified fasting state were included in the prospective DPOG TDM study (www.trialregister.nl, NL6695). PK sampling occurred 4, 8 and 12 weeks after start of treatment, and every 12 weeks thereafter. Pazopanib concentrations were measured with LC-MS/MS and Cmin was calculated. In case of Cmin < 20.5 mg/L and acceptable toxicity, a dose intervention was recommended. As a first step, intake moments were split (i.e. 400 mg BID). Secondly, concomitant intake with food was recommended. Results: In total, 34 pts were included (19 STS, 15 RCC), of whom 158 PK samples were collected. Eleven pts (32%) were underdosed and had at least 1 PK sample below the target. In 24% of the pts a PK-guided intervention could be performed, which was successful in 6 pts (75%). Median Cmin increased from 15 mg/L to 32 mg/L (p = 0.027). Eventually, 3 pts went back to 800 mg QD due to toxicity, after which Cmin remained ≥ 20.5 mg/L in 2 pts. In pts with adequate exposure throughout the study, median Cmin was 32 mg/L (range 23 – 65 mg/L). In 3 pts, a PK-guided intervention could not be performed, due to progression (n = 1) or logistical issues (n = 2). Twelve pts (35%) received a dose reduction due to toxicity (lowest dose was 200 mg QAD), exposure remained adequate at this reduced dose in all pts. For STS pts, median PFS was 19.8 months in pts with Cmin < 20.5 mg/L who did need an intervention vs. 6.4 months in pts with all Cmin ≥ 20.5 mg/L (not significant). For RCC pts, this was 15.5 months vs. 7.4 months, respectively (not significant). Conclusions: This prospective study shows that PK-guided dose optimization of pazopanib using cost-neutral interventions is feasible in daily practice. A PK-guided intervention was performed in 24% of the patients, which was successful in 75% of these patients. Clinical trial information: NL6695 .

scholarly journals Rapid point-of-care anti-infliximab antibodies detection in clinical practice: comparison with ELISA and potential for improving therapeutic drug monitoring in IBD patients

2021 ◽  
Vol 14 ◽  
pp. 175628482199990
Author(s):  
Sonia Facchin ◽  
Andrea Buda ◽  
Romilda Cardin ◽  
Nada Agbariah ◽  
Fabiana Zingone ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Point Of Care ◽  
Drug Clearance ◽  
Elisa Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Therapeutic Drug ◽  
Drug Concentrations ◽  
Inflammatory Bowel

Anti-drug antibodies can interfere with the activity of anti-tumor necrosis factor (TNF) agents by increasing drug clearance via direct neutralization. The presence of anti-drug antibodies is clinically relevant when trough drug concentrations are undetectable or sub-therapeutic. However, traditional immunoassay is not easily and rapidly accessible, making the translation of the results into treatment adjustment difficult. The availability of a point-of-care (POC) test for therapeutic drug monitoring (TDM) might represent an important step forward for improving the management of inflammatory bowel disease (IBD) patients in clinical practice. In this pilot study, we compared the results obtained with POC tests with those obtained by enzyme-linked immunosorbent assay (ELISA) in a group of IBD patients treated with Infliximab (IFX). We showed that POC test can reliably detect presence of antibody-to-IFX with 100% of specificity and 76% sensitivity, in strong agreement with the ELISA test ( k-coefficient = 0.84).

scholarly journals Proposal of initial and maintenance dosing regimens with linezolid for renal impairment patients

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hitoshi Kawasuji ◽  
Yasuhiro Tsuji ◽  
Chika Ogami ◽  
Kou Kimoto ◽  
Akitoshi Ueno ◽  
...  
Keyword(s):  
Renal Impairment ◽  
Standard Dose ◽  
Fixed Dose ◽  
Therapeutic Drug ◽  
Clinical Failure ◽  
Therapeutic Concentration ◽  
Reduced Dose ◽  
Increased Risk ◽  
Dosing Regimens ◽  
Multivariable Analyses

