Therapeutic Drug Monitoring In Clinical Practice Research Articles

Therapeutic drug monitoring in inflammatory bowel disease: A practical approach.

The global burden of inflammatory bowel diseases (IBD) is estimated at 4.9 million and the global prevalence exceeds 0.3%. Multiple newer therapeutic agents have broadened the options for the therapy of IBD in the last three decades. Thiopurines, however, have retained their place as maintenance therapy in IBD, especially in resource-constrained setting. But thiopurines have narrow therapeutic range, often needing discontinuation due to side effects or lack of efficacy. Biologic agents revolutionized the treatment of IBD, but the efficacy is lost in 50% of patient after one year. These outcomes are often due to inadequate drug concentrations that may lead to thedevelopment of antibodies as well as pharmacodynamic failure. Therapeutic drug monitoring (TDM) was proposed to reduce loss of response and to optimize the therapy in patients on thiopurine and biologic therapy. TDM is based on exposure-response relationship, suggesting a positive correlation between elevated serum anti-TNF concentrations and favorable therapeutic outcomes. TDM has multiple facets. This article discusses the benefits, evidence and limitations of TDM. The practical use of TDM in clinical practice is highlighted. Newer developments in the field and their relevance in practice are discussed.

P565 Capillary blood based self-collection device for infliximab therapeutic drug monitoring

Abstract Background Patient friendly new devices may improve therapeutic drug monitoring (TDM) in inflammatory bowel disease (IBD). Our objective was to evaluate an infliximab (IFX) precision guided dosing tool from capillary blood collected using an upper-arm self-collection device amongst IBD patients and compare its performances to gold standard venous blood collected using venipuncture. Methods Patients under maintenance therapy with IFX were recruited from a single IBD center and enrolled in the BEST (Bayesian Estimates Sustaining Trough) study. BEST is a prospective real world evidence clinical utility study to establish the value of an IFX Bayesian forecasting tool in the optimal management of IBD. Blood specimens were collected prospectively, at midcycle or at trough. Capillary blood specimens were collected using an upper arm self-collection device (Tasso Inc., Seattle, WA) connected to a serum separator tube. Paired venous blood was collected using venipuncture. IFX concentrations and antibodies to IFX (ATI) status were measured using drug tolerant homogenous mobility shift assay, albumin levels were measured using nephelometry. IFX Clearance was calculated using nonlinear mixed effect model with Bayesian priors. Statistical analysis consisted of Deming regression. Results Overall, 27 patients (n=9 with UC, mean age=37 years, weight=79 Kg) were enrolled. Median IFX dosing was 10 mg/Kg, and median dosing frequency every 6 weeks. A total of n=58 serum pairs isolated from capillary and venous blood were tested. PK profiles measured from venous blood were optimal during maintenance with no immune response detected (ATI < 3.1 U/mL) and most patients had IFX concentration at trough above 5 µg/mL (98%, median 15.4 µg/mL IQR: 10.9-28.0 µg/mL) and low Clearance (< 0.294 L/day: 89%; median 0.200 L/day IQR: 0.170-0.248 L/day). IFX concentrations and Clearance levels were comparable between venous and capillary blood with high correlation (R2= 0.975; slope =0.928; and R2=0.978; slope =1.035, respectively) (figure). In capillary blood specimens collected at midcycle (median 14 days before the next infusion, n=12 pairs), median IFX concentration was 38.3 µg/mL (IQR: 31.2-64.7 µg/mL) and declined to 21.9 µg/mL (IQR: 14.1-44.5 µg/mL) at trough. There was a high correlation between forecasted and measured trough concentrations in capillary blood (R2=0.925; Deming’s slope=1.093). Similar results were observed with venous blood pairs (R2=0.983; Deming’s slope=1.024). Conclusion IFX therapeutic drug monitoring using patient self-collection of capillary blood performed as well as standard venous blood measurement. This collection method may facilitate the implementation of point of care TDM in clinical practice.

