Leading Cardiologists Say It’s Time to Rethink Genetic Testing for CYP2C19 and Plavix
“The thing that hit me in the face, was that virtually all the events were in those homozygotes”
- Dr. C. Michael Gibson, Duke University
Dr. Gibson and Dr. Kirtane from Duke University reconsider genetic testing for CYP2C19 based on the GIFT sub-study of GRAVITAS presented last week at ACC. The study clearly showed that poor metabolizers (CYP2C19 *2 homozygotes) were at high risk of treatment failure and that dose adjustment showed response improvement in heterozygotes.
Dr. C. Michael Gibson: I was not one that defended the FDA’s decision about genetic testing and recommendations, but now, you know, you kind of wonder, should you be doing some testing to identify these (2C19) homozygotes?
Dr Ajay Kirtane: I was completely in same camp as you were at that time and it seemed that it was premature to release a statement like that, but after assessing this and realizing that…I’m wondering if maybe we should spend more effort trying to find these non responders for the homozygous gene.
See their six minute video here: http://www.vimeo.com/22008430
See details of the study at: http://www.theheart.org/article/1208199.do
Odds ratio (95% CI) for platelet reactivity above 230 PRU at 30 days according to CYP2C19*2 carrier status
| Group | Clopidogrel 150 mg | Clopidogrel 75 mg |
| No loss-of-function allele | 1.0 | 1.0 |
| 1 loss-of-function allele | 1.62 (0.93-2.85) | 2.67 (1.48-4.82) |
| 2 loss-of-function alleles | 11.20 (2.02-62.09) | 10.55 (1.19-93.57) |
Adjusted hazard ratios for CV death, MI, or stent thrombosis according to CYP2C19 genotype
| Group | HR (95% CI) |
| No loss-of-function allele | 1.0 |
| 1 loss-of-function allele | 1.07 (0.91-1.25) |
| 2 loss-of-function alleles | 1.67 (1.09-2.56) |
If you’ve been sitting on the fence regarding whether to implement this simple genetic test please take a moment to consider this month’s GIFT findings, the JAMA Mega meta-analysis from Oct 2010 and the FDA black box warning from March 2010.
Call Genelex today at 800-837-8362 x 2851 to order our simple buccal swab or blood test kits. Testing is covered 70% of the time in full by private insurance. Medicare covers Plavix testing 100%. It’s our goal to help ensure safe and accurate prescribing through actionable science.