A framework for economic evaluation of therapeutic drug monitoring-guided dosing in oncology.

The standard approach for dose individualization of chemotherapy in the oncology setting has long been based on body surface area (BSA) as a measure of body size. However, for many anticancer drugs, administration of dosages based on BSA may result in some patients receiving supratherapeutic or subtherapeutic concentrations due to substantial interindividual pharmacokinetic variability. Therapeutic drug monitoring (TDM)-guided dosing aims to ensure that the patient's serum drug concentration is in a target range which has been shown to produce optimal clinical outcomes. The management of several malignancies is now moving away from using traditional intravenous chemotherapy to longer-term treatment with targeted molecular therapies. These targeted anticancer drugs are currently dosed based on a fixed dose for all patients. The pharmacokinetic characteristics of most of these drugs (e.g., tyrosine-kinase inhibitors) support implementation of individualized dosing via TDM. However, prior to adopting TDM-guided dosing in oncology settings, the economic efficiency and value for money of introducing TDM interventions should be critically and systematically examined along with the impacts on patient care and outcomes. Yet, current evidence in this area is limited, and more generally, there is lack of methodological guidance on how to identify, estimate and value clinical and cost information necessary to conduct economic evaluations of TDM interventions. In this paper, we propose a coherent framework for conducting economic evaluation of TDM interventions in oncology settings and discuss some practical challenges of conducting economic evaluations of TDM.

The cost-effectiveness of therapeutic drug monitoring for the prescription drug-based treatment of chronic myeloid leukemia.

BACKGROUND: A recent study demonstrating the use of Therapeutic Drug Monitoring (TDM) in patients with chronic myeloid leukemia (CML) resulted in a higher response rate with imatinib (IM) than demonstrated in second-generation tyrosine kinase inhibitor studies. The cost-effectiveness of TDM combined with IM (IM TDM) in first-line CML treatment has not yet been studied. OBJECTIVES: To determine the cost-effectiveness of IM TDM for the first-line treatment of CML compared to tyrosine kinase inhibitor only treatment. METHODS: A recently published cost-effectiveness model of tyrosine kinase inhibitor-treatment in CML was modified to include IM TDM as a first-line tyrosine kinase inhibitor-based CML treatment option. Efficacy inputs for major molecular response (MMR) rates were taken from previously published studies: IM TDM 65%, dasatinib 52%, nilotinib 53%. Annual tyrosine kinase inhibitor drug prices were derived from the Federal Supply Schedule (FSS) and the average and lowest wholesale acquisition costs (WAC) reported in the Red Book; the annual cost of TDM was $228. Other input costs modeled in the original CML CEA model were updated to 2016 US dollars using the medical service component of the Consumer Price Index. A US payer perspective was used with a 5-year time horizon and a 3.0% discount rate. The model compared first-line IM TDM versus IM alone, nilotinib (NIL) or dasatinib (DAS) in terms of the following outcomes: costs, quality-adjusted life-years (QALYs), and cost-effectiveness (total cost/QALY). Deterministic and probabilistic sensitivity analyses were performed using all key clinical and economic parameters. RESULTS: This study found that IM TDM dominates IM alone with $15,452 to $36,940 in savings and 0.25 higher QALYs. Using FSS, per patient total costs for IM and IM TDM were $270,905 and $233,965, respectively.; Using average WAC, these costs were $461,657 and $446,205, and using lowest WAC, these costs were $366,966 and $350,090. The results comparing first line using of IM TDM to NIL/DAS found that TDM IM had higher QALYs and lower costs (0.08 QALYs lower, and $117,006 to $172,420 savings per patient [varying by price basis]). Thus, in terms of cost-effectiveness, IM TDM dominates NIL/DAS with both lower costs and higher QALYs. CONCLUSIONS: IM TDM is a clinically and economically viable first-line treatment option for CML. DISCLOSURES: This study was funded by Saladax Biomedical. Salamone is an employee of Saladax Biomedical. This study was presented at the IATDMCT Congress, September 2018, Brisbane, Australia.

Development and validation of a simple, selective, and sensitive LC-MS/MS assay for the quantification of remdesivir in human plasma.

