Graft function and pregnancy outcomes after kidney transplantation.

BACKGROUND: After kidney transplantation, pregnancy and graft function may have a reciprocal interaction. We evaluated the influence of graft function on the course of pregnancy and vice versa. METHODS: We performed a retrospective observational study of 92 pregnancies beyond the first trimester in 67 women after renal transplantation from 1972 to 2019. Pre-pregnancy eGFR was correlated with outcome parameters; graft function was evaluated by Kaplan Meier analysis. The course of graft function in 28 women who became pregnant after kidney transplantation with an eGFR of < 50 mL/min/1.73m2 was compared to a control group of 79 non-pregnant women after kidney transplantation during a comparable time period and with a matched basal graft function. RESULTS: Live births were 90.5% (fetal death n = 9). Maternal complications of pregnancy were preeclampsia 24% (graft loss 1, fetal death 3), graft rejection 5.4% (graft loss 1), hemolytic uremic syndrome 2% (graft loss 1, fetal death 1), maternal hemorrhage 2% (fetal death 1), urinary obstruction 10%, and cesarian section. (76%). Fetal complications were low gestational age (34.44 ± 5.02 weeks) and low birth weight (2322.26 ± 781.98 g). Mean pre-pregnancy eGFR was 59.39 ± 17.62 mL/min/1.73m2 (15% of cases < 40 mL/min/1.73m2). Pre-pregnancy eGFR correlated with gestation week at delivery (R = 0.393, p = 0.01) and with percent eGFR decline during pregnancy (R = 0.243, p = 0.04). Pregnancy-related eGFR decline was inversely correlated with the time from end of pregnancy to chronic graft failure or maternal death (R = -0.47, p = 0.001). Kaplan Meier curves comparing women with pre-pregnancy eGFR of ≥ 50 to < 50 mL/min showed a significantly longer post-pregnancy graft survival in the higher eGFR group (p = 0.04). Women after kidney transplantation who became pregnant with a low eGFR of > 25 to < 50 mL/min/1.73m2 had a marked decline of renal function compared to a matched non-pregnant control group (eGFR decline in percent of basal eGFR 19.34 ± 22.10%, n = 28, versus 2.61 ± 10.95%, n = 79, p < 0.0001). CONCLUSIONS: After renal transplantation, pre-pregnancy graft function has a key role for pregnancy outcomes and graft function. In women with a low pre-pregnancy eGFR, pregnancy per se has a deleterious influence on graft function. TRIAL REGISTRATION: Since this was a retrospective observational case series and written consent of the patients was obtained for publication, according to our ethics' board the analysis was exempt from IRB approval. Clinical Trial Registration was not done. The study protocol was approved by the Ethics Committee of Hannover Medical School, Chairman Prof. Dr. H. D. Troeger, Hannover, December 12, 2015 (IRB No. 2995-2015).

Chemotherapeutic agents eligible for prior dosing in pancreatic cancer patients requiring hemodialysis: a systematic review
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AIMS: New chemotherapeutic agents prolong survival of patients with pancreatic ductal adenocarcinoma (PDAC). Although their incidence is rising, patients with end-stage renal disease (ESRD) requiring hemodialysis (HD) are not included in the phase III trials evaluating the effects of these chemotherapies. Many experts recommend applying chemotherapy after HD using a reduced dose. Alternatively, the concept of prior dosing allows for the application of dialyzable chemotherapeutic drugs using a normal dose, with an HD followed shortly after to mimic normal renal function. In this work, we provide guidance for clinicians on how to use chemotherapy in patients with PDAC on HD and how to identify substances suitable for prior dosing. MATERIALS AND METHODS: We systematically searched PubMed, from inception to September 2016, for published studies describing patients with ESRD on HD who received chemotherapies commonly applied in PDAC, including gemcitabine, fluorouracil (5-FU), capecitabine, oxaliplatin, irinotecan, docetaxel, erlotinib, sunitinib, S-1, and afatinib. Applied dosages, described toxicities, application time relative to HD, and pharmacokinetic measurements of the drug and its metabolites were assessed. Quantitative analysis of the drug plasma concentrations, including half-life during and in between HD and fraction of the drug eliminated during HD, were assessed. RESULTS: We identified 56 studies describing 128 patients with ESRD undergoing HD during chemotherapeutic treatment. Quantitative pharmacokinetic analysis revealed that the following substances are dialyzable and thus suitable for application using the prior-dosing method: gemcitabine, 5-FU, oxaliplatin, irinotecan, and S-1. CONCLUSION: This work supports the application of dialyzable chemotherapeutic agents in patients with PDAC in standard dose when HD is performed shortly after the infusion.
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Early Flow Disturbances of Tunnelled Haemodialysis Catheters and Topographic Landmarks in Chest X-Ray.

