Great Job Mike! 2C19 meets the grade!

I was flipping through the internal medicine news yesterday when I saw a colleague. Mike Murray, Clinical Chief up at the Brigham who had given me some good advice re: being a fellow and academia......

He and a couple other internal medicine geneticists write a column called "Genetics in Your Practice"

Which is a welcome addition to what my wife and I (Both Internists) believe is one of the best print publications out there for keeping ahead of the curve with IM and subspecialties....

Well,
Mike wrote about Plavix, which, as you know, I have been all over since the studies came out in January showing significant differences in outcomes clinically with patients who cannot activate Plavix. Why was I all over it? Because it had met some criteria which I think will define what a good PGx test is......

I have as of yet failed to detail precisely what these criteria are.....It just so happens, Mike did a brilliant job of it.....So without further ado. Dr. Mike Murray, Internists, ID specialist AND geneticist defining the criteria....

From Internal Medicine News

So, what will bring a breakthrough application in pharmacogenetics? I believe that a true breakthrough into the mainstream will occur when the gene-drug pair has many or all of these characteristics:

▸ A widely used drug. There are currently some excellent examples of gene-drug pairs as models for the clinical application of pharmacogenetics; however, they happen to be with drugs used by only a small number of subspecialists. A true breakthrough application will need to be a widely used medication.

▸ An “essential” drug. Although we may eventually get to pharmacogenetics testing for almost all medications, a true breakthrough application will not be for a drug for which the application is usually elective (e.g., onychomycosis therapy) or for a drug that has equivalent substitutes inside or outside of the class (e.g., a diuretic for hypertension).

▸ Potentially severe consequences from use of the drug without pharmacogenetics guidance. The motivation for using a pharmacogenetics approach is mainly safety or efficacy. The breakthrough application will need to help the prescriber avoid morbidity or mortality associated with side effects or ineffective treatment.

▸ A narrow therapeutic window. Aminoglycoside antibiotics are classic examples of drugs with a narrow therapeutic window, where underdosing can lead to disease progression and overdosing can cause adverse effects.

▸ Pharmacoeconomic advantage. The application of new technology to guide gene-drug decision making will be more attractive for clinical uptake in instances where it offers cost savings.

▸ Straightforward genetic interpretation. Much of current genetic testing deals with complex interpretations of sequence data where variants unique to the individual patient have to be judged as causative, noncausative, or of unknown significance. In 2009 the most straightforward diagnostic genetic testing is based on screening for common variants that confer increased relative risk.

▸ Validated significance of gene-drug pair. There will always be varied levels of confidence in any data set; however, replication of significant correlation in more than one large, well-designed study will be the most likely to be associated with rapid clinical uptake.

This is precisely what Plavix is......And it is precisely why it will lead personalized medicine this year.......Not genome scans, not whole genomes, Plavix pharmacogenomics...... Mike, yet again, you have crystallized criteria which I often find nebulous......

The Sherpa Says: If we judge all tests by this criteria we would be better off.......Imagine how many less tests would be ordered. Bad for business, great for medicine......