Therapeutic Drug Monitoring: Role for a Pharmacist in Multidisciplinary Antiretroviral Management

2005 ◽  
Vol 18 (4) ◽  
pp. 310-321
Author(s):  
Judianne C. Slish ◽  
Linda M. Catanzaro ◽  
Olanrewaju Okusanya ◽  
Lisa M. Demeter ◽  
Mary Albrecht ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Drug Exposure ◽  
Treatment Guidelines ◽  
Management Strategies ◽  
Additional Patient ◽  
Fixed Dose ◽  
Therapeutic Drug ◽  
Multiple Drug ◽  
Clinical Tool

The current treatment guidelines for HIV pharmacotherapy recommend combinations of antiretrovirals (ARVs) to achieve optimal suppression of HIV replication. However, the initiation and long-term management of ARV therapy in a patient is often complicated by variable medication adherence, complex medication use with multiple drug interactions, the occurrence of drug toxicity, and drug therapy for comorbid conditions that require additional patient education and laboratory monitoring. For these reasons, the inclusion of a well-trained pharmacist in multidisciplinary health system management strategies has been increasing. Furthermore, the use of fixed-dose ARVs is accompanied by considerable interpatient variation in pharmacokinetics yielding a range of drug exposures from any given ARV dose. One approach to overcoming this variable drug exposure is to use plasma concentration monitoring (eg, therapeutic drug monitoring [TDM]) as a clinical tool to adjust doses to achieve targeted concentration ranges, often in conjunction with HIV resistance tests. While data in support of TDM are emerging, the development of programs that include an HIV pharmaceutical care specialist and an adherence program with an integrated clinical pharmacology resource that can provide reliable TDM assays has been reported and provides the rationale for including pharmacists in the implementation of ARV TDM programs.

Is There a Role for Therapeutic Drug Monitoring of Anti-TNF Monoclonal Antibodies in Inflammatory Bowel Disease

2015 ◽  
Vol 33 (Suppl. 1) ◽  
pp. 70-77 ◽  
Author(s):  
Filip Baert
Keyword(s):  
Monoclonal Antibodies ◽  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Treatment Guidelines ◽  
Therapeutic Drug ◽  
Serum Concentrations ◽  
Short Term ◽  
Clear Dose Response ◽  
Inflammatory Bowel

In recent years it has become clear that therapeutic drug monitoring can be an important tool to optimize outcome and costs of anti TNF treatment including the subcutaneous and fully human monoclonal antibodies. There is a clear dose response curve between early serum concentrations of all monoclonal antibodies and response both short term and long term. The wide variations in early serum concentrations are insufficiently explained by classic pharmacokinetic factors. Low early concentrations can lead to anti-drug antibody formation and ensuing loss of response. Therapeutic drug monitoring allows to rationalize the current practice of dose optimization and the use of concomitant immunomodulator treatment. However more prospective studies are needed before strong recommendations can enter treatment guidelines.

scholarly journals P346 Single-centre experience of ustekinumab: Therapeutic drug monitoring in Crohn’s disease patients

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S331-S333
Author(s):  
C Liefferinckx ◽  
M Fassin ◽  
D Thomas ◽  
C Minsart ◽  
A Cremer ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Therapeutic Drug Monitoring ◽  
Crohn's Disease ◽  
Median Time ◽  
Real World ◽  
Drug Monitoring ◽  
Drug Exposure ◽  
Therapeutic Drug ◽  
Loss Of Response

