Just before the end of 2012, German pharmaceutical firm Boehringer-Ingelheim got even more bad news about its flagship product, Pradaxa (dabigatran). On 19 December, the U.S. Food and Drug Administration (FDA) issued a warning against using the drug for patients with mechanical heart valves. A drug study in Europe had to be stopped when it was found that patients who had been fitted with mechanical prosthetic heart valves were at greater risk of forming clots and experiencing dangerous hemorrhages. The safety announcement went on to warn against the use of Pradaxa in patients with a type of artificial heart valve known as biologic heart valves – which are created from natural tissue, stating that such use of the drug “has not been evaluated and cannot be recommended.”
In the wake of this news, Australia's Pharmaceutical Benefits Advisory Committee (PBAC) is now reconsidering an earlier decision recommending that the country's government health service cover the cost of the drug for patients.
Still, everyone seems willing to bend over backwards to help BI. The PBAC has invited BI to submit new data on the drug; earlier in November, the FDA went through insurance records going back over four years with a fine-toothed comb in order to demonstrated that “rates of gastrointestinal or intracranial bleeding were no more prevalent” for Pradaxa patients than for those taking Coumadin (warfarin). Naturally, BI's own data came to the same conclusion.
At the same time, physicians who otherwise appreciate Pradaxa because of its relative lack of side effects are still expressing concern over the lack of an antidote. Part of the problem is that cardiologists may be prescribing Pradaxa to patients with reduced kidney function. BI recommends that patients have their kidneys tested before having Pradaxa prescribed for them. The reason is that Pradaxa leaves the bloodstream through the kidneys (this is why emergency dialysis is usually the only treatment for patients who suffer hemorrhaging). One potential problem here is that Pradaxa is usually prescribed by cardiologists and general practitioners – who may not be aware that a patient may have kidney problems. (In light of the fact that BI does recommend tests for kidney function, this brings up the issue of physician liability.)
Dr. Mark Mosely, who runs the emergency room at Wesley Medical Center in Wichita, Kansas, told the New York Times that he nonetheless found it “shocking” the the FDA approved Pradaxa when there was clearly no antidote for excessive bleeding.
The FDA continues to defend Pradaxa; it is unlikely that the private, profit-driven U.S. health care system will issue any strong warnings when there are billions of dollars at stake. The Australian government on the other hand has no such motivation other than watching out for the health of its citizens.
N/A. “FDA Drug Safety Communication: Pradaxa (dabigatran etexilate mesylate) Should Not Be Used in Patients With Mechanical Prosthetic Heart Valves.” Available at http://www.fda.gov/Drugs/DrugSafety/ucm332912.htm.
Palmer, Eric. “Long-Term Study Reinforces Safety Record of Blockbuster Pradaxa.” Fierce Pharma, 7 November 2012. Available at http://www.fiercepharma.com/story/long-term-study-reinforces-safety-record-blockbuster-pradaxa/2012-11-07.
Taylor, Lynn. “Australia: Warning Over Pradaxa PBS Listing.” Pharma Times Online. Available at http://www.pharmatimes.com/Article/12-12-20/Australia_warning_over_Pradaxa_PBS_listing.aspx
Thomas, Katie. “A Promising Drug With a Flaw.” New York Times, 2 November 2012.