Remdesivir, formerly GS-5734, has recently become the first antiviral drug approved by the U.S. Food and Drug Administration (FDA) to treat COVID-19, the disease caused by SARS-CoV-2. Therapeutic dosing and pharmacokinetic studies require a simple, sensitive, and selective validated assay to quantify drug concentrations in clinical samples. Therefore, we developed a rapid and sensitive LC-MS/MS assay for the quantification of remdesivir in human plasma with its deuterium-labeled analog, remdesivir-2H5, as the internal standard. Chromatographic separation was achieved on a Phenomenex® Synergi™ HPLC Fusion-RP (100 × 2 mm, 4 µm) column by gradient elution. Excellent accuracy and precision (<5.2% within-run variations and. <9.8% between-run variations) were obtained over the range of 0.5-5000 ng/mL. The assay met the FDA Bioanalytical Guidelines for selectivity and specificity, and low inter-matrix lot variability (<2.7%) was observed for extraction efficiency (77%) and matrix effect (123%) studies. Further, stability tests showed that the analyte does not degrade under working conditions, nor during freezing and thawing processes.

Clinical pharmacist interventions in managing Key Monitoring Drugs in China.

OBJECTIVE: Drug-related problems (DRPs) are common in hospitalized patients receiving Key Monitoring Drugs. Clinical pharmacy services have the potential to minimize drug-related harm and improve patient care. The aim of this study is to standardize the clinical application of Key Monitoring Drugs and reduce drug-related problems (DRPs) and associated costs, using clinical pharmacist interventions. PATIENTS AND METHODS: Clinical pharmacists formulate management measures for Key Monitoring Drugs using evidence-based medicine and analyze the DRPs of Key Monitoring Drugs in China at the Shandong Provincial Third Hospital over a period of five years, from 2015 to 2019. RESULTS: In 2019, the total cost of the use of Key Monitoring Drugs decreased by 10.12 million CNY, in comparison with the cost in 2015. The proportion of revenue generated from Key Monitoring Drugs also decreased by 11.49% compared with 2015. In addition, the cost per capita of Key Monitoring Drugs has gradually decreased; this resulted in a saving of 580.07 CNY per capita in 2019 compared with 2015. Over this time, the DRPs associated with Key Monitoring Drugs decreased by 45.50%. Through administrative intervention, prescription review, information management, and pharmaco-economic evaluation, a scientific management system for Key Monitoring Drugs has been established over this time, which standardizes the use of Key Monitoring Drugs and reduces their associated costs. CONCLUSIONS: Clinical pharmacists' interventions can assist in the early detection of drug-related problems associated with Key Monitoring Drugs and prevent any resulting harm to patients.

Cost-Effectiveness Assessment of Monitoring Abiraterone Levels in Metastatic Castration-Resistant Prostate Cancer Patients.

OBJECTIVES: Abiraterone acetate is registered for the treatment of metastatic castration-sensitive and resistant prostate cancer (mCRPC). Treatment outcome is associated with plasma trough concentrations (Cmin) of abiraterone. Patients with a plasma Cmin below the target of 8.4 ng/mL may benefit from treatment optimization by dose increase or concomitant intake with food. This study aims to investigate the cost-effectiveness of monitoring abiraterone Cmin in patients with mCRPC. METHODS: A Markov model was built with health states progression-free survival, progressed disease, and death. The benefits of monitoring abiraterone Cmin followed by a dose increase or food intervention were modeled via a difference in the percentage of patients achieving adequate Cmin taking a healthcare payer perspective. Deterministic and probabilistic sensitivity analyses were performed to assess uncertainties and their impac to the incremental cost-effectiveness ratio (ICER). RESULTS: Monitoring abiraterone followed by a dose increase resulted in 0.149 incremental quality-adjusted life-years (QALYs) with €22 145 incremental costs and an ICER of €177 821/QALY. The food intervention assumed equal effects and estimated incremental costs of €7599, resulting in an ICER of €61 019/QALY. The likelihoods of therapeutic drug monitoring (TDM) with a dose increase or food intervention being cost-effective were 8.04%and 81.9%, respectively. CONCLUSIONS: Monitoring abiraterone followed by a dose increase is not cost-effective in patients with mCRPC from a healthcare payer perspective. Monitoring in combination with a food intervention is likely to be cost-effective. This cost-effectiveness assessment may assist decision making in future integration of abiraterone TDM followed by a food intervention into standard abiraterone acetate treatment practices of mCRPC patients.

Appropriateness of tacrolimus therapeutic drug monitoring timing in the emergency department.

