Benefit Of Therapeutic Drug Monitoring Research Articles

Results of the first international quality control programme for oral targeted oncolytics.

With the rising number of oral targeted oncolytics and growing awareness of the benefits of therapeutic drug monitoring (TDM) within the field of oncology, it is expected that the requests for quantifying concentrations of these drugs will increase. It is important to (cross-)validate available assays and ensure its quality, as results may lead to altered dosing recommendations. Therefore, we aimed to evaluate the performance of laboratories measuring concentrations of targeted oral oncolytics in a one-time international quality control (QC) programme. Participating laboratories received a set of plasma samples containing low, medium and high concentrations of imatinib, sunitinib, desethylsunitinib, pazopanib, cabozantinib, olaparib, enzalutamide, desmethylenzalutamide and abiraterone, with the request to report their results back within five weeks after shipment. Accuracy was defined acceptable if measurements where within 85%-115% from the weighed-in reference concentrations. Besides descriptive statistics, an exploratory ANOVA was performed. Seventeen laboratories from six countries reported 243 results. Overall, 80.7% of all measurements were within the predefined range of acceptable accuracy. Laboratories performed best in quantifying imatinib and poorest in quantifying desethylsunitinib (median absolute inaccuracy respectively 4.0% (interquartile range (IQR) 1.8%-6.5%) and 15.5% (IQR 8.8%-34.9%)). The poorest performance of desethylsunitinib might be caused by using the stable-isotope-labelled sunitinib instead of desethylsunitinib as an internal standard, or due to the light-induced cis(Z)/trans(E) isomerization of (desethyl)sunitinib. Overall, drug substance and performing laboratory seemed to influence the absolute inaccuracy (F = 16.4; p < 0.001 and F = 35.5; p < 0.001, respectively). Considering this is the first evaluation of an international QC programme for oral targeted oncolytics, an impressive high percentage of measurements were within the predefined range of accuracy. Cross-validation of assays that are used for dose optimization of oncolytics will secure the performance and will protect patients from incorrect advices.

Ustekinumab trough levels in children with Crohn's disease refractory to anti-tumor necrosis factor agents: a prospective case series of off-label use.

Background: Ustekinumab is used off-label in pediatric Crohn's disease refractory to anti-tumor necrosis factor. Data on optimal dosing, target trough levels, and potential benefit of therapeutic drug monitoring in children treated with ustekinumab are limited. Materials and Methods: We describe a series of six adolescents who consented to be treated with ustekinumab. We measured their trough levels, C-reactive protein, and fecal calprotectin before every administration. Results: Standard adult dosing was effective to achieve biochemical remission (fecal calprotectin < 250mg/kg) in one patient and clinical remission (resolution of symptoms) in another. The other four patients failed to respond on standard dosing and underwent intravenous re-induction and interval shortening to increase ustekinumab trough levels. This resulted in biochemical remission in one patient and clinical remission in another, suggesting an exposure-response relationship. The remaining two patients had no therapeutic benefit, and ustekinumab was discontinued. Conclusion: In this report, we show that ustekinumab can induce remission in pediatric patients with anti-tumor necrosis factor refractory Crohn's disease. It is worth escalating the dose before abandoning the drug as ineffective. Prospective studies in children are needed to determine long-term efficacy of ustekinumab, usefulness of therapeutic drug monitoring strategies, and, if applicable, optimal target trough levels.

Translated article] Influence of augmented renal clearance in the lower incidence of linezolid-related haematological toxicity