Meropenem PK/PD Variability and Renal Function: "We Go Together".

Meropenem is a carbapenem antibiotic widely employed for serious bacterial infections. Therapeutic drug monitoring (TDM) is a strategy to optimize dosing, especially in critically ill patients. This study aims to show how TDM influences the management of meropenem in a real-life setting, not limited to intensive care units. From December 2021 to February 2022, we retrospectively analyzed 195 meropenem serum concentrations (Css). We characterized patients according to meropenem exposure, focusing on the renal function impact. A total of 36% (n = 51) of the overall observed patients (n = 144) were in the therapeutic range (8-16 mg/L), whereas 64% (n = 93) required a meropenem dose modification (37 patients (26%) underexposed; 53 (38%) overexposed). We found a strong relationship between renal function and meropenem concentrations (correlation coefficient = -0.7; p-value < 0.001). We observed different dose-normalized meropenem exposure (Css/D) among renal-impaired (severe and moderate), normal, and hyperfiltrating patients, with a median (interquartile range) of 13.1 (10.9-20.2), 7.9 (6.1-9.5), 3.8 (2.6-6.0), and 2.4 (1.6-2.7), respectively (p-value < 0.001). Meropenem TDM in clinical practice allows modification of dosing in patients inadequately exposed to meropenem to maximize antibiotic efficacy and minimize the risk of antibiotic resistance, especially in renal alterations despite standard dose adaptations.

A comparison of pharmacokinetics software for therapeutic drug monitoring of piperacillin in patients with severe infections

ObjectiveTo evaluate the predictive performance of population pharmacokinetic models for piperacillin (PIP) available in the software MwPharm, TDMx and ID-ODs for initial dosing selection and therapeutic drug monitoring (TDM) purposes.MethodsThis...

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.

Optimizing therapeutic drug monitoring in inflammatory bowel disease: a focus on therapeutic monoclonal antibodies

ABSTRACT Introduction Therapeutic drug monitoring (TDM) is useful for optimizing monoclonal antibodies (mAbs) for the treatment of immune-mediated inflammatory disorders including inflammatory bowel disease (IBD). However, TDM in clinical practice is still restricted by long turnaround times between sampling and results and the fact that dosing of mAbs to a target drug concentration is challenging due to high pharmacokinetic (PK) variability at both a population and patient level. Overcoming these barriers may be addressed by point-of-care (POC) assays, model-informed precision dosing (MIPD), and pharmacogenetics/pharmacogenomics. Areas covered This review provides an overview of the optimization of TDM of mAbs in IBD including POC testing, MIPD, and pharmacogenetics. Expert opinion Recent advances in sampling, quantification, and support of clinical decisions include POC assays and PK dashboards, which may allow for prompt and precise application of TDM in clinical practice. Future perspectives toward a more personalized implementation of TDM could include the incorporation of pharmacogenetics/pharmacogenomics to identify subgroups of patients who would benefit more from proactive TDM or combination therapy such as those prone to immunogenicity and/or accelerated drug clearance. However, there are still challenges regarding the implementation of these innovative approaches, and more data from prospective studies and randomized controlled trials are needed.

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.

Development of a simultaneous analytical method for clozapine and its metabolites in human plasma using liquid chromatography/electrospray ionization tandem mass spectrometry with linear range adjusted by in-source collision-induced dissociation.