Abstract Background Linezolid is administered as a fixed dose to all patients despite evidence of overexposure and thrombocytopenia in renal impairment. The aims of this study were to evaluate the risk of thrombocytopenia and the utility of therapeutic drug monitoring (TDM), and to propose alternate dosing regimens in patients with renal impairment. Methods We retrospectively reviewed patients ≥13 years old for whom serum linezolid trough concentration (Cmin) was measured during linezolid treatment. Patients with episodes of infection were divided into groups by presence of renal impairment (RI group) or absence of renal impairment (non-RI group), and by use of Cmin-based TDM (TDM group) or not (non-TDM group) during linezolid treatment. Results In the 108 patients examined by multivariable analyses, renal impairment was independently associated with increased risk of thrombocytopenia (OR 3.17, 95%CI 1.10–9.12) and higher Cmin. Analysis of the utility of TDM in the RI group showed that clinical failure rate was significantly lower in the TDM subgroup than in the non-TDM subgroup. Furthermore, in the RI group, dosage adjustments were needed in 90.5% of the TDM subgroup. All episodes administered a reduced dose of 300 mg every 12 h in the RI group showed Cmin ≥ 2.0 mg/L. Additional analysis of 53 episodes in which Cmin was measured within 48 h after starting administration showed that the initial standard dose for 2 days was sufficient to rapidly reach an effective therapeutic concentration in the RI group. Conclusions Empirical dose reduction to 300 mg every 12 h after administration of the initial fixed dose for 2 days and Cmin-based TDM may improve safety outcomes while maintaining appropriate efficacy among patients with renal impairment.

Immunosuppressant quantification in intravenous microdialysate – towards novel quasi-continuous therapeutic drug monitoring in transplanted patients

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Susanne Weber ◽  
Sara Tombelli ◽  
Ambra Giannetti ◽  
Cosimo Trono ◽  
Mark O’Connell ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Real Time ◽  
Drug Monitoring ◽  
Time Course ◽  
Drug Dosage ◽  
Immunosuppressive Drug ◽  
Therapeutic Drug ◽  
Continuous Sampling ◽  
Real Time Analysis ◽  
Drug Concentrations

AbstractObjectivesTherapeutic drug monitoring (TDM) plays a crucial role in personalized medicine. It helps clinicians to tailor drug dosage for optimized therapy through understanding the underlying complex pharmacokinetics and pharmacodynamics. Conventional, non-continuous TDM fails to provide real-time information, which is particularly important for the initial phase of immunosuppressant therapy, e.g., with cyclosporine (CsA) and mycophenolic acid (MPA).MethodsWe analyzed the time course over 8 h of total and free of immunosuppressive drug (CsA and MPA) concentrations measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 16 kidney transplant patients. Besides repeated blood sampling, intravenous microdialysis was used for continuous sampling. Free drug concentrations were determined from ultracentrifuged EDTA-plasma (UC) and compared with the drug concentrations in the respective microdialysate (µD). µDs were additionally analyzed for free CsA using a novel immunosensor chip integrated into a fluorescence detection platform. The potential of microdialysis coupled with an optical immunosensor for the TDM of immunosuppressants was assessed.ResultsUsing LC-MS/MS, the free concentrations of CsA (fCsA) and MPA (fMPA) were detectable and the time courses of total and free CsA comparable. fCsA and fMPA and area-under-the-curves (AUCs) in µDs correlated well with those determined in UCs (r≥0.79 and r≥0.88, respectively). Moreover, fCsA in µDs measured with the immunosensor correlated clearly with those determined by LC-MS/MS (r=0.82).ConclusionsThe new microdialysis-supported immunosensor allows real-time analysis of immunosuppressants and tailor-made dosing according to the AUC concept. It readily lends itself to future applications as minimally invasive and continuous near-patient TDM.

Pharmacokinetic Properties of New Antiepileptic Drugs

2005 ◽  
Vol 18 (6) ◽  
pp. 444-460 ◽  
Author(s):  
Michele Y. Splinter
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Interactions ◽  
Antiepileptic Drugs ◽  
Drug Monitoring ◽  
The United States ◽  
Therapeutic Drug ◽  
Kinetic Properties ◽  
New Antiepileptic Drugs ◽  
Drug Concentrations ◽  
Pharmacokinetic Properties

