Anders Åsberg

Bio: Anders Åsberg is an academic researcher from Oslo University Hospital. The author has contributed to research in topics: Transplantation & Kidney transplantation. The author has an hindex of 42, co-authored 213 publications receiving 5288 citations. Previous affiliations of Anders Åsberg include Akershus University Hospital & University of Oslo.

Therapeutic Drug Monitoring of Tacrolimus-Personalized Therapy : Second Consensus Report

Abstract: Ten years ago, a consensus report on the optimization of tacrolimus was published in this journal. In 2017, the Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicity (IATDMCT) decided to issue an updated consensus report considering the most relevant advances in tacrolimus pharmacokinetics (PK), pharmacogenetics (PG), pharmacodynamics, and immunologic biomarkers, with the aim to provide analytical and drug-exposure recommendations to assist TDM professionals and clinicians to individualize tacrolimus TDM and treatment. The consensus is based on in-depth literature searches regarding each topic that is addressed in this document. Thirty-seven international experts in the field of TDM of tacrolimus as well as its PG and biomarkers contributed to the drafting of sections most relevant for their expertise. Whenever applicable, the quality of evidence and the strength of recommendations were graded according to a published grading guide. After iterated editing, the final version of the complete document was approved by all authors. For each category of solid organ and stem cell transplantation, the current state of PK monitoring is discussed and the specific targets of tacrolimus trough concentrations (predose sample C0) are presented for subgroups of patients along with the grading of these recommendations. In addition, tacrolimus area under the concentration-time curve determination is proposed as the best TDM option early after transplantation, at the time of immunosuppression minimization, for special populations, and specific clinical situations. For indications other than transplantation, the potentially effective tacrolimus concentrations in systemic treatment are discussed without formal grading. The importance of consistency, calibration, proficiency testing, and the requirement for standardization and need for traceability and reference materials is highlighted. The status for alternative approaches for tacrolimus TDM is presented including dried blood spots, volumetric absorptive microsampling, and the development of intracellular measurements of tacrolimus. The association between CYP3A5 genotype and tacrolimus dose requirement is consistent (Grading A I). So far, pharmacodynamic and immunologic biomarkers have not entered routine monitoring, but determination of residual nuclear factor of activated T cells-regulated gene expression supports the identification of renal transplant recipients at risk of rejection, infections, and malignancy (B II). In addition, monitoring intracellular T-cell IFN-g production can help to identify kidney and liver transplant recipients at high risk of acute rejection (B II) and select good candidates for immunosuppression minimization (B II). Although cell-free DNA seems a promising biomarker of acute donor injury and to assess the minimally effective C0 of tacrolimus, multicenter prospective interventional studies are required to better evaluate its clinical utility in solid organ transplantation. Population PK models including CYP3A5 and CYP3A4 genotypes will be considered to guide initial tacrolimus dosing. Future studies should investigate the clinical benefit of time-to-event models to better evaluate biomarkers as predictive of personal response, the risk of rejection, and graft outcome. The Expert Committee concludes that considerable advances in the different fields of tacrolimus monitoring have been achieved during this last decade. Continued efforts should focus on the opportunities to implement in clinical routine the combination of new standardized PK approaches with PG, and valid biomarkers to further personalize tacrolimus therapy and to improve long-term outcomes for treated patients.

The European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) Registry Annual Report 2016: a summary.

Abstract: Background This article summarizes the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) Registry's 2015 Annual Report. It describes the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in 2015 within 36 countries. Methods In 2016 and 2017, the ERA-EDTA Registry received data on patients who were undergoing RRT for ESRD in 2015, from 52 national or regional renal registries. Thirty-two registries provided individual patient-level data and 20 provided aggregated-level data. The incidence, prevalence and survival probabilities of these patients were determined. Results In 2015, 81 373 individuals commenced RRT for ESRD, equating to an overall unadjusted incidence rate of 119 per million population (pmp). The incidence ranged by 10-fold, from 24 pmp in Ukraine to 232 pmp in the Czech Republic. Of the patients commencing RRT, almost two-thirds were men, over half were aged ≥65 years and a quarter had diabetes mellitus as their primary renal diagnosis. Treatment modality at the start of RRT was haemodialysis for 85% of the patients, peritoneal dialysis for 11% and a kidney transplant for 4%. By Day 91 of commencing RRT, 82% of patients were receiving haemodialysis, 13% peritoneal dialysis and 5% had a kidney transplant. On 31 December 2015, 546 783 individuals were receiving RRT for ESRD, corresponding to an unadjusted prevalence of 801 pmp. This ranged throughout Europe by more than 10-fold, from 178 pmp in Ukraine to 1824 pmp in Portugal. In 2015, 21 056 kidney transplantations were performed, equating to an overall unadjusted transplant rate of 31 pmp. This varied from 2 pmp in Ukraine to 94 pmp in the Spanish region of Cantabria. For patients commencing RRT during 2006-10, the 5-year unadjusted patient survival probabilities on all RRT modalities combined was 50.0% (95% confidence interval 49.9-50.1).

Exposure of atorvastatin is unchanged but lactone and acid metabolites are increased several-fold in patients with atorvastatin-induced myopathy.