BACKGROUND/AIMS: The position of the tip of tunnelled haemodialysis (HD) catheters (THC) might influence flow characteristics during HD. In chest X-ray (CXR), carina-related landmarks may be practicable to verify the THC position, and tip-carina distance (TCD) might be useful to predict early-flow dysfunctions. METHODS: In this single-centre, retrospective study, the TCD and the angle between the distal catheter and the body vertical axis (tip-body vertical-angle [TVA]) was measured in 115 THC by post-procedure CXR with 2 investigators. The parameters were proved to be feasible by interrater-reliability and correlated with the incidence of flow-dysfunction within 10 days after insertion. RESULTS: Steep-aligned (TVA <40°, p < 0.01) and deep-ending catheters (TCD: right-sighted >1.5 cm or left-sighted >4.5 cm below the carina; p < 0.01) showed a significantly less dysfunction with a good interrater-reliability (R[TVA] = 0.8, R[TCD] = 0.9). CONCLUSIONS: Carina-related landmarks in CXR might be helpful to predict early-flow dysfunctions. However, randomized studies will be necessary to confirm this in fluoroscopic-guided placement during the insertion of THC.

Correlation between pharmacokinetics of tacrolimus and pharmacodynamics on NFAT-regulated gene expression in stable kidney transplant recipients
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Gene expression regulated by the transcription factor NFAT (nuclear factor of activated T-cells) has been proposed for monitoring the pharmacodynamic effect of calcineurin inhibitors. We aimed to correlate the pharmacokinetics of tacrolimus with the suppression of NFAT-regulated gene expression. Tacrolimus trough (Ctrough) and peak concentrations (Cpeak) were measured by LC-MS. The effect on NFAT-regulated gene expression at trough (Etrough) and at peak levels (Epeak) were determined by qRT-PCR. The pharmacodynamic concentration producing the half-maximum effect (CE50) and the Hill coefficient (H) were estimated from Etrough and from Epeak. Ten stable kidney transplant recipients on triple immunosuppression with prednisolone, mycophenolate, and tacrolimus were analyzed. Median age was 58 years, median time since transplant was 84 months, and median serum creatinine was 249 µmol/L. The immunosuppressive effect on NFAT-regulated genes at trough concentrations was 38% (Etrough), and the effect at peak concentrations was 59% (Epeak) of maximum immunosuppression (Emax). The pharmacodynamic parameters of the action of tacrolimus were estimated with the Hill coefficient H at 1.5 and the CE50 at 6.7 ng/mL. Accordingly, the pharmacodynamic threshold concentration was estimated at 0.9 ng/mL and the ceiling concentration at 48 ng/mL, indicating a wide span between target trough and peak levels. The low Hill coefficient indicates concentration-dependent pharmacodynamics of tacrolimus on NFAT transcripts. Therefore, the extension of the administration interval to 24 hours is not likely to jeopardize the immunosuppressive effect of the prolonged-release tacrolimus preparations. 
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Survey among nephrologists in Germany: current practice and management of pregnant women on dialysis
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BACKGROUND: To assess the experience and practice patterns of nephrologists in Germany with regard to the care of pregnant women on dialysis. METHODS: The 26-item internet survey sent by email asked for demographic information, subjective proficiency, maternal and fetal complications, treatment approaches and goals. RESULTS: Of the 2,015 surveys sent out, 200 (10%) were available for evaluation. 38% of respondents never provided care, whereas 62% treated at least one pregnant patient on dialysis. In 306 total reported cases of pregnant women on dialysis, 58% became pregnant while on maintenance dialysis, and 42% developed dialysis-dependent renal failure in the course of pregnancy. For women on peritoneal dialysis (PD), only 22% of the nephrologists would continue PD until delivery, while 78% would convert to hemodialysis either immediately or shortly before delivery. 40% of the respondents reported complications in either mother or child. 45% of the respondents routinely provided prenatal counseling, and 2/3 of the nephrologists did not routinely perform fetal monitoring. While we found a significant difference in self-reported proficiency between nephrologists having and those not having treated pregnant women on dialysis, only 40% of all physicians felt confident in treating pregnant women on dialysis. CONCLUSIONS: Our survey demonstrates that the practice of nephrologists in treating pregnant women on dialysis differs significantly. These findings highlight the need for European guidelines to standardize the care of pregnant dialysis patients.
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CC Chemokine Ligand 18 in ANCA-Associated Crescentic GN.