ObjectivesLinezolid is an oxazolidin commonly related to the development of haematological toxicity, being renal clearance the major factor involved in the drug clearance. The aim of this study is to evaluate the influence of increased filtration rates in the incidence of linezolid-induced haematological toxicity by comparing augmented renal clearance (ARC) patients versus normal renal function patients. Material and methodsA retrospective, observational study was conducted on hospitalized patients treated with linezolid for 5 days or more during 2014–2019 period. Patients with a filtration rate of ≥130 mL/min versus reference patients (60–90 mL/min) were compared. Haematological toxicity was defined as a decrease of 25% in platelets, of 25% in haemoglobin, and/or 50% in neutrophils from baseline. Toxicity relevance was classified according to Common Terminology Criteria for Adverse Events v5. Incidence of haematological toxicity between groups was studied by chi-square and Fisher test. Furthermore, percentage diminution of all 3 parameters was calculated and compared by Mann–Whitney test and treatment interruption and transfusion requirements were registered. Results30 ARC patients and 38 reference patients were included. Haematological toxicity was observed in 16.66% of ARC patients vs 44.74% of reference patients (P=.014); thrombocytopenia in 13.33% vs 36.84% (P=.051), anaemia in 3.3% vs 10.52% (P=.374) and neutropenia in 10% vs 23.68% (P=.204). Median percentage of platelets decrease in ARC patients was −10.36 (−193.33–62.03) vs 2.68 (−163.16–82.71) in reference patients (P=.333), while haemoglobin decrease was 2.50 (−12.12–25.93) vs 9.09 (−17.72–30.63) (P=.047) and neutrophils decrease was 9.14 (−73.91–76.47) vs 27.33 (−86.66–90.90) (P=.093). 10.5% of normal renal function patients reported at least 1 adverse event grade 3 or superior while 2.6% of them interrupted treatment and 5.2% had transfusion requirements. No major events or interruptions were reported in ARC patients. ConclusionOur findings suggest a lower incidence and clinical relevance of haematological toxicity in augmented renal clearance patients. Thrombocytopenia was the major event in both populations. This might be related to a lower exposure to the drug due to the higher clearance and likely lower therapeutic efficiency. These results suggest a potential benefit of therapeutic drug monitoring on high risk patients.

Influencia de la hiperfiltración glomerular en la menor toxicidad hematológica inducida por linezolid

ObjectivesLinezolid is an oxazolidin commonly related to the development of hematological toxicity, being renal clearance the major factor involved in the drug clearance. The aim of this study is to evaluate the influence of increased filtration rates in the incidence of linezolid-induced hematological toxicity by comparing augmented renal clearance (ARC) patients versus normal renal function patients. Material and methodsA retrospective, observational study was conducted on hospitalized patients treated with linezolid for 5 days or more during 2014–2019 period. Patients with a filtration rate of ≥130 mL/min versus reference patients (60–90 mL/min) were compared. Hematological toxicity was defined as a decrease of 25% in platelets, of 25% in hemoglobin and/or 50% in neutrophils from baseline. Toxicity relevance was classified according to Common Terminology Criteria for Adverse Events v5. Incidence of hematological toxicity between groups was studied by chi-square and Fisher test. Furthermore, percentaje disminution of all three parameters was calculated and compared by Mann–Whitney test and treatment interruption and tranfusion requirements were registered. Results30 ARC patients and 38 reference patients were included. Hematological toxicity was observed in 16.66% of ARC patients vs 44.74% of reference patients (p = 0.014); thrombocytopenia in 13.33% vs 36.84% (p = 0.051), anemia in 3.3% vs 10.52% (p = 0.374) and neutropenia in 10% vs 23.68% (p = 0.204). Median percentaje of platelets decrease in ARC patients was −10.36 (−193.33–62.03) vs 2.68 (−163.16–82.71) in reference patients (p = 0.333), while hemoglobin decrease was 2.50 (−12.12–25.93) vs 9.09 (−17.72–30.63) (p = 0.047) and neutrophils decrease was 9.14 (−73.91–76.47) vs 27.33 (−86.66–90.90) (p = 0.093). 10.5% of normal renal function patients reported at least one adverse event grade 3 or superior while 2.6% of them interrupted treatment and 5.2% had tranfusion requirements. No major events or interruptions were reported in ARC patients. ConclusionOur findings suggest a lower incidence and clinical relevance of hematological toxicity in augmented renal clearance patients. Thrombocytopenia was the major event in both populations. This might be related to a lower exposure to the drug due to the higher clearance and likely lower therapeutic efficiency. These results suggest a potential benefit of therapeutic drug monitoring on high risk patients.

