Rivaroxaban (Xarelto) for stroke prevention in non-valvular atrial fibrillation

• Rivaroxaban is a direct factor Xa inhibitor oral anticoagulant
  Rivaroxaban taken once daily has demonstrated efficacy in stroke prevention in people with non-valvular atrial fibrillation (NVAF).
• Rivaroxaban was non-inferior to warfarin for stroke reduction in NVAF
  In clinical trials, rivaroxaban efficacy was superior to that of warfarin in the safety-on-treatment population but not the intention-to-treat population and with a similar incidence of major bleeding.
• People well controlled by warfarin will probably not benefit from changing to rivaroxaban
  There is no clinical advantage in changing from warfarin for people who are well controlled (time in therapeutic range [INR 2.0–3.0] ≥ 60%). However, people who are not well controlled on warfarin may benefit from rivaroxaban.
• Coagulation monitoring is not required; however, there is no antidote for rivaroxaban-induced bleeding
  Advise patients to seek urgent medical attention for unexplained bruising, blood in the urine or black stools.
• Be cautious when switching between warfarin and rivaroxaban
  There is limited evidence on switching from or to other anticoagulants. Consult the product information.
• Rivaroxaban is contraindicated in people with NVAF with either significant hepatic disease with an increased INR, or severe renal impairment
  Do not use in people with hepatic disease (Child–Pugh grade B or C) who also have coagulopathy-associated bleeding risk, or in people with severe renal impairment (creatinine clearance [CrCl] < 30 mL/min).

What is known about this drug

Rivaroxaban is an oral anticoagulant that inhibits factor Xa.

Rivaroxaban 20 mg once daily (or 15 mg once daily in people with moderate renal impairment, [creatinine clearance 30–49 mL/min]) is non-inferior to warfarin in preventing stroke or systemic embolic events (1.7% vs 2.2% of events per year; hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.66 to 0.96, p < 0.001).¹

Rivaroxaban is non-inferior to warfarin with respect to any major bleeding (5.6% vs 5.4%; HR 1.04, 95% CI 0.90 to 1.20, p = 0.576).¹ There were significantly fewer intracranial haemorrhages with rivaroxaban (absolute risk reduction 0.2% per year) but gastrointestinal bleeding was significantly more common (absolute risk increase 1.0% per year).¹

Areas of uncertainty

There have been no head-to-head studies of rivaroxaban with other newer oral anticoagulants.

Safety data are currently limited to < 2 years' follow-up.¹

The benefits of rivaroxaban for people with low risk of stroke and those well-controlled on warfarin have not been demonstrated.¹

There is no validated antidote available for rivaroxaban and experience of switching between anticoagulants is limited.^{1, 2}

There are no data regarding the use of rivaroxaban in people already known to be unsuitable for warfarin therapy. The safety of rivaroxaban has not been established in people at high risk of bleeding as these people were excluded from the pivotal randomised clinical trial.²

What does NPS MedicineWise say?

There is no evidence to show that people with an INR consistently in the therapeutic range (2.0–3.0) will benefit clinically from a switch to rivaroxaban.

Rivaroxaban is an alternative to consider for people at risk of stroke and who, for reasons other than poor compliance, cannot be suitably controlled on warfarin (i.e. unable to maintain INR consistently within the therapeutic range).

People with a history of poor compliance may be unsuitable for rivaroxaban due to its short half-life, resulting in increased risk of stroke if doses are missed. In these circumstances, warfarin remains preferable, as it has a longer half-life and compliance can be monitored.

Rivaroxaban may be an option for people:

• who are compliant with warfarin but who have difficulty in maintaining INR in the therapeutic range
• who experience drug or major drug–food interactions with warfarin
• with poor venous access for INR monitoring and for whom point of care testing is not possible
• for whom regular INR monitoring is impractical.