Clozapine (CLZ) is a key drug in treatment-resistant schizophrenia. Therapeutic drug monitoring (TDM) of CLZ and its metabolites, N-desmethylclozapine and clozapine N-oxide, is required to monitor and manage the risks of side effects. Although quantification methods for TDM have been developed for CLZ and its metabolites, they were not sufficiently accurate for the quantification of CLZ owing to the upper limits of the calibration curves. An analytical method using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry was developed and validated for the simultaneous measurement of CLZ and its metabolites in human plasma. To expand the concentration range of the calibration curves, we used a linear range shift technique using in-source collision-induced dissociation (CID). Using our approach, the linearity and quantitative range were improved compared to those reported by previous studies, and were sufficient for TDM in clinical practice. The intra- and inter-assay accuracy was 84.6%-114.8%, and the intra- and inter-assay precisions were ≤9.1% and ≤9.9%, respectively. Moreover, all samples from patients with treatment-resistant schizophrenia were successfully quantified. Therefore, our novel analytical method using in-source CID had the appropriate performance to measure the plasma concentrations of CLZ and its metabolites for TDM in clinical practice.

Personalised antimicrobial dosing: standing on the shoulders of giants

Suboptimal use of antimicrobial drugs contributes to increasing antimicrobial resistance and may lead to therapeutic failure at the individual patient level. Considering the significant pharmacokinetic (PK) variation in special patient populations and the variability in pathogen susceptibility, personalised dosing of antimicrobial drugs is pivotal. Dosing based on PK and pharmacodynamic properties of antibiotics guided by therapeutic drug monitoring (TDM) maximises efficacy and minimises toxicity for individual patients. Model-informed precision dosing (MIPD) provides a means of predicting drug response and dose requirements in individual patients based on individual patient and pathogen characteristics. Clear concentration targets should be defined to make use of MIPD and TDM in clinical practice. Target selection, validation and publication in the drug label should be part of drug licensing.

Barriers and opportunities for the clinical implementation of therapeutic drug monitoring in oncology.

There are few fields of medicine in which the individualisation of medicines is more important than in the area of oncology. Under-dosing can have significant ramifications due to the potential for therapeutic failure and cancer progression; by contrast, over-dosing may lead to severe treatment-limiting side effects, such as agranulocytosis and neutropenia. Both circumstances lead to poor patient prognosis and contribute to the high mortality rates still seen in oncology. The concept of dose individualisation tailors dosing for each individual patient to ensure optimal drug exposure and best clinical outcomes. While the value of this strategy is well recognised, it has seen little translation to clinical application. However, it is important to recognise that the clinical setting of oncology is unlike that for which therapeutic drug monitoring (TDM) is currently the cornerstone of therapy (e.g. antimicrobials). Whilst there is much to learn from these established TDM settings, the challenges presented in the treatment of cancer must be considered to ensure the implementation of TDM in clinical practice. Recent advancements in a range of scientific disciplines have the capacity to address the current system limitations and significantly enhance the use of anticancer medicines to improve patient health. This review examines opportunities presented by these innovative scientific methodologies, specifically sampling strategies, bioanalytics and dosing decision support, to enable optimal practice and facilitate the clinical implementation of TDM in oncology.

P582 Adalimumab therapeutic drug monitoring: Does time of testing matter?