On the benefits of therapeutic drug monitoring for patients undergoing treatment with antipsychotic agents.

On the benefits of therapeutic drug monitoring for patients undergoing treatment with antipsychotic agents.

Clinical benefits of therapeutic drug monitoring of vancomycin therapy in patients with postoperative intracerebral hemorrhage: a retrospective cohort study

ObjectiveThe objective of this study was to investigate the clinical efficacy and safety of conducting therapeutic drug monitoring (TDM) of vancomycin in patients with postoperative intracerebral haemorrhage.MethodsWe conducted a retrospective...

Intérêt des dosages pharmacologiques d’immunosuppresseurs et immunomodulateurs dans la prise en charge des maladies autoimmunes

The pharmacokinetics of drugs, such as immunosuppressants, justify the need of measuring their blood concentrations in order to adjust their dosage. Therapeutic Drug Monitoring (TDM) of ciclosporin, tacrolimus and mycophenolate mofetil has shown its benefit particularly in the management of renal transplantees, in order to prevent graft rejection. When prescribed in autoimmune diseases, their pharmacokinetic variability and the variability of clinical response would justify TDM in practice. TDM may be useful in systemic lupus, for hydroxychloroquine, in order to monitor patient compliance. Despite insufficient data in the literature, for mycophenolate mofetil, TDM would permit to maintain clinical remission in adults and children with lupus nephritis, as well as in mucosal pemphigoid and idiopathic nephrotic syndrome in children. Studies are still necessary to validate the thresholds and TDM conditions. For azathioprine, TPMT phenotyping is recommended before prescription. For methotrexate, tacrolimus and ciclosporin, data are still sparse on the benefit of TDM, although it may improve tolerance to tacrolimus in lupus. Finally, for infliximab, in case of loss of response in maintenance, TDM may be proposed in parallel with detection of anti-drug antibodies.

1112. Vancomycin Nephrotoxicity Relative to Alternative Antibiotic Treatments: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BackgroundVancomycin is one of the most frequently prescribed antibiotics. Existing clinical evidence on vancomycin nephrotoxicity is limited to observational studies which are prone to confounding and bias. The purpose of this systematic review and meta-analysis is to compare acute kidney injury between vancomycin and comparator anti-methicillin resistant Staphylococcus aureus (MRSA) antibiotics using randomized controlled trial (RCT) data.MethodsPubMed and Embase were searched for RCTs comparing intravenous vancomycin to other anti-MRSA antibiotics in adult patients, published from 1990 to January 2021. Studies were included if they reported comparative data on renal outcomes. The primary outcome was change in renal function, referred to as ‘nephrotoxicity’ in this study. Studies where another known nephrotoxic medication was part of study therapy in any treatment group were excluded. Eighteen studies met the inclusion criteria, and two independent reviewers assessed the risk of bias. Data on nephrotoxicity definition, comparator drug, infection type, vancomycin dosing strategy, duration of treatment, and concurrent gram-negative coverage were extracted. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Figure 1. Flow chart of article selection.ResultsOf 1,426 studies identified, 18 encompassing 8,966 patients were included. Treatment with vancomycin was associated with significantly increased odds of nephrotoxicity (OR, 2.41; 95% CI, 1.71 to 3.40; P< 0.00001) relative to its alternatives. A subgroup analysis grouping studies by reported vancomycin dosing approach revealed a stronger association between vancomycin and nephrotoxicity in studies with fixed-dose vancomycin regimens (OR 5.31; 95% CI 1.93 to 14.56; P=0.001) relative to studies with vancomycin therapeutic drug monitoring (TDM) (OR 2.17; 95% CI 1.51 to 3.13; P< 0.0001). Figure 2. Forest plot indicating the risk of nephrotoxicity associated with vancomycin vs. comparators. Odds ratios (ORs) and 95% confidence intervals (95% CIs) are shown for each study and the pooled analysis using a random effects model and the Mantel-Haenszel method. OR>1 means that the risk of kidney injury in the vancomycin group is greater than that in the comparator group.Figure 3. Forest plot indicating a strong association between vancomycin and nephrotoxicity in studies with fixed-dose vancomycin regimens relative to studies with vancomycin therapeutic drug monitoring (TDM). Odds ratios (ORs) and 95% confidence intervals (95% CIs) are shown for each study and the pooled analysis using a random effects model and the Mantel-Haenszel method. OR>1 means that the risk of kidney injury in the vancomycin group is greater than that in the comparator group.Table 1. Summary of included studies. ConclusionThis analysis shows that intravenous vancomycin is associated with greater odds of renal toxicity relative to alternative antibiotics. This effect was not as pronounced in studies where vancomycin TDM was used potentially indicating benefit of TDM although further study is required to confirm this.Disclosures All Authors: No reported disclosures

