Vanderbilt has added genetic screening for the drug tacrolimus to its personalize medicine pharmacogenomics program PREDICT. The new drug screening protocol was added following data that shows a single genetic variation largely impacts different dose requirements for patients.
Tacrolimus is one of the most commonly prescribed drugs for organ transplant recipients and is essential for patients receiving new hearts, kidneys and other organ transplants because the drug suppresses the body's immune system to prevent organ rejection. The drug however can have potentially harmful side effects if not used in precise amounts. Genetic testing through PREDICT offers important benefits to Vanderbilt's patients due to the variance in individuals' requirements for how much tacrolimus is needed to prevent organ rejection.
PREDICT provides Vanderbilt's patients a personalized pharmacologic profile tailored to each patient.
Marketed as Prograf, tacrolimus has a narrow therapeutic window. If too little of the drug is used acute transplant rejection may occur. Too much can cause serious side effects, including a form of diabetes and squamous cell skin cancer.
"This is an example of a striking variation in genetics by ancestry," said Dan Roden, M.D., assistant vice chancellor for Personalized Medicine. For example, African Americans are more likely to require higher doses of tacrolimus.
More than 2,800 Vanderbilt patients have been found to carry this genetic variation and more than 600 of them are adults who have received or are awaiting heart or kidney transplants.
This information is now included routinely in the electronic health record. Doctors who prescribe tacrolimus receive notifications that they may need to adjust the dose if their patients carry the genetic variation.
Tacrolimus is the fifth drug for which pharmacogenomic information is included in the patient's electronic health record at Vanderbilt. The other drugs are the anti-platelet drug clopidogrel (Plavix), the anti-coagulant warfarin, the cholesterol-lowering drug simvastatin (Zocor), and thiopurine therapies, which are used to treat certain cancers and autoimmune disorders.
Since it was launched in August 2010, PREDICT has genotyped more than 14,000 Vanderbilt patients for 184 different genetic variations that affect the body's response to various drugs.
More than 12,000 of the patients, 88 percent, have genetic variations that increase their risk of adverse effects from one or more of the five drugs currently included in the electronic health record, said Julie Field, Ph.D., PREDICT project manager.
As the value of genetic testing becomes established for other drugs, this information will be added, Field said.
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