David Czock

Prof. Dr. David Czock

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Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 January 2013 in British Journal of Clinical Pharmacology
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Journal Article
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BGBarbara Grün
Barbara Grün
MKMichael K. Kiessling
Michael K. Kiessling
JBJuergen Burhenne
Juergen Burhenne
KRKlaus‐Dieter Riedel
Klaus‐Dieter Riedel
Johanna WeissJohanna Weiss
Johanna Weiss
DCDavid Czock
David Czock
Aims: Metformin pharmacokinetics depends on the presence and activity of membrane‐bound drug transporters and may be affected by transport inhibitors. The aim of this study was to investigate the effects of trimethoprim on metformin pharmacokinetics and genetic modulation by organic cation transporter 2 (OCT2) and multidrug and toxin extrusion 1 (MATE1) polymorphisms.Methods: Twenty‐four healthy volunteers received metformin 500 mg three times daily for 10 days and trimethoprim 200 mg twice daily from day 5 to 10. Effects of trimethoprim on steady‐state metformin pharmacokinetics were analysed.Results: In the population as a whole, trimethoprim significantly reduced the apparent systemic metformin clearance (CL/F) from 74 to 54 l h−1 and renal metformin clearance from 31 to 21 l h−1, and prolonged half‐life from 2.7 to 3.6 h (all P < 0.01). This resulted in an increase in the maximal plasma concentration by 38% and in the area under the plasma concentration–time curve by 37%. In volunteers polymorphic for both OCT2 and MATE1, trimethoprim had no relevant inhibitory effects on metformin kinetics. Trimethoprim was associated with a decrease in creatinine clearance from 133 to 106 ml min−1 (P < 0.01) and an increase in plasma lactate from 0.94 to 1.2 mmol l−1 (P = 0.016).Conclusions: The extent of inhibition by trimethoprim was moderate, but might be clinically relevant in patients with borderline renal function or high‐dose metformin.

1 August 2019 in BMC Geriatrics
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Journal Article
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AZAndrea Zülke
Andrea Zülke
TLTobias Luck
Tobias Luck
APAl Pa
Al Pa
WHWolfgang Hoffmann
Wolfgang Hoffmann
JTJochen René Thyrian
Jochen René Thyrian
SRSteffi G. Riedel-Heller
Steffi G. Riedel-Heller
In the absence of treatment options, the WHO emphasizes the identification of effective prevention strategies as a key element to counteract the dementia epidemic. Regarding the complex nature of dementia, trials simultaneously targeting multiple risk factors should be particularly effective for prevention. So far, however, only few such multi-component trials have been launched, but yielding promising results. In Germany, comparable initiatives are lacking, and translation of these complex interventions into routine care was not yet done. Therefore, AgeWell.de will be conducted as the first multi-component prevention trial in Germany which is closely linked to the primary care setting. AgeWell.de will be designed as a multi-centric, cluster-randomized controlled multi-component prevention trial. Participants will be older community-dwelling general practitioner (GP) patients (60–77 years; n = 1,152) with increased dementia risk according to CAIDE (Cardiovascular Risk Factors, Aging, and Incidence of Dementia) Dementia Risk Score. Recruitment will take place at 5 study sites across Germany. GP practices will be randomized to either intervention A (advanced) or B (basic). GPs will be blinded to their respective group assignment, as will be the statistician conducting the randomization. The multi-component intervention (A) includes nutritional counseling, physical activity, cognitive training, optimization of medication, management of vascular risk factors, social activity, and, if necessary, further specific interventions targeting grief and depression. Intervention B includes general health advice on the intervention components and GP treatment as usual. We hypothesize that over the 2-year follow-up period the intervention group A will benefit significantly from the intervention program in terms of preserved cognitive function/delayed cognitive decline (primary outcome), and other relevant (secondary) outcomes (e.g. quality of life, social activities, depressive symptomatology, cost-effectiveness). AgeWell.de will be the first multi-component trial targeting risk of cognitive decline in older adults in Germany. Compared to previous trials, AgeWell.de covers an even broader set of interventions suggested to be beneficial for the intended outcomes. The findings will add substantial knowledge on modifiable lifestyle factors to prevent or delay cognitive decline. German Clinical Trials Register (reference number: DRKS00013555 ).

1 February 2011 in Therapeutic Drug Monitoring
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Journal Article
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AHArwa Msc Hassan
Arwa Msc Hassan
JBJuergen Burhenne
Juergen Burhenne
KRKlaus-Dieter Msc Riedel
Klaus-Dieter Msc Riedel
Johanna WeissJohanna Weiss
Johanna Weiss
GMGerd Mikus
Gerd Mikus
DCDavid Czock
David Czock
Very low voriconazole concentrations are commonly observed during therapeutic drug monitoring. Possible mechanisms include inappropriate dose selection, rapid metabolism (as a result of genetic polymorphisms or enzyme induction), and also nonadherence. We aimed to develop a method to distinguish between rapid metabolism of and nonadherence to voriconazole by quantification of voriconazole metabolites. In addition, the relevance of common genetic polymorphisms of CYP2C19 was assessed. In a retrospective study, samples with voriconazole concentrations 0.2 μg/mL or less in routine therapeutic drug monitoring (as quantified by high-performance liquid chromatography) were evaluated. Voriconazole and its N-oxide metabolite were quantified in residual blood using a highly sensitive liquid chromatography-tandem mass spectroscopy method (lower limit of quantitation = 0.03 μg/mL). Genetic polymorphisms of CYP2C19 were determined by real-time polymerase chain reaction using the hybridization probe format and the polymerase chain reaction-random fragment length polymorphism format. A total of 747 routine therapeutic drug monitoring plasma/blood samples of 335 patients treated with systemic voriconazole were analyzed and in 18.7% of all samples, voriconazole concentrations 0.2 μg/mL or less were found. In 32 samples (30 patients) with adequate dosage and timing of blood withdrawal, nonadherence was strongly suspected in seven patients because voriconazole-N-oxide concentrations were below 0.03 μg/mL, which was not observed in a reference group of 51 healthy volunteers with controlled drug intake. In 10 patients, of whom EDTA blood was available, the ultrarapid metabolizer genotype (CYP2C19*1\*17, CYP2C19*17\*17) was found in 80% and its prevalence was significantly higher as compared to a reference group (P = 0.02). In conclusion, quantification of voriconazole-N-oxide allowed for detection of suspected nonadherence in one of four patients with very low voriconazole concentrations. In the remaining patients, ultrarapid metabolism resulting from the CYP2C19*17 polymorphism appears to play a major role. Thus, in the case of voriconazole therapy failure, both nonadherence and genetic factors have to be considered.