ANCA-associated vasculitis is the most frequent cause of crescentic GN. To define new molecular and/or cellular biomarkers of this disease in the kidney, we performed microarray analyses of renal biopsy samples from patients with ANCA-associated crescentic GN. Expression profiles were correlated with clinical data in a prospective study of patients with renal ANCA disease. CC chemokine ligand 18 (CCL18), acting through CC chemokine receptor 8 (CCR8) on mononuclear cells, was identified as the most upregulated chemotactic cytokine in patients with newly diagnosed ANCA-associated crescentic GN. Macrophages and myeloid dendritic cells in the kidney were detected as CCL18-producing cells. The density of CCL18(+) cells correlated with crescent formation, interstitial inflammation, and impairment of renal function. CCL18 protein levels were higher in sera of patients with renal ANCA disease compared with those in sera of patients with other forms of crescentic GN. CCL18 serum levels were higher in patients who suffered from ANCA-associated renal relapses compared with those in patients who remained in remission. Using a murine model of crescentic GN, we explored the effects of the CCL18 murine functional analog CCL8 and its receptor CCR8 on kidney function and morphology. Compared with wild-type mice, Ccr8(-/-) mice had significantly less infiltration of pathogenic mononuclear phagocytes. Furthermore, Ccr8(-/-) mice maintained renal function better and had reduced renal tissue injury. In summary, our data indicate that CCL18 drives renal inflammation through CCR8-expressing cells and could serve as a biomarker for disease activity and renal relapse in ANCA-associated crescentic GN.

Time of effect duration and administration interval for sitagliptin in patients with kidney failure.

A measure correlating the time course of the effect with the time course of concentrations could be helpful in drug dosing. We propose a new equation with explicit solutions for calculating the effect duration. A specific effect fraction is selected (fr) and the time of fractional effect duration (TED.fr) can be derived as a function of the elimination half-life by combining linear elimination kinetics with sigmoid effect dynamics. This new measure is applied to the example of sitagliptin, whose elimination half-life increases from 10.1 to 28.4 h in patients with kidney failure. Under normal multiple-dose conditions, the 24-h sitagliptin administration interval corresponds to a 0.90 time of fractional effect duration (TED.90). A dose reduction to one-fourth or 25 mg every 24 h is proposed for patients with kidney failure; this results in a TED.90 of 45 h, i.e. 21 h longer than the proposed 24-h administration interval (+88 %). The proportional dosing alternative of 100 mg every 96 h would result in a TED.90 of 64 h, which is 32 h less than the 96-h administration interval (-33 %). With a half dose of 50 mg and a doubled administration interval of 48 h, the TED.90 is 51 h in kidney failure, only 3 h longer than the latter administration interval (+6 %). We conclude that our general equation can be applied to rapidly calculate the specific time of effect duration for the different dose schedules.

Influence of ATLG serum levels on CD3/CD19-depleted hematopoietic grafts and on immune recovery in pediatric haplo-HSCT.

ABSTRACT: Anti-T lymphocyte globulin (ATLG) significantly reduces the risk of engraftment failure in allogeneic hematopoietic stem cell transplant (HSCT) but hampers posttransplant immune reconstitution. We hypothesized that in patients receiving haploidentical CD3/CD19-depleted grafts, these double-edged effects could be better balanced by attaining high ATLG serum concentrations before transplant but as low as possible on the day of transplant. Therefore, we moved the start of ATLG application to day -12 and determined serum concentrations of T-cell-specific ATLG in pediatric patients treated with 3 established dosing regimens (15, 30, or 60 mg/kg). Corresponding mean T-cell-specific ATLG serum concentrations at day 0 were 1.14, 2.99, or 12.10 µg/mL, respectively. Higher ATLG doses correlated with higher peak levels at days -8 and -7 and reduced graft rejection, whereas lower ATLG doses correlated with significantly faster posttransplant recovery of T and natural killer cells. The rate of graft-versus-host disease remained low, independent of ATLG doses. Moreover, in vitro assays showed that ATLG concentrations of 2.0 µg/mL and lower only slightly reduced the activity of natural killer cells, and therefore, the function of such effector cells might be preserved in the grafts. Pharmacokinetic analysis, compatible with linear first-order kinetics, revealed similar half-life values, independent of ATLG doses. Hence, the day on which a desired ATLG serum level is reached can be calculated before HSCT. Our retrospective study demonstrates the relevance of dosing and time of administration of ATLG on engraftment and immune recovery in ex vivo CD3/CD19-depleted haploidentical HSCT.

Development of a sensitive phospho-p70 S6 kinase ELISA to quantify mTOR proliferation signal inhibition.

BACKGROUND: Drug blood levels can only serve as a surrogate because of the lack of information on the drug's direct pharmacological effects in the individual patient. Measurement of the mammalian target of rapamycin (mTOR) activity dependent on the phosphorylation status of p70 S6 kinase (p70 S6K) offers a practical way for monitoring pharmacodynamic drug activity, with the potential to better assess the state of immunosuppression in individual patients. MATERIAL AND METHODS: Here, we established a novel in vitro model system by treating Jurkat cells and peripheral blood mononuclear cells with different concentrations of sirolimus after stimulation with phorbol 12-myristate 13-acetate. RESULTS: A dose-dependent reduction of the p70 S6K phosphorylation status was demonstrated by Western blot and a newly established enzyme-linked immunosorbent assay (ELISA). Relative phospho-p70 S6K values from ELISA and relative densities from Western blot analysis in peripheral blood mononuclear cells revealed a strong correlation (Spearman correlation coefficient r s = 0.7, P = 0.01). Finally, parallel assays confirmed a sirolimus dose-dependent reduction of cytokine production and cell proliferation in the in vitro model. CONCLUSIONS: Pharmacodynamic monitoring of mTOR inhibition with a p70 S6K ELISA could guide mTOR inhibitor immunosuppression therapy toward a more individualized therapy. The usage of this technique now has to be evaluated in a clinical series of patients.

Effect of low-osmolar contrast medium iopromide and iso-osmolar iodixanol on DNA fragmentation in renal tubular cell culture.