Therapeutic drug monitoring of newer generation antiseizure medications at the point of treatment failure

PurposeThe benefit of therapeutic drug monitoring (TDM) of newer generation antiseizure medications (ASM) has been little studied. A recent randomized study suggested that TDM at each medical visit did not bring a significant benefit, but the study did not investigate TDM in cases of treatment failure. Accordingly, we realized a post hoc analysis of this trial. MethodsWe analyzed 282 TDMs in 136 patients. We compared TDM performed at visits after treatment failure versus without treatment failure, reporting the proportion of drug levels out of range and the prescriber's adherence to dosage recommendations according to measured drug levels. ResultsThere was no statistical difference in terms of proportion of out of range plasma drug levels (47% vs 50%, p = 0.7) or adherence of prescribers to the clinical pharmacologists’ dosage recommendations (21% vs 30%, p = 0.6) between visits after treatment failure and visits without treatment failure, respectively. Knowledge of prior drug levels did not modify the results. ConclusionSystematic TDM at appointments following treatment failure showed similar results to TDM at visits without treatment failure. The prescribers’ adherence with dosage recommendations was low in both cases. It is not clear whether better prescriber adherence would improve patient outcome. Furthermore, the ability to detect poor patient compliance is limited in a planned outpatient appointment. The study setting does not reflect on the general usefulness of TDM.

Clinical Benefit of Therapeutic Drug Monitoring in Colorectal Cancer Patients Who Received Fluorouracil-Based Chemotherapy.

BackgroundThe impact of therapeutic drug management (TDM) on reducing toxicity and improving efficacy in colorectal cancer (CRC) patients receiving fluorouracil-based chemotherapy is still unclear.Material/MethodsA total of 207 patients (Study Group n=54, Historical Group n=153) with metastatic colorectal cancer were enrolled. All of them received 6 administrations of the 5-FU based regimens. Initial 5-FU dosing of all patients was calculated using body surface area (BSA). In the Study Group, individual exposure during each cycle was measured using a nanoparticle immunoassay, and the 5-FU blood concentration was calculated using the area under the curve (AUC). We adjusted the 5-FU infusion dose of the next cycle based on the AUC data of the previous cycle to achieve the target of 20–30 mg×h/L.ResultsIn the fourth cycle, patients in the target concentration range (AUC mean, 26.3 mg×h/L; Median, 28 mg×h/L; Range, 14–38 mg×h/L; CV, 22.4%) accounted for 46.8% of all patients, which were more than the ones in the first cycle (P<0.001). 5-FU TDM significantly reduced the toxicity of chemotherapy and improved its efficacy. The Study Group (30/289) showed a lower percentage of severe adverse events than that in the Historical Group (185/447) (P<0.001). The incidences of complete response and partial response in the Study Group were higher than those in the Historical Group (P=0.032).ConclusionsTDM in colorectal cancer can reduce toxicity, improve efficacy and clinical outcome, and can be routinely used in 5-FU-based chemotherapy.

