A “real world” analysis of records on over 11,000 patients around the world who suffer from atrial fibrillation finds that risk of hemorrhaging and stroke associated with Xarelto (rivaroxaban) was similar or lower than what was seen during clinical trials. In a report published in the current issue of the Journal of the American College of Cardiology, lead author Dr. Paulus Kirchhhof writes,
“Overall, rivaroxaban showed a favorable safety profile, with greater than 96% of the pooled rivaroxaban population not experiencing any of the events of treatment-emergent major bleeding, stroke/non-CNS systemic embolism (SE) or all-cause death over a follow-up period of approximately one year.”
Here is the rub: the data was collected from the XANTUS program, a series of clinical trials that were funded by Xarelto maker Bayer Healthcare. Furthermore, Kirchhof, who heads the Institute of Cardiovascular Sciences at the University of Birmingham (U.K.), has received support for his research from Bayer Healthcare, among other major pharmaceutical companies.
There were also limitations on the study. Patients from the U.S. and China (outside of Hong Kong) were excluded, and patients whose records were examined had elected to participate – which might have resulted in selection bias.
The study was accompanied by an editorial by Canadian cardiologist Jeff Healey MD of McMaster University in Ontario. In his editorial, Dr. Healey notes that the age range of patients who participated and suffered from co-morbidities such as hypertension, diabetes and prior history of stroke were similar to the RE-LY Atrial Fibrillation Registry, which contains data on 15,400 patients from 46 countries who have received emergency treatment for the condition. This suggests that “…these patients are reasonably representative of the larger population of individuals with AF.”
The RE-LY study compared warfarin with Pradaxa (dabigatran), another new oral anti-coagulant (NOAC) medication manufactured by Boehringer-Ingelheim. Like Xaretlo, Pradaxa has been associated with serious, uncontrollable bleeding (an antidote for Pradaxa was approved by the FDA in 2015). And, like the XANTUS studies, RE-LY was funded by the manufacturer.
In the Disclosures section of a scientific paper that Dr. Healey co-authored in 2012 that appeared in the journal Circulation, it was noted that Healey has also received “consulting fees, lecture fees and grant support” from Bayer as well as Boehringer-Ingelheim.
Do these associations mean, and the fact that the studies in question were funded by the manufacturer mean, the results are biased? Not necessarily. Nonetheless, given Big Pharma’s track record, it would be an excellent idea for these results to be confirmed by outside, independent research. An earlier clinical trial involving Xarelto, known as ROCKET-AF, was also funded by Bayer. There have been serious questions about that study, which compared Xarelto to warfarin. Among the concerns was the use of a faulty blood meter used to measure clotting factor. these concerns led to an investigation by the British Medical Journal. In 2015, Bayer also funded a study claiming that Xarelto did not cause serious hemorrhaging.
Current lawsuits against Bayer and its partner Janssen Pharmaceuticals over Xarelto allege that the manufacturers were aware of the product’s bleeding dangers. Such allegations, as well as the pharmaceutical industry’s history of going to great lengths to preserve its profit margins, strongly suggest that any industry-funded studies of medications be confirmed by independent sources.