The newly low cost of Plavix, one of the biggest-selling drugs, is intensifying debate among cardiologists over how to make sure patients get optimal benefit from any blood-thinning medication.A generic version of Plavix became available this month so there is an incentive to switch patients to it.But, nearly a third of patients prescribed a blood thinner to prevent heart attack or stroke have a genetic variation that limits their response to Plavix. For these patients, some doctors prescribe Effient or Brilinta, two rival drugs used by far fewer patients. Although these cost more than the generic version of Plavix, they don't appear to be affected by the genetic variation. Some researchers also are studying whether increasing the dose of Plavix can overcome the genetic limitation....Tests are available to assess a patient's responsiveness to Plavix. But factors besides genetics, such as diabetes, can affect the drug's performance. And so far no study has shown that identifying poor responders and switching them to alternative therapies reduces their risk....Absent more definitive evidence, health plans are expected to steer patients away from more expensive strategies in favor of generic Plavix. "We have switching programs to help get patients to the lowest cost agent," says Steve Miller, chief medical officer of Express Scripts Inc., which manages prescriptions for 90 million Americans....More than 50 million Americans with cardiovascular disease have taken the drug since it was approved in the U.S. in 1997....Doctors expect the generic version of Plavix, called clopidogrel, will initially cost about $1 a day. That compares with the wholesale cost of $6.44 a day for brand-name Plavix and similar prices for Eli Lilly & Co.'s Effient, at $6.38 a day, and AstraZeneca PLC's Brilinta, which lists for $7.68 per day. Doctors hope the lower price for generic Plavix will encourage more patients to stay on the medicine once they start taking it....
At Brigham and Women's Hospital, in Boston, doctors are making Brilinta their preferred drug, says cardiologist Christopher Cannon. But his colleague Jessica Mega led a recent study that found tripling the dose of clopidogrel adequately blocked clotting of platelets for most patients resistant to the standard dose. Whether that translates into reduced risk of heart attacks hasn't yet been shown.Dr. [Eric] Topol and his colleagues at Scripps and doctors at Vanderbilt University offer patients genetic testing to help guide decisions on anti-platelet therapy. They also are studying whether the strategy improves care for those resistant to Plavix.
There is no question that Plavix has been a blockbuster ""blood-thinning" agent over the years. Because of its familiarity among physicians, I suspect that there would be a tendency for them to favor the Plavix generic now coming to market. However and as noted above, "nearly a third of patients prescribed a blood thinner to prevent heart attack or stroke have a genetic variation that limits their response to Plavix." Understandably, there are studies underway to determine whether tripling of the dose of clopidogrel adequately blocks platelet clotting AND reduces the incidence of future heart attacks.
Here's a quote from the deCODEhealth web site , one of the companies that offers the relevant genetic testing prior to the selection of the most appropriate drug to administer:
Analyzes five SNPs in the SNP gene that affect response to the anti-platelet drug clopidogrel. This test identifies those who may need adjustment of their clopidogrel dose or who should be put on an alternative medication to prevent recurrent adverse cardiovascular events.
To restate the obvious, the cost of the genetic testing would need to get factored into the savings realized by the use of the generic equivalent but this would be a one-time cost compared to the savings of using the generic over a lifetime. The cost differences between the generic clopidogrel and Effient and Brilinta, as noted above, are very significant.