| 1. |
- Howard, Rebecca, et al.
(författare)
-
Genotyping for CYP2C9 and VKORC1 alleles by a novel point of care assay with HyBeacon® probes
- 2011
-
Ingår i: Clinica Chimica Acta. - : Elsevier BV. - 0009-8981 .- 1873-3492. ; 412:23-24, s. 2063-2069
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 2. |
- van Schie, Rianne M. F., et al.
(författare)
-
Genotype-guided dosing of coumarin derivatives : the European pharmacogenetics of anticoagulant therapy (EU-PACT) trial design
- 2009
-
Ingår i: Pharmacogenomics (London). - : Future Medicine Ltd. - 1462-2416 .- 1744-8042. ; 10:10, s. 1687-1695
-
Tidskriftsartikel (refereegranskat)abstract
- The narrow therapeutic range and wide interpatient variability in dose requirement make anticoagulation response to coumarin derivatives unpredictable. As a result, patients require frequent monitoring to avert adverse effects and maintain therapeutic efficacy. Polymorphisms in VKORC1 and CYP2C9 jointly account for about 40% of the interindividual variability in dose requirements. To date, several pharmacogenetic-guided dosing algorithms for coumarin derivatives, predominately for warfarin, have been developed. However, the potential benefit of these dosing algorithms in terms of their safety and clinical utility has not been adequately investigated in randomized settings. The European Pharmacogenetics of Anticoagulant Therapy (EU-PACT) trial will assess, in a single-blinded and randomized controlled trial with a follow-up period of 3 months, the safety and clinical utility of genotype-guided dosing in daily practice for the three main coumarin derivatives used in Europe. The primary outcome measure is the percentage time in the therapeutic range for international normalized ratio. This report describes the design and protocol for the trial.
|
|
| 3. |
- Verhoef, Talitha I., et al.
(författare)
-
A Randomized Trial of Genotype-Guided Dosing of Acenocoumarol and Phenprocoumon
- 2013
-
Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 369:24, s. 2304-2312
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Observational evidence suggests that the use of a genotype-guided dosing algorithm may increase the effectiveness and safety of acenocoumarol and phenprocoumon therapy.Methods: We conducted two single-blind, randomized trials comparing a genotype-guided dosing algorithm that included clinical variables and genotyping for CYP2C9 and VKORC1 with a dosing algorithm that included only clinical variables, for the initiation of acenocoumarol or phenprocoumon treatment in patients with atrial fibrillation or venous thromboembolism. The primary outcome was the percentage of time in the target range for the international normalized ratio (INR; target range, 2.0 to 3.0) in the 12-week period after the initiation of therapy. Owing to low enrollment, the two trials were combined for analysis. The primary outcome was assessed in patients who remained in the trial for at least 10 weeks.Results: A total of 548 patients were enrolled (273 patients in the genotype-guided group and 275 in the control group). The follow-up was at least 10 weeks for 239 patients in the genotype-guided group and 245 in the control group. The percentage of time in the therapeutic INR range was 61.6% for patients receiving genotype-guided dosing and 60.2% for those receiving clinically guided dosing (P=0.52). There were no significant differences between the two groups for several secondary outcomes. The percentage of time in the therapeutic range during the first 4 weeks after the initiation of treatment in the two groups was 52.8% and 47.5% (P=0.02), respectively. There were no significant differences with respect to the incidence of bleeding or thromboembolic events.Conclusions: Genotype-guided dosing of acenocoumarol or phenprocoumon did not improve the percentage of time in the therapeutic INR range during the 12 weeks after the initiation of therapy.
|
|
| 4. |
- Verhoef, Talitha I, et al.
(författare)
-
A systematic review of cost-effectiveness analyses of pharmacogenetic-guided dosing in treatment with coumarin derivatives.
- 2010
-
Ingår i: Pharmacogenomics (London). - : Future Medicine Ltd. - 1462-2416 .- 1744-8042. ; 11:7, s. 989-1002
-
Tidskriftsartikel (refereegranskat)abstract
- Anticoagulant therapy with coumarin derivatives is often sub- or supra-therapeutic, resulting in an increased risk of thromboembolic events or hemorrhage, respectively. Pharmacogenetic-guided dosing has been proposed as an effective way of reducing bleeding rates. Clinical trials to confirm the safety, efficacy and effectiveness of this strategy are ongoing, but in addition, it is also necessary to consider the cost-effectiveness of this strategy. This article describes the findings of a systematic review of published cost-effectiveness analyses of pharmacogenetic-guided dosing of coumarin derivatives. Similarities and differences in the approaches used were examined and the quality of the analyses was assessed. The results of the analyses are not sufficient to determine whether or not pharmacogenetic-guided dosing of coumarins is cost effective. More reliable cost-effectiveness estimates need to become available before it is possible to recommend whether or not this strategy should be applied in clinical practice.
|
|
