Most would reserve rivaroxaban as second-line therapy for patients with chronic atrial fibrillation

February 1, 2012

Respondents to a Formulary readers' poll would reserve the use of newly approved rivaroxaban (Xarelto, Janssen) for the management of chronic atrial fibrillation (AF) to those patients who have contraindications to warfarin, had unmanageable side effects to warfarin, or in whom warfarin was ineffective.

Some 57% of the poll respondents would reserve rivaroxaban to the above circumstances, while only 8% would use it as first-line therapy in all patients to prevent stroke in patients with chronic AF. Twenty-one percent indicated that they would leave the use of rivaroxaban entirely up to the discretion of the clinician based upon individual patient circumstances.

Readers' reluctance to use warfarin as first-line therapy in all patients is prudent, said Ruth Ann C. Opdycke, PharmD, MS, president at TPG Healthcare Consulting LLC. "Most new therapies are approved based on very controlled clinical trials. Consequently, we don't really understand the full ramifications of their use in the general population until they've been approved and out for general use," she said.

Because rivaroxaban was shown to be noninferior but not superior to warfarin, reserving rivaroxaban for second-line use makes sense, said Leslie A. Vitin, PharmD, assistant clinical professor in pharmacy practice, Northeastern University-Bouve College of Health Sciences, Boston.

Both warfarin and rivaroxaban carry a risk of bleeding, Dr Vitin said, but clinicians are familiar with the need for regular monitoring of the International Normalized Ratio (INR) with warfarin. Patients can derive other benefits from coming into a clinic for regular monitoring of their INR, argued Dr Opdycke, including more frequent outcomes assessment.

With rivaroxaban proven to be noninferior to warfarin for stroke prevention in chronic AF in a pivotal phase 3 trial, the needs of the patient should be considered in the choice of anticoagulant as first-line therapy for this indication, said C. Michael White, PharmD, professor of pharmacy, University of Connecticut, and director of the Evidence-Based Practice Center at the University of Connecticut/Hartford Hospital. "Too often the patient is left out of the equation," he said.

Rivaroxaban would have an edge for patients in whom compliance is an issue, said Dr White. This patient might include an older individual who lacks an adequate support system and who would have difficulty traveling to a clinic for regular monitoring.

An increased rate of stroke was observed in patients who had stopped taking rivaroxaban for 28 days, which leads to the question, "what if a patient who is nonadherent to warfarin is nonadherent to rivaroxaban and decides to go off of it for 7 days or 10 days; do we see that potentially increased risk of stroke as well?" said Dr Vitin.

A final consideration is that rivaroxaban is irreversible, said Drs White and Vitin.