PURPOSE: Evaluate the appropriateness of the timing of serum samples collected in the emergency department (ED) for tacrolimus (TAC) measurement. METHODS: Single-center, retrospective review of TAC samples collected in the ED from September 1 to October 31, 2017. The primary evaluation was incidence of inappropriate sample collection for TAC measurement, defined as samples not collected 12 h (±2 h; 10-14 h) after the last dose, or within 2 h of the next dose if last known dose time was not documented. Incidence of repeat TAC measurements obtained within 24 h of ED presentation (if initial sample collection inappropriate), inappropriate TAC regimen adjustments, and healthcare costs of inappropriate TAC measurements was evaluated. Data collection included patient demographics, ED visit information, TAC measurement and timing related to last or next dose, changes to TAC regimen, and ED disposition. Descriptive data are reported. RESULTS: Sixty-two patients were included. Forty-one (66%) initial TAC measurements were collected inappropriately in the ED. No patients had a regimen adjustment as a result of inappropriate concentration collection, but 32 patients (78%) did require a repeat measurement within 24 h of ED presentation due to initial inappropriate collection. Costs associated with incorrectly collected TAC measurements were $2,647.78 for the two-month time period and this is extrapolated to an estimated $15,886.68 annual expense for patients. CONCLUSIONS: Inappropriate sample collection for TAC measurements was common in the ED, resulting in frequent repeat laboratory draws and increased healthcare costs.

Monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia.

The surveillance strategy for patients taking low dose cabergoline for hyperprolactinaemia is controversial. As more evidence has emerged that the risks of cardiac valvulopathy in this population of patients are low, fewer and fewer endocrinologists adhere strictly to the original medicines and healthcare products agency MHRA guidance of "at least" annual echocardiography. Strict adherence to this guidance would be costly in monetary terms (£5.76 million/year in the UK) and also in resource use (90,000 extra echocardiograms/year). This article reviews the proposed pathophysiological mechanism underlying the phenomenon of dopamine agonist valvulopathy, the characteristic echocardiographic changes seen, summarises the published literature on the incidence of valvulopathy with low dose cabergoline and examines the previous and current evidence-based screening guidelines.

Cost-effectiveness of point-of-care testing with task-shifting for HIV care in South Africa: a modelling study.

BACKGROUND: The number of people on antiretroviral therapy (ART) requiring treatment monitoring in low-resource settings is rapidly increasing. Point-of-care (POC) testing for ART monitoring might alleviate burden on centralised laboratories and improve clinical outcomes, but its cost-effectiveness is unknown. METHODS: We used cost and effectiveness data from the STREAM trial in South Africa (February, 2017-October, 2018), which evaluated POC testing for viral load, CD4 count, and creatinine, with task shifting from professional to lower-cadre registered nurses compared with laboratory-based testing without task shifting (standard of care). We parameterised an agent-based network model, EMOD-HIV, to project the impact of implementing this intervention in South Africa over 20 years, simulating approximately 175 000 individuals per run. We assumed POC monitoring increased viral suppression by 9 percentage points, enrolment into community-based ART delivery by 25 percentage points, and switching to second-line ART by 1 percentage point compared with standard of care, as reported in the STREAM trial. We evaluated POC implementation in varying clinic sizes (10-50 patient initiating ART per month). We calculated incremental cost-effectiveness ratios (ICERs) and report the mean and 90% model variability of 250 runs, using a cost-effectiveness threshold of US$500 per disability-adjusted life-year (DALY) averted for our main analysis. FINDINGS: POC testing at 70% coverage of patients on ART was projected to reduce HIV infections by 4·5% (90% model variability 1·6 to 7·6) and HIV-related deaths by 3·9% (2·0 to 6·0). In clinics with 30 ART initiations per month, the intervention had an ICER of $197 (90% model variability -27 to 863) per DALY averted; results remained cost-effective when varying background viral suppression, ART dropout, intervention effectiveness, and reduction in HIV transmissibility. At higher clinic volumes (≥40 ART initiations per month), POC testing was cost-saving and at lower clinic volumes (20 ART initiations per month) the ICER was $734 (93 to 2569). A scenario that assumed POC testing did not increase enrolment into community ART delivery produced ICERs that exceeded the cost-effectiveness threshold for all clinic volumes. INTERPRETATION: POC testing is a promising strategy to cost-effectively improve patient outcomes in moderately sized clinics in South Africa. Results are most sensitive to changes in intervention impact on enrolment into community-based ART delivery. FUNDING: National Institutes of Health.

