@article{TaurinesFeketePreussWiedenhoffetal.2022,
  author    = {Taurines, R. and Fekete, S. and Preuss-Wiedenhoff, A. and Warnke, A. and Wewetzer, C. and Plener, P. and Burger, R. and Gerlach, M. and Romanos, M. and Egberts, K. M.},
  title     = {Therapeutic drug monitoring in children and adolescents with schizophrenia and other psychotic disorders using risperidone},
  series = {Journal of Neural Transmission},
  volume    = {129},
  journal   = {Journal of Neural Transmission},
  number    = {5-6},
  doi       = {10.1007/s00702-022-02485-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324833},
  pages     = {689-701},
  year      = {2022},
  abstract  = {Risperidone is commonly used to treat different psychiatric disorders worldwide. Knowledge on dose-concentration relationships of risperidone treatment in children and adolescents with schizophrenia or other psychotic disorders is, however, scarce and no age-specific therapeutic ranges have been established yet. Multicenter data of a therapeutic drug monitoring service were analyzed to evaluate the relationship between risperidone dose and serum concentration of the active moiety (risperidone (RIS) plus its main metabolite 9-hydroxyrisperidone (9-OH-RIS)) in children and adolescents with psychotic disorders. Patient characteristics, doses, serum concentrations and therapeutic outcomes were assessed by standardized measures. The study also aimed to evaluate whether the therapeutic reference range for adults (20-60 ng/ml) is applicable for minors. In the 64 patients (aged 11-18 years) included, a positive correlation between daily dose and the active moiety (RIS\(_{am}\)) concentration was found (r\(_s\) = 0.49, p = 0.001) with variation in dose explaining 24\% (r\(_s\)\(^2\) = 0.240) of the variability in serum concentrations. While the RIS\(_{am}\) concentration showed no difference, RIS as well 9-OH-RIS concentrations and the parent to metabolite ratio varied significantly in patients with co-medication of a CYP2D6 inhibitor. Patients with extrapyramidal symptoms (EPS) had on average higher RIS\(_{am}\) concentrations than patients without (p = 0.05). Considering EPS, the upper threshold of the therapeutic range of RIS\(_{am}\) was determined to be 33 ng/ml. A rough estimation method also indicated a possibly decreased lower limit of the preliminary therapeutic range in minors compared to adults. These preliminary data may contribute to the definition of a therapeutic window in children and adolescents with schizophrenic disorders treated with risperidone. TDM is recommended in this vulnerable population to prevent concentration-related adverse drug reactions.},
  language  = {en}
}
@article{AghaiZimmermannKurlbaumetal.2021,
  author    = {Aghai, Fatemeh and Zimmermann, Sebastian and Kurlbaum, Max and Jung, Pius and Pelzer, Theo and Klinker, Hartwig and Isberner, Nora and Scherf-Clavel, Oliver},
  title     = {Development and validation of a sensitive liquid chromatography tandem mass spectrometry assay for the simultaneous determination of ten kinase inhibitors in human serum and plasma},
  series = {Analytical and Bioanalytical Chemistry},
  volume    = {413},
  journal   = {Analytical and Bioanalytical Chemistry},
  issn      = {1618-2642},
  doi       = {10.1007/s00216-020-03031-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231925},
  pages     = {599-612},
  year      = {2021},
  abstract  = {A liquid chromatography tandem mass spectrometry method for the analysis of ten kinase inhibitors (afatinib, axitinib, bosutinib,cabozantinib, dabrafenib, lenvatinib, nilotinib, osimertinib, ruxolitinib, and trametinib) in human serum and plasma for theapplication in daily clinical routine has been developed and validated according to the US Food and Drug Administration andEuropean Medicines Agency validation guidelines for bioanalytical methods. After protein precipitation of plasma samples withacetonitrile, chromatographic separation was performed at ambient temperature using a Waters XBridge® Phenyl 3.5μm(2.1×50 mm) column. The mobile phases consisted of water-methanol (9:1, v/v) with 10 mM ammonium bicarbonate as phase A andmethanol-water (9:1, v/v) with 10 mM ammonium bicarbonate as phase B. Gradient elution was applied at a flow rate of 400μL/min. Analytes were detected and quantified using multiple reaction monitoring in electrospray ionization positive mode. Stableisotopically labeled compounds of each kinase