Potential Reversal Agent For Xarelto Submitted For FDA Approval

Portola Pharmaceuticals
, a small company which was founded in 2003 in California, is in the process of performing clinical trials involving a potential reversal agent for the blood thinner, Xarelto.

In November of 2015, it was announced that phase 3 of the clinical trials, in which the drug andexanet alfa or a placebo was given to a group of healthy volunteers, the drug showed an immediate and almost complete reversal of the effects of Xarelto. The company has now moved on to phase 4, in which the drug is being administered to patients who have taken the blood thinners apixaban, rivaroxaban, edoxaban, and enoxaparin. In light of their success, the company filed for an Accelerated Approval Biologics License, which would allow them to market the product to the medical community and the public. 

The FDA has already given the drug the designated title of “Breakthrough Therapy”. According to the administration, a “breakthrough therapy is a drug:

  • intended alone or in combination with one or more other drugs to treat a serious or life-threatening disease or condition and
  • preliminary clinical evidence indicates the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development.”

If this classification is given, the administration has promised to assist in expediting the development and the review of the drug.

Many of the plaintiffs involved in the more than 5000 Xarelto lawsuits filed against drug manufacturers Janssen Pharmaceuticals and Bayer, Inc., have mixed emotions about the development of this drug. On one hand, they are thrilled that someone is working to develop an antidote for an otherwise antidote-less drug – a development that may save thousands of lives. On the other hand, many of the plaintiffs have voiced concerns about the FDA approval process in the past and they believe that rushing that process may lead to oversights.

Xarelto Lawsuits

Lawsuits filed by plaintiffs from all across the country over the last several years allege that the drug Xarelto caused serious harm or death in a patient due to the drug’s side effects. So many complaints have been filed that the Judicial Panel on Multidistrict Litigation consolidated the federally-filed complaints into MDL 2592.

Many agree that the most dangerous aspect of the drug is the fact that, until now, there has been no known antidote for the drug. This means that once the anticlotting process begins, there is no way for doctors to stop it, even if a patient begins to bleed excessively and is in danger of exsanguinating. When other, older, blood thinners are used, doctors can administer Vitamin K to reverse the anticlotting properties. With Xarelto, the patient must be given a blood transfusion – a treatment that all too often isn’t successful.

In addition to not having an antidote, the drug increases the risk of a patient suffering from:

  • stroke
  • brain hemorrhage
  • spinal bleeding
  • pulmonary embolism
  • GI bleeds

Many believe that more could have been done to prevent these risks and side effects from hurting patients.

Potential Issues With Xarelto’s FDA Approval

Xarelto was given it’s FDA approval in 2011 after going through several clinical trial phases. Recently, however, both the FDA and the plaintiffs involved in the ongoing litigation have questioned whether or not the data from those trials were accurate or not. The reason questions are being raised is that the international normalised ratio (INR) device used in the trials has been recalled.

It has been determined that when used in the clinical trials that compared Warfarin to Xarelto, it is possible that the device may have skewed the readings on the Warfarin leading to results that made the older blood thinner look like it was not as effective or as safe as Xarelto. An editor working for the BMJ reported that “A falsely low reading could mean that patients had their Warfarin dose unnecessarily increased, leading to a greater risk of bleeding.


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