Abstract Background Whilst anti-TNF drugs such as adalimumab (ADL) have revolutionised the management of inflammatory bowel disease treatment outcomes are not universally favourable with 30% primary non-response (PNR) and 46% secondary loss of response (SLOR) rates reported.1,2 Therapeutic drug monitoring (TDM)—the measurement of serum drug levels and anti-drug antibodies—has become popular with clinicians who use it to optimise biologic therapy through serum drug-level guided dose adjustment. Conventionally TDM is based on the interpretation of trough drug levels (DL) which are obtained by drawing a blood sample immediately prior to the next drug dose. Obtaining an ADL trough DL can be challenging as the drug is administered as a subcutaneous injection usually in the patient’s own home. The aim of this project was to determine the current use of non-trough ADL TDM in clinical practice and determine whether timing of ADL TDM in relation to the next planned dose is clinically important. Methods All ADL DLs performed in 2018 in the Scottish Biologic TDM service3 were identified. DLs were included for patients in sustained clinical remission (SCR), on 40mg every other week dosing, and if the time from the last dose was ≤14 days. TDM performed during induction and for PNR or SLOR were excluded, as were patients on nonstandard dosing or with missing data on dose and interval. Results were analysed by quartile according to time from the last drug dose. Results 338 DLs were included. Median DL is 8µg/ml (range &amp;lt;0.4–36). Median time from last dose is 12 (range 0–14) days. The first quartile (n = 83, median 5 (range 0–7) days) had a median DL of 8.2µg/ml (&amp;lt;0.4–28.1). The second quartile (n = 90, median 11 (8–12) days) had a median DL of 7.9µg/ml (&amp;lt;0.4–36). The third quartile (n = 80, 13 days from last dose) had a median DL of 8µg/ml (&amp;lt;0.4 – 28.1). fourth quartile samples (n = 85, 14 days from last dose – true trough DLs) had a median DL of 8 µg/ml (&amp;lt;0.4–34.8). No relationship was identified between observed DL and the time of DL testing (ρ= -0.3162, p = 0.23). Conclusion It is not necessary to use trough DLs when performing ADL TDM for individuals in SCR. These data should give clinicians the confidence to use opportunistic ADL TDM testing in a clinical setting. Further work should be undertaken on non-trough testing of ADL DLs in other clinical scenarios. Disclosure Biogen GmbH contributed funding for this research. Authors had full editorial control and approval of all content. References

Therapeutic drug monitoring with vedolizumab in inflammatory bowel disease.

Therapeutic drug monitoring (TDM) is a useful tool for decision-making process in patients with inflammatory bowel disease (IBD) treated with anti TNF-α drugs, especially when experiencing loss of response. Growing evidences support the existence of exposure-response relationship with vedolizumab, but the utility and the appropriate use of TDM in clinical practice is still under debate. In this review, we summarize all evidences supporting a TDM-guided approach for patients treated with vedolizumab, suggesting three potential scenarios: 1) early prediction of long-term outcomes; 2) verifying the best strategy in case of loss of response; 3) maximizing therapeutic efficacy during maintenance treatment. Vedolizumab through concentrations <20 µg/mL at week 6 and >12 µg/mL seem to be associated with more favorable outcomes. No comparative studies have been conducted so far to demonstrate the advantage of adopting a TDM-guided versus an empirical approach for managing primary or secondary nonresponses. The frequency of antibodies to vedolizumab detection is quite low (up to 4% in pivotal trials), suggesting, unlike of anti TNF-α agents, a low probability of experiencing an immune-mediated pharmacokinetic failure in clinical practice. Future prospective and controlled studies are warranted to establish the guidance on the use of a TDM-guided approach with vedolizumab in clinical practice.

