Push forward LC-MS-based therapeutic drug monitoring and pharmacometabolomics for anti-tuberculosis precision dosing and comprehensive clinical management

The spread of tuberculosis(TB),especially multidrug-resistant TB and extensively drug-resistant TB,has strongly motivated the research and development of new anti-TB drugs.New strategies to facilitate drug combinations,including pharmacokinetics-guided dose optimization and toxicology studies of first-and second-line anti-TB drugs have also been introduced and recommended.Liquid chromatography-mass spectrometry(LC-MS)has arguably become the gold standard in the analysis of both endo-and exo-genous compounds.This technique has been applied successfully not only for therapeutic drug monitoring(TDM)but also for pharmacometabolomics analysis.TDM improves the effectiveness of treatment,reduces adverse drug reactions,and the likelihood of drug resistance development in TB patients by determining dosage regimens that produce concentrations within the therapeutic target window.Based on TDM,the dose would be optimized individually to achieve favorable outcomes.Pharmacometabolomics is essential in generating and validating hypotheses regarding the metabolism of anti-TB drugs,aiding in the discovery of potential biomarkers for TB diagnostics,treatment monitoring,and outcome evaluation.This article highlighted the current progresses in TDM of anti-TB drugs based on LC-MS bioassay in the last two decades.Besides,we discussed the advantages and disadvantages of this technique in practical use.The pressing need for non-invasive sampling approaches and stability studies of anti-TB drugs was highlighted.Lastly,we provided perspectives on the prospects of combining LC-MS-based TDM and pharmacometabolomics with other advanced strategies(pharmacometrics,drug and vaccine developments,machine learning/artificial intelligence,among others)to encapsulate in an all-inclusive approach to improve treatment outcomes of TB patients.

Pretreatment and analysis techniques development of TKIs in biological samples for pharmacokinetic studies and therapeutic drug monitoring

Tyrosine kinase inhibitors(TKIs)have emerged as the first-line small molecule drugs in many cancer therapies,exerting their effects by impeding aberrant cell growth and proliferation through the modulation of tyrosine kinase-mediated signaling pathways.However,there exists a substantial inter-individual variability in the concentrations of certain TKIs and their metabolites,which may render patients with compromised immune function susceptible to diverse infections despite receiving theoretically efficacious anticancer treatments,alongside other potential side effects or adverse reactions.Therefore,an urgent need exists for an up-to-date review concerning the biological matrices relevant to bioanalysis and the sampling methods,clinical pharmacokinetics,and therapeutic drug monitoring of different TKIs.This paper provides a comprehensive overview of the advancements in pretreatment methods,such as protein precipitation(PPT),liquid-liquid extraction(LLE),solid-phase extraction(SPE),micro-SPE(μ-SPE),magnetic SPE(MSPE),and vortex-assisted dispersive SPE(VA-DSPE)achieved since 2017.It also highlights the latest analysis techniques such as newly developed high performance liquid chromatography(HPLC)and high-resolution mass spectrometry(HRMS)methods,capillary electrophoresis(CE),gas chromatography(GC),supercritical fluid chromatography(SFC)procedures,surface plasmon resonance(SPR)assays as well as novel nanoprobes-based biosensing techniques.In addition,a comparison is made between the advantages and disadvantages of different approaches while presenting critical challenges and prospects in pharmacokinetic studies and therapeutic drug monitoring.

Is tumor necrosis factor-α monoclonal therapy with proactive therapeutic drug monitoring optimized for inflammatory bowel disease? Network meta-analysis