A patient-initiated DMARD self-monitoring service for people with rheumatoid or psoriatic arthritis: a cost-effectiveness analysis.

OBJECTIVE: To determine whether a patient-initiated DMARD self-monitoring service for people on MTX is a cost-effective model of care for patients with RA or PsA. METHODS: An economic evaluation was undertaken alongside a randomized controlled trial involving 100 patients. Outcome measures were quality of life and ESR assessed at baseline and post-intervention. Costs were calculated for healthcare usage using a United Kingdom National Health Service economic perspective. Sensitivity analysis was performed to explore the impact of nurse-led telephone helplines. Uncertainty around the cost-effectiveness ratios was estimated by bootstrapping and analysing the cost-effectiveness planes. RESULTS: Fifty-two patients received the intervention and 48 usual care. The difference in mean cost per case indicated that the intervention was £263 more expensive (P < 0.001; 95% CI: £149.14, £375.86) when the helpline costs were accounted for and £94 cheaper (P = 0.08; 95% CI: -£199.26, £10.41) when these costs were absorbed by the usual service. There were, however, statistically significant savings for the patient (P = 0.02; 95% CI: -£28.98, £3.00). When costs and effectiveness measures of ESR and quality of life measured, using the Short Form-12v1, were combined this did not show the patient-initiated service to be cost-effective at a statistically significant level. CONCLUSION: This patient-initiated service led to reductions in primary and secondary healthcare services that translated into reduced costs, in comparison with usual care, but were not cost-effective. Further work is needed to establish how nurse-led telephone triage services are integrated into rheumatology services and the associated costs of setting up and delivering them. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, ISRCTN21613721.

Cost-effectiveness of therapeutic drug monitoring in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is increasingly common, and results in significant morbidity. Traditional therapies include corticosteroids, aminosalicylates, thiopurines and methotrexate but in more recent years biologics have transformed the management of IBD. However, these agents come with a significant financial cost, making them unavailable for many patients worldwide. Therapeutic drug monitoring (TDM) is an important means to optimise clinical outcomes from pharmacotherapy. Recent studies have also focussed on the cost-effectiveness as an outcome of TDM. TDM of traditional therapies is principally mediated through improved disease control. Cost-savings from TDM of biologic therapies arises mainly from reduced pharmaceutical use with equitable clinical outcomes. This review considers the cost-effectiveness of TDM for IBD therapies, with a focus on recent research into biologic TDM.

[Significant Changes Associated with the Transition from Outsourcing to In-hospital Therapeutic Drug Monitoring of Novel Antiepileptics].

For many of the novel antiepileptics, immunoassays, used for routine therapeutic drug monitoring (TDM), cannot be used. We could monitor eight novel antiepileptics using an LC/MS method since July 2017. The purpose of this study was to evaluate the significant changes associated with the transition from outsourcing to in-hospital monitoring of novel antiepileptics. The number of measurements of novel antiepileptics was significantly increased during the first (p<0.01) and second (p<0.001) years of in-hospital monitoring as compared to that one year prior to in-hospital monitoring which was outsourced. The proportion of measurements of novel antiepileptics to all antiepileptics was 19.7%, 31.1%, and 38.4% during outsourcing, and first, and second years of in-hospital monitoring, respectively. The measurement cost was significantly reduced during the first (p<0.001) and second (p<0.001) years of in-hospital monitoring as compared to that during outsourcing. In addition, the revenue from TDM of antiepileptic drugs was significantly increased during the first (p<0.05) and second (p<0.01) years of in-hospital monitoring as compared with that during outsourcing. In conclusion, the switch from outsourcing to in-hospital monitoring led to an increase in the number of orders, a reduction in the measurement-related expenses of novel antiepileptics, and an increase in the revenue from TDM of antiepileptic drugs, which could promote the proper use of novel antiepileptics through TDM.

Point-of-Care Therapeutic Drug Monitoring for Precision Dosing of Immunosuppressive Drugs.

