Pharmacogenetic Dosing of Warfarin

Purpose:

Warfarin is now the most commonly used oral anticoagulant. This drug has inter-individual variability due to the genetic polymorphisms in the warfarin metabolizing enzyme, CYP2C9 and warfarin target, VKORC1. The investigators' team developed a pharmacogenetic dosing algorithm which can predict patients required warfarin dose, thus could prevent warfarin induced warfarin adverse events.

Methods:

The investigators recruited patients with indications for warfarin, the genotypes of VKORC1 and CYP2C9 were determined by the hospitals and verified by National Center for Genome Medicine. The investigators then randomized the patients to one of three arms: 1. Warfarin dose predicted by dosing algorithm developed by the International Warfarin pharmacogenetic Consortium (IWPC), 2. Algorithm developed by the Taiwan Warfarin Consortium and 3. Standard of care. The investigators aimed to determine whether using genetic dosing algorithm can lead to more stable dose and safer use of the drug.

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Key information

Conditions

Stroke Arrhythmias, Cardiac Atrial Fibrillation Atrial Flutter Brain Diseases Cardiovascular Diseases Central Nervous System Diseases Cerebrovascular Disorders Embolism and Thrombosis Heart Diseases Nervous System Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Thrombosis Vascular Diseases Venous Thrombosis

Age range

20 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Kaohsiung Medical University, Kaohsiung City, Taiwan

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Patients must give their informed consent and complete the case report form.
Patients must be over the age of 20.
Patients have clinical indications for warfarin therapy but do not have any prior warfarin treatment.

Exclusion criteria

Patients who did not complete the informed consent form or the CRF
Patients who are less than the age of 20.
Patients who had prior or is currently on warfarin treatment.
Patients who have hemorrhagic tendencies or hemorrhagic diseases defined as copious bleeding caused by viral or bacterial infections; cancer and hepatic dysfunction defined as GOP and GPT values three times higher than normal value
Patients who has Vitamin K deficiency
Female patients who is currently pregnant

Treatment and study plan

Standard of care dosing for warfarin

Behavioral

Genotype-guided dosingTaiwan algorithm for warfarin

Genetic

Genotype-guided dosing IWPC algorithm for warfarin

Genetic

Primary outcomes

Time spent in target INR range

Time frame: first month of therapy

time spent in target INR range Time in the target INR Range will be the primary endpoints because of its strong association with adverse events: patients with subtherapeutic INR values are at increased risk of thrombosis and patients with high INR values are at increased risk of hemorrhage during warfarin treatment initiation.

Sponsors and collaborators

Lead sponsor

Academia Sinica, Taiwan

Other

Collaborators

Chang Gung Memorial Hospital
China Medical University Hospital
Kaohsiung Medical University

Registry information

Important dates

Study start: 2009
Primary completion: 2013
Study completion: 2013
First posted: Feb 19, 2014
Registry last updated: Feb 19, 2014

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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