1.
2.
Kowalec, Kaarina, et al.
(author)
Characteristics associated with drug-induced liver injury from interferon beta in multiple sclerosis patients
2014
In: Expert Opinion on Drug Safety. - : Informa Healthcare. - 1474-0338 .- 1744-764X. ; 13:10, s. 1305-1317
Research review (peer-reviewed) abstract
Objective: To identify and characterize drug-induced liver injury (DILI) associated with IFN-beta in multiple sclerosis (MS) using recommended criteria. Methods: This retrospective, mixed methods design included a cohort of IFN-beta exposed MS patients from British Columbia (BC), Canada and a series of DILI cases from other Canadian provinces and two adverse drug reaction (ADR) networks (USA and Sweden). Associations between sex, age and IFN-beta product, and DILI were explored in BC cohort using Cox proportional hazard analyses. Characteristics, including the time to DILI, were compared between sites. Results: In BC, 18/942 (1.9%) of IFN-beta exposed MS patients met criteria for DILI, with a trend toward an increased risk for women and those exposed to IFN-beta-1a SC (44 mcg 3 x weekly) (adjusted Hazard Ratios: 3.15; 95% CI: 0.72 - 13.72, p = 0.13 and 6.26; 95% CI: 0.78 - 50.39, p = 0.08, respectively). Twenty-four additional cases were identified from other sites; the median time to DILI was comparable between BC and other Canadian cases (105 and 90 days, respectively), but longer for the ADR network cases (590 days, p = 0.006). Conclusions: Approximately 1 in 50 IFN-beta exposed patients developed DILI in BC, Canada. Identification of DILI cases from diverse sources highlighted that this reaction occurs even after years of exposure.
3.
Alfirevic, A., et al.
(author)
Phenotype Standardization for Statin-Induced Myotoxicity
2014
In: Clinical Pharmacology and Therapeutics. - : Springer Science and Business Media LLC. - 0009-9236 .- 1532-6535. ; 96:4, s. 470-476
Research review (peer-reviewed) abstract
Statins are widely used lipid-lowering drugs that are effective in reducing cardiovascular disease risk. Although they are generally well tolerated, they can cause muscle toxicity, which can lead to severe rhabdomyolysis. Research in this area has been hampered to some extent by the lack of standardized nomenclature and phenotypic definitions. We have used numerical and descriptive classifications and developed an algorithm to define statin-related myotoxicity phenotypes, including myalgia, myopathy, rhabdomyolysis, and necrotizing autoimmune myopathy.
4.
Eriksson, Niclas, 1978-
(author)
On the Prediction of Warfarin Dose
2012
Doctoral thesis (other academic/artistic) abstract
Warfarin is one of the most widely used anticoagulants in the world. Treatment is complicated by a large inter-individual variation in the dose needed to reach adequate levels of anticoagulation i.e. INR 2.0 – 3.0. The objective of this thesis was to evaluate which factors, mainly genetic but also non-genetic, that affect the response to warfarin in terms of required maintenance dose, efficacy and safety with special focus on warfarin dose prediction.Through candidate gene and genome-wide studies, we have shown that the genes CYP2C9 and VKORC1 are the major determinants of warfarin maintenance dose. By combining the SNPs CYP2C9 *2, CYP2C9 *3 and VKORC1 rs9923231 with the clinical factors age, height, weight, ethnicity, amiodarone and use of inducers (carbamazepine, phenytoin or rifampicin) into a prediction model (the IWPC model) we can explain 43 % to 51 % of the variation in warfarin maintenance dose. Patients requiring doses < 29 mg/week and doses ≥ 49 mg/week benefitted the most from pharmacogenetic dosing. Further, we have shown that the difference across ethnicities in percent variance explained by VKORC1 was largely accounted for by the allele frequency of rs9923231. Other novel genes affecting maintenance dose (NEDD4 and DDHD1), as well as the replicated CYP4F2 gene, have small effects on dose predictions and are not likely to be cost-effective, unless inexpensive genotyping is available.Three types of prediction models for warfarin dosing exist: maintenance dose models, loading dose models and dose revision models. The combination of these three models is currently being used in the warfarin treatment arm of the European Pharmacogenetics of Anticoagulant Therapy (EU-PACT) study. Other clinical trials aiming to prove the clinical validity and utility of pharmacogenetic dosing are also underway.The future of pharmacogenetic warfarin dosing relies on results from these ongoing studies, the availability of inexpensive genotyping and the cost-effectiveness of pharmacogenetic driven warfarin dosing compared with new oral anticoagulant drugs.
5.
Hamberg, Anna-Karin, 1964-, et al.