Abstract Background Therapeutic drug monitoring (TDM) is a diagnostic tool in the monitoring of anti-TNF therapies. Yet, the benefit for TDM of new biologics such as ustekinumab (USK) is still controversial in real-world experiences. Methods This monocentric retrospective study aims to correlate USK trough levels (TLs) with clinical and endoscopic data. All patients have given written consent to the Biobank (B2011/005). Endoscopic disease was defined as quiescent in absence of endoscopic lesions, mild disease in presence of few superficial ulcerations, moderate in presence of several ulcers and severe in presence of numerous deep ulcers and/or inflammatory stenosis. 313 serum USK samples from 67 Crohn’s disease patients were used to measure USK TL (USK ELISA, apDia) while 88 samples (at week 16, and before and after optimisation) were used to measure anti-drug antibody (ADA), using a drug-tolerant affinity capture elution anti-ustekinumab assay Results Demographic and baseline data of our population are presented in Table 1. The median follow-up was 73 weeks (IQR 39–92). An optimisation due to loss of response was required in 44.8% of patients (n = 30) after a median time of 38 weeks (IQR 24–55). To evaluate the drug efficacy, an endoscopy was performed in 61% of cases at a median time of 35 weeks (IQR 27–47). TLs were 5.2 µg/ml (IQR 2.1–8.8), 1.7 µg/ml (IQR 0.3–4.3) and 2.6 µg/ml (IQR 0.6–4.1) at week 8, 16 and 24, respectively. TLs at week 8 were correlated to the induction IV dose administrated (r = 0.3, p = 0.03). At week 16, low TLs were associated with higher endoscopic activity in the follow-up (p = 0.02), although this was not the case at week 8 (p = 0.5) (Figure 1). Patients not requiring an optimisation had higher TLs in maintenance than patients requiring optimisation (2.45 µg/ml (IQR 1.3–4.4) vs. 1.15 µg/ml (IQR 0.1–2.24), p = 0.008). Obviously, optimisation significantly increased TLs (1.15 µg/ml (IQR 0.1–2.24) vs. 6.6 µg/ml (IQR 2.3–11.3), p < 0.001). ADA were undetectable in all the measured samples in maintenance. Conclusion This real-world experience confirms a drug exposure-endoscopic response relationship. Week 16 seems to be an appropriate time point to monitor drug exposure. Earlier USK TLs, at week 8, appear less valuable to be monitored due to the influence of initial IV dose. The absence of immunogenicity suggests that it is not a key driver in the loss of response.

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

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

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

scholarly journals Therapeutic drug monitoring of voriconazole: a case report of multiple drug interactions in a patient with an increased CYP2C19 activity

2014 ◽  
Vol 11 (1) ◽  
pp. 25 ◽  
Author(s):  
Yassine Bouatou ◽  
Caroline Samer ◽  
Kuntheavy Ing Lorenzini ◽  
Youssef Daali ◽  
Samira Daou ◽  
...  
Keyword(s):  
Case Report ◽  
Therapeutic Drug Monitoring ◽  
Drug Interactions ◽  
Drug Monitoring ◽  
Therapeutic Drug ◽  
Multiple Drug

scholarly journals Model-Optimized Fluconazole Dose Selection for Critically Ill Patients Improves Early Pharmacodynamic Target Attainment without the Need for Therapeutic Drug Monitoring

2020 ◽  
Vol 65 (3) ◽  
Author(s):  
Indy Sandaradura ◽  
Jessica Wojciechowski ◽  
Deborah J. E. Marriott ◽  
Richard O. Day ◽  
Sophie Stocker ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Critically Ill ◽  
Drug Monitoring ◽  
Critically Ill Patients ◽  
Drug Exposure ◽  
Fungal Infections ◽  
Therapeutic Drug ◽  
Target Attainment ◽  
Dose Selection ◽  
Dose Individualization

ABSTRACT Fluconazole has been associated with higher mortality compared with the echinocandins in patients treated for invasive candida infections. Underexposure from current fluconazole dosing regimens may contribute to these worse outcomes, so alternative dosing strategies require study. The objective of this study was to evaluate fluconazole drug exposure in critically ill patients comparing a novel model-optimized dose selection method with established approaches over a standard 14-day (336-h) treatment course. Target attainment was evaluated in a representative population of 1,000 critically ill adult patients for (i) guideline dosing (800-mg loading and 400-mg maintenance dosing adjusted to renal function), (ii) guideline dosing followed by therapeutic drug monitoring (TDM)-guided dose adjustment, and (iii) model-optimized dose selection based on patient factors (without TDM). Assuming a MIC of 2 mg/liter, free fluconazole 24-h area under the curve (fAUC24) targets of ≥200 mg · h/liter and <800 mg · h/liter were used for assessment of target attainment. Guideline dosing resulted in underexposure in 21% of patients at 48 h and in 23% of patients at 336 h. The TDM-guided strategy did not influence 0- to 48-h target attainment due to inherent procedural delays but resulted in 37% of patients being underexposed at 336 h. Model-optimized dosing resulted in ≥98% of patients meeting efficacy targets throughout the treatment course, while resulting in less overexposure compared with guideline dosing (7% versus 14%) at 336 h. Model-optimized dose selection enables fluconazole dose individualization in critical illness from the outset of therapy and should enable reevaluation of the comparative effectiveness of this drug in patients with severe fungal infections.

