Japan asks Boehringer to warn docs on Pradaxa

One anticipated risk of Boehringer Ingelheim's new blood thinner Pradaxa has led to an unexpected warning. Japanese regulators have asked the German company to notify doctors about potentially deadly bleeding in some Pradaxa patients, Reuters reports. Doctors need to be warned not only about the bleeding risks with the drug--marketed as Prazaxa in that country--but also that there's no antidote to counteract bleeding if it starts, the regulators said.

With warfarin, the old drug Pradaxa seeks to replace, bleeding can be quickly treated with vitamin K. Neither Pradaxa nor any of the others in a new class of warfarin alternatives has a similar antidote. This new generation of drugs includes Xarelto, marketed by Bayer and Johnson & Johnson ($JNJ); Eliquis, the Bristol-Myers Squibb ($BMY)/Pfizer ($PFE) med that's awaiting U.S. approval; and Daiichi Sankyo's Lixiana.

The lack of an antidote isn't a surprise. Nor is the bleeding risk with Pradaxa; it's clearly stated on the drug's label. The rate of serious bleeding with Pradaxa was 3.3% per year, Boehringer's fact sheet states, compared with 3.6% with warfarin; the rate of GI bleeding was higher with Pradaxa, however, at 1.6%, compared with 1.1% in warfarin patients. Most of the Japanese patients who developed problems had bleeding in their GI tracts. And just because the stats are listed doesn't mean that all doctors are up-to-date on the risks.

Japanese officials suggest that patients older than 70 may need a lower dose of Pradaxa. Currently, the 110-mg dose is recommended for patients 80 and older. Boehringer says it's cooperating with the government on the warning, Reuters says, and that it's in the company's best interest to have the medicine prescribed within the recommended guidelines.

- read the Reuters news