759 A UK National Survey of Therapeutic Drug Monitoring With Anti-TNF Medications in IBD

INTRODUCTION: A growing body of evidence supports use of therapeutic drug monitoring (TDM) in improving efficacy and cost-effectiveness of anti-TNF therapy in patients with inflammatory bowel disease (IBD). Existing and evolving knowledge of TDM in clinical practice is less well understood. Our objective was to assess attitudes and barriers to TDM use with anti-TNF's in the UK. METHODS: A 17-question survey was distributed to members of the British Society of Gastroenterology. Information on clinician characteristics, demographics, use and barriers towards implementing TDM with anti-TNF's was collected. Logistic regression was used to predict factors influencing TDM use. RESULTS: 243 respondents participated (51.6% male) of which 237 respondents met inclusion criteria; treating &gt;5 IBD patients and at least 1 with an anti-TNF per month. Of the total respondents, 45% were Consultant Gastroenterologists (GI), 40% IBD Nurse Specialists (CNS) and 15% GI Specialist Registrars (SPR). Of these 237 respondents, TDM was used by 95.7% for secondary loss of response; 71.4% for primary non-response and 53.6% used TDM proactively. Barriers for TDM use were time lag in receiving results (27.1%), lack of awareness of guidelines (15.6%), and cost (11.9%). Clinicians working at a teaching hospital were more likely to use TDM compared to a district hospital (OR 2.6, 95% CI 0.71-9.8). IBD CNS and GI SPR used TDM more often, when compared to Consultant GI (OR 2.6, 95% CI 0.69-10 &amp; OR 1.5, 95% CI 0.3-7.2 respectively). Clinicians practising for &gt;20 years were more likely to check TDM than less experienced clinicians (OR 4.1, 95% CI 0.4-41.8). Clinicians with large volume IBD practice (&gt;50% IBD patients per month) were more likely to check TDM than those seeing fewer IBD patients (OR 45.6, 95% CI 7.5-275). Proactive TDM was more likely to be used by clinicians working in a tertiary care setting (OR 2.25, 95% CI 0.84-6.05), IBD CNS (OR 1.2, 95% CI 0.6-2.1), clinicians managing large volume IBD practice (OR 10.8, 95% CI 1.2-90) and clinicians with 5-9 years of experience in practice (OR 2.6 &amp; CI 1.04-6.42). CONCLUSION: Significant barriers to TDM implementation in the UK are time lag from test to result, lack of awareness of current guidelines and evolving knowledge, cost and less experience. Validation of point of care testing, lower cost assays, and wider dissemination of current evolving paradigms with updated recommendations may further optimise treatment with anti-TNF therapies.

Abstract P125: Determining Patient and Provider Acceptance of Therapeutic Drug Monitoring to Improve Medication Adherence

Objective: Therapeutic drug monitoring (TDM) is the assessment of medication adherence by detection of a drug or its metabolites in blood or urine samples. TDM-guided feedback has been shown to improve medication adherence and subsequent blood pressure (BP) control in patients with resistant hypertension. Herein, we sought to evaluate the attitudes of patients with uncontrolled hypertension as well as their providers towards incorporating TDM in clinical practice. Methods: We conducted a qualitative study consisting of in-depth, cognitive interviews in 10 patients seen in Parkland General Cardiology and Internal Medicine Clinics with uncontrolled hypertension. The patients were asked a series of 9 standardized questions to elicit their attitudes towards TDM use in the management of hypertension after informed consent. In addition, 10 providers, including faculty, trainees, and pharmacists, were also interviewed, using the same questionnaire to evaluate their attitudes of incorporating TDM in hypertension management. Results: Of the patients interviewed, 90% (9 of 10) were supportive of TDM use in clinical practice. Similarly, 100% (10 of 10) of providers thought TDM was a good idea and should be used regularly. On subsequent questioning, 78% (7 of 9) of patients who felt TDM was a good idea expressed reservation that TDM could negatively impact the physician-patient relationship. Nonetheless, 86% (6 of 7) of these patients felt TDM could be a useful tool to identifying and solving non-adherence of antihypertensive drugs, if providers are mindful of patients’ unique circumstances. Amongst providers, 90% (9 of 10) felt TDM may negatively impact the physician-patient relationship, yet felt TDM could still be useful in addressing non-adherence. Conclusion: TDM was found to be well accepted amongst patients and providers, though between 80-90% of patients and providers still had concerns that TDM could negatively impact the physician-patient relationship. However, the majority of patients and providers believed that TDM could be an effective tool in identifying and solving barriers to adherence, if the providers are sensitive to the patients’ specific needs. Our survey suggested feasibility of adopting TDM in improving medication adherence.

Development and clinical applications of the dried blood spot method for therapeutic drug monitoring of anti-epileptic drugs.