Benefits of Therapeutic Drug Monitoring of First Line Antituberculosis Drugs

Abstract Tuberculosis is an airborne infectious disease that remains a huge global health-related issue nowadays. Despite constant approvals of newly developed drugs, the use of first-line antituberculosis medicines seems reasonable in drug-susceptible Mycobacterium tuberculosis strains. Therapeutic drug monitoring presents a useful technique for the determination of plasma drug concentration to adjust appropriate dose regimes. In tuberculosis treatment, therapeutic drug monitoring is aiding clinicians in selecting an optimal therapeutic level, which is essential for the personalisation of therapy. This review is aimed at clarifying the use of therapeutic drug monitoring of the first-line antituberculosis drugs in routine clinical practice.

Blood Levels to Optimize Antipsychotic Treatment in Clinical Practice: A Joint Consensus Statement of the American Society of Clinical Psychopharmacology and the Therapeutic Drug Monitoring Task Force of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie.

The quantification of antipsychotic levels in blood, also known as therapeutic drug monitoring (TDM), is a potentially useful tool of modern personalized therapy that can be applied to augment antipsychotic use and dosing decisions. The application of TDM for antipsychotics can be helpful in numerous challenging clinical scenarios, such as lack of therapeutic response, relapse, or adverse drug reactions (ADRs) related to antipsychotic treatment. The benefits of TDM may be particularly evident in the treatment of highly vulnerable patient subgroups, such as children, adolescents, pregnant women, and the elderly. The main aim of this article is to aid clinicians who routinely prescribe antipsychotics to successfully apply TDM in routine clinical practice in order to help optimize the efficacy and safety of those antipsychotics. Participants were clinicians and researchers, members of the American Society of Clinical Psychopharmacology, and the Therapeutic Drug Monitoring Task Force of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (Association of Neuropsychopharmacology and Pharmacopsychiatry). TDM literature on antipsychotics was critically reviewed to provide a condensed clinical decision-making algorithm with therapeutic reference ranges for blood antipsychotic levels, within which patients are most likely to respond and tolerate treatment, although TDM is not equally recommended/supported for all antipsychotics. A preliminary draft was prepared and circulated to the writing group members. Consensus was achieved in all cases, and resulting recommendations focused on following areas: steady-state and sampling time, levels of recommendations, indications, therapeutic reference ranges and laboratory alert levels, practical issues, and interpretation, as well as limitations. The utilization of TDM as a tool for problem solving in antipsychotic treatment offers a unique method to improve safety and efficacy. This consensus statement summarizes essential information on the routine use of TDM for antipsychotics and encourages clinicians to perform TDM with the appropriate indications as part of the clinical decision-making process.

Associations between certolizumab pegol serum levels, anti-drug antibodies and treatment response in patients with inflammatory joint diseases: data from the NOR-DMARD study

ObjectivesTo identify a therapeutic target interval for certolizumab pegol drug levels and examine the influence of anti-drug antibodies in patients with inflammatory joint diseases.MethodsCertolizumab pegol and anti-drug antibody levels were measured in serum samples collected after 3 months of certolizumab pegol treatment in 268 patients with inflammatory joint diseases (116 axial spondyloarthritis, 91 rheumatoid arthritis and 61 psoriatic arthritis) in the NOR-DMARD study. Treatment response was defined by Ankylosing Spondylitis Disease Activity Score Clinically important improvement in axial spondyloarthritis, European League Against Rheumatism good/moderate response in rheumatoid arthritis, and improvement in 28-joint Disease Activity Score of ≥ 0.6 in PsA. Serum drug levels and anti-drug antibodies were analysed using automated in-house assays.ResultsCertolizumab pegol serum levels varied considerably between individuals (median (IQR) 32.9 (17.3–43.9) mg/L). Certolizumab pegol level ≥ 20 mg/L was associated with treatment response for the total inflammatory joint disease population, with odds ratio (OR) 2.3 (95% CI 1.2–4.5, P = 0.01) and OR 1.9 (95% CI 1.0–3.5, P = 0.05) after 3 and 6 months of treatment, respectively. For individual diagnoses, this association was most consistent for axial spondyloarthritis, with OR 3.4 (95% CI 1.0–11.1, P < 0.05) and OR 3.3 (95% CI 1.0–10.8, P < 0.05), respectively. Certolizumab pegol level > 40 mg/L was not associated with any additional benefit for any of the diagnoses. Anti-drug antibodies were detected in 6.1% (19/310) of samples and were associated with low certolizumab pegol levels (P < 0.01).ConclusionsSerum certolizumab pegol levels 20–40 mg/L were associated with treatment response in inflammatory joint diseases. Our study is the first to show this association in axial spondyloarthritis and psoriatic arthritis patients. The results suggest a possible benefit of therapeutic drug monitoring in patients with inflammatory joint disease on certolizumab pegol treatment.Trial registrationNCT01581294, April 2012.

