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Dabigatran Addition to the list Explanation for addition Pharmaceutical company suggestion: “Dabigatran is the only novel oral anticoagulant with an approved reversal agent when specific reversal of the anticoagulant effects of Dabigatran is required for emergency surgery/urgent procedures or life-threatening or uncontrolled bleeding. The antidote, Praxbind (idarucizumab), provides immediate, complete and sustained reversal of the anticoagulant effects of Pradaxa within minutes. Dabigatran is an oral direct thrombin inhibitor for the prevention of stroke and systemic embolism in patients with Atrial Fibrillation, and for the treatment of venous thromboembolism events (deep vein thrombosis [DVT], pulmonary embolism [PE], and prevention of recurrent DVT and PE.” anticoagulants in Clean Meds Essential Medication List warfarin rivaroxaban Note: In August of 2015, the NOAC were reviewed and rivaroxaban was added to the list (weak recommendation). We are now revisiting that decision based on the antidote. The previous literature search on NOACs is included at the end of this package. We have also included the results from a recent network meta-analysis comparing the efficacy and safety of rivaroxaban vs. dabigatran in patients with atrial fibrillation. Proietti, M. and G.Y. Lip, Antidotes to non-vitamin K oral anticoagulants: necessary or not? Expert Opin Pharmacother, 2015. 16(11): p. 1573-6. Health Canada approved Praxbind™ (idarucizumab) on May 16th, 2016. Other targeted antidotes have not been approved for use in Canada. Syed, Y.Y., Idarucizumab: A Review as a Reversal Agent for Dabigatran. Am J Cardiovasc Drugs, 2016. 16(4): p. 297-304. Idarucizumab is a humanized monoclonal antibody fragment developed as a specific reversal agent for dabigatran. Idarucizumab Therapeutic efficacy In the ongoing, multicentre, prospective, single-arm, phase 3 trial (RE-VERSE AD), a total of 90 patients were enrolled into 1 of 2 groups: group A patients (n = 51) experienced uncontrolled, life-threatening bleeding, whereas group B patients (n = 39) required urgent surgery that could not be delayed. Patients received idarucizumab 5 g intravenously as two 2.5-g per 50-mL bolus infusions. An interim analysis demonsrated Idarucizumab 5 g reversed dabigatran-induced prolongation of dilute thrombin time (dTT) and ecarin clotting time (ECT) within minutes. The median maximum percentage reversal was 100 % for both assays (primary endpoint). After idarucizumab administration, bleeding stopped in 97 % of evaluable patients in the bleeding cohort within 24 h (median time to cessation of bleeding was 11.4 h), and the rate of normal intraoperative haemostasis was 92 % in the surgical cohort.” Yogaratnam, D., et al., Idarucizumab for Reversal of Dabigatran. Ann Pharmacother, 2016 Safety In the RE-VERSE AD trial, the most frequent AEs were the following: hypokalemia (7%), delirium (7%), constipation (7%), pyrexia (6%), and pneumonia (7/123, 6%). Thromboembolic events (3 deep vein thromboses, 2 PEs, 1 ischemic stroke, and 1 non–ST-elevation myocardial infarction) occurred in 5 patients receiving idarucizumab. None of these patients received antithrombotic therapy at onset of these events. [3] Ruff, C.T., R.P. Giugliano, and E.M. Antman, Management of Bleeding With Non-Vitamin K Antagonist Oral Anticoagulants in the Era of Specific Reversal Agents. Circulation, 2016. 134(3): p. 248-61. Andexanet Alfa “Andexanet alfa (andexanet) is a specific reversal agent for direct (apixaban, rivaroxaban, and edoxaban) and indirect (low-molecular-weight heparins and fondaparinux) FXa inhibitors that act through antithrombin. It is a modified human recombinant FXa decoy protein that is catalytically inactive.” “In phase 2 studies, andexanet demonstrated rapid, dose-dependent reversal of anticoagulant effects (antiFXa activity, unbound FXa concentrations, restoration of thrombin potential) in healthy volunteers administered apixaban, rivaroxaban, or enoxaparin.” In 2 parallel RCTs, Andexanet Alfa were given to healthy older volunteers 50-75 years of age pretreated with apixaban and rivaroxaban. “Anti-FXa activity was rapidly (within 2–5 minutes) reduced by 92% to 94% with andexanet bolus in comparison with 18% to 21% for placebo (P<0.001for both studies)… Similar decreases were observed for unbound plasma concentrations of apixaban and rivaroxaban. No thrombotic or serious adverse events were reported” “The ongoing ANNEXA-4 phase 3b to 4 study (http://www.clinicaltrials.gov, NCT02329327) is evaluating the efficacy and safety of andexanet in patients taking FXa inhibitors with acute major bleeding. Andexanet has been granted breakthrough therapy designation by the FDA, in which expedited review is provided for therapies to treat serious or life-threatening conditions, often based on preliminary clinical evidence demonstrating substantial improvement over other therapies/existing care. The Prescription Drug User Fee Act date for andexanet is August 17, 2016, which is the target date for the FDA to complete its review and take action on the application.” Ciraparantag Ciraparantag is a small synthetic water-soluble molecule developed as a reversal agent for unfractionated heparin, low-molecular-weight heparins, fondaparinux, and the oral direct Xa and IIa inhibitors. “When added to whole blood spiked with rivaroxaban or apixaban from healthy human volunteers, ciraparantag reversed anti-FXa activity in a dose-dependent fashion… In a phase 1 dose-ranging study in healthy volunteers (n=80) administered a single dose of edoxaban 60 mg, ciraparantag decreased wholeblood clotting times to within 10% of baseline values within 10 minutes with single intravenous doses of 100 to 300 mg.84 Reversal was sustained for 24 hours.” It was granted the fast track designation by the FDA but has not been approved. Literature Review Question: What is the comparative efficacy and safety of rivaroxaban vs. dabigatran in patients with atrial fibrillation? Morimoto, T., et al., Comparative efficacy and safety of novel oral anticoagulants in patients with atrial fibrillation: A network meta-analysis with the adjustment for the possible bias from open label studies. J Cardiol, 2015. 66(6): p. 466-74. Objective This study was designed to compare efficacy and safety among novel oral anticoagulants (NOACs), Data collection Network meta-analyses of RCTs in preventing thromboembolic events and major bleeding in patients with atrial fibrillation, 9 studies were included in the primary analysis. Endpoints The primary endpoint was a composite of stroke and systemic embolism. Secondary endpoints included stroke and myocardial infarction. We included major bleeding as a safety endpoint. Other endpoints of interest included: all-cause death, ischemic stroke (including stroke of unknown origin), hemorrhagic stroke, and intracranial hemorrhage. Results “Primary composite endpoint (stroke and systemic embolism): All NOACs were found to perform similarly except for dabigatran 110mg and edoxaban 30mg.” (Figure 3 B, C and F). Higher odds ratio = worse outcome “Major bleeding risk was similar between dabigatran 110 mg and 150 mg, and rivaroxaban” (Fig. 4B, C, and F). Higher odds ratio = worse outcome “Rivaroxaban was superior in reducing myocardial infarction compared to both dabigatran 110mg and 150mg.” (Figure 6 B, C, F). Higher odds ratio = worse outcome. “Apixaban and rivaroxaban were found to be superior to dabigatran 110 mg in reducing ischemic stroke and stroke of unknown origin” Figure not shown here. LITERATURE PACKAGE FROM AUGUST 2015 Literature Review Question: What is the efficacy of novel OACs for stroke prevention in atrial fibrillation? Literature Search: eCPS – Cardiovascular Disorders: Supraventricular Tachycardia CPG via CMA - Guidelines for the Management of Atrial Fibrillation Meta-analysis taken from references of the CPG Medline: “novel anticoagulants AND atrial fibrillation AND 2014-2015 AND meta-analysis/review” A major challenge for clinicians in following this recommendation (#5) is that the current reimbursement systems in Canada are not aligned with it. Verma, Atul, et al. "2014 focused update of the Canadian Cardiovascular Society guidelines for the management of atrial fibrillation." Canadian Journal of Cardiology 30.10 (2014): 1114-1130. Systematic review of stroke prevention in AF (2015) With the availability of 4 different NOACs as well as the VKAs, physicians now have a choice and can fit the drug to the patient. Various patient characteristics may influence the initial choice of one drug over another (Table 4). In the absence of head-to-head clinical trials, clinicians cannot directly compare one NOAC against another. Nevertheless, regulatory bodies and health economic analyses have performed indirect comparisons of one agent against another using warfarinas the comparator; such indirect comparisons (or network metaanalyses) should be interpreted with some caution given heterogeneity in trial inclusion-exclusion criteria, quality of INR control.73Overall, there are few substantial differences in efficacy, although 150mg of dabigatran twice daily may offer the greatest potency by reducing both ischemic and hemorrhagic stroke, and it has a similar risk of major bleeding as warfarin. For safety, the best bleeding profile is seen with 110 mg of dabigatran twice daily, apixaban, and edoxaban.74-76 Lip, Gregory YH, and Deirdre A. Lane. "Stroke Prevention in Atrial Fibrillation: A Systematic Review." JAMA 313.19 (2015): 1950-1962. Guidelines for the Management of Atrial Fibrillation (2014) Note: OAC – oral anticoagulants, NOAC - novel direct oral anticoagulants The NOACs apixaban, dabigatran, edoxaban, and rivaroxaban were developed to overcome the major limitations associated with warfarin and other vitamin K antagonists. All 4 agents have been evaluated in large, blinded, RCTs involving > 70,000 patients.15-18 The trials of apixaban, dabigatran, and rivaroxaban were summarized in the 2012 CCS update2 and since then numerous publications have provided details about interactions with age, time in the therapeutic range, renal dysfunction, and previous stroke or transient ischemic attack (TIA). Edoxaban, the most recent agent, was compared with warfarin in the Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48 (ENGAGE AF-TIMI 48) trial.18 There were 21,105 patients (mean CHADS2 score ¼ 2.8) randomized double blind to edoxaban 30 mg once daily, edoxaban 60 mg once daily, or warfarin. The principal outcome rates (stroke or systemic embolism) were noninferior to warfarin for both doses of edoxaban and neither dose was superior to warfarin, although there was a trend toward benefit with the higher dose. Bleeding rates were significantly lower for both doses of edoxaban. Intracranial bleeding was significantly less with both doses of edoxaban than warfarin. Each of the NOACs was found to be noninferior to warfarin for the outcome of all stroke or systemic embolism. None of them caused more major bleeding and all were superior for the outcome of intracranial hemorrhage. A meta-analysis of the 4 RCTs19 found the following for the higher-dose regimens vs warfarin: stroke or systemic embolism (RR, 0.81; 95% confidence interval [CI], 0.73-0.91; P < 0.0001), intracranial hemorrhage (RR, 0.48; 95% CI, 0.39-0.59; P < 0.0001), gastrointestinal bleeding (RR, 1.25; 95% CI, 1.01-1.55; P ¼ 0.04), all-cause mortality (RR, 0.90; 95% CI, 0.85-0.95; P ¼ 0.0003). Comparison of the lower-dose regimens with warfarin showed similar rates of stroke or systemic embolism, significantly less intracranial bleeding, and significantly less mortality. Based on these observations coupled with greater convenience for patients and physicians, the Guidelines Committee continues to recommend NOACs over warfarin for nonvalvular AF. There have been no published trials directly comparing the various NOACs, and it is unlikely that any will be conducted in the near future. In the absence of any such direct comparative data, the CCS expert panel discussed the possibility that the balance of efficacy and safety might influence clinicians to choose one agent over another. Indirect comparisons using appropriate statistical methods have been performed but their limitations have to be acknowledged.20,21 Differences in baseline populations and in the designs of the key RCTs affect the ability to make any definitive comparisons between the NOACs. Any differences in efficacy that might exist among the NOACs, and even the difference in efficacy between warfarin and each of the NOACs, is very small compared with the reduction of stroke with any OAC compared with no OAC. The panel also reviewed the data within various subgroups of patients in the RCTs. It appears that the benefit-to-risk ratio of dabigatran 150 mg vs warfarin is more favourable among patients aged < 75 years, but less favourable in those aged 75 years, among whom dabigatran 110 mg is the better choice.22 For apixaban and rivaroxaban, the balance of efficacy and safety does not differ between patients 75 vs < 75 years. Dabigatran elimination is more dependent on renal clearance, so rivaroxaban and apixaban might be preferred for estimated glomerular filtration rates (eGFRs) of 30-50 mL/ min/1.73 m2. The initial publication from the Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY) trial showed an excess of myocardial infarction with dabigatran over warfarin but the difference was insignificant when additional events were considered. Meta-analyses have consistently shown more myocardial infarction with dabigatran, although less total mortality, but a recent Food and Drug Administration study showed equivalent rates of myocardial infarction in patients taking dabigatran compared with patients taking warfarin.23 Gastrointestinal bleeding is more common in patients taking dabigatran 150 mg twice daily and rivaroxaban vs warfarin. The finding for dabigatran was confirmed by a large Food and Drug Administration cohort study.23 Patients taking dabigatran also had significantly more dyspepsia and earlier discontinuation of study Meta-analysis of NOACs (2014) Our results show that stroke and systemic embolic events were significantly reduced in patients receiving new oral anticoagulants. This benefit was mainly driven by substantial protection against haemorrhagic stroke, which was reduced by half. Conceptually, haemorrhagic stroke is a complication of anticoagulant treatment even though it is part of the overall efficacy assessment of these drugs. Importantly, overall intracranial haemorrhage (which includes haemorrhagic stroke) was reduced by roughly half, which represents a substantial benefit of treatment with new oral anticoagulants. Intracranial haemorrhage is a feared and often fatal complication of anticoagulant treatment and about one in six first hospital admissions for this disorder are related to such treatment.26 For the prevention of ischaemic stroke, the new oral anticoagulants had similar efficacy to warfarin, which itself is very effective in this regard and reduces ischaemic stroke by two-thirds compared with placebo.27 In general, the new oral anticoagulants had a favourable safety profile compared with warfarin; however, they were associated with an increase in gastrointestinal bleeding. They were also associated with a significant reduction in all cause-mortality compared with warfarin. Ruff, Christian T., et al. "Comparison of the efficacy and safety of new oral anticoagulants with warfarin in patients with atrial fibrillation: a meta-analysis of randomised trials." The Lancet 383.9921 (2014): 955-962. eCPS (2014) Warfarin and ASA have been used for many years, although ASA is less effective than warfarin. Apixaban, dabigatran and rivaroxaban are approved for prevention of systemic embolism in patients with atrial fibrillation (see Table 8). Approval of dabigatran was based largely on the RE-LY study, which randomized patients to warfarin or dabigatran.17 Dabigatran 150 mg twice a day was superior to warfarin in preventing stroke and systemic embolism. Rivaroxaban was compared to warfarin in the ROCKET-AF trial and was found noninferior to warfarin.18 Apixaban was shown to be superior to ASA in the AVERROES study19 and to warfarin in the ARISTOTLE study.20 CCS guidelines suggest that when an oral anticoagulant is indicated, most patients should receive apixaban, dabigatran or rivaroxaban.5 The preference for 1 of the new oral anticoagulants over warfarin is less marked among patients already receiving warfarin with stable INRs and no bleeding complications. Other factors (e.g., cost, renal function) may also influence drug choice. The combination of clopidogrel and ASA is recommended by the CCS for stroke prevention in low-risk patients with stable coronary artery disease, acute coronary syndrome or percutaneous coronary intervention.13 The summary of recommendations for antithrombotic therapy in patients with atrial fibrillation or atrial flutter and coronary artery disease is shown in Figure 5 - Summary of Recommendations for Antithrombotic Management in Patients with Coronary Artery Disease . Table 8: Drug Therapy for Prevention of Systemic Embolism in Patients with Supraventricular Tachycardia Class Drug Direct Factor apixaban Xa Eliquis Inhibitors Dose Usual: 5 mg BID po If serum creatinine >133 mmoL/L and patient either >80 y or ≤60 kg: 2.5 mg BID po Adverse Effects Bleeding. Drug Interactions Contraindicated in combination with strong inhibitors of both CYP3A4 and P-gp (e.g., itraconazole, ritonavir). Costa $$$$ Class Drug Dose Adverse Effects Costa Drug Interactions Direct Factor rivaroxaban 20 mg daily po Xa Xarelto Moderate renal Inhibitors impairment (ClCr 30–49 mL/min): 15 mg daily po Bleeding. Contraindicated in combination with strong inhibitors of both CYP3A4 and P-gp (e.g., itraconazole, ritonavir). Direct Thrombin Inhibitors dabigatran Pradaxa Usual: 150 mg BID po Patients with increased bleeding risk or >80 y: 110 mg BID po Bleeding, gastric intolerance. Contraindicated in combination $$$$ with strong inhibitors of P-gp (e.g., ketoconazole). Caution with other drugs acting on P-gp. Vitamin K Antagonists warfarin Coumadin, generics Dose to maintain INR between 2 and 3 Bleeding, skin necrosis. Many potential interactions. Contraindicated in Substrate for CYP2C9 and other pregnancy. isoenzymes. Legend: $ <$10 $$ $10–50 $$$ $50–90 $$$ $ $$$$ $90–130 Cardiovascular Disorders: Supraventricular Tachycardia; David Birnie, MD and Pablo Nery, MD; Date of revision: May 2014 ODB Formulary Generic Name APIXABAN Brand Name, Strength & Dosage MFR Form Eliquis 2.5mg, 5mg Tab Xarelto RIVAROXABAN 10mg, 15mg, 20 mg Tab Drug Benefit Price Amount InterLimited Therapeutic MOHLTC changeables Use Notes Pays BQU 1.6000 1.6000 NO YES NO BAH 2.8400 2.8400 NO YES NO DABIGATRAN ETEXILATE Pradaxa 110mg, 150mg Cap BOE 1.6000 1.6000 NO YES NO WARFARIN Apo-Warfarin 1mg -10mg Tab APX 0.0674 0.1211 0.0674 0.1211 YES NO YES