CAVEATS: Questions about study population, duration remain
This was an open-label study—neither patients nor investigators were blinded to the group assignments after randomization. The investigators suspected more recurrent VTE in those receiving rivaroxaban, which could have biased their findings in favor of the standard treatment. However, actual rates of recurrence were similar.
Study participants were <60 years old, on average, which may limit extrapolation to an older population. This trial lasted 12 months; the effects of longer treatment with rivaroxaban are unknown. Bayer HealthCare and Janssen Pharmaceuticals, who jointly manufacture rivaroxaban, funded the study.
CHALLENGES TO IMPLEMENTATION: Cost and lack of antidote may limit use
Rivaroxaban is more expensive than warfarin: A one-month supply costs approximately $260, while a month’s supply of warfarin plus lab monitoring runs less than $100.7 What’s more, factor Xa inhibitors, unlike VKAs, do not have a readily available pharmacologic antidote.
Acknowledgement
The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center for Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.
