Emergent Reversal of Novel Oral Anticoagulants · Department of Pharmacy Services l May 1, 2017 l 2...
Transcript of Emergent Reversal of Novel Oral Anticoagulants · Department of Pharmacy Services l May 1, 2017 l 2...
Department of Pharmacy Services l May 1, 2017 l 1
Emergent Reversal of
Novel Oral Anticoagulants
Ohio Society of Health-System Pharmacists
78th Annual Meeting
Alexis Luckey, PharmD, BCPS
Pharmacy Clinical Specialist, Critical Care
Contact: [email protected]
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Learning Objectives
• Pharmacists
– Describe characteristics of novel oral anticoagulants (NOACs).
– Interpret the NOACs effect on coagulation assays.
– Discuss the pharmacologic reversal of NOACs during life-
threatening bleeding.
– Discuss the NOAC antidotes in the pipeline.
• Technicians
– Discuss the role of pharmacologic reversal of NOACs in
management of patients with life-threatening bleeding.
No conflicts of interest to disclose.
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Oral Anticoagulants
• Vitamin K antagonists (VKAs)
–Warfarin
• Direct thrombin inhibitor (DTI)
–Dabigatran
• Factor Xa inhibitors
–Rivaroxaban
–Apixaban
–Edoxaban
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Novel Oral Anticoagulants
(NOACs) =
Direct Oral Anticoagulants
(DOACs) =
Target Specific Oral
Anticoagulants (TSOACs)
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https://www.pradaxapro.com/sites/all/themes/pradaxapro/images/pages/1.2.1_moa_chart.jpg
NOACs
• Advantages
– Predictable pharmacokinetics
– Rapid onset of action
– Comparable safety and efficacy
• Challenges
– Bleeding risks
– Lab monitoring
– Emergent reversal
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Thrombosis Journal. 2014;12:8.
Pharmacokinetics of NOACs
Dabigatran Rivaroxaban Apixaban
Bioavailability 6% 60-80% 50-85%
Time to peak 1-2 hours 2-4 hours 1-3 hours
Metabolism Conjugation;
no CYP
involvement
CYP 3A4 CYP 3A4
Renal
Excretion
80% 33% 25%
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Thrombosis Journal. 2014;12:8.
Metabolism of NOACs
Dabigatran Rivaroxaban Apixaban
Renal
Impairment
6-fold higher
exposure when
CrCl 10-30
mL/min
1.6 fold higher
exposure when
CrCl 15-29
mL/min
1.44 fold higher
exposure when
CrCl 15-29
mL/min
Hepatic
Impairment
N/A 2.3 fold increase
exposure in
Child-Pugh B
N/A
Age 30% increase in
trough
concentrations
in age >75
Mean AUC 1.5
fold higher in
age >65
Mean AUC 1.3
fold higher in
age >65
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Thrombosis Journal. 2014;12:8.
Clinical Lab Monitoring of NOACs
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• Prolonged aPTT (activated partial thromboplastin time)
– May indicate an anticoagulant effect of dabigatran
– Normal aPTT may exclude anticoagulation
– Can be insensitive to FXa inhibitors: not recommended for
routine monitoring
• Prolonged PT (prothrombin time)
– May indicate an anticoagulant effect of the FXa inhibitors,
rivaroxaban>apixaban,edoxaban
– Normal PT may exclude significant drug levels of rivaroxaban
*Ask the patient*
Circulation. 2016;134:248-61. Critical Care.2016;20:273.
Clinical Lab Monitoring of NOACs
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• TT (thrombin time)
– Most sensitive test for dabigatran
– dTT (dilute thrombin time) quantifies dabigatran drug levels
• Anti-FXa chromogenic assay
– Recommended for rivaroxban, apixaban, and edoxaban
Important Note: Validation required and not universally available.
Often with delayed turnaround time that diminishes usefulness in
emergent situations.
*Ask the patient*
Circulation. 2016;134:248-61. Critical Care.2016;20:273.
Strategies for Anticoagulation Reversal
• Ideally managed by pre-determined institutional
guidelines
• Influenced by
– Pharmacology of specific agent
– Urgency of clinical situation
– Severity of bleeding
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Strategies for Anticoagulation Reversal
• All strategies preceded by appropriate supportive and
symptomatic treatment
• Observation and withholding anticoagulation
• Administering a specific reversal agent if one is
available
• Administration of supplemental clotting factors either
via fresh frozen plasma (FFP) or prothrombin complex
concentrates (PCCs)
• Administration of prohemostatic agents such as
activated prothrombin complex concentrated (aPCC or
FEIBA) or reconstituted factors VIIa (rFVIIa)
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Thrombosis Journal. 2014;12:8
Supportive Measures
• Minor bleeds
– Temporary discontinuation of anticoagulation for several doses
• Significant bleeds may require:
– Local management
– Volume resuscitation
– Consideration of red blood cell and platelet transfusion
• Role of oral activated charcoal
• Role of hemodialysis
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Circulation. 2016;134:248-61.