BACKGROUND: Intravascular administration of iodinated contrast media continues to be a common cause of hospital-acquired acute kidney injury. Accumulating evidence suggests that radiocontrast agent-induced nephrotoxicity is associated with increased oxidative stress, which leads to renal tissue damage with DNA fragmentation. We therefore tested whether an iso-osmolar contrast medium (iodixanol) causes less oxidative DNA damage to renal tubular cells than a low-osmolar contrast medium (iopromide). METHODS: HK-2 cells (human proximal renal tubular cell line) were incubated at different time points (10 min-2 h) with increasing concentrations (20-120 mg/ml iodine) of iodixanol or of iopromide. Oxidative DNA damage to renal tubular cells was measured by alkaline comet assay (single-cell gel electrophoresis). RESULTS: Both iso- and low-osmolar contrast agents induced time- and concentration-dependent DNA fragmentation. DNA fragmentation was maximal at 2 h with 120 mg/ml iodine for iopromide (32 ± 27 tail moments) and iodixanol (46 ± 41 tail moments); both were significantly different from the control value with 3.15 ± 1.6 tail moments (Student's t test; p < 0.001). After 1 and 2 h and for all concentrations, iodixanol produced significantly higher DNA fragmentation than iopromide (ANOVA for 1 h p = 0.039 and 2 h p = 0.025, respectively). CONCLUSION: We were able to demonstrate for the first time that an iso-osmolar contrast medium induced even greater oxidative stress and DNA damage than a low-osmolar agent in HK-2 cells. This could provide an explanation for the nephrotoxicity that also is observed with iodixanol in clinical practice.

Clinical Pharmacokinetics and Pharmacodynamics of Voclosporin.

Voclosporin is an approved option for the long-term treatment of lupus nephritis. We aimed to provide a narrative review of the pharmacokinetics and pharmacodynamics of voclosporin. In addition, we derived values for pharmacokinetic and pharmacodynamic parameters by graphical analysis of published diagrams. Compared with cyclosporin, low-dose voclosporin is associated with a lower nephrotoxicity risk and, compared to tacrolimus, with a lower diabetes risk. After repetitive dosing of 23.7 mg twice daily and at target trough concentrations of 10-20 ng/mL, the dominant or effect-indicative half-life is estimated at 7 hours. Compared with the pharmacodynamics of cyclosporin, the potency of voclosporin is stronger, with a lower concentration CE50 of 50 ng/mL already producing the half-maximum immunosuppressive effect. The Hill coefficient can be predicted to be low at H = 1.3, indicating a concentration-dependent effect on the immune system. The corresponding effect bisection time of 10 hours allows for dosing every 12 hours. Accordingly, the trough concentration will be above the threshold concentration that produces 5% of the maximum effect of 5.2 ng/mL for immunosuppression but below both the predicted threshold of 30 ng/mL for nephrotoxicity and the predicted threshold of 40 ng/mL for new-onset diabetes. The pharmacokinetic and pharmacodynamic properties suggest the use of low-dose voclosporin combined with mycophenolate and low-dose glucocorticoids for immunosuppressive maintenance therapy.

Enemy or friend: the personal and the factual patient-physician relationship.

Physicians are expected to place the patient's interests above their own. Such prioritization has worldwide consent. It constitutes the difference between medicine and other professions. The present conceptual opinion paper summarizes the authors' clinical experience with patient care and student teaching during the last 45 years. The authors comment on their own conception by referring to present debates and prominent statements from the past. Fundamental changes in medicine have taken place over the last five decades. New diseases have emerged while diagnostic and therapeutic options for patients have grown steadily - along with healthcare costs. At the same time, economic and legal constraints for physicians have increased, as has moral pressure. The interaction of physicians with patients has gradually shifted from a personal to a factual relationship. In the factual, more formal relationship, the patient and physician represent equal partners of a legal contract, which jeopardizes the prioritization of the patient's interests. The formal relationship implies defensiveness. By contrast, in the personal relationship, the physician adopts an existentialist commitment while simultaneously enabling and respecting the patient's autonomous decision-making. The authors argue for the personal relationship. However, the patient and physician are no friends. Consequently, the physician in effect competes with the patient from a knowledge-based but opposite position. Both need to make efforts to consent and maintain the relationship even when they dissent. This implies that the physician does not simply comply with the patient's wishes.