Authority required (Streamlined)
Prevention of stroke or systemic embolism

The patient must have non-valvular atrial fibrillation and one or more of the following risk factors for developing stroke or systemic ischaemic embolism:

• prior stroke (ischaemic or unknown type), transient ischaemic attack or non-central nervous system (CNS) systemic embolism
• age 75 years or older
• hypertension
• diabetes mellitus
• heart failure and/or left ventricular ejection fraction 35% or less.³

May be prescribed by nurse practitioners (shared care model)

Authorised nurse practitioners may prescribe this medicine when care of a patient is shared between a nurse practitioner and medical practitioner in a formalised arrangement with an agreed management plan. See the PBS website for more information on nurse practitioner PBS prescribing.

Rivaroxaban is an oral direct factor Xa inhibitor that is taken once daily for stroke prevention in non-valvular atrial fibrillation (NVAF). Rivaroxaban has a short half-life (5–13 hours, depending on age) with peak concentration attained 2–4 hours after dosing.⁴ Rivaroxaban has a dual mode of elimination — one-third of the active drug is eliminated unchanged in the urine and two-thirds are metabolised by the liver.⁵

Rivaroxaban is PBS listed for preventing stroke or systemic embolism in patients with NVAF and one or more risk factors for developing stroke or systemic embolism (see 'PBS listing' section). Rivaroxaban is also PBS listed for:

• prevention of venous thromboembolism after hip or knee replacement surgery [see the August 2009 NPS RADAR review ‘Rivaroxaban (Xarelto) for preventing venous thromboembolism after hip or knee replacement surgery’]
• treatment of acute symptomatic deep vein thrombosis, acute symptomatic pulmonary embolism and for the prevention of venous thromboembolism recurrence in people with a history of venous thromboembolism.

People with NVAF who are at increased risk of stroke, and in whom warfarin is otherwise contraindicated, may benefit from the use of an oral anticoagulant such as rivaroxaban. However, there are no data regarding the use of rivaroxaban in people already known to be unsuitable for warfarin therapy. While warfarin has been the mainstay therapy for stroke prevention in NVAF, several studies have indicated suboptimal usage, with many patients identified with low time in the therapeutic range (TTR).^6–8

Determine the need for anticoagulation

Guidelines recommend the CHADS₂ (or the CHA₂DS₂-VASc) thromboembolic risk scoring system to assist in the decision whether to initiate an oral anticoagulant.⁹ The CHADS₂ score rates risk from 0 to 6, with ≥ 1 indicating the requirement for an oral anticoagulant. The more predictive CHA₂DS₂-VASc score ranges from 0 to 9, with a score of ≥ 2 for females aged <65 years or ≥ 1 for males regarded as an indication for long-term oral anticoagulation.¹⁰ View more information about the CHADS₂ schema.

The requirement for anticoagulation should always be balanced against risk of bleeding. A recently derived scoring schema for predicting the bleeding risk in people with NVAF (HAS-BLED, [hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly, drugs/alcohol concomitantly]) may also be a useful assessment tool.^11,12

The current Australian Therapeutic Guidelines recommends either warfarin or dabigatran for people with NVAF and at least one other risk factor for stroke.⁹ The Australian Medicines Handbook states that either warfarin, dabigatran or rivaroxaban for people with NVAF and at least one other risk factor for stroke.¹³ International guidelines such as the Canadian Agency for Drugs and Technologies in Health, the National Institute for Health and Clinical Excellence (UK) and the American College of Chest Physicians also provide recommendations for use of the various newer anticoagulants.^14–16

Review current anticoagulant control when considering rivaroxaban for people with NVAF

Rivaroxaban is an option alongside warfarin, dabigatran or apixaban for people with NVAF and at risk of stroke. People on warfarin with INR consistently within the TTR (INR 2.0–3.0, TTR >60%) will probably not benefit clinically from a switch to rivaroxaban.^3,14,15,17

Consider rivaroxaban for people who are unable to take warfarin because of either:

• drug interactions
• inability to maintain dietary restrictions
• poor venous access for INR monitoring
• difficulty with regular INR monitoring.