Eight new antiepileptic drugs (AEDs) have been approved for use within the United States within the past decade. They are felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, and zonisamide. These afford clinicians with more options to increase efficacy and tolerability in the treatment of patients with epilepsy. Pharmacokinetic properties and drug interactions with other AEDs and other medications taken for comorbidities are individually discussed for each of these new agents. Drug concentrations are not routinely monitored for these newer agents, and there have been few studies designed to investigate their concentration-effect relationships. For most of these medications, the concentrations observed in responders and nonresponders overlap considerably and levels associated with efficacy are often associated with adverse events, complicating the definition of target ranges. Also, epilepsy manifests itself sporadically causing difficulty in clinically monitoring efficacy of medications. Therapeutic drug monitoring provides for the individualization of treatment for these agents, which is important because they demonstrate significant variability in inter- and intraindividual pharmaco-kinetic properties. Therapeutic drug monitoring also allows for identification of noncompliance, drug interactions, and toxicity. Current knowledge of the relationships between efficacy, toxicity, and drug concentrations is discussed.

scholarly journals N22 Nurse led therapeutic drug monitoring (TDM) of Infliximab in IBD

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S667-S668
Author(s):  
S Gleeson ◽  
K Sugrue ◽  
M Buckley ◽  
J McCarthy
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Trough Concentration ◽  
Drug Monitoring ◽  
Response Assessment ◽  
Symptom Improvement ◽  
Therapeutic Drug ◽  
Serum Samples ◽  
Drug Concentrations ◽  
Biologic Response ◽  
Trough Levels

Abstract Background Therapeutic drug monitoring (TDM) is the clinical practice of measuring serum drug concentrations to guide clinical decision making. Achieving therapeutic drug concentrations has been associated with clinical, endoscopic and histological outcomes in IBD. The use of TDM offers a more personalised treatment approach and is associated with sustained clinical remission. Proactive TDM was introduced to the Mercy University Hospital in 2014 for all patients on biologics. Methods One hundred patients receiving biologic infusion (Infliximab) were evaluated post induction (week 12) for therapeutic drug trough concentration and for clinical response. Serum samples were taken from all IBD patients at week 12. Biologic response assessment forms were complete for all patients to assess symptom improvement. Results Thirty-five per cent of patients had sub therapeutic trough levels at week 12. They subsequently received 3 increased doses of 10mgs/kg and levels were rechecked. Of these 90% achieved therapeutic levels after the dose escalation. 65% of patients had therapeutic levels at week 12. There was a correlation between therapeutic trough levels and patient reported improvement of clinical symptoms in 85% of respondents. Conclusion TDM in our unit facilitates appropriate dose 100 patients receiving biologic infusion (Infliximab) were evaluated post induction (week 12) for therapeutic drug trough concentration and for clinical response. Serum samples were taken from all IBD patients at week 12. Biologic response assessment forms were complete for all patients to assess symptom improvement.

scholarly journals Therapeutic drug monitoring in special populations

1998 ◽  
Vol 44 (2) ◽  
pp. 415-419 ◽  
Author(s):  
Philip D Walson
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Diagnostic Testing ◽  
Drug Effects ◽  
Special Populations ◽  
Therapeutic Drug ◽  
Drug Reactions ◽  
Drug Concentrations ◽  
Dosing Regimens ◽  
Multiple Drugs

Abstract Therapeutic drug monitoring (TDM) is commonly used to maintain “therapeutic” drug concentrations. Even in compliant patients, with “average” drug kinetics, TDM is useful to identify the causes of unwanted or unexpected responses, prevent unnecessary diagnostic testing, improve clinical outcomes, and even save lives. TDM has greatest promise in certain special populations who are: (a) prone to under- or overrespond to usual dosing regimens, (b) least able to tolerate, recognize, or communicate drug effects, or who are (c) intentionally or accidentally misdosed. TDM is especially useful in patients at the extremes of age, in adolescents, and in patients who are either taking multiple drugs or expressing unusual pharmacokinetics as a result of physiological, environmental, or genetic causes. Less-well-appreciated uses of TDM include prevention of dangerousunderdosing of patients, investigation of adverse drug reactions, and identification of serious medication errors, even for a number of drugs that are not traditionally monitored. TDM can be useful for some drugs in any patient and for most drugs in some special populations.