Anti-epileptic drugs (AEDs) have various pharmacokinetic profiles, inter-individual variabilities, high possibilities of drug-drug interactions and narrow therapeutic indices. To provide optimal treatment for patients, therapeutic drug monitoring (TDM) is necessary. However, TDM requires sufficient quantities of blood samples to measure drug concentrations. Therefore, TDM could be a burden, particularly in paediatric cases. A good alternative that overcomes these disadvantages is the dried blood spot (DBS) method, which is simple, convenient to use and less invasive, requiring a lower quantity of blood than traditional blood sampling methods. However, the DBS method is affected by haematocrit (Hct) levels to varying extents depending on the drug properties. In addition, different papers with varying characteristics are available for use when applying the DBS method. Therefore, it has not yet been applied to TDM in clinical practice. To achieve this, several steps are required, including method development, method validation and clinical validation. Currently, the development status of the DBS method is different for each AED and unclear. Therefore, we assessed the development status of the following 19 AEDs in 26 studies: lamotrigine, valproic acid, levetiracetam, phenytoin, topiramate, carbamazepine, carbamazepine epoxide, gabapentin, phenobarbital, pregabalin, clobazam, clonazepam, ethosuximide, felbamate, monohydroxycarbamazepine, nitrazepam, rufinamide, vigabatrin and zonisamide. Among them, carbamazepine, lamotrigine, topiramate and valproic acid have been developed such that they are nearly available for TDM. In addition, Whatman 903 Protein Saver Cards and concentration analysis by liquid chromatography with triple quadrupole mass spectrometer were used most often.

Appropriate Therapeutic Drug Monitoring of Biologic Agents for Patients With Inflammatory Bowel Diseases

Therapeutic drug monitoring (TDM) is widely available for biologic therapies in patients with inflammatory bowel disease (IBD). We reviewed current data and provided expert opinion regarding the clinical utility of TDM for biologic therapies in IBD. We used a modified Delphi method to establish consensus. A comprehensive literature review was performed regarding the use of TDM of biologic therapy in IBD and presented to international IBD specialists. Subsequently, 28 statements on the application of TDM in clinical practice were rated on a scale of 1 to 10 (1 = strongly disagree and 10 = strongly agree) by each of the panellists. Statements were accepted if 80% or more of the participants agreed with a score ≥7. The remaining statements were discussed and revised based on the available evidence followed by a second round of voting. The panel agreed on 24 (86%) statements. For anti-tumor necrosis factor (anti-TNF) therapies, proactive TDM was found to be appropriate after induction and at least once during maintenance therapy, but this was not the case for the other biologics. Reactive TDM was appropriate for all agents both for primary non-response and secondary loss of response. The panellists also agreed on several statements regarding TDM and appropriate drug and anti-drug antibody (ADA) concentration thresholds for biologics in specific clinical scenarios. Consensus was achieved towards the utility of TDM of biologics in IBD, particularly anti-TNF therapies. More data are needed especially on non-anti-TNF biologics to further define optimal drug concentration and ADA thresholds as these can vary depending on the therapeutic outcomes assessed.

Personalized medicine for oral molecular-targeted anticancer drugs

Therapeutic drug monitoring (TDM) is carried out by evaluating drug plasma (or serum) concentrations in response to individual optimal treatments by dose adjustment to improve efficacy or avoid side effects. Many molecular-targeted anticancer drugs show exposure-efficacy and exposure-toxicity relationships. Therefore, plasma concentrations of anticancer drugs can be used as biomarkers. However, to carry out TDM, therapeutic target ranges indicating exposure-response (efficacy/toxicity) relationships must be determined. In Japan, treatment fees for managing the TDM of imatinib and sunitinib have been assessed since 2012 and 2018, respectively. In therapy for imatinib or sunitinib using TDM, reduced toxicity, discontinuation rates, and costs for treatments as well asimproved clinical efficacy have been noted. To establish the use of TDM in clinical practice, it is necessary to determine target plasma concentrations (minimum effective concentration or minimum toxic concentration) of many molecular-targeted anticancer drugs by retrospective and prospective clinical trials. In these clinical trials, analytical methods with high precision are needed. By carrying out TDM, we may determine the optimal anticancer therapy for patients as precision medicine after the start of therapy.