Pharmacokinetic predictions for patients with renal impairment: focus on peptides and protein drugs.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • Renal impairment may affect the pharmacokinetics of peptide and protein drugs. • Molecular size is a predictor. Small molecules are eliminated by the kidneys, whereas large molecules (>67 kDa) are not. • Urinary recovery of peptide and protein drugs in healthy volunteers is not predictive for pharmacokinetic changes in patients with renal impairment. WHAT THIS STUDY ADDS: • An apparently continuous non-linear relationship between molecular weight and pharmacokinetic alterations as observed in patients with severe renal impairment or end-stage renal disease is described. • Potentially relevant pharmacokinetic changes were found for drugs with a molecular weight below 50 kDa. • Analysis of observed pharmacokinetics in patients with severe renal impairment may be a useful approach, especially when urinary recovery in healthy volunteers is not predictive. AIM: Drug dosage adjustments in renal impairment are usually based on estimated individual pharmacokinetics. The extent of pharmacokinetic changes in patients with renal impairment must be known for this estimation. If measured data are not available, an estimate based on drug elimination in urine of healthy subjects or patients with normal renal function is commonly made. This is not reliable, however, if renal drug metabolism is involved, as is presumably the case for many peptide and protein drugs. In the present study a new method to predict pharmacokinetic changes for such drugs based on molecular weight was derived. METHODS: Articles reporting measured pharmacokinetics of peptide and protein drugs in patients with severe renal impairment or end-stage renal disease were identified from the scientific literature, the pharmacokinetic parameter values were extracted and a statistical data synthesis was performed. A sigmoid E(max) model was applied and fitted to the data and the prediction error was analyzed. RESULTS: Overall, 98 peptide and protein drugs were identified. Relevant pharmacokinetic data in patients with renal impairment were found for 21 of these drugs. The average drug clearance was 30% and the average prolongation in half-life was 3.1-fold for low molecular weight peptides or proteins. The median root squared percentage of the prediction error was 18% (drug clearance) and 12% (half-life). CONCLUSION: An apparently continuous non-linear relationship between molecular weight and pharmacokinetic alterations in patients with severe renal impairment was found. The derived equations could be used as a rough guide for decisions on drug dosage adjustments in such patients.

Pharmacokinetics and pharmacodynamics of mycophenolate sodium (EC-MPS) co-administered with cyclosporine in the early-phase post-kidney transplantation.

Mycophenolate drug levels are decreased by co-administration of cyclosporine. However, mycophenolate levels may be associated with insufficient immunosuppression. We investigated the pharmacokinetics of 720 mg mycophenolate sodium (EC-MPS) and inosine monophosphate dehydrogenase (IMPDH) activity under co-medication with cyclosporine and steroids within the first 30 d after kidney transplantation (n = 24). Blood samples were drawn at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 12 h after the morning dose. Plasma concentrations of mycophenolic acid, its glucuronide metabolites (MPAG; AcMPAG), and free MPA were determined using validated HPLC-DAD. IMPDH activity in leukocytes was analyzed chromatographically. Only six of 24 patients had an MPA-AUC(12h) within the putative therapeutic range of 40-60 mg/L·h. MPA clearance was high with 29 L/h. fMPA-AUC(12h) (r = -0.429, p = 0.04) and MPAG-AUC(12h) correlated significantly with the glomerular filtration rate, while total MPA did not. The MPAG-AUC(12h) was about 52-fold higher than the corresponding values for MPA, whereas the AcMPAG-AUC(12h) reached about 20.4% of the respective MPA-AUC(12h.) We found significant correlations between IMPDH inhibition and MPA concentration (r = -0.665; p < 0.0001), fMPA (r = -0.446; p = 0.003), and AcMPAG (r = -0.459; p = 0.002) but not with MPAG. Only 25% of the patients attained the therapeutic range for MPA-AUC under standard EC-MPS dose during the early-phase post-transplantation. We recommend that EC-MPS should be given in higher doses (3 × 720 mg) in the early post-transplant period when co-administered with cyclosporine.

Increased major bleeding risk in patients with kidney dysfunction receiving enoxaparin: a meta-analysis.