inhibitor were used as internal standards. The acquisition time was 7.0 min perrun. All analytes and internal standards eluted within 3.0 min. The calibration curves were linear over the range of 2-500 ng/mLfor afatinib, axitinib, bosutinib, lenvatinib, ruxolitinib, and trametinib, and 6-1500 ng/mL for cabozantinib, dabrafenib, nilotinib,and osimertinib (coefficients of correlation≥0.99). Validation assays for accuracy and precision, matrix effect, recovery,carryover, and stability were appropriate according to regulatory agencies. The rapid and sensitive assay ensures high throughputand was successfully applied to monitor concentrations of kinase inhibitors in patients.},
  language  = {en}
}
@article{IsbernerKrausGrigoleitetal.2021,
  author    = {Isberner, Nora and Kraus, Sabrina and Grigoleit, G{\"o}tz Ulrich and Aghai, Fatemeh and Kurlbaum, Max and Zimmermann, Sebastian and Klinker, Hartwig and Scherf-Clavel, Oliver},
  title     = {Ruxolitinib exposure in patients with acute and chronic graft versus host disease in routine clinical practice-a prospective single-center trial},
  series = {Cancer Chemotherapy and Pharmacology},
  volume    = {88},
  journal   = {Cancer Chemotherapy and Pharmacology},
  number    = {6},
  issn      = {1432-0843},
  doi       = {10.1007/s00280-021-04351-w},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266476},
  pages     = {973-983},
  year      = {2021},
  abstract  = {Purpose Knowledge on Ruxolitinib exposure in patients with graft versus host disease (GvHD) is scarce. The purpose of this prospective study was to analyze Ruxolitinib concentrations of GvHD patients and to investigate effects of CYP3A4 and CYP2C9 inhibitors and other covariates as well as concentration-dependent effects. Methods 262 blood samples of 29 patients with acute or chronic GvHD who were administered Ruxolitinib during clinical routine were analyzed. A population pharmacokinetic model obtained from myelofibrosis patients was adapted to our population and was used to identify relevant pharmacokinetic properties and covariates on drug exposure. Relationships between Ruxolitinib exposure and adverse events were assessed. Results Median of individual mean trough serum concentrations was 39.9 ng/mL at 10 mg twice daily (IQR 27.1 ng/mL, range 5.6-99.8 ng/mL). Applying a population pharmacokinetic model revealed that concentrations in our cohort were significantly higher compared to myelofibrosis patients receiving the same daily dose (p < 0.001). Increased Ruxolitinib exposure was caused by a significant reduction in Ruxolitinib clearance by approximately 50\%. Additional comedication with at least one strong CYP3A4 or CYP2C9 inhibitor led to a further reduction by 15\% (p < 0.05). No other covariate affected pharmacokinetics significantly. Mean trough concentrations of patients requiring dose reduction related to adverse events were significantly elevated (p < 0.05). Conclusion Ruxolitinib exposure is increased in GvHD patients in comparison to myelofibrosis patients due to reduced clearance and comedication with CYP3A4 or CYP2C9 inhibitors. Elevated Ruxolitinib trough concentrations might be a surrogate for toxicity.},
  language  = {en}
}
@article{McLaughlinSchmulensonTeplytskaetal.2021,
  author    = {Mc Laughlin, Anna M. and Schmulenson, Eduard and Teplytska, Olga and Zimmermann, Sebastian and Opitz, Patrick and Groenland, Stefanie L. and Huitema, Alwin D. R. and Steeghs, Neeltje and M{\"u}ller, Lothar and Fuxius, Stefan and Illerhaus, Gerald and Joerger, Markus and Mayer, Frank and Fuhr, Uwe and Holdenrieder, Stefan and Hempel, Georg and Scherf-Clavel, Oliver and Jaehde, Ulrich and Kloft, Charlotte},
  title     = {Developing a nationwide infrastructure for therapeutic drug monitoring of targeted oral anticancer drugs: the ON-TARGET study protocol},
  series = {Cancers},
  volume    = {13},
  journal   = {Cancers},
  number    = {24},
  issn      = {2072-6694},
  doi       = {10.3390/cancers13246281},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252196},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{SchraderRieseKurlbaumetal.2021,
  author    = {Schrader, Nikolas and Riese, Thorsten and Kurlbaum, Max and Meybohm, Patrick and Kredel, Markus and Surat, G{\"u}zin and Scherf-Clavel, Oliver and Strate, Alexander and Pospiech, Andreas and Hoppe, Kerstin},