BACKGROUND: Immunosuppressive drugs (ISD) are an essential tool in the treatment of transplant rejection and immune-mediated diseases. Therapeutic drug monitoring (TDM) for determination of ISD concentrations in biological samples is an important instrument for dose personalization for improving efficacy while reducing side effects. While currently ISD concentration measurements are performed at specialized, centralized facilities, making the process complex and laborious for the patient, various innovative technical solutions have recently been proposed for bringing TDM to the point-of-care (POC). CONTENT: In this review, we evaluate current ISD-TDM and its value, limitations, and proposed implementations. Then, we discuss the potential of POC-TDM in the era of personalized medicine, and provide an updated review on the unmet needs and available technological solutions for the development of POC-TDM devices for ISD monitoring. Finally, we provide concrete suggestions for the generation of a meaningful and more patient-centric process for ISD monitoring. SUMMARY: POC-based ISD monitoring may improve clinical care by reducing turnaround time, by enabling more frequent measurements in order to obtain meaningful pharmacokinetic data (i.e., area under the curve) faster reaction in case of problems and by increasing patient convenience and compliance. The analysis of the ISD-TDM field prompts the evolution of POC testing toward the development of fully integrated platforms able to support clinical decision-making. We identify 4 major areas requiring careful combined implementation: patient usability, data meaningfulness, clinicians' acceptance, and cost-effectiveness.

Rapid quantification of tenofovir in umbilical cord plasma and amniotic fluid in hepatitis B mono-infected pregnant women during labor by ultra-performance liquid chromatography/tandem mass spectrometry.

RATIONALE: Tenofovir (TFV) is a first-line antiviral agent against hepatitis B virus (HBV) and is recommended for the prevention of mother-to-infant transmission of HBV. To study the distribution of TFV in umbilical cord plasma and amniotic fluid of HBV-infected pregnant women, a rapid and sensitive method for TFV determination was developed and validated. METHODS: The quantification method was developed using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). The analytes were separated on an Acquity UPLC HSS T3 column under gradient elution with methanol and 0.01% ammonia solution in 10 mM ammonium acetate/water. This is the first reported method for the determination of TFV using alkaline rather than acidic mobile phases. Linearity, accuracy, precision, limit of quantification, specificity and stability were assessed. RESULTS: Detection of TFV was achieved within 4 min. The calibration curves for TFV quantification showed excellent linearity in the range of 1-500 ng/mL. The intra- and interbatch precision and accuracy ranged from -4.35% to 6.92%. This method was successfully applied to determination of samples from 50 HBV mono-infected women undergoing tenofovir disoproxil fumarate therapy. The mean concentrations of TFV in the umbilical cord and amniotic fluid samples were 29.2 (4.6-86) and 470.9 (156-902) ng/mL, respectively, which showed a moderate positive correlation (r = 0.5299, P<0.001). CONCLUSIONS: A simple, rapid but sensitive bioanalytical method to determine TFV concentration in both umbilical cord plasma and amniotic fluid using LC/MS/MS was developed and applied to HBV-infected women during labor who were undergoing TDF therapy, which will help us understand the efficacy and safety of tenofovir during pregnancy.

Proactive Vs Reactive Therapeutic Drug Monitoring of Infliximab in Crohn's Disease: A Cost-Effectiveness Analysis in a Simulated Cohort.

BACKGROUND: Therapeutic drug monitoring (TDM) is increasingly performed for Infliximab (IFX) in patients with Crohn's disease (CD). Reactive TDM is a cost-effective strategy to empiric IFX dose escalation. The cost-effectiveness of proactive TDM is unknown. The aim of this study is to assess the cost-effectiveness of proactive vs reactive TDM in a simulated population of CD patients on IFX. METHODS: We developed a stochastic simulation model of CD patients on IFX and evaluated the expected health costs and outcomes of a proactive TDM strategy compared with a reactive strategy. The proactive strategy measured IFX concentration and antibody status every 6 months, or at the time of a flare, and dosed IFX to a therapeutic window. The reactive strategy only did so at the time of a flare. RESULTS: The proactive strategy led to fewer flares than the reactive strategy. More patients stayed on IFX in the proactive vs reactive strategy (63.4% vs 58.8% at year 5). From a health sector perspective, a proactive strategy was marginally cost-effective compared with a reactive strategy (incremental cost-effectiveness ratio of $146,494 per quality-adjusted life year), assuming a 40% of the wholesale price of IFX. The results were most sensitive to risk of flaring with a low IFX concentration and the cost of IFX. CONCLUSIONS: Assuming 40% of the average wholesale acquisition cost of biologic therapies, proactive TDM for IFX is marginally cost-effective compared with a reactive TDM strategy. As the cost of infliximab decreases, a proactive monitoring strategy is more cost-effective.