Therapeutic Drug Monitoring of Second-Generation Antipsychotics for the Estimation of Early Drug Effect in First-Episode Psychosis: A Cross-sectional Assessment.

Studies on therapeutic drug monitoring (TDM) of second-generation antipsychotics (SGAs) have provided conflicting results regarding the association between dose, plasma concentrations, and drug effect and have focused rather on analyzing how individual drugs work. No study has attempted to process data from different SGAs globally to offer a panoramic view of the utility of TDM in clinical practice, and data on patients with first-episode psychosis (FEP) are lacking. This study aimed to assess the relationship between dose, plasma concentrations, and drug effect in a sample of patients with FEP, regardless of the SGA prescribed. Data from 64 compliant patients treated with the same SGA during a 2-month follow-up were recorded. Clinical symptoms were assessed using the Positive and Negative Symptoms Scale and the Montgomery-Åsberg Depression Rating Scale. Adverse effects were rated using the Udvalg für Kliniske Undersogelser scale. SGA doses were standardized to chlorpromazine equivalents, and patients were classified into 3 different ranges according to their plasma concentrations (subtherapeutic, therapeutic, and supratherapeutic). Plasma concentration ranges were proportionally related to dose. Patients with supratherapeutic plasma concentrations were treated with doses significantly higher than those with subtherapeutic concentrations. Dose and plasma concentrations were not associated with early drug effect. TDM seems unable to accurately estimate the early effects of SGAs in FEP. Ours is the first study to categorize plasma concentrations of SGAs into ranges for joint processing of data from a larger number of patients.

Golimumab pharmacokinetics in ulcerative colitis: a literature review.

Golimumab (GLM) is the latest anti-tumor necrosis factor (TNF) that gained its marketing license. Thanks to the PURSUIT induction and maintenance trials, it was approved for the treatment of ulcerative colitis (UC) in 2013. The other anti-TNF drugs available are infliximab and adalimumab. These two drugs have validated algorithms concerning prescription and therapeutic drug monitoring (TDM) but little is known about GLM. The available data on GLM's exposure-response relationship in UC are from the PURSUIT trials and are recently published. The data reveal all the factors that may impact the pharmacokinetic (PK) parameters: dosage, body weight (BW), concomitant drugs, the presence of anti-drug antibodies (ADAbs), sex and age. In addition, the GLM trough level at steady-state appears to be correlated with the patient's improvement which may make it a precious indicator to predict the clinical response. There is, however, no consensus on a possible therapeutic level or cutoff associated with clinical response, remission, or any other outcome measure such as endoscopic healing in UC. This lack of a threshold value, and its validation with different assay techniques, makes it difficult to use GLM TDM in clinical practice. As with other anti-TNF agents, GLM is associated with development of ADAbs, of which the prevalence and effects are still insufficiently described. The objective of this review is to describe current data and understanding of the PK of GLM including serum concentrations of GLM and ADAbs in UC patients. Better understanding of these parameters could lead to improved patient care with GLM.

Therapeutic drug monitoring of vancomycin: a guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society.

Guideline development should be based on the quality of evidence, balance of benefits and harms, economic evaluation and patients' views and preferences. Therefore, these factors were considered in the development of a new guideline for therapeutic drug monitoring (TDM) of vancomycin. To develop an evidence-based guideline for vancomycin TDM and to promote standardized vancomycin TDM in clinical practice in China. We referred to the WHO Handbook for Guideline Development and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to rate the quality of evidence and grade the strength of recommendations, according to economic evaluation and patients' views and preferences. We used the GRADE Grid method to formulate the recommendations. The guideline presents recommendations about who should receive vancomycin TDM, how to monitor vancomycin efficacy and renal safety, therapeutic trough concentrations, time to start initial vancomycin TDM, loading dose and how to administer and adjust the vancomycin dose. We developed an evidence-based guideline for vancomycin TDM, which provides recommendations for clinicians and pharmacists to conduct vancomycin TDM in China.