PURPOSE: The elimination half-life and consequently the accumulation of enoxaparin increase as glomerular filtration rate (GFR) decreases. A dose adjustment for patients with a GFR <30 ml/min is recommended and considered relatively safe. Our intention was to identify whether the use of enoxaparin is safe and to determine what impact an enoxaparin dose adjustment has on patients with a GFR <60 ml/min. METHODS: A PubMed search and meta-analysis of literature were performed. Studies were analyzed to compare enoxaparin versus other heparins/heparinoids and investigate enoxaparin at different stages of kidney dysfunction. Only controlled trials were considered, and the enoxaparin dose had to be specified. The clinical endpoint was defined as apparent major bleeding. RESULTS: Out of 1,027 publications, 20 studies met the criteria and were analyzed. Our meta-analysis shows that enoxaparin major bleeding complications at a GFR < 60 ml/min increase significantly, with a relative risk (RR) of 1.67 [95% confidence interval (CI) 1.12-2.50) compared with other anticoagulants (p = 0.01). RR for patients on enoxaparin therapy increases exponentially with each stage of chronic kidney disease (CKD stage 1-5) [RR = 0.585 x exp(0.524 x CKD)]. Despite dose adjustment, the major bleeding risk is still significantly increased in patients with a GFR < 60 ml/min versus those with a GFR > 60 ml/min. CONCLUSION: Only patients with a GFR > 60 ml/min can be safely treated with enoxaparin.

Diagnostic pathways for exclusion and diagnosis of kidney diseases.

In 2006, the German Society for Clinical Chemistry and Laboratory Medicine together with the Society of Nephrology founded a working group with the aim to develop diagnostic pathways for the detection and differentiation of renal diseases. Based on existing recommendations, these pathways may be structured to be a basis for implementation into hospital and laboratory information systems. The present paper describes the contents of these pathways regarding glomerular filtration rate, hematuria, leukocyturia and proteinuria.

Clinical Pharmacokinetics and Pharmacodynamics of Roxadustat.

The pharmacokinetics of roxadustat are well characterized, with an apparent volume of distribution after oral administration of 22-57 L, apparent clearance of 1.2-2.65 L/h, and renal clearance of 0.030-0.026 L/h in healthy volunteers; the elimination half-life is 9.6-16 h. Plasma binding is 99% and the fraction eliminated by hemodialysis is 2.34%. As an interpretation of the pharmacodynamics of roxadustat, we proposed a concept with a hypothetical cascade of two subsequent effects, first on erythropoetin (EPO) and second on hemoglobin (delta Hb). The primary effect on EPO is observed within a few hours after roxadustat administration and can be modeled using the sigmoidal Hill equation. The concentration at half-maximum effect can be inferred at 10-36 µg/mL, the Hill coefficient at 3.3, and the effect bisection time at 10-17 h, corresponding to EPO half-life. The subsequent effect on hemoglobin (delta Hb) is observed after several weeks and can be interpreted as an irreversible, dose proportional, unsaturable effect, continuing in agreement with the lifespan of red blood cells of 63-112 days.

Drug dosing consideration in patients with acute and chronic kidney disease-a clinical update from Kidney Disease: Improving Global Outcomes (KDIGO).

Drug dosage adjustment for patients with acute or chronic kidney disease is an accepted standard of practice. The challenge is how to accurately estimate a patient's kidney function in both acute and chronic kidney disease and determine the influence of renal replacement therapies on drug disposition. Kidney Disease: Improving Global Outcomes (KDIGO) held a conference to investigate these issues and propose recommendations for practitioners, researchers, and those involved in the drug development and regulatory arenas. The conference attendees discussed the major challenges facing drug dosage adjustment for patients with kidney disease. In particular, although glomerular filtration rate is the metric used to guide dose adjustment, kidney disease does affect nonrenal clearances, and this is not adequately considered in most pharmacokinetic studies. There are also inadequate studies in patients receiving all forms of renal replacement therapy and in the pediatric population. The conference generated 37 recommendations for clinical practice, 32 recommendations for future research directions, and 24 recommendations for regulatory agencies (US Food and Drug Administration and European Medicines Agency) to enhance the quality of pharmacokinetic and pharmacodynamic information available to clinicians. The KDIGO Conference highlighted the gaps and focused on crafting paths to the future that will stimulate research and improve the global outcomes of patients with acute and chronic kidney disease.