A randomized evaluation of on-site monitoring nested in a multinational randomized trial.

BACKGROUND: Evidence from prospectively designed studies to guide on-site monitoring practices for randomized trials is limited. A cluster randomized study, nested within the Strategic Timing of AntiRetroviral Treatment (START) trial, was conducted to evaluate on-site monitoring. METHODS: Sites were randomized to either annual on-site monitoring or no on-site monitoring. All sites were centrally monitored, and local monitoring was carried out twice each year. Randomization was stratified by country and projected enrollment in START. The primary outcome was a participant-level composite outcome including components for eligibility errors, consent violations, use of antiretroviral treatment not recommended by protocol, late reporting of START primary and secondary clinical endpoints (defined as the event being reported more than 6 months from occurrence), and data alteration and fraud. Logistic regression fixed effect hierarchical models were used to compare on-site versus no on-site monitoring for the primary composite outcome and its components. Odds ratios and 95% confidence intervals comparing on-site monitoring versus no on-site monitoring are cited. RESULTS: In total, 99 sites (2107 participants) were randomized to receive annual on-site monitoring and 97 sites (2264 participants) were randomized to be monitored only centrally and locally. The two monitoring groups were well balanced at entry. In the on-site monitoring group, 469 annual on-site monitoring visits were conducted, and 134 participants (6.4%) in 56 of 99 sites (57%) had a primary monitoring outcome. In the no on-site monitoring group, 85 participants (3.8%) in 34 of 97 sites (35%) had a primary monitoring outcome (odds ratio = 1.7; 95% confidence interval: 1.1-2.7; p = 0.03). Informed consent violations accounted for most outcomes in each group (56 vs 41 participants). The largest odds ratio was for eligibility violations (odds ratio = 12.2; 95% confidence interval: 1.8-85.2; p = 0.01). The number of participants with a late START primary endpoint was similar for each monitoring group (23 vs 16 participants). Late START grade 4 and unscheduled hospitalization events were found for 34 participants in the on-site monitoring group and 19 participants in the no on-site monitoring group (odds ratio = 2.0; 95% confidence interval: 1.1-3.7; p = 0.02). There were no cases of data alteration or fraud. Based on the travel budget for on-site monitoring and the hours spent conducting on-site monitoring, the estimated cost of on-site monitoring was over US$2 million. CONCLUSION: On-site monitoring led to the identification of more eligibility and consent violations and START clinical events being reported more than 6 months from occurrence as compared to no on-site monitoring. Considering the nature of the excess monitoring outcomes identified at sites receiving on-site monitoring, as well as the cost of on-site monitoring, the value to the START study was limited.

Rapid drug detection in whole blood droplets using a desorption electrospray ionization static profiling approach - a proof-of-concept.

RATIONALE: The introduction of desorption electrospray ionization (DESI) - and ambient desorption/ionization (ADI) ion sources in general - in the 2000s has opened new possibilities for mass spectrometric (MS) analyses of biological sample surfaces. DESI allows for a rapid screening of solid samples because no sample preparation is needed and the analysis is performed at atmospheric pressure. In the present study, we used DESI as an ion source for the rapid detection of a small molecule in blood droplets deposited on glass slides. METHODS: Blood was spiked with different concentrations of a model drug, mebendazole. One microliter blood droplets of each preparation were deposited on the surface of a glass slide and analyzed by DESI, either in imaging or profiling mode. RESULTS: The results suggested that DESI imaging mode was not appropriate for the detection of mebendazole in blood droplets as an initial solvation time was necessary before the obtention of signal. A profiling approach consisting of analyzing a single position of the blood droplet was used for further analysis and allowed mebendazole to be detected in the fg range and to monitor the volume of sample analyzed. CONCLUSIONS: The study suggests that profiling mode at a single position is adequate for DESI analyses in whole blood droplets. This proof-of-concept study illustrates the potential of DESI profiling as a possible alternative to liquid chromatography/MS analyses of whole blood, when analyses are needed within a restricted time. Rapid detection methods in blood at atmospheric pressure may find interesting applications in the fields of toxicology and pharmacology.

