Study of Genetic Factors Other Than CYP2C9 and VKORC1 That Influence Warfarin Dose Requirements in a South-east Asian Population

January 21, 2014 updated by: National University Hospital, Singapore
Warfarin is a commonly used anti-coagulant, but has a narrow therapeutic index and wide inter-individual and inter-ethnic variation in dose requirements. Several genetic and non-genetic factors have been identified that could influence warfarin dose requirements. However, current known predictive factors could only explain about 50-60% of warfarin dose variability. Inter-ethnic differences in genetic influences on warfarin dose requirements also exist. We hypothesize that genetic factors other than CYP2C9 and VKORC1 may influence warfarin dosing and serve to further optimize warfarin dosing.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Study Type

Observational

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Singapore
      • Singapore, Singapore, 119074
        • Recruiting
        • National University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Germline DNA will be genotyped for variants in genes in the anti-coagulation pathway, including CYP4F2, GGCX and EPHX1. The germline DNA was previously collected from a warfarin study (C/00/510, NUH, C/00/535, TTSH, PI-Dr Goh Boon Cher). Samples were anonymized, and data analysis will be done without patient identifiers. Germline DNA previously collected from 279 patients who were on maintenance warfarin dose will be genotyped.

The clinical data that has been collected and will be used for the study include: gender, race, age, body weight, maintenance warfarin dose, serum albumin, two consecutive stable INR values, and indications for warfarin use.

Description

Inclusion Criteria:

  • patients receiving maintenance warfarin therapy with a stable therapeutic international normalized ratio (INR) between 2 and 3 for at least 3 months,
  • patients recruited from the anticoagulation clinics at the National University Hospital and Tan Tock Seng Hospital in Singapore between June 2002 and June 2004 for a previous genotyping study (C/00/510, NUH; C/00/535, TTSH, PI-Dr Goh Boon Cher).

Exclusion Criteria:

  • patients below 21 years old, or
  • patients with liver disease, malabsorption or chronic diarrheal diseases, or
  • patients taking drugs that may potentially interact with warfarin.

Dietary advice to avoid foods that may interfere with warfarin pharmacokinetics will be given to patients during warfarin therapy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Blood Collection
Biological: Blood collection

What is the study measuring?

Primary Outcome Measures

Outcome Measure
To identify genetic variants other than CYP2C9 and VKORC1 that may influence warfarin dose requirements in a multi-ethnic population in Singapore.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National University Hospital, Singapore

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2013

Primary Completion (Anticipated)

December 1, 2014

Study Completion (Anticipated)

December 1, 2014

Study Registration Dates

First Submitted

January 15, 2010

First Submitted That Met QC Criteria

January 15, 2010

First Posted (Estimate)

January 18, 2010

Study Record Updates

Last Update Posted (Estimate)

January 22, 2014

Last Update Submitted That Met QC Criteria

January 21, 2014

Last Verified

January 1, 2014

More Information

Terms related to this study

Other Study ID Numbers

  • PK03/32/09

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Cancer

Clinical Trials on Blood collection

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Canada

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe