While Boehringer Ingeleheim Pharmaceuticals continues to work on an antidote for Pradaxa bleeding, a new round of Pradaxa lawsuits are being filed in state courts.

In May 2014, Boehringer Ingelheim agreed to pay over $650 million to settle about 4,000 such claims. The payout is expected to average $150,000 per claim. These settled claims were part of a multidistrict litigation, or MDL, that had been going on since April 2012 in federal court.

Now, the company is facing a second wave of Pradaxa lawsuits, this time in various state courts.

According to a motion filed in the MDL by the attorneys serving on the plaintiff’s steering committee, those attorneys had become aware of several other claimants waiting in the wings to file Pradaxa bleeding lawsuits in state court, and who had no interest in pursuing their claims as part of the MDL.

Judge David Herndon ruled that the new, post-settlement claimants would not be entitled to the discovery received by plaintiffs’ counsel in the MDL.

Pradaxa is also known by the generic name dabigatran. When the FDA approved it in 2010, it was the first new oral anticoagulant to enter the market in over fifty years. For those decades before, warfarin (also sold under the brand name Coumadin) was the anticoagulant of choice.

Warfarin came with drawbacks, in that it required regular blood tests and dosage adjustments to keep the level of medication just right. It also required dietary restrictions, as too much vitamin K would counteract warfarin’s anticoagulant effect.

Initial clinical studies suggested Pradaxa could make a suitable alternative to warfarin. Pradaxa appeared to be at least as effective as warfarin at preventing blood clots. Pradaxa also did not require the same ongoing blood tests or dietary restrictions that warfarin did, making Pradaxa easier to use.

Later studies, however, began to reveal a risk of Pradaxa bleeding. One study at the University of Pittsburgh examined the medical history of 9,400 men and women with atrial fibrillation; some took warfarin, others took Pradaxa.

The researchers found a higher percentage of the Pradaxa patients experienced a major bleeding event compared to the warfarin patients.

In May 2014, the FDA announced the results of a new study looking at over 134,000 Medicare patients taking either Pradaxa or warfarin. Although the Pradaxa patients did show a lower risk of clot-related strokes, they also showed a higher risk of major gastrointestinal bleeding as compared to the warfarin patients.

Despite Pradaxa’s advantages over warfarin, it also has one significant drawback: while excessive warfarin bleeding can be slowed by administering vitamin K, there is no such reversal agent on the market that can control Pradaxa bleeding. Boehringer Ingelheim is currently seeking approval for the drug idarucizumab, which trials show may make a suitable Pradaxa antidote.

The elevated risk of major bleeding events associated with Pradaxa has already been the subject of thousands of Pradaxa lawsuits.

Plaintiffs alleged that Boehringer Ingelheim failed to properly address the risk of Pradaxa bleeding by, for example, investigating more potential antidotes or by not withholding Pradaxa from the market until a safe and effective antidote is found.