A Randomized Controlled Trial to Assess the Clinical Benefits of a Pharmacogenetics-Guided Dosing Regimen for Calculating Warfarin Maintenance Dose
试验速览
- 阶段
- 3 期
- 入组人数
- 320
- 试验地点
- 2
- 主要终点
- No. of dosage titrations required to achieve targeted INR at 3 months of initializing warfarin.
研究概览
简要总结
Interethnic differences in warfarin dose requirements in the Asian population have been well described. Our previous studies showed that warfarin maintenance doses in our multi-ethnic population were closely related to patient demographics and genetic polymorphisms in cytochrome(CYP)P4502C9 and vitamin K epoxide reductase complex subunit 1(VKORC1). A retrospective regression model combining these predictors accounts for 57.8% of the variability in warfarin dose.
详细描述
Hypothesis
We hypothesize that warfarin dose requirement could be more accurately predicted using a simplified genotyping procedure requiring the identification of a single CYP2C9 allele and a single nucleotide polymorphism of VKORC1 to discern between the 2 major haplotypes H1 and H7.
Aims: The aim is to compare the clinical benefits of genetics-guided dosing versus traditional trial and error dosing with protocol guided-adjustments. Two secondary objectives are (1) to prospectively evaluate a dosing algorithm built on demographics and genetic predictors; (2) to assess the feasibility of a simplified test for CYP2C9*3 and VKORC1 SNP in clinical practice.
Methodology: A randomized controlled trial targeted at accruing 100 patients with indication for wafarin therapy. The endpoint for comparing genetics-guided dosing against traditional dosing method at the anticoagulant clinic is the number of dosage titrations to achieve targeted International Normalized Ratio (INR) at 1, 2 and 3 months of initializing warfarin. Upon reaching steady-state, pharmacokinetics of warfarin R- and S-isomers will be assessed for correlation with dose requirements based. An assay for easy identification of genetic polymorphisms required in this dosing regimen in a clinic setting will also be validated.
Significance: This concerted, multi-disciplinary effort to bring pharmacogenetics-based therapy from bench to bedside has the potential to reduce the efforts incurred with multiple dose titrations of the most commonly prescribed oral anticoagulant. With the aid of mathematical modeling, a simplified and more cost-effective genotyping method could be implementation for the future treatment and prophylaxis of thromboembolic diseases.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •At least 18 years of age
- •New indication for warfarin therapy
- •No previous history of liver disease; transaminases must be less than 3 times upper limit of normal and bilirubin within normal range
- •No previous history of malabsorption syndrome or chronic diarrheal conditions
- •Written, informed consent
排除标准
- •Uncontrolled hypertension
- •Peptic ulcer disease
- •Any other medical conditions as deemed unfit for warfarin therapy based on clinical judgement of primary physician
研究组 & 干预措施
Pharmacogenetics-guided dosing group
For patients randomized to the pharmacogenetics-guided dosing group, this 10mls of blood will be immediately sent for genotyping studies. Genotyping results will be available for pharmacogenetics-guided dosing within 3 working days, (ranging 3 to 5 days). During this period, if patients need to be initiated on anticoagulation, a low molecular weight heparin, Fraxiparine, will be given. Fraxiparine will be overlapped with warfarin for 2 to 3 days until target INR is achieved. Elective cases should have the pharmacogenetics-based warfarin dose available at the time of warfarin therapy.
干预措施: Warfarin Sodium (Drug)
Traditional dosing group
For patients randomized to the traditional dosing regime, the blood will be stored and genotyped retrospectively at the end of the study. Overlapping of warfarin with Fraxiparine or heparin till target INR is achieved is allowed for this group as per normal clinical practice. All warfarin dosage adjustments based on INR results will be according to the current protocol used by the NUH Anticoagulant Clinic.
干预措施: Warfarin Sodium (Drug)
结局指标
主要结局
No. of dosage titrations required to achieve targeted INR at 3 months of initializing warfarin.
时间窗: 3 months
1. Number of dosage titrations/adjustments required to achieve targeted International Normalized Ratio (INR) at 3 months of initializing warfarin. The number of titrations refers to the number of times warfarin dosage was adjusted when INR was out of target range (\>1.9 and ≤ 3.1) or in response to an adverse event or therapeutic failure. This endpoint will be compiled every 4 weeks, up to 3 months after the initialization of warfarin therapy
次要结局
- pharmacokinetics of warfarin R- and S-enantiomers(3 months)
研究者
Haematology-Oncology
Dr. Goh Boon Cher
National University Hospital, Singapore