DPYD and Fluorouracil-Based Chemotherapy: Mini Review and Case Report.

5-Fluorouracil remains a foundational component of chemotherapy for solid tumour malignancies. While considered a generally safe and effective chemotherapeutic, 5-fluorouracil has demonstrated severe adverse event rates of up to 30%. Understanding the pharmacokinetics of 5-fluorouracil can improve the precision medicine approaches to this therapy. A single enzyme, dihydropyrimidine dehydrogenase (DPD), mediates 80% of 5-fluorouracil elimination, through hepatic metabolism. Importantly, it has been known for over 30-years that adverse events during 5-fluorouracil therapy are linked to high systemic exposure, and to those patients who exhibit DPD deficiency. To date, pre-treatment screening for DPD deficiency in patients with planned 5-fluorouracil-based therapy is not a standard of care. Here we provide a focused review of 5-fluorouracil metabolism, and the efforts to improve predictive dosing through screening for DPD deficiency. We also outline the history of key discoveries relating to DPD deficiency and include relevant information on the potential benefit of therapeutic drug monitoring of 5-fluorouracil. Finally, we present a brief case report that highlights a limitation of pharmacogenetics, where we carried out therapeutic drug monitoring of 5-fluorouracil in an orthotopic liver transplant recipient. This case supports the development of robust multimodality precision medicine services, capable of accommodating complex clinical dilemmas.

The Benefit of Therapeutic Drug Monitoring of Vancomycin in a Respiratory ICU; A Patient with Acute Kidney Injury: A Case Report

Introduction: Vancomycin damage to the kidney is one of the severe adverse reactions. The primary objective of this study was to discuss how the clinical pharmacists should deal with the results of therapeutic drug monitoring (TDM) for Vancomycin. Case Presentation: A case of severe acute kidney injury in a 60-year-old woman receiving Vancomycin as empirical therapy is reported here. The patient was admitted to the respiratory intensive care unit (RICU) of the First Affiliated Hospital of Bengbu Medical College, China, on 15 Oct 2015. On Day 7, the steady-state serum trough concentration and peak concentration of Vancomycin were 102.2 and 111.9 μg/mL, respectively. Clinical pharmacists immediately contacted the clinicians and advised them to discontinue Vancomycin therapy as soon as possible, and the proposal was adopted. On Day 8, serum creatinine (SCr) increased to 719 μmol/L, and creatinine clearance rate (CrCl) decreased to 6 mL/min; then, the patient was given dialysis treatment. After she underwent dialysis treatment, SCr decreased to 330 μmol/L and CrCl increased to 14 mL/min on Day 19; then, the patient was discharged after she accepted the doctor’s advice to start a home-dialysis program outside the hospital. Conclusions: In this case, clinical pharmacists contacted the doctor to avoid further aggravated renal damage timely when they found a significant increase in Vancomycin concentrations. It indicates that the Vancomycin level can be used as an indirect marker of renal function as increased Vancomycin level results from and contributes to acute kidney injury.

Clinically important neutralizing anti-drug antibodies detected with an in-house competitive ELISA.

