The Rocket-AF Trial and Defective Devices
The Rocket-AF trial was a clinical trial which was used to compare two drugs used by patients with atrial fibrillation – rivaroxaban (Xarelto) and warfarin. The goal of the trial was to determine whether or not Xarelto was ‘noninferior’ to warfarin to preventing both stroke and systemic thromboembolism (obstruction of a blood vessel by a blood clot). Although the results of the trial indicated that Xarelto was, in fact, noninferior to warfarin, there have since been many issues raised with the validity of those results. The debate as to the quality of the results achieved in this trial continues to this day.
The Design of the Trial
As is the case with any kind of formal medical trial, the guidelines for Rocket-AF were laid out in great detail before the trial began. The design of the trial was to use a total of 14,264 participants. Of that group, 7,131 were to be given Xarelto, while the other 7,133 were to be prescribed warfarin. Patients from a total of 45 countries were to participate in the study, and those were enrolled during a four-year period of time from 2006-2009.
Participants had to be at least 18 years of age and they needed to be suffering from nonvalvular atrial fibrillation. There were a number of criteria which needed to be met in order for a patient to be included in the survey. A partial list of those criteria included a life expectancy of more than two years, non-pregnancy, no known HIV, no experimental drug use within 30 days, and more.
Administration of Medication
The major difference between Xarelto and warfarin is the lack of a need for laboratory monitoring when taking Xarelto. Those taking warfarin need to be monitored in order to ensure the appropriate dosage is administered – with Xarelto, that is not the case. Instead, the same dosage is taken once-daily, greatly simplifying the process. The appeal to this type of medication is obvious for the average patient, as using Xarelto could in theory be significantly more convenient than the use of warfarin.
Those in the study who were provided Xarelto were given dosages of either 20mg daily or 15mg daily, depending on their needs as assessed by a doctor. On the other hand, the group who was provided warfarin was medicated to a targeted INR value of 2-3. INR stands for international normalized ratio, which is a calculation related to the time it takes for an individual’s blood to clot. A normal INR for someone who is considered healthy is 1.1 or lower. However, for those with atrial fibrillation, a score in the range of 2-3 is often targeted. Therefore, it was the goal of this study to maintain those on warfarin within that range.
Defective Device Problems
One of the key components of this trial was the administration of the proper dose of warfarin based in INR readings. However, in the time since the trial was completed, it has come to light that some of the devices used to achieve that reading may have been defective. The device used during the trial has since been recalled, leading some to question the accuracy of the results of this trial as a whole.
In general, the defective devices used during the trial were prone to providing readings which were lower than they should have been. When that was the case, the dose of warfarin would have been increased by the doctor in order to bring the INR back up into the 2-3 range. This dose would then have been too much for the actual needs of the patient, since the defective device would have given the doctor incorrect information regarding the patient’s INR.
As the purpose of the Rocket-AF trial was to compare the performance of Xarelto to warfarin when treating those with atrial defibrillation, the possibility that warfarin was administered incorrectly could easily skew the eventual findings of the trial. Xarelto was seen to be noninferior to warfarin based on the outcome of Rocket-AF, but some are concerned that this result was reached only because of the was warfarin was incorrectly administered. If those devices were functioning properly and the INR readings led to accurate warfarin dosing, there may have been a different outcome.
The Big Picture
As a potential patient, it is important to keep the big picture in mind when thinking about the Rocket-AF trial. The defective devices which were used during the trial may not necessarily void the entire findings of the study, but they should certainly cast a degree of doubt on the confidence which can be placed in these results. Anyone trying to decide between the use of Xarelto and warfarin for treatment of their atrial fibrillation should look beyond just the results of the Rocket-AF trial in order to make their selection.
Given the ongoing lawsuits related to the side effects which can result from the use of Xarelto, it is important for all Xarelto patients to watch their health carefully while on this drug. If you or a loved one has been harmed by Xarelto, you may want to consider the possibility of taking legal action against Johnson & Johnson and Bayer, the makers of Xarelto. Thousands of suits have already been filed due to the damage that this drug has caused, and more are certain to follow. Speak with your doctor immediately if any serious side effects appear, and consider legal action if those side effects have caused damage in your life.