Abstract: Background The most serious side effect from statin treatment is myopathy, which may proceed to rhabdomyolysis. This is the first study to investigate whether the pharmacokinetics of either atorvastatin or its metabolites, or both, is altered in patients with atorvastatin-related myopathy compared with healthy controls. Methods A 24-hour pharmacokinetic investigation was performed in 14 patients with atorvastatin-related myopathy. Relevant polymorphisms in SLCO1B1 (encoding organic anion transporting polypeptide 1B1), MDR1/ABCB1 (encoding P-glycoprotein), and CYP3A5 (encoding cytochrome P450 3A5) were determined. Data from 15 healthy volunteers were used as controls. Results No statistically significant difference in systemic exposure of atorvastatin was observed between the 2 groups. However, patients with atorvastatin-related myopathy had 2.4-fold and 3.1-fold higher systemic exposures of the metabolites atorvastatin lactone (P < .01) and p-hydroxyatorvastatin (P < .01), respectively, compared with controls. There were no differences in frequencies of SLCO1B1, MDR1, and CYP3A5 polymorphisms between the 2 groups. Conclusions This study disclosed a distinct difference in the pharmacokinetics of atorvastatin metabolites between patients with atorvastatin-related myopathy and healthy control subjects. These results are of importance in the further search for the mechanism of statin-induced myopathy. Clinical Pharmacology & Therapeutics (2006) 79, 532–539; doi: 10.1016/j.clpt.2006.02.014

SLCO1B1 variants and statin-induced myopathy--a genomewide study

Abstract: Background Lowering low-density lipoprotein cholesterol with statin therapy results in substantial reductions in cardiovascular events, and larger reductions in cholesterol may produce larger benefits. In rare cases, myopathy occurs in association with statin therapy, especially when the statins are administered at higher doses and with certain other medications. Methods We carried out a genomewide association study using approximately 300,000 markers (and additional fine-mapping) in 85 subjects with definite or incipient myopathy and 90 controls, all of whom were taking 80 mg of simvastatin daily as part of a trial involving 12,000 participants. Replication was tested in a trial of 40 mg of simvastatin daily involving 20,000 participants. Results The genomewide scan yielded a single strong association of myopathy with the rs4363657 single-nucleotide polymorphism (SNP) located within SLCO1B1 on chromosome 12 (P=4x10(-9)). SLCO1B1 encodes the organic anion-transporting polypeptide OATP1B1, which has been shown to regulate the hepatic uptake of statins. The noncoding rs4363657 SNP was in nearly complete linkage disequilibrium with the nonsynonymous rs4149056 SNP (r(2)=0.97), which has been linked to statin metabolism. The prevalence of the rs4149056 C allele in the population was 15%. The odds ratio for myopathy was 4.5 (95% confidence interval [CI], 2.6 to 7.7) per copy of the C allele, and 16.9 (95% CI, 4.7 to 61.1) in CC as compared with TT homozygotes. More than 60% of these myopathy cases could be attributed to the C variant. The association of rs4149056 with myopathy was replicated in the trial of 40 mg of simvastatin daily, which also showed an association between rs4149056 and the cholesterol-lowering effects of simvastatin. No SNPs in any other region were clearly associated with myopathy. Conclusions We have identified common variants in SLCO1B1 that are strongly associated with an increased risk of statin-induced myopathy. Genotyping these variants may help to achieve the benefits of statin therapy more safely and effectively. (Current Controlled Trials number, ISRCTN74348595.)

Determinants of pulse wave velocity in healthy people and in the presence of cardiovascular risk factors

Abstract: Aims Carotid–femoral pulse wave velocity (PWV), a direct measure of aortic stiffness, has become increasingly important for total cardiovascular (CV) risk estimation. Its application as a routine tool for clinical patient evaluation has been hampered by the absence of reference values. The aim of the present study is to establish reference and normal values for PWV based on a large European population. Methods and results We gathered data from 16 867 subjects and patients from 13 different centres across eight European countries, in which PWV and basic clinical parameters were measured. Of these, 11 092 individuals were free from overt CV disease, non-diabetic and untreated by either anti-hypertensive or lipid-lowering drugs and constituted the reference value population, of which the subset with optimal/normal blood pressures (BPs) (n = 1455) is the normal value population. Prior to data pooling, PWV values were converted to a common standard using established conversion formulae. Subjects were categorized by age decade and further subdivided according to BP categories. Pulse wave velocity increased with age and BP category; the increase with age being more pronounced for higher BP categories and the increase with BP being more important for older subjects. The distribution of PWV with age and BP category is described and reference values for PWV are established. Normal values are proposed based on the PWV values observed in the non-hypertensive subpopulation who had no additional CV risk factors. Conclusion The present study is the first to establish reference and normal values for PWV, combining a sizeable European population after standardizing results for different methods of PWV measurement.

The Third International Consensus Guidelines on the Management of Cytomegalovirus in Solid-organ Transplantation

Abstract: Cytomegalovirus (CMV) remains one of the most common infections after solid organ transplantation, resulting in significant morbidity, graft loss, and occasional mortality. Management of CMV varies considerably among transplant centers. A panel of experts on CMV and solid organ transplant was convened by The Infectious Diseases Section of The Transplantation Society to develop evidence and expert opinion-based consensus guidelines on CMV management including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues.

Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use in investigating mechanisms of hepatotoxicity, cell signaling and ADME.

Abstract: This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4α, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4α), resulting in up- and downregulation of hundreds of genes. An understanding of these changes is crucial for a correct interpretation of in vitro data. The possibilities and limitations of the most useful liver in vitro systems are summarized, including three-dimensional culture techniques, co-cultures with non-parenchymal cells, hepatospheres, precision cut liver slices and the isolated perfused liver. Also discussed is how closely hepatoma, stem cell and iPS cell-derived hepatocyte-like-cells resemble real hepatocytes. Finally, a summary is given of the state of the art of liver in vitro and mathematical modeling systems that are currently used in the pharmaceutical industry with an emphasis on drug metabolism, prediction of clearance, drug interaction, transporter studies and hepatotoxicity. One key message is that despite our enthusiasm for in vitro systems, we must never lose sight of the in vivo situation. Although hepatocytes have been isolated for decades, the hunt for relevant alternative systems has only just begun.