BACKGROUND The efficacy and safety of anti-tumor necrosis factor-α(TNF-α)monoclonal antibody therapy[adalimumab(ADA)and infliximab(IFX)]with therapeutic drug monitoring(TDM),which has been proposed for inflammatory bowel disease(IBD)patients,are still controversial.AIM To determine the efficacy and safety of anti-TNF-αmonoclonal antibody therapy with proactive TDM in patients with IBD and to determine which subtype of IBD patients is most suitable for proactive TDM interventions.METHODS As of July 2023,we searched for randomized controlled trials(RCTs)and observa-tional studies in PubMed,Embase,and the Cochrane Library to compare anti-TNF-αmonoclonal antibody therapy with proactive TDM with therapy with reactive TDM or empiric therapy.Pairwise and network meta-analyses were used to determine the IBD patient subtype that achieved clinical remission and to determine the need for surgery.RESULTS This systematic review and meta-analysis yielded 13 studies after exclusion,and the baseline indicators were balanced.We found a significant increase in the number of patients who achieved clinical remission in the ADA[odds ratio(OR)=1.416,95%confidence interval(CI):1.196-1.676]and RCT(OR=1.393,95%CI:1.182-1.641)subgroups and a significant decrease in the number of patients who needed surgery in the proactive vs reactive(OR=0.237,95%CI:0.101-0.558)and IFX+ADA(OR=0.137,95%CI:0.032-0.588)subgroups,and the overall risk of adverse events was reduced(OR=0.579,95%CI:0.391-0.858)according to the pairwise meta-analysis.Moreover,the network meta-analysis results suggested that patients with IBD treated with ADA(OR=1.39,95%CI:1.19-1.63)were more likely to undergo TDM,especially in comparison with patients with reactive TDM(OR=1.38,95%CI:1.07-1.77).CONCLUSION Proactive TDM is more suitable for IBD patients treated with ADA and has obvious advantages over reactive TDM.We recommend proactive TDM in IBD patients who are treated with ADA.

Determination of Voriconazole in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry: Application in Therapeutic Drug Monitoring

A sensitive, accurate and robust Liquid Chromatography Tandem Mass Spectrometry method has been developed and validated to measure voriconazole trough levels in human plasma. The plasma samples were mixed with fluconazole as an Internal Standard and directed to protein precipitation and drug extraction. An aliquot of 1 μl was injected into the chromatographic system and separated by the Acquity BEH C18 column at a flow rate of 0.30 ml/min in a gradient mobile phase consisting of acetonitrile, Ultrapure water (UPW), methanol and formic acid. Voriconazole was detected by a Triple Quadrupole Detector (TQD) operating on Multiple Reaction Monitoring (MRM) and a positive ion mode Electrospray ionization (ESI) Q1 mass: 350.1 m/z, Q3 mass: 281.1 m/z. Method linearity of the calibration curve (0.10 - 8.00 μg/ml) indicated a correlation coefficient r ≥ 0.99. The intra and inter-assay accuracy was within 85% - 115% and the intra and inter-assay precision was ≤5.76%. Voriconazole recovery percentage was between 97.69 - 119.62%. The method was successively applied in routine voriconazole TDM.

Evidence of voriconazole pharmacokinetic variability in children and adolescents with haematological disease: proposal for therapeutic drug monitoring optimisation

Objective:Voriconazole(VCZ)is a triazole antifungal agent widely used in immunocompromised patients with suspected or proven invasive fungal infections.The achievement of therapeutic range(1-5 mg/L)is essential to maximize VCZ efficacy,as its pharmacokinetics is characterized by a wide inter-and intra-individual variability.This study aims to quantify the variability of VCZ trough concentrations in children and adolescents with haematological diseases and optimize therapeutic drug monitoring in clinical practice.Methods:We analysed the monitoring concentrations of all children(<18 years old)treated with VCZ in the Haematology Department of Robert DebréHospital between January 2014 and December 2016.Demographic,clinical data,and VCZ dosing and monitoring concentrations measured by high-performance liquid chromatography with ultraviolet detection(HPLC-UV)were analysed.Non-parametric tests were performed using SPSS IBM 24.0.Results:380 trough VCZ concentrations at steady-state(Ctrough,ss)were available in 79 children:45.6%had first Ctrough,ss in the therapeutic range at first monitoring,46.8%had Ctrough,ss below 1 mg/L and 7.6%had Ctrough,ss over 5 mg/L.Forty-one patients were treated with recommended doses but only 53%of them reached the therapeutic range.There was no impact of age,sex,biological parameters,or indication of VCZ on Ctrough,ss values.The number of Ctrough,ss in the therapeutic range increases with the number of monitoring per patient following dosage adaptations.Conclusion:The wide inter-and intra-individual variability of VCZ trough concentrations at recommended doses confirm the need to standardize VCZ monitoring and identify factors to be considered to prospectively adapt treatment for each patient.