Rivaroxaban may be suitable for people with AF who do not have prosthetic heart valves or significant valvular disease, who are at increased risk of stroke and for whom warfarin is unsuitable or who cannot achieve a stable INR with warfarin.

Warfarin, rivaroxaban, dabigatran and apixaban are all PBS listed for the prevention of stroke and systemic embolism in people with NVAF and at least one other risk factor for stroke (see also Medicinewise News: Good anticoagulant practice).

The efficacy of rivaroxaban for reducing incidence of combined stroke and systemic embolism in patients with NVAF and a moderate to high risk of stroke (CHADS₂ score of ≥ 2) was compared with that of dose-adjusted warfarin in a double-blind, double-dummy randomised controlled trial (ROCKET-AF, 1.9 years, n = 14,264).¹

Rivaroxaban non-inferior to warfarin in reducing stroke and systemic embolism

In the ROCKET-AF trial, rivaroxaban was non-inferior (pre-specified margin of 1.46) to dose-adjusted warfarin in patients with NVAF and a moderate to high risk of stroke (CHADS₂ score ≥ 2) in both the intention-to-treat population (all patients who underwent randomisation and were followed for events during treatment or after premature discontinuation) and the per-protocol population (all patients who received at least one dose of a study drug, did not have a major protocol violation and were followed for events occurring during the study or within 2 days after discontinuation).

The superiority analysis was performed using the safety-on-treatment population (all patients who received at least one dose of a study drug, regardless of adherence to protocol and were followed for events while on study or within 2 days after discontinuation).^1,2 The efficacy of rivaroxaban was only superior to that of dose-adjusted warfarin using the safety-on-treatment population but not when analysed using the intention-to-treat population (Table 1).¹

Table 1.
Rates of stroke or systemic emboli per year in ROCKET-AF^1,2,18

* All patients who received at least one dose of a study drug, did not have a major protocol violation and were followed for events during the study or within 2 days after discontinuation

† All patients who underwent randomisation and were followed for events during treatment or after premature discontinuation

‡ All patients who received at least one dose of a study drug, regardless of adherence to protocol and were followed for events during the study or within 2 days after discontinuation

Similar results were reported in the Japanese trial of rivaroxaban (J-ROCKET-AF), in which rivaroxaban was demonstrated to be non-inferior to warfarin.¹⁹

Subset analyses from the ROCKET-AF study indicated the relative efficacy and safety results were consistent in patients with or without previous stroke or transient ischaemic attack.²⁰

People with well-controlled INR on warfarin will probably not benefit clinically from switching to rivaroxaban

Carefully assess people whose INR is stable within the therapeutic range (INR 2.0–3.0) before switching to rivaroxaban. Data from the ROCKET-AF trial indicate that rivaroxaban was non-inferior to warfarin irrespective of the time the participants' INR remained within therapeutic range.² However, in a subgroup analysis of event rates in patients whose TTR was above the clinical trial median (57.8%), rivaroxaban did not meet the definition of non-inferiority.³ Similarly, a centre-based subgroup analysis of time below therapeutic range indicated that at sites where control of INR was very good, treatment with rivaroxaban was not as effective as treatment with warfarin.²¹ This is also reflected in current international guidelines, and a switch in therapy for people who are currently well controlled by warfarin will probably not be justified on clinical grounds.^14,15

No head-to-head trials of rivaroxaban versus dabigatran

Dabigatran, a direct thrombin (factor IIa) inhibitor, received a positive PBAC recommendation for PBS listing for stroke prevention in NVAF based on the results of the global dabigatran/warfarin-controlled RE-LY trial.²² Dabigatran was PBS listed for this indication in September 2013 — for additional information on dabigatran see the NPS RADAR review Dabigatran (Pradaxa) for stroke prevention in patients with non-valvular atrial fibrillation and the Australian Prescriber article 'New oral anticoagulant drugs – mechanisms of action'.

Several indirect comparative studies have been reported but interpretation of these data is problematic due to differences in study design between the two pivotal clinical trials.^23–27. The ROCKET-AF trial was a double-blind, double-dummy, randomised controlled trial whereas the RE-LY trial was an open-label, randomised controlled trial.^1,22 In addition, 50.4% of participants in the RE-LY trial were warfarin naïve whereas only 37.5% of ROCKET-AF trial participants were warfarin naïve. The mean CHADS₂ score of ROCKET-AF trial participants was 3.5, reflected also in the 54.9% of participants who had previous stroke, while in the RE-LY trial, participants had a mean CHADS₂ score of 2.1 and 20.3% of trial participants had a previous history of stroke.^1,22

Differing definitions of bleeding and the use of different exclusion criteria that prevented patients with certain comorbidities from entering the study, but which may be present in people presenting in routine clinical practice, are also of concern.^1,22 The higher average risk of stroke (mean CHADS₂ score = 3.5) and the lower TTR observed in ROCKET-AF trial participants may not necessarily reflect the Australian population and a patient's current INR must be taken into account when assessing the benefits of new treatments.²⁸

The requirement for anticoagulation should always be balanced against risk of bleeding. As with warfarin, bleeding is the greatest safety concern with rivaroxaban. However, unlike the situation with warfarin, there is no validated test for measuring coagulation levels and there is currently no validated antidote to the effects of rivaroxaban. Avoid rivaroxaban in people who have clinically significant active bleeding (e.g. intracranial bleeding, gastrointestinal bleeding) or who have increased risk of clinically significant bleeding such as venous ulcers or intraocular lesions.

Report suspected adverse reactions to the TGA online or by using the 'Blue Card' distributed once a year with Australian Prescriber. For information about reporting adverse reactions, see the TGA website.

Reduced intracranial bleeding but more GI bleeding, epistaxis and haematuria

In the ROCKET-AF study the incidence of major and clinically relevant non-major bleeding was similar with rivaroxaban and dose-adjusted warfarin (Table 2).^1,2 There were significantly fewer intracranial bleeds (absolute risk reduction 0.2% per year) but gastrointestinal bleeding was significantly more common (absolute risk increase 1.0% per year).^1,2

Epistaxis and haematuria also occurred more frequently in the rivaroxaban arm (both p < 0.05).¹

Table 2.
Rates of bleeding per year in the ROCKET-AF safety-on-treatment population*^1,2

‡ Excludes 20 patients in the rivaroxaban arm and eight patients in the warfarin arm who did not take the first study dose

§ NNT/NNH is based on events reported in the trial population over the duration of the clinical trial (1.9 years)

No coagulation monitoring test is available for rivaroxaban

Unlike the case with warfarin, INR is not predictive of the effects of rivaroxaban; INR results may be increased while a person is on rivaroxaban.²⁹ There are no reliable tests available to monitor anticoagulant effect or patient compliance for rivaroxaban. Prothrombin time is not a reliable test for determining either therapeutic or adverse effects of rivaroxaban.

Caution required when switching from warfarin to rivaroxaban

Stop warfarin, monitor INR and start rivaroxaban once INR is ≤ 3.0. Refer to the rivaroxaban product information for guidance when switching people with NVAF from warfarin to rivaroxaban.⁴

Switching from rivaroxaban to warfarin and other oral anticoagulants

Discontinuing rivaroxaban without introducing an adequate alternate anticoagulant places people with NVAF at increased risk of thromboembolic events, including stroke. Significantly more patients switching from rivaroxaban to warfarin than those already on warfarin had strokes during the first month after withdrawal from the ROCKET-AF study (22 vs 7, p = 0.008).² No clinical trial data are available to guide switching people from rivaroxaban to warfarin. As rivaroxaban affects INR, INR measurements made during co-administration with warfarin may not be useful for determining the appropriate dose of warfarin (refer to the rivaroxaban product information for further details).⁴

Rivaroxaban is contraindicated in people with:

• severe renal impairment — both rivaroxaban 15 mg and 20 mg are contraindicated in people with creatinine clearance (CrCl) < 30 mL/min
• significant hepatic disease (including moderate and severe hepatic impairment, i.e. Child–Pugh grade B or C) which is associated with coagulopathy leading to a clinically relevant bleeding risk (see: Child–Pugh classification of liver disease). No data are available for severe hepatic impairment
• concomitant treatment with strong inhibitors of both CYP3A4 and P-glycoprotein. These include HIV protease inhibitors (e.g. ritonavir) or systemically administered azole antimycotics (e.g. ketoconazole).

For people who are using rivaroxaban, caution is required:

• with a known bleeding risk — weigh the risk of thromboembolic events against the risk of bleeding
• when spinal or epidural anaesthesia or lumbar puncture is indicated, as patients may be at increased risk of spinal haematoma which can result in long-term or permanent paralysis
• with concomitant use of strong CYP3A4 inducers such as rifampicin, phenytoin, carbamazepine, phenobarbitone or St John's wort as this may lead to reduced rivaroxaban plasma concentrations and increased embolic risk.

Advise premenopausal women taking rivaroxaban to be aware that menstrual bleeding may be intensified and/or prolonged.

The PBAC recommended the PBS listing of rivaroxaban for the prevention of stroke in patients with NVAF on a cost-effectiveness basis compared with warfarin for the two outcomes bleeding and haemorrhagic stroke. The PBAC considered rivaroxaban to be superior to warfarin with respect to the rate of intracranial bleeding and haemorrhagic stroke.³

The PBAC previously recommended that the submission of rivaroxaban for the prevention of stroke and systemic embolism in patients with NVAF be rejected in March 2012. At this time the PBAC considered that there was uncertainty around the clinical evidence to support the claim and resultant uncertainty in the economic analysis.¹⁷

The recommended dose is 20 mg taken orally once daily (15 mg in moderate renal impairment, CrCl 30–49 mL/min) taken with food and preferably at the same time each day. Taking rivaroxaban with food can increase the maximum plasma concentration by 76% in both the 15 mg and 20 mg strengths.^4,5

No dose adjustment is required for extreme body weight alone (< 50 kg or > 120 kg); however, calculate CrCl using the Cockcroft–Gault formula in such cases. Close surveillance is required in people with a body weight < 50 kg.

Surgery and interventions

Discontinuation of rivaroxaban should be guided by clinical judgement. When possible rivaroxaban should be discontinued at least 24 hours before any procedure.

Refer to Medicinewise News: Good anticoagulant practice Advise patients and carers to:

• seek urgent medical attention for unexplained bruising, blood in the urine or black stools or prolonged bleeding
• tell their health professional at each consultation that they are taking rivaroxaban
• ensure compliance with the single-dosing regimen, due to the short half-life of rivaroxaban
• take rivaroxaban with food
• replace a missed dose immediately on the same day and continue on the following day with the once-daily intake as before
• avoid non-prescription medicines containing aspirin; use paracetamol instead.

Discuss the rivaroxaban (Xarelto) consumer medicine information (CMI) leaflet with the patient.

Medicine Update

An NPS Medicine Update article on Xarelto is available for consumers. Medicine Update helps consumers to ask the right questions about new medicines, and helps them compare the potential benefits and harms of a new medicine with those of other medicines.

Updated September 2013 to reflect PBS listing of apixaban and dabigatran for the prevention of stroke and systemic embolism in people with NVAF.

Revised and updated August 2013 to reflect the changes to the PBS listing for rivaroxaban, effective 1 August 2013, and the TGA registration of apixaban for the prevention of stroke and systemic embolism in people with NVAF.

First published December 2012.