(author)
Warfarin dose prediction in children using pharmacometric bridging : comparison with published pharmacogenetic dosing algorithms
2013
In: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 69:6, s. 1275-1283
Journal article (peer-reviewed) abstract
PurposeNumerous studies have investigated causes of warfarin dose variability in adults whereas studies in children are limited both in numbers and size. Mechanism-based population modelling provides an opportunity to condense and propagate prior knowledge from one population to another. The main objectives with this study were to evaluate the predictive performance of a theoretically bridged adult warfarin model in children, and to compare accuracy in dose prediction relative to published warfarin algorithms for children.MethodAn adult population PK/PD-model for warfarin, with CYP2C9 and VKORC1 genotype, age and target INR as dose predictors, was bridged to children using allometric scaling methods. Its predictive properties were evaluated in an external dataset of children 0-18 years old, including comparison of dose prediction accuracy with three pharmacogenetics-based algorithms for children.ResultsOverall, the bridged model predicted INR response well in 64 warfarin treated Swedish children (median age 4.3 years), but with a tendency to over predict INR in children ≤ 2 years old. The bridged model predicted 20 of 49 children (41%) within ± 20% of actual maintenance dose (median age 7.2 years). In comparison the published dosing algorithms predicted 33-41% of the children within ± 20% of actual dose. Dose optimization with the bridged model based on up to three individual INR observations increased the proportion within ± 20% of actual dose to 70%.ConclusionA mechanism-based population model developed on adult data provides a promising first step towards more individualized warfarin therapy in children.
6.
Howard, Rebecca, et al.
(author)
Genotyping for CYP2C9 and VKORC1 alleles by a novel point of care assay with HyBeacon® probes
2011
In: Clinica Chimica Acta. - : Elsevier BV. - 0009-8981 .- 1873-3492. ; 412:23-24, s. 2063-2069
Journal article (peer-reviewed) abstract
BACKGROUND: Coumarin anticoagulants such as warfarin are used to treat and prevent thromboembolic events in patients. The required dosage is difficult to predict and the risk of over or under anticoagulation are dependent on several environmental and clinical factors, such as concurrent medication, diet, age and genotype for polymorphisms in two genes CYP2C9 and VKORC1.METHODS: A novel fluorescent PCR genotyping assay using HyBeacon® probes, was developed to enable clinical staff to genotype the CYP2C9*2 and CYP2C9*3 alleles and the VKORC1 G-1639A polymorphism directly from unextracted blood samples. A prototype PCR instrument, Genie 1, suitable for point of care use was developed to carry out the assays. The panel of tests was validated by analysing blood samples from 156 individuals and comparing genotypes with data obtained using DNA samples from the same individuals. The accuracy of genotypes obtained with the Genie 1 was compared against results from well validated real time PCR and PCR-restriction fragment length polymorphism analysis.RESULTS: Identical results were obtained for the newly developed HyBeacon® method and the validation method in all cases except for one where no result was obtained for the VKORC1 polymorphism on the Genie instrument. The samples used for validation represented all six possible *2 and *3 allele-related CYP2C9 genotypes and all three VKORC1 G-1639A genotypes.CONCLUSIONS: We observed excellent accuracy for the newly developed method which can determine genotype in less than 2 h.
7.
Ramsey, L. B., et al.
(author)
The Clinical Pharmacogenetics Implementation Consortium Guideline for SLCO1B1 and Simvastatin-Induced Myopathy : 2014 Update
2014
In: Clinical Pharmacology and Therapeutics. - : Springer Science and Business Media LLC. - 0009-9236 .- 1532-6535. ; 96:4, s. 423-428
Journal article (peer-reviewed) abstract
Simvastatin is among the most commonly used prescription medications for cholesterol reduction. A single coding single-nucleotide polymorphism, rs4149056T>C, in SLCO1B1 increases systemic exposure to simvastatin and the risk of muscle toxicity. We summarize evidence from the literature supporting this association and provide therapeutic recommendations for simvastatin based on SLCO1B1 genotype. This article is an update to the 2012 Clinical Pharmacogenetics Implementation Consortium guideline for SLCO1B1 and simvastatin-induced myopathy.
8.
Wadelius, Mia, et al.
(author)
Phenotype Standardization of Angioedema in the Head and Neck Region Caused by Agents Acting on the Angiotensin System
2014
In: Clinical Pharmacology and Therapeutics. - : Nature Publishing Group. - 0009-9236 .- 1532-6535. ; 96:4, s. 477-481
Research review (peer-reviewed) abstract
Angioedema is a potentially life-threatening adverse reaction to angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. To study the genetic etiology of this rare adverse event, international consortia and multicenter recruitment of patients are needed. To reduce patient heterogeneity, we have standardized the phenotype. In brief, it comprises swelling in the head and neck region that first occurs during treatment. It should not coincide with urticaria or have another likely cause such as hereditary angioedema.