In vivo solid phase microextraction for therapeutic monitoring and pharmacometabolomic fingerprinting of lung during in vivo lung perfusion of FOLFOX

In vivo lung perfusion(IVLP)is a novel isolated lung technique developed to enable the local,in situ administration of high-dose chemotherapy to treat metastatic lung cancer.Combination therapy using folinic acid(FOL),5-fluorouracil(F),and oxaliplatin(OX)(FOLFOX)is routinely employed to treat several types of solid tumours in various tissues.However,F is characterized by large interpatient variability with respect to plasma concentration,which necessitates close monitoring during treatments using of this compound.Since plasma drug concentrations often do not reflect tissue drug concentrations,it is essential to utilize sample-preparation methods specifically suited to monitoring drug levels in target organs.In this work,in vivo solid-phase microextraction(in vivo SPME)is proposed as an effective tool for quantitative therapeutic drug monitoring of FOLFOX in porcine lungs during pre-clinical IVLP and intravenous(IV)trials.The concomitant extraction of other endogenous and exogenous small molecules from the lung and their detection via liquid chromatography coupled to high resolution mass spectrometry(LC-HRMS)enabled an assessment of FOLFOX's impact on the metabolomic profile of the lung and revealed the metabolic pathways associated with the route of administration(IVLP vs.IV)and the therapy itself.This study also shows that the immediate instrumental analysis of metabolomic samples is ideal,as long-term storage at80℃ results in changes in the metabolite content in the sample extracts.

A simulation study of sampling time point designing for therapeutic drug monitoring based on a population pharmacokinetic model

Aim To develop a method to estimate population pharmacokinetic parameters with the limited sampling time points provided clinically during therapeutic drug monitoring. Methods Various simulations were attempted using a one-compartment open model with the first order absorption to determine PK parameter estimates with different sampling strategies as a validation of the method. The estimated parameters were further verified by comparing to the observed values. Results The samples collected at the single time point close to the non-informative sampling time point designed by this method led to bias and inaccurate parameter estimations. Furthermore, the relationship between the estimated non-informative sampling time points and the values of the parameter was examined. The non-informative sampling time points have been developed under some typical occasions and the results were plotted to show the tendency. As a result, one non-informative time point was demonstrated to be appropriate for clearance and two for both volume of distribution and constant of absorption in the present study. It was found that the estimates of the non-informative sampling time points developed in the method increase with increases of volume of distribution and the decrease of clearance and constant of absorption. Conclusion A rational sampling strategy during therapeutic drug monitoring can be established using the method present in the study.

对炎症性肠病患者开展抗TNF-α制剂TDM的国内外指南/共识的质量评价

目的评价对炎症性肠病(IBD)患者开展抗肿瘤坏死因子α(TNF-α)制剂治疗药物监测(TDM)的指南/共识的质量。方法检索PubMed、Embase、中国知网、万方数据和维普网以及国内外指南/共识发布网站,收集针对IBD患者开展抗TNF-α制剂TDM的指南/专家共识。检索时限均为建库至2023年6月。由2名研究者独立筛选文献、提取资料后,采用指南研究与评价工具Ⅱ对纳入指南/共识的方法学质量进行评价,并汇总纳入指南/共识的主要推荐意见。结果共纳入9篇文献,3篇为指南,6篇为共识。9篇指南/共识在范围和目的、参与人员、制定的严谨性、表达的清晰性、应用性和编辑独立性6个维度的标准化百分比分别为90.43%、41.98%、52.55%、85.49%、19.00%、76.85%。8篇指南/共识的推荐级别为B级,1篇共识的推荐级别为C级。主要推荐意见涉及TDM应用场景、阈值范围、策略调整、检测方法以及结果解读。大部分指南/共识均推荐对失应答患者应进行被动TDM;建议根据预期的治疗结果设定TDM浓度范围,并结合疾病状况和TDM结果进行策略调整,且建议同一患者采用相同的检测方法。部分指南/共识认为,生物类似药和原研药不存在结果解读差异。结论纳入的指南/共识总体质量一般,推荐意见较为统一。临床工作者需要了解该类药物TDM的特点和局限性,并结合具体的临床治疗目标去解读和运用监测结果。

