Medicare skeptical of gene-guided warfarin use

When the FDA suggested a gene test for patients given warfarin, a blood thinner, that guidance was hailed as a big step toward the long-promised, much-vaunted era of personalized medicine. By ID'ing people more likely to suffer bleeding side effects from the drug--and offering dosage guidance for those with particular gene variants--the diagnostic test might prevent costly complications and improve care at the same time.

Too bad the Centers for Medicare and Medicaid Services aren't keen on paying for it. The agency says it will finance the tests as part of clinical trials to gather evidence that they improve patient care--because so far, in its view, that evidence is lacking.

Here's the deal, as explained by the New York Times. The warfarin response tests cost $50 to $500 and highlight variations in two specific genes. Some trials have shown that having this info on genetic variation can help docs pinpoint the proper warfarin dosage. And that's important, because even small changes in dosage can have big effects, either on the not-enough-thinning side or the so-much-thinning-it's dangerous side. Thousands have to seek hospital care for warfarin complications every year.

Show us the outcomes, Medicare says. So far, there's little proof that genetic testing actually lowers the risk of blood clots or hemorrhages, the NYT reports. But personalized-medicine advocates say outcomes studies might not be cost-effective for diagnostics. Other experts agree with Medicare's assessment. The CMS decision is open for public comment for the next 30 days, so get your two cents in while you can.

Meanwhile, you might want to gear up for the next personalized-medicine debate: Over KRAS gene testing for cancer patients, now that multiple studies show that tumors with one type of the gene respond to certain oncology meds, while other tumors don't. FDA is still mulling the idea of requiring KRAS diagnostics; Euro-regulators recommend it.

- read the NYT piece [1]

Related Articles:
Gene test helps refine warfarin dosage [2]
Warfarin label to include genetic test suggestion [3] (Aug 2007)
Warfarin label change spotlights molecular diagnostics [4] (Aug 2007)
Personalized medicine advances with new genetic test [5] (Feb 2007)