Concomitant intake of abiraterone and food to increase pharmacokinetic exposure: Real-life data from a therapeutic drug monitoring program.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 3117-3117 ◽  
Author(s):  
Stefanie L. Groenland ◽  
Andre M. Bergman ◽  
Alwin Huitema ◽  
Neeltje Steeghs
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Monitoring Program ◽  
Real Life ◽  
Progression Free Survival ◽  
Abiraterone Acetate ◽  
Fixed Dose ◽  
Therapeutic Drug ◽  
Castration Resistant Prostate Cancer ◽  
Regular Treatment

3117 Background: Abiraterone acetate is registered for the treatment of metastatic castration resistant prostate cancer. Pharmacokinetic (PK) exposure has been linked to efficacy, since patients with Cmin ≥ 8.4 ng/mL have a significantly longer progression free survival compared to patients with a Cmin below this threshold (7.4 vs. 12.2 months, p = 0.044) (Carton, 2017). At the recommended fixed dose of 1000 mg QD administered in a modified fasting state, 35% of patients do not reach this efficacy threshold (Carton, 2017), providing a strong rationale for therapeutic drug monitoring (TDM). Since a clinically relevant food effect has been established, concomitant intake of abiraterone and food could offer a cost-neutral solution in case of low exposure (Chi, 2015). This study aims to evaluate whether PK-guided abiraterone dosing is feasible and results in an increased proportion of patients with concentrations above the target. Methods: Patients starting regular treatment with abiraterone were included. PK sampling occurred 4, 8 and 12 weeks after start of treatment, and every 12 weeks thereafter. Abiraterone concentrations were measured and Cmin was calculated. In case of Cmin < 8.4 ng/mL and acceptable toxicity, a PK-guided intervention was advised. As a first step, concomitant intake of abiraterone and a light meal or a snack was advised. Results: In total, 35 patients were included, of which 18 patients (51%) had at least one Cmin < 8.4 ng/mL. These patients were advised to take abiraterone concomitantly with food, after which Cmin increased significantly from 5.6 (47%) ng/mL [mean (CV%)] to 40.6 (110%) ng/mL (p = 0.006) without additional toxicities. This intervention led to adequate exposure in 15 patients (83%). Seventeen patients had all Cmin levels ≥ 8.4 ng/mL, in these patients mean Cmin was 31.5 (65%) ng/mL. Conclusions: TDM of abiraterone was applied in clinical practice and proved to be feasible. Concomitant intake with food resulted into a significant increase in Cmin and offers a cost-neutral opportunity to optimize treatment for patients with low PK exposure. Up to 100 patients will be included to evaluate the effect of PK-guided abiraterone dosing on treatment efficacy. Clinical trial information: NL6695.

scholarly journals Therapeutic Drug Monitoring of Piperacillin-Tazobactam Using Spent Dialysate Effluent in Patients Receiving Continuous Venovenous Hemodialysis

2010 ◽  
Vol 55 (2) ◽  
pp. 557-560 ◽  
Author(s):  
Michael J. Connor ◽  
Charbel Salem ◽  
Seth R. Bauer ◽  
Christina L. Hofmann ◽  
Joseph Groszek ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Kidney Injury ◽  
Therapeutic Drug ◽  
Plasma Drug ◽  
Drug Dosing ◽  
Drug Levels ◽  
Drug Concentrations ◽  
Continuous Venovenous Hemodialysis ◽  
Dosing Strategies

ABSTRACTSepsis and multisystem organ failure are common diagnoses affecting nearly three-quarters of a million Americans annually. Infection is the leading cause of death in acute kidney injury, and the majority of critically ill patients who receive continuous dialysis also receive antibiotics. Dialysis equipment and prescriptions have gradually changed over time, raising concern that current drug dosing recommendations in the literature may result in underdosing of antibiotics. Our research group directed its attention toward antibiotic dosing strategies in patients with acute renal failure (ARF), and we sought data confirming that patients receiving continuous dialysis and antibiotics actually were achieving therapeutic plasma drug levels during treatment. In the course of those investigations, we explored “fast-track” strategies to estimate plasma drug concentrations. As most antimicrobial antibiotics are small molecules and should pass freely through modern high-flux hemodialyzer filters, we hypothesized that continuous renal replacement therapy (CRRT) effluent could be used as the medium for drug concentration measurement by reverse-phase high-pressure liquid chromatography (HPLC). Here we present the first data demonstrating this approach for piperacillin-tazobactam. Paired blood and dialysate trough-peak-trough samples were drawn from 19 patients receiving piperacillin-tazobactam and continuous venovenous hemodialysis (CVVHD). Total, free, and dialysate drug concentrations were measured by HPLC. Dialysate drug levels predicted plasma free drug levels well (r2= 0.91 and 0.92 for piperacillin and tazobactam, respectively) in all patients. These data suggest a strategy for therapeutic drug monitoring that minimizes blood loss from phlebotomy and simplifies analytic procedures.

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