实体器官移植受者接受霉酚酸类药物TDM的意愿调查

目的调查实体器官移植受者接受霉酚酸类(MPA)药物治疗药物监测(TDM)的意愿,并探究相关影响因素,为相关指南推荐意见形成及临床决策优化提供参考。方法采用横断面研究设计法,设计MPA TDM患者意愿调查问卷,选取2022年4月14日至2022年6月27日在北京市两家三级甲等综合医院接受MPA类药物治疗的实体器官移植受者进行调研。采用Likert 5级评分法对患者接受MPA TDM的意愿进行评分,采用Pearson相关分析和二元Logistic回归分析患者接受MPA TDM的意愿影响因素及其相关性,采用非参数检验和χ2检验对影响患者意愿决策的因素进行排序及一致性分析。结果共收集到有效问卷140份,有效回收率为77.35%。140例患者接受MPA TDM的平均意愿得分为(4.01±0.65)分,表明总体意愿值较高;有116例(82.86%)患者表示愿意或非常愿意接受MPA TDM;既往接受过TDM与未接受过TDM患者的意愿得分差异有统计学意义[(4.30±0.53)分vs.(3.80±0.65)分,P<0.001]。患者对MPA TDM的了解程度、重视程度与接受意愿呈显著正相关(P<0.001)。患者决策影响因素排序具有统计学上的一致性(P<0.001),影响程度由大到小分别为治疗有效性、安全性、舒适程度、经济性及时间成本。结论实体器官移植受者对MPA TDM的接受意愿较高,MPA TDM既往就诊经历和对MPA TDM的了解、重视程度为影响患者意愿的主要因素。

Therapeutic drug monitoring in inflammatory bowel disease:The dawn of reactive monitoring

Inflammatory bowel disease(IBD)is a chronic condition that significantly affects the quality of life of its patients.Biologic drugs have been the mainstay treatment in the management of IBD patients but despite their significant contribution,there remains a proportion of patients that do not respond or lose response to treatment.Therapeutic drug monitoring(TDM)involves measuring levels of serum drug concentrations and anti-drug antibodies.TDM of biologic drugs initially emerged to understand treatment failure in other immune mediated inflammatory diseases.This was then introduced in IBD to rationalize primary non-response or secondary loss of response,given that low serum drug concentrations or the formation of anti-drug antibodies are variably associated with treatment failure.The aim of this narrative review is to provide an overview regarding the current use of TDM in clinical practice and to present the evidence available regarding its use in both proactive and reactive clinical settings in preventing and managing treatment failure.This review also presents the existing evidence regarding the association of various clinical outcomes with specific thresholds of drug concentrations,in everyday practice.A narrative review of published articles and conference abstracts regarding the use of TDM in IBD management,through an electronic search using PubMed and ScienceDirect.TDM has proven to be superior and more cost effective in guiding management of patients with treatment failure compared to empiric dose escalation or change in treatment.Despite a trend towards an association between clinical outcomes and drug concentrations,proactive TDM based strategies have not been shown to achieve clear benefit in long-term outcomes.In the clinical setting,TDM has proven to be useful in managing IBD patients,and its use in the reactive setting,as an additional tool to help manage patients with treatment failure,is being promoted as newer guidelines and consensus groups implement TDM as part of the management plan.

A Protocol for Developing a Clinical Practice Guideline for Therapeutic Drug Monitoring of Vancomycin

This study aimed to develop a guideline for therapeutic drug monitoring（TDM） of vancomycin. We adopted the new guideline definition from the Institute of Medicine（IOM）, adhered closely to the six domains of the Appraisal of Guidelines for Research ＆ Evaluation Ⅱ（AGREE Ⅱ）, and made recommendations based on systematic reviews. We established a Guideline Steering Group and a Guideline Development Group, formulated 12 questions in the form of Population, Intervention, Comparison, Outcome（PICO） and completed a literature search. As far as we know, we will develop the first evidenced-based guideline for vancomycin TDM under the framework of the Grade of Recommendations Assessment, Development and Evaluation（GRADE）.