Simple and sensitive method for the analysis of 14 antituberculosis drugs using liquid chromatography/tandem mass spectrometry in human plasma.

Monitoring plasma concentration and adjusting doses of antituberculosis (TB) drugs are beneficial for improving responses to drug treatment and avoiding adverse drug reactions. A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to measure the plasma concentrations of 14 anti-TB drugs: ethambutol, isoniazid, pyrazinamide, levofloxacin, gatifloxacin, moxifloxacin, prothionamide, linezolid, rifampin, rifapentine, rifabutin, cycloserine, p-aminosalicylic acid, and clofazimine. METHODS: Human plasma was precipitated by acetonitrile and was subsequently separated by an AQ-C18 column with a gradient elution. Drug concentrations were determined using multiple reaction monitoring in positive ion electrospray ionization mode. According to pharmacokinetic data of patients, the peak concentration ranges and the timing of blood collection were determined. RESULTS: Intra- and interday precision was < 14.8%. Linearity, accuracy, extraction recovery, and matrix effect were acceptable for each drug. The stability of the method satisfied different storage conditions. CONCLUSIONS: The method allowed the sensitive and reproducible determination of 14 frequently used anti-TB drugs which has already been of benefit for some TB patients.

Cost effectiveness of therapeutic drug monitoring for imatinib administration in chronic myeloid leukemia.

BACKGROUND: Imatinib mesylate (IM) is a first-line treatment option for patients with chronic myeloid leukemia (CML). Patients who fail or are intolerant to IM therapy are treated with more expensive second and third-generation tyrosine kinase inhibitors. Patients show wide variation in trough concentrations in response to standard dosing. Thus, many patients receive subtherapeutic or supratherapeutic doses. Therapeutic drug monitoring (TDM) may improve dose management that, in turn, may reduce costs and improve outcomes. However, TDM also adds to the cost of patient care. The objective of this study was to determine the cost-effectiveness of TDM for generic IM therapy. METHODS: We developed a microsimulation model for the trough plasma concentration of IM which is related to a cytogenetic or molecular response. We compared two cohorts: one with TDM and one without TDM (NTDM). The lifetime incremental cost-effectiveness ratio (ICER) was calculated using quality-adjusted life years (QALYs) as the effectiveness measure. One-way and probabilistic sensitivity analyses were performed. RESULTS: The lifetime cost and QALY of treatment with TDM were $2,137K [95% Ci: 2,079K; 2,174K] and 12.37 [95% CI: 12.07; 12.55], respectively. The cost and QALY of NTDM were $2,132K [95% CI: 2,091K; 2,197K] and 12.23 [95% CI: 11.96; 12.50], respectively. The incremental cost and QALY for TDM relative to NTDM was $4,417 [95% CI: -52,582; 32,097]) and 0.15 [95% CI: -0.13; 0.28]. The ICER for TDM relative to NTDM was $30,450/QALY. Probabilistic sensitivity analysis showed that TDM was cost-effective relative to NTDM in 90% of the tested scenarios at a willingness-to-pay threshold of $100,000/QALY. CONCLUSIONS: Although the impact of TDM is modest, the cost-effectiveness over a lifetime horizon (societal perspective, ($30,450/QALY) falls within the acceptable range (< $100k/QALY).

A geospatial model to determine the spatial cost-efficiency of anticoagulation drug therapy: Patients' perspective.

Most atrial fibrillation (AF) patients need anticoagulation management to reduce the risk of thromboembolic events and stroke. Currently, two major drug therapies are available: warfarin and direct oral anticoagulant (DOAC). This study examined the spatial costs of these therapies and derived the least-cost market areas for both therapies in the study area. The concepts of spatial costs and the principles of forming market areas were used as theoretical starting points, and the patients' travel, time-loss, and medication cost parameters combined with geographical information systems methods were incorporated into the geospatial model. Results showed that for AF patients who live near the international normalized ratio (INR) monitoring sample collection point and have less than 15 annual INR monitoring visits, warfarin therapy resulted in the lowest cost regardless of patient's travel mode and their assumed working or retirement status. If the AF patient needs more frequent INR monitoring visits or lives farther from the nearest sample collection point, DOAC would be the least costly option. The modelled results reveal the variety and importance of patients' cost of time loss and travel costs when a physician selects the appropriate anticoagulation therapy.