Therapeutic drug monitoring of TNF-alpha inhibitors is crucial for evaluating patients with inflammatory diseases on a personalized level. It has been clinically observed that many patients receiving TNF-alpha inhibitors, with negative drug and anti-drug antibody results from bridging ELISA (bELISA), lose their drug response over time, despite dose optimization. Our aims were to develop innovative in-house competitive ELISAs (cELISAs) for the detection of neutralizing antibodies against infliximab and adalimumab and compare their results to reporter gene assay (RGA) and in-house bELISA. Furthermore, we aimed to evaluate patient anti-drug antibody results in regard to their clinical records and potential benefits of therapeutic drug monitoring with the novel cELISAs. Sera of patients treated with infliximab (n = 46) or adalimumab (n = 31), having undetectable drug levels, were tested with our in-house cELISA. Briefly, samples were incubated with a fixed amount of drug and the neutralizing capacity of the samples was determined. The cELISA results were compared to RGA and bELISA results using Spearman's correlation coefficient. Additionally, patient clinical data were evaluated in line with the results of cELISA, bELISA, and RGA using the Kaplan-Meier analysis and the Log Rank test. Both anti-infliximab and anti-adalimumab cELISAs showed very good correlation to RGA (r = 0.932, p < 0.0001 and r = 0.947, p < 0.0001, respectively). Furthermore, a positive result in anti-infliximab cELISA can predict treatment failure in 100% of patients with negative bELISA, while a positive result in anti-adalimumab cELISA can predict treatment failure in 80% of patients with negative bELISA. Taken together, we developed innovative cELISAs enabling quantification of functional and neutralizing anti-drug antibodies, comparable to RGA. The association between cELISA results and loss of drug response in patients identified clinically important anti-drug antibodies, as measured by cELISA.

Chromatographic methods in HIV medicine: Application to therapeutic drug monitoring.

HIV antiretroviral therapy spans several different drug classes, meant to combat various aspects of viral infection and replication. Many authors have argued the benefits of therapeutic drug monitoring (TDM) for the HIV patient including compliance assurance and assessment of appropriate drug concentrations; however, the array of drug chemistries and combinations makes TDM an arduous task. HPLC-UV and LC-MS/MS are both frequent instruments for the quantification of HIV drugs in biological matrices with investigators striving to balance sensitivity and affordability. Plasma, the dominant matrix for these analyses, is prepared using protein precipitation, liquid-liquid extraction or solid-phase extraction depending on the specific complement of analytes. Despite the range of polarities found in drug classes relevant to HIV therapeutics, most chromatographic separations utilize a hydrophobic column (C18 ). Additionally, as the clinically relevant samples for these assays are infected with HIV, along with possible co-infections, another important aspect of sample preparation concerns viral inactivation. Although not routine in clinical practice, many published analytical methods from the previous two decades have demonstrated the ability to conduct TDM in HIV patients receiving various medicinal combinations. This review summarizes the analytical methods relevant to TDM of HIV drugs, while highlighting respective challenges.

Therapeutic drug monitoring of atypical antipsychotics.

The paper presents an overview and analysis of the results of research on therapeutic ranges of concentrations and receptor occupancy, mainly D2 receptors, in the treatment with some atypical antipsychotic drugs. Amisulpride, aripiprazole, clozapine, quetiapine, olanzapine, risperidone, paliperidone, sertindole, and ziprasidone were taken into account. The benefits of therapeutic drug monitoring to optimize the effectiveness of treatment and avoid side effects or toxicity were shown. The safety of patients, with the possibility to use the lowest effective dose, is an undoubted profit of TDM. This helps to avoid overdosing resulting in adverse events (with particular emphasis on extrapyramidal symptoms and seizures).The need and desirability of TDM is due to the inter -and intraindividual differences in the pharmacokinetics of drugs, because only some of them have a close correlation between dose and plasma concentration. The plasma concentration correlates well with the occupancy of D2 receptors. The efficient and safe level is determined at 60-80%. Based on the knowledge of the indications for TDM and therapeutic concentration ranges, amisulpride, clozapine and olanzapine have the highest level of recommendation to use TDM. Therapeutic ranges of plasma concentrations of the analyzed drugs were determined to be 200-320 ng/ml for amisulpride, 150-210 ng/ml for aripiprazole, over 350-500 ng/ml for clozapine, 50-500 ng/ml for quetiapine, 20-40 ng/ml for olanzapine, 20-60 ng/ml for risperidone and paliperidone, 50-100 ng/ml for sertindole and 50-130 ng/ml for ziprasidone.