Potential use of a dried saliva spot(DSS)in therapeutic drug monitoring and disease diagnosis

In recent years,scientific researchers have increasingly become interested in noninvasive sampling methods for therapeutic drug monitoring and disease diagnosis.As a result,dried saliva spot(DSS),which is a sampling technique for collecting dried saliva samples,has been widely used as an alternative matrix to serum for the detection of target molecules.Coupling the DSS method with a highly sensitive detection instrument improves the efficiency of the preparation and analysis of biological samples.Furthermore,dried blood spots,dried plasma spots,and dried matrix spots,which are similar to those of the DSS method,are discussed.Compared with alternative biological fluids used in dried spot methods,including serum,tears,urine,and plasma,saliva has the advantage of convenience in terms of sample collection from children or persons with disabilities.This review aims to provide integral strategies and guidelines for dried spot methods to analyze biological samples by illustrating several dried spot methods.Herein,we summarize recent advancements in DSS methods from June 2014 to March 2021 and discuss the advantages and disadvantages of the key aspects of this method,including sample preparation and method validation.Finally,we outline the challenges and prospects of such methods in practical applications.

Therapeutic drug monitoring in inflammatory bowel disease:At the right time in the right place

Therapeutic drug monitoring(TDM)was one of most sought-after objective tools to determine therapeutic efficiency of different biologics and its role in the management of patients with inflammatory bowel disease(IBD)was regarded with great anticipation.But implementation of the TDM in clinical practice was challenged by several factors including uncertainty of the optimal cut-off values,assay variable sensitivity in detecting drug levels and antibodies and,most importantly,individual pharmacokinetics.While reactive TDM was embraced in clinical practice as a useful tool in assessing lack of response to therapy,the utility of proactive TDM in managing IBD therapy is still challenged by the lack of consistency between evidence.Described here,there are four groups of IBD patients for whom proactive TDM has the potential to greatly impact their therapeutic outcomes:Patients with perianal Crohn’s disease,patients with severe ulcerative colitis,pregnant women with IBD and children.As the future of IBD management moves towards personalizing treatment,TDM will be an important decision node in a machine learning based algorithm predicting the best strategy to maximize treatment results while minimizing the loss of response to therapy.

Early proactive monitoring of DNA-thioguanine in patients with Crohn’s disease predicts thiopurine-induced late leucopenia in NUDT15/TPMT normal metabolizers

BACKGROUND Thiopurine-induced leucopenia significantly hinders the wide application of thiopurines.Dose optimization guided by nudix hydrolase 15(NUDT15)has significantly reduced the early leucopenia rate,but there are no definitive biomarkers for late risk leucopenia prediction.AIM To determine the predictive value of early monitoring of DNA-thioguanine(DNATG)or 6-thioguanine nucleotides(6TGN)for late leucopenia under a NUDT15-guided thiopurine dosing strategy in patients with Crohn’s disease(CD).METHODS Blood samples were collected within two months after thiopurine initiation for detection of metabolite concentrations.Late leucopenia was defined as a leukocyte count<3.5×10^(9)/L over two months.RESULTS Of 148 patients studied,late leucopenia was observed in 15.6%(17/109)of NUDT15/thiopurine methyltransferase(TPMT)normal and 64.1%(25/39)of intermediate metabolizers.In patients suffering late leucopenia,early DNATG levels were significantly higher than in those who did not develop late leucopenia(P=4.9×10^(-13)).The DNATG threshold of 319.43 fmol/μg DNA could predict late leucopenia in the entire sample with an area under the curve(AUC)of 0.855(sensitivity 83%,specificity 81%),and in NUDT15/TPMT normal metabolizers,the predictive performance of a threshold of 315.72 fmol/μg DNA was much more remarkable with an AUC of 0.902(sensitivity 88%,specificity 85%).6TGN had a relatively poor correlation with late leucopenia whether in the entire sample(P=0.021)or NUDT15/TPMT normal or intermediate metabolizers(P=0.018,P=0.55,respectively).CONCLUSION Proactive therapeutic drug monitoring of DNATG could be an effective strategy to prevent late leucopenia in both NUDT15/TPMT normal and intermediate metabolizers with CD,especially the former.