  title     = {Personalized antibiotic therapy for the critically ill: Implementation strategies and effects on clinical outcome of piperacillin therapeutic drug monitoring — a descriptive retrospective analysis},
  series = {Antibiotics},
  volume    = {10},
  journal   = {Antibiotics},
  number    = {12},
  issn      = {2079-6382},
  doi       = {10.3390/antibiotics10121452},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250052},
  year      = {2021},
  abstract  = {Therapeutic drug monitoring (TDM) is increasingly relevant for an individualized antibiotic therapy and subsequently a necessary tool to reduce multidrug-resistant pathogens, especially in light of diminishing antimicrobial capabilities. Critical illness is associated with profound pharmacokinetic and pharmacodynamic alterations, which challenge dose finding and the application of particularly hydrophilic drugs such as β-lactam antibiotics. Methods: Implementation strategy, potential benefit, and practicability of the developed standard operating procedures were retrospectively analyzed from January to December 2020. Furthermore, the efficacy of the proposed dosing target of piperacillin in critically ill patients was evaluated. Results: In total, 160 patients received piperacillin/tazobactam therapy and were subsequently included in the study. Of them, 114 patients received piperacillin/tazobactam by continuous infusion and had at least one measurement of piperacillin serum level according to the standard operating procedure. In total, 271 measurements were performed with an average level of 79.0 ± 46.0 mg/L. Seventy-one piperacillin levels exceeded 100 mg/L and six levels were lower than 22.5 mg/L. The high-level and the low-level group differed significantly in infection laboratory parameters (CRP (mg/dL) 20.18 ± 11.71 vs. 5.75 ± 5.33) and renal function [glomerular filtration rate (mL/min/1.75 m2) 40.85 ± 26.74 vs. 120.50 ± 70.48]. Conclusions: Piperacillin levels are unpredictable in critically ill patients. TDM during piperacillin/tazobactam therapy is highly recommended for all patients. Although our implementation strategy was effective, further strategies implemented into the daily clinical workflow might support the health care staff and increase the clinicians' alertness.},
  language  = {en}
}
@article{FeketeEgbertsPreissleretal.2021,
  author    = {Fekete, Stefanie and Egberts, K. and Preissler, T. and Wewetzer, C. and Mehler-Wex, C. and Romanos, M. and Gerlach, M.},
  title     = {Estimation of a preliminary therapeutic reference range for children and adolescents with tic disorders treated with tiapride},
  series = {European Journal of Clinical Pharmacology},
  volume    = {77},
  journal   = {European Journal of Clinical Pharmacology},
  number    = {2},
  doi       = {10.1007/s00228-020-03000-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-279893},
  pages     = {163-170},
  year      = {2021},
  abstract  = {Purpose Tiapride is commonly used in Europe for the treatment of tics. The aim of this study was to examine the relationship between dose and serum concentrations of tiapride and potential influential pharmacokinetic factors in children and adolescents. In addition, a preliminary therapeutic reference range for children and adolescents with tics treated with tiapride was calculated. Methods Children and adolescents treated with tiapride at three university hospitals and two departments of child and adolescents psychiatry in Germany and Austria were included in the study. Patient characteristics, doses, serum concentrations, and therapeutic outcome were assessed during clinical routine care using standardised measures. Results In the 49 paediatric patients (83.7\% male, mean age = 12.5 years), a positive correlation was found between tiapride dose (median 6.9 mg/kg, range 0.97-19.35) and serum concentration with marked inter-individual variability. The variation in dose explained 57\% of the inter-patient variability in tiapride serum concentrations; age, gender, and concomitant medication did not contribute to the variability. The symptoms improved in 83.3\% of the patients. 27.1\% of the patients had mild or moderate ADRs. No patient suffered from severe ADRs. Conclusions This study shows that tiapride treatment was effective and safe in most patients with tics. Compared with the therapeutic concentration range established for adults with Chorea Huntington, our data hinted at a lower lower limit (560 ng/ml) and similar upper limit (2000 ng/ml).},
  language  = {en}
}