Phase II trial of TI-CE high dose chemotherapy (HDCT) with drug monitoring for individual carboplatin dosing in patients with relapsed advanced germ cell tumors: A multicentric prospective GETUG trial.

401 Background: HDCT is a valid option of treatment for relapsed advanced GCTs pts. The results of the TICE regimen as salvage therapy in poor risk pts demonstrated a 50% complete response (CR) but with very high variability of measured carboplatin area under the curve (AUC) (between 10.9-36.7 for target AUC = 24 mg.min/mL). We initiated a phase II trial of TICE with therapeutic drug monitoring (TDM) for individual carboplatin dosing in order to target the 3-day AUC to 24 mg/min/mL. Methods: Were included pts with unfavorable relapsed GCTs , secondarily classified according to the International Prognostic Factors Study Group. Pts were treated according the TICE regimen with two cycles combining paclitaxel and ifosfamide followed by three cycles HDCT: carboplatin plus etoposide with stem cell support. Carboplatin dose was adapted on day 3 based on carboplatin clearance (Cl) at day 1, in order to reach the target AUC. The primary endpoint was the CR rate (cCR sCR pCR). A Simon Minimax design was performed using the following hypothesis: p0 = 50%, p1 = 65 α = 5%, β = 10%. Results: Between 03/2009 and 11/2015 101 pts were accrued, 60 pts were treated in first relapse (34 classified as high and very high-risk) and 41 in 2ndor more relapse. 72 pts (71%) received the whole treatment, 12 pts (10%) did not receive any cycle of HDCT. 29pts (26%) stopped treatment earlier, 8 for toxicity. Three pts died on treatment. 35/79 (44.3%) evaluable pts achieved a CR. 19 pts (24%) presented a PRm-. The mean observed carboplatin AUC was 24.5 mg.min/mL (between 18.9 and 28.8) at C1.Following TDM, the modification of the total carboplatin dose during C1 was comprised between -33% and +44%, showing the benefit of TDM in comparison with individual dosing based only on carboplatin Cl predicted according to patient’s renal characteristics. Conclusions: The CR rate observed in this very poor prognosis population was 44.3% and 69.6% CR + PRm-. Carboplatin dose individualization based on TDM allowed to reach more accurately the target AUC compared to previous reports. Clinical trial information: NCT00864318.

Monitoring of complement activation biomarkers and eculizumab in complement-mediated renal disorders.

Various complement-mediated renal disorders are treated currently with the complement inhibitor eculizumab. By blocking the cleavage of C5, this monoclonal antibody prevents cell damage caused by complement-mediated inflammation. We included 23 patients with atypical haemolytic uraemic syndrome (aHUS, n = 12), C3 glomerulopathies (C3G, n = 9) and acute antibody-mediated renal graft rejection (AMR, n = 2), treated with eculizumab in 12 hospitals in Germany. We explored the course of complement activation biomarkers and the benefit of therapeutic drug monitoring of eculizumab. Complement activation was assessed by analysing the haemolytic complement function of the classical (CH50) and the alternative pathway (APH50), C3 and the activation products C3d, C5a and sC5b-9 prior to, 3 and 6 months after eculizumab treatment. Eculizumab concentrations were determined by a newly established specific enzyme-linked immunosorbent assay (ELISA). Serum eculizumab concentrations up to 1082 μg/ml point to drug accumulation, especially in paediatric patients. Loss of the therapeutic antibody via urine with concentrations up to 56 μg/ml correlated with proteinuria. In aHUS patients, effective complement inhibition was demonstrated by significant reductions of CH50, APH50, C3d and sC5b-9 levels, whereas C5a levels were only reduced significantly after 6 months' treatment. C3G patients presented increased C3d and consistently low C3 levels, reflecting ongoing complement activation and consumption at the C3 level, despite eculizumab treatment. A comprehensive complement analysis together with drug monitoring is required to distinguish mode of complement activation and efficacy of eculizumab treatment in distinct renal disorders. Accumulation of the anti-C5 antibody points to the need for a patient-orientated tailored therapy.