Development of a competitive enzyme-linked immunosorbent assay for therapeutic drug monitoring of afatinib

Afatinib is an oral tyrosine kinase inhibitor(TKI) approved for treating advanced non-small cell lung cancer. It is necessary to develop a simple quantification method for TKIs in order to facilitate therapeutic drug monitoring(TDM) in clinical settings. This study sought to develop a simple and sensitive competitive enzyme-linked immunosorbent assay(ELISA) to quantify afatinib in plasma for routine pharmacokinetic applications. An anti-afatinib antibody was obtained using(S)-N-4-(3-chloro-4-fluorophenyl)-7-(tetrahydrofuran-3-yloxy)-quinazoline-4,6-diamine(CTQD), which has the same substructure as afatinib, as a hapten. Enzyme labeling of afatinib with horseradish peroxidase was similarly performed using CTQD. A simple competitive ELISA for afatinib was developed based on the principle of direct competition between afatinib and the enzyme marker for the anti-afatinib antibody, which had been immobilized on the plastic surface of a microtiter plate. Plasma afatinib concentrations below the limit of quantification of 30 pg/mL were reproducibly measurable. Also, the values of plasma afatinib levels measured from 20 patients were comparable with those measured by high-performance liquid chromatography, and there was a strong correlation between the values determined by both methods(Y=0.976 X – 0.207, r=0.975). As indicated by its specificity and sensitivity, this newly developed ELISA for afatinib is an important tool for TDM and studies of the pharmacokinetics of afatinib.

Appropriateness of Amikacin Dose Prescription, Monitoring and Safety during Hospitalization as an Impact of Clinical Pharmacologist Intervention, in the Israeli Regional Hospital

Background: Use of inappropriate amikacin dose is one of the most important factors in inducing toxicity, prolonged hospitalization as well as in increasing patient’s mortality. Objective: The aims of this study are the analysis of amikacin dose, serum level and the examination of the effectiveness of the clinical pharmacologist (CP) therapeutic drug monitoring (TDM) intervention to guarantee the safety of amikacin use. Methods: This is a one-year retrospective observational chart review study, which evaluates amikacin dose, serum drug level, development of adverse effects in patients on amikacin with or without CP TDM consultation. Results: Amikacin was prescribed for 393 complex patients, with median age 83. Amikacin group (AG) included 140 (32%) courses with CP consultation (AG1) and 292 (68%) courses without CP consultation (AG2). The distribution of most study characteristics in both groups was similar including amikacin dose (9-10 mg/kg/day), renal failure (14%) and mortality (12%). Acceptance for CP consultation was in 46% of amikacin courses and dose changes were done in 63% after CP intervention. Prolonged antibiotic course (4.6 ± 1.5 vs 3.8 ± 1.6 days, p < 0.0001) and the patient’s hemodynamic instability (15% vs 7%, p = 0.01) were more frequent in the AG1 compared to the AG2. There was a strong association between CP consultation and prolonged hospitalization (p = 0.005), while no association between it and amikacin adverse effects, renal failure or mortality. Conclusions: There was no trend to reducing amikacin toxicity, days of hospitaliza tion or mortality in patients with CP consultation. CP TDM intervention was more in the management of complicated clinical situations. However, it is necessary to optimize it.

Therapeutic drug monitoring in inflammatory bowel disease treatments

Recently,biological drugs have played a leading role in the treatment of inflammatory bowel disease,and therapeutic drug monitoring(TDM)may be useful in maximizing their effectiveness.TDM involves the measurement of serum drug and anti-drug antibodies concentrations as the basis for dosage adjustments or drug conversions to achieve a higher response rate.We believe that concentration thresholds should be individualized based on patients’disease severity,extent and phenotype,and therapeutic purposes should also be considered,with higher cut-offs mainly needed for endoscopic and fistula healing than for symptomatic remission.Proactive and reactive TDM can help optimize treatment,especially in patients receiving anti-tumour necrosis factor,and guide dose adjustment or drug conversion with lower cost.TDM is a promising approach to achieve precision medicine and targeted medicine in the future.

