Applying Pharmacogenetic Algorithms to Individualize Dosing of Warfarin

Completed · Phase 2/Phase 3

Conditions studied: Thromboembolism

In brief

The purpose of this study is to determine whether DNA analysis improves the efficiency of dosing and safety in patients who are being started on warfarin therapy.Warfarin, a blood thinner (anticoagulant) prescribed to 1-2 million patients in the United States, is a leading cause of drug-related adverse events (e.g., severe bleeding), in large part due to dramatic (20-fold) differences between individuals in dose requirements. At least half of this variability now can be explained by 3 common genetic variants, age, body size, and sex; however, warfarin therapy continues to begin with the same dose in every patient with the correct individual dose determined by trial and error. This study proposes to determine genetic variations the same day from DNA simply obtained by swabbing the inside of the cheek and use this information to determine the proper dose regimen individually in each patient. The aim is to show that the investigators can achieve more rapid, efficient, and safe dosing in up to 500-1000 individuals who are initiating warfarin therapy for various clotting disorders across a large healthcare system in order to demonstrate improved dosing effectiveness, efficiency, and safety with genetic-based dosing, which could lead to a nationwide application resulting in as much as a $1 billion dollar annual benefit in healthcare outcomes.

Key facts

Study ID

NCT00927862

Run by

Intermountain Health Care, Inc.

People needed

2415

Starts

2008-08-01

Expected to finish

2011-06-01

Last updated by the study team

2012-09-25

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• New participants will be those >=18 years old who are appropriate candidates for and being initiated on warfarin therapy with target international normalized prothrombin time ratio (INR) range of either 2-3 or 2.5-3.5 and with intent to be treated for at least 1 month and willing to sign informed consent.
• Those with target INR 2.5-3.5 may be enrolled with dose adjustment for this higher target per Gage et-al. (i.e., 11% increase in dose).
• Dose modification also will be made for amiodarone based on prior, published experience (i.e., 22% decrease in dose).

You may not qualify if…

• Those not appropriate for warfarin (e.g., pregnancy) or for pharmacogenetic (PG)-guided dosing for any reason,
• Those having received rifampin within 3 weeks,
• Those with severe co-morbidities (e.g., creatinine > 2.5,hepatic insufficiency, active malignancy, advanced physiological age, noncompliance risk, expected survival <6 months), and
• Physician or patient preference.

Where it is running

• Intermountain Healthcare Hospitals and Clinics — Salt Lake City, Utah, United States

Full record on ClinicalTrials.gov

Trial information comes from ClinicalTrials.gov and is refreshed daily. TrialsForMe does not provide medical care and does not run the studies it lists.