scholarly journals Developing a Nationwide Infrastructure for Therapeutic Drug Monitoring of Targeted Oral Anticancer Drugs: The ON-TARGET Study Protocol

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6281
Author(s):  
Anna Mc Laughlin ◽  
Eduard Schmulenson ◽  
Olga Teplytska ◽  
Sebastian Zimmermann ◽  
Patrick Opitz ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Anticancer Drugs ◽  
Drug Monitoring ◽  
Drug Exposure ◽  
Plasma Concentrations ◽  
Blood Sampling ◽  
Therapeutic Drug ◽  
Study Phase ◽  
Blood Samples ◽  
Drug Concentrations

Exposure-efficacy and/or exposure-toxicity relationships have been identified for up to 80% of oral anticancer drugs (OADs). Usually, OADs are administered at fixed doses despite their high interindividual pharmacokinetic variability resulting in large differences in drug exposure. Consequently, a substantial proportion of patients receive a suboptimal dose. Therapeutic Drug Monitoring (TDM), i.e., dosing based on measured drug concentrations, may be used to improve treatment outcomes. The prospective, multicenter, non-interventional ON-TARGET study (DRKS00025325) aims to investigate the potential of routine TDM to reduce adverse drug reactions in renal cell carcinoma patients receiving axitinib or cabozantinib. Furthermore, the feasibility of using volumetric absorptive microsampling (VAMS), a minimally invasive and easy to handle blood sampling technique, for sample collection is examined. During routine visits, blood samples are collected and sent to bioanalytical laboratories. Venous and VAMS blood samples are collected in the first study phase to facilitate home-based capillary blood sampling in the second study phase. Within one week, the drug plasma concentrations are measured, interpreted, and reported back to the physician. Patients report their drug intake and toxicity using PRO-CTCAE-based questionnaires in dedicated diaries. Ultimately, the ON-TARGET study aims to develop a nationwide infrastructure for TDM for oral anticancer drugs.

Therapeutic drug monitoring of nivolumab in clinical practice: Preliminary experience.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e14089-e14089
Author(s):  
Manuel Sureda ◽  
Ana Catalán-Latorre ◽  
Juan José Mata ◽  
Vanesa Escudero ◽  
Antonio Brugarolas
Keyword(s):  
Clinical Practice ◽  
Steady State ◽  
Therapeutic Drug Monitoring ◽  
Solid Tumors ◽  
Drug Monitoring ◽  
Cell Cancer ◽  
Plasma Concentrations ◽  
Fixed Dose ◽  
Therapeutic Drug ◽  
Multiple Tumor

e14089 Background: Fixed dose schemes, regardless of body weight, have been accepted by the regulatory agencies for the PD-1 targeting antibodies. Zaho X. and Ratain M. have elucidated that the mean steady state concentrations of nivolumab (N) at flat-doses of 240 mg Q2W or 480 mg Q4W were 57 µg/mL and 47 µg/mL, respectively. These levels are very similar to those observed at the dosage of 3 mg/kg Q2W. Considering the long half-life of N, its mechanism of action and the absence of correlation between exposure and response or toxicity at clinically tested doses, other schemes can be explored. Moreover, therapeutic drug monitoring (TDM) can contribute to individualize and optimize dosage. We determined serum N levels in patients with solid tumors. Methods: The PK profile of N was analyzed in 15 patients with solid tumors who received 3 mg/kg Q2W from May 2017 through January 2019. Eligible patients had non-small-cell lung cancer (n = 7), urothelial cancer (n = 1), gastric cancer (n = 1), breast cancer (n = 1), renal cell cancer (n = 1), colorectal cancer (n = 1), prostate cancer (n = 1), melanoma (n = 1) and sarcoma (n = 1). Free N serum concentrations were determined with a quantitative ELISA capable of detecting ≥ 0.3 µg/mL (Shikari Q-Nivo, Matriks Biotek, Ankara, Turkey). A total of 28 TDM were done after steady state (6th and 26th cycle). Results: For different reasons, 9 patients received N at 3, 4, 5, 6 or 7 week intervals once the steady state was reached. In these patients, a median reduction of 20.8% (6.7% - 43.0%) of the received doses was observed. Mean plasma concentrations of N observed after administration every 2 weeks was 73.5±32.5 µg/mL (n = 9). Once the steady state was reached, mean plasma concentrations at 3, 4, 5, 6 or 7 weeks, were 54.0±1.3 µg/mL (n = 2), 45.1±25.3 µg/mL (n = 7), 42.9±29.5 µg/mL (n = 5) and 24.4±11.7 µg/mL (n = 5), respectively. No statistically significant differences were observed in the serum levels of N between the dosing intervals of 3, 4 and 5 weeks and the standard regimen (Q2W) (p > 0.05). These data are similar to those described by Long G.V. et al. that compared N pharmacokinetic exposure for the 480 mg Q4W schedule simulated in 3817 patients across multiple tumor types with those for the 3 mg/kg Q2W and 240 mg Q2W schedules. Conclusions: The incorporation of the TDM of N in routine clinical practice could help to maintain a therapeutic drug plasma concentration with lower or less frequent doses, adding a financial benefit, without decreasing clinical efficacy. Further randomized trials to explore alternative dosing schemes of N, including personalization through TDM, are warranted

Population Pharmacokinetic (PK) Modeling of Hydroxyurea for Therapeutic Drug Monitoring Applications in Children and Adolescents with Sickle Cell Disease

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2136-2136
Author(s):  
Pawel Wiczling ◽  
Robert I. Liem ◽  
Julie A. Panepinto ◽  
Uttam Garg ◽  
Susan M. Abdel-Rahman ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Sickle Cell ◽  
Drug Monitoring ◽  
Drug Exposure ◽  
Oral Drug ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Average Dose ◽  
Intersubject Variability ◽  
Exposure Response

Abstract Abstract 2136 Introduction: Sickle cell anemia (SCA) is an inherited disorder of abnormal hemoglobin synthesis. Hydroxyurea (HU) is the only disease modifying agent available for use in patients with SCA. Clinically, HU has been shown to decrease pain, number of transfusions, and development of acute chest syndrome as well as improve life expectancy in adults with SCA. Although HU is increasingly utilized to treat children with SCA, drug exposure-response relationships and therapeutic drug monitoring are not well characterized in the pediatric population. The exposure-response relationships of HU are currently being evaluated as is the potential role of therapeutic drug monitoring. Objective: The objective of this study was to develop a population pharmacokinetic (PK) model sufficient to describe HU disposition in serum and urine following oral drug administration in pediatric patients. Such a model is required for exploring concentration-effect relationships in children with SCA taking HU. Methods: PK was determined in 20 subjects (mean age 10.5 yr, range 5–17 yr) with SCA either as a single dose (SD, n=6, average dose 17.4 mg/kg) or at steady state (SS, n=14, average daily dose 25.5 mg/kg). Blood and urine samples for HU assay were taken throughout the 24 hour period post HU administration. HU was quantitated by a validated gas chromatography–mass spectrometry (GC-MS) method. Population nonlinear mixed-effect modeling was done using NONMEM software. Measured HU concentrations at specific sampling time points were compared to model predicted area under the curves (AUCs) to find the most predictive relationship. Results: A one-compartment model with first-order absorption and two elimination pathways (metabolic and renal) was used. The mean absorption rate constant differed for children < 8.5 years of age (19.5 h−1) as compared to those ≥ 8.5 years of age (2.1 h−1) and demonstrated high intersubject variability (76%). The population apparent volume of distribution (V/F) was 21.3 L (for an average weight patient of 30.7 kg) with an intersubject variability of 24.7%. The apparent renal (CLu/F) and metabolic (CLm/F) clearance was 3.47 L/hr and 3.52 L/hr, respectively, with the same between subject variability of 42%. Significant relationships (p<0.005) between both CL/F and V/F and body weight were found with these parameters increasing by 2.96% and 2.49%, respectively, for every kilogram difference from the median weight. Significant linear correlations were apparent between the plasma HU concentration at 0.75, 1, 1.5, 2, 4, and 6 hours post-dose; the most significant (p<0.01, r2 =0.71) occurring at 1.5 hours. Conclusion: In children with SCA, a population PK model parameterized from a classical PK study of HU was successful in describing HU disposition in plasma and urine. Data from the model also demonstrated that HU plasma concentrations at 1.5 or 2 hours after an oral dose of the drug were especially predictive of systemic drug exposure (as reflected by AUC). Data from this study also suggest that there may be age related differences in absorption rates. Further studies are warranted to confirm this finding. Disclosures: Off Label Use: Hydroxyurea is not labeled for use in children.

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