Updates in therapeutic drug monitoring in inflammatory bowel disease

Biologics and immunomodulators(IMM)are generally considered the most effective therapies for the treatment of ulcerative colitis and Crohn’s disease.However,despite the efficacy of these therapies,many patients either have a primary lack of response or a secondary loss of response to these medications.Therapeutic drug monitoring(TDM)is a systematic approach to managing such patients.In this review,we summarize the latest data on TDM,including reactive and proactive TDM,in patients with inflammatory bowel disease on biologics and/or IMM.

Therapeutic Drug Monitoring of Chelating Agent Deferoxamine for <i>β</i>-Thalassemia Major Patients

Therapeutic drug monitoring is used to prevent or decrease the risk associated with the toxic effects of medication. This study aims to evaluate the potential advantages of Therapeutic Drug Monitoring (TDM) of subcutaneous Deferoxamine injection and prevention of clinical problems in β-thalassaemia major patients. Patients & Methods: Fifty-four thalassemia patients were allocated into two groups;missing, and not missing deferoxamine dose. TDM of Deferoxamine injection and it clinical outcomes was critically studied under the following subheadings: assessment of the adequacy of Deferoxamine usage, serum peak and trough concentrations of Deferoxamine and ferroxamine with needed pharmacokinetics, cardiac parameters and biomarkers, biochemical and hematological indices, adverse effects/toxicity, urinary assessment of Fe, Zn, selenium, and copper levels, compliance to treatment, dose adjustment in correlation to therapeutic index and life style. Results: Demographic data showed no significant difference. Peak plasma concentrations were 144.83±69 and 43.54±39.16 μg/L, while trough concentrations were 33±26.32 and 31.13±21.58 μg/L of Deferoxamine and ferroxamine, respectively. The elimination rate constant was 0.0237±0.00029 min-1, half-life was 34 min, and distribution volume was 0.93±0.078. Although cardiac parameters showed no significant differences, there were significant differences in CK-MB, and hsCRP levels;troponin I value could not be detected. Biochemical and hematological studies showed significant differences in Ferritin B, urea, SGPT, SGOT, alkaline phosphatase, serum albumin and serum calcium. Assessment of adverse effects/toxicity showed significant differences. The correlation of serum ferritin to therapeutic index, and the life style including Vitamin C and/or E administration were assessed for the compliance to treatment. Conclusion: Therapeutic monitoring of chelation therapy by Deferoxamine in β-thalassemia patients is necessary to ensure effective treatment, compliance, and to avoid adverse side effects and toxicity.

Comparison of Measured Trough Values after Deriving the Initial Dose Setting of Vancomycin with a Conventional Computer Software and a Nomogram Based on the Revised Japanese 2016 Therapeutic Drug Monitoring Guidelines for Antimicrobial Agents

Background: Due to the relatively high renal toxicity of vancomycin injection (VCM), setting an initial dose that achieves a trough that ranges between 10 and 20 μg/mL on day 3 is important to ensure safety and minimize side-effects, especially for patients with low renal function. To address these issues, the revised 2016 Therapeutic Drug Monitoring (TDM) Guidelines for Antimicrobial Agents (GL2016) proposed the use of a renal function-based, estimate glomerular filtration rate (eGFR) nomogram for setting the dose of VCM in Japan. Methods: Our hospital introduced the use of the GL2016 in September 2016 for the patients administered VCM. After setting the initial VCM dose using 1) a conventional VCM analysis software and 2) the GL2016 eGFR nomogram, the measured trough values on day 3 were compared and evaluated in this study. Results: With the VCM analysis software, the mean measured trough value in the a-total group (n = 53) was 12.8 ± 4.7 μg/mL. With the eGFR nomogram, the mean measured trough value in the b-total group (n = 13) was 9.6 ± 4.6 μg/mL. However, when the different severities of renal function were compared, the mean measured trough value was more significantly lower in the b-1 group than in the a-1 group among subjects with G2 and above (eGFR ≥ 60 mL/min/1.73 m2), but it was similar between the a-2 group and the b-2 group among subjects with G3 and below (eGFR 60 mL/min/1.73 m2). The proportion of subjects reaching the various trough ranges shows similar tendency. Conclusions: These data suggested that the measured trough value on day 3 was generally lower when the initial dose was established using the eGFR nomogram based on the GL2016, and this was especially prominent among patients with normal renal function. As for subjects with low renal function, the trough values were relatively high while ensuring safety.