Warfarin pharmacogenetics a waiting game

Like Miller Lite in a Munich beer garden, pharmacogenetic testing to guide initial warfarin dosing is a tough sell. Who wants to persuade unwilling customers to pay for an unproven, unreimbursed test that even the experts pass up?

But if few are clamoring to use PGx for warfarin dosing, no one is placing it on the dustheap, either. The potential rewards are too enticing. That’s why even one of the more discouraged-sounding leaders in the field—say hello to Alan Wu, PhD—refuses to give up. “I always want to have the subject in the limelight, so we can have a discussion on it. If there’s no discussion, that means it’s dead. And I don’t think that’s the case,” says Dr. Wu, professor, laboratory medicine, University of California, San Francisco, and laboratory director, Clinical Chemistry Laboratory, San Francisco General Hospital.

Still, Dr. Wu can be forgiven for sounding blue. No professional groups have endorsed genotype testing for warfarin. Reimbursement discussions are virtually nonexistent. That, in turn, has squeezed vendors—in recent years, the number of companies that provide reagents and platforms for warfarin pharmacogenetic testing has dropped by half, to two.

Even at his own institution, Dr. Wu has been less than persuasive. Despite SFGH’s participation in promising studies, his clinical colleagues remain skeptical. “It’s been a disappointment for me,” he says. “I continue to write, continue to do studies, and hope that eventually we’ll see utilization. But right now, it’s not happening.

“We’ve tried everything,” he continues. “We’ve tried the educational route; we tried doing research studies with them; we tried to offer testing at reduced prices. And it just hasn’t come. It’s been frustrating.” [more]