25 March 2019 in British Journal of Clinical Pharmacology
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ABAntonia Brings
Antonia Brings
MLMarie‐Louise Lehmann
Marie‐Louise Lehmann
KFKathrin I. Foerster
Kathrin I. Foerster
JBJürgen Burhenne
Jürgen Burhenne
Johanna WeissJohanna Weiss
Johanna Weiss
DCDavid Czock
David Czock

SRSusanne Roehr
Susanne Roehr
AZAndrea Zülke
Andrea Zülke
MLMelanie Luppa
Melanie Luppa
CBChristian Brettschneider
Christian Brettschneider
MWMarina Weißenborn
Marina Weißenborn
SRSteffi G. Riedel-Heller
Steffi G. Riedel-Heller
Targeting dementia prevention, first trials addressing multiple modifiable risk factors showed promising results in at-risk populations. In Germany, AgeWell.de is the first large-scale initiative investigating the effectiveness of a multi-component lifestyle intervention against cognitive decline. We aimed to investigate the recruitment process and baseline characteristics of the AgeWell.de participants to gain an understanding of the at-risk population and who engages in the intervention. General practitioners across five study sites recruited participants (aged 60–77 years, Cardiovascular Risk Factors, Aging, and Incidence of Dementia/CAIDE dementia risk score ≥ 9). Structured face-to-face interviews were conducted with eligible participants, including neuropsychological assessments. We analyzed group differences between (1) eligible vs. non-eligible participants, (2) participants vs. non-participants, and (3) between intervention groups. Of 1176 eligible participants, 146 (12.5%) dropped out before baseline; the study population was thus 1030 individuals. Non-participants did not differ from participants in key sociodemographic factors and dementia risk. Study participants were M = 69.0 (SD = 4.9) years old, and 52.1% were women. The average Montreal Cognitive Assessment/MoCA score was 24.5 (SD = 3.1), indicating a rather mildly cognitively impaired study population; however, 39.4% scored ≥ 26, thus being cognitively unimpaired. The bandwidth of cognitive states bears the interesting potential for differential trial outcome analyses. However, trial conduction is impacted by the COVID-19 pandemic, requiring adjustments to the study protocol with yet unclear methodological consequences.

23 March 2020 in Journal of Clinical Investigation
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Journal Article
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CMChristian Morath
Christian Morath
ASAnita Schmitt
Anita Schmitt
CKChristian Kleist
Christian Kleist
VDVolker Daniel
Volker Daniel
GOGerhard Opelz
Gerhard Opelz
PTPeter Terness
Peter Terness
BACKGROUND. Preclinical experiments have shown that donor blood cells, modified in vitro by an alkylating agent (modified immune cells [MICs]), induced long-term specific immunosuppression against the allogeneic donor. METHODS. In this phase I trial, patients received either 1.5 × 106 MICs per kg BW on day –2 (n = 3, group A), or 1.5 × 108 MICs per kg BW on day –2 (n = 3, group B) or day –7 (n = 4, group C) before living donor kidney transplantation in addition to post-transplantation immunosuppression. The primary outcome measure was the frequency of adverse events (AEs) until day 30 (study phase) with follow-up out to day 360. RESULTS. MIC infusions were extremely well tolerated. During the study phase, 10 treated patients experienced a total of 69 AEs that were unlikely to be related or not related to MIC infusion. No donor-specific human leukocyte antigen Abs or rejection episodes were noted, even though the patients received up to 1.3 × 1010 donor mononuclear cells before transplantation. Group C patients with low immunosuppression during follow-up showed no in vitro reactivity against stimulatory donor blood cells on day 360, whereas reactivity against third-party cells was still preserved. Frequencies of CD19+CD24hiCD38hi transitional B lymphocytes (Bregs) increased from a median of 6% before MIC infusion to 20% on day 180, which was 19- and 68-fold higher, respectively, than in 2 independent cohorts of transplanted controls. The majority of Bregs produced the immunosuppressive cytokine IL-10. MIC-treated patients showed the Immune Tolerance Network operational tolerance signature. CONCLUSION. MIC administration was safe and could be a future tool for the targeted induction of tolerogenic Bregs. TRIAL REGISTRATION. EudraCT number: 2014-002086-30; ClinicalTrials.gov identifier: NCT02560220. FUNDING. Federal Ministry for Economic Affairs and Technology, Berlin, Germany, and TolerogenixX GmbH, Heidelberg, Germany.