Fresh Frozen Plasma
• Not used to reverse anticoagulant effects of NOACs
• May be used a plasma expander
• PCCs preferred over FFP if replacement of coagulation
factor is required
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Circulation. 2016;134:248-61.
Prothrombin Complex Concentrates (PCCs)/
activated Prothrombin Complex Concentrates (aPCCs)
• PCCs
– Plasma-derived products that contain 3 or 4 clotting factors in
addition to variable amounts of heparin and proteins C & S
– Unactivated 4-factor PCC: Kcentra®
– Vitamin K + Kcentra ® in warfarin reversal
• aPCCs
– A.k.a. factor VIII inhibitor bypassing activity
– Contains mostly activated factor VII along with mainly
unactivated factors II, IX, and X
– Activated 4-factor PCC: FEIBA®
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Circulation. 2016;134:248-61.
Recombinant Activated Factor VII
• rFVIIa: Novoseven®
• In vitro and ex vivo studies demonstrate variable
efficacy to reverse coagulation parameters
attributable to NOACs
• No clinical trials investigating NOAC reversal with
rFVIIa
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Circulation. 2016;134:248-61.
FFP aPCC
(FEIBA®)
PCC
(Kcentra®)
rFVIIa
(Novoseven®)
Time to
effect
Hours Peak effect in
15-30 mins
~10 mins ~10 mins
Advantages All factors;
limited
thrombosis
risk
Rapid; small
volume;
provides factor
VII
Rapid; small
volume;
provides factor
VII
Rapid; small
volume; without
infection risk
Dis-
advantages
Risk of fluid
O/L; Prep
delay;
infectious
risk; ABO
matching;
infusion
reactions
Increased
thrombotic
complication
risk greatest
with activated
factors
Thrombotic
complications;
contraindicated
in HIT
Increased
thrombotic
complication risk
greatest with
activated factors
Department of Pharmacy Services l May 1, 2017 l 17
Curr Opin Crit Care.2015;21:127-33.
Efficacy Results
• Some but limited data with safety and efficacy
• Increased risk of thrombotic complications
– Higher with activated factors
• Reserved for patients taking NOACs who present with
life-threatening bleeding despite general supportive
measures or who require emergency surgery
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Circulation. 2016;134:248-61. Critical Care.2016;20:249. Curr Opin Crit Care.2015;21:127-33. Thrombosis Journal. 2014;12:8
Idarucizumab (Praxbind®)
• Specific reversal agent for dabigatran
• Chemical Structure: humanized monoclonal antibody
fragment
• Binding: noncompetitive binding to dabigatran
• Onset: <5 mins
• Half-life: initial 47 mins; terminal 10.3 hrs
• Elimination: renal
• Dosing: 5 g (2.5 g x 2 doses)
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Circulation. 2016;134:248-61.
Approaches to Reversal
• First steps to severe and life-threatening hemorrhage:
– Addressing hemodynamic stability
– Immediate discontinuation of anticoagulation
– Consider activated charcoal based on time since ingestion
– Obtain stat labs
– Screening
• Administer hemostatic agent of choice or specific
reversal agent if indicated
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Circulation. 2016;134:248-61.
Dosing
Unactivated 4-factor
PCCs
(Kcentra®)
50 IU/kg;
maximum 5,000 IU
aPCCs
(FEIBA®)
50-100 units/kg;
maximum 200 units/kg daily
rFVIIa
(Novoseven®)
90 µg/kg
idarucizumab
(Praxbind®) 5 g
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Curr Opin Crit Care.2015;21:127-33. Critical Care.2016;20:249.
The Future…
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Andexanet alfa Ciraparantag
Target
Anticoagulants
Oral FXa inhibitors, LMWHs,
fondaparinux
Oral FXa inhibitors,
dabigatran, LMWHs,
fondaparinux, UFH
Structure Type Modified recombinant FXa
protein
Synthetic small
molecule
I.V. Dosage For apixaban: 400 mg bolus
4 mg/min cont. inf. x 2 hr
For rivaroxaban: 800 mg bolus
8 mg/min cont. inf. x 2 hr
Undetermined
Common
Adverse
Effects
Mild-moderate infusion reactions Transient mild perioral
and facial flushing;
distortion of sense of
taste
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Am J Health-Syst Pharm.2017;74(2):54-61.
In Development: Andexanet alfa
• Specific reversal agent for oral FXa inhibitors,
LMWHs, fondaparinux
• Binding: competitive binding to direct FXa inhibitors or
to indirect FXa inhibitor-activated thrombin
• Onset: 2 mins
• Half-life: terminal 6 hrs
• Elimination: not reported
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Circulation. 2016;134:248-61.
In Development: Ciraparantag
• Specific reversal agent for oral FXa inhibitors, dabigatran,
LMWHs, fondaparinux, and UFH
• Binding: covalent hydrogen bonding
• Onset: 5-10 mins
• Half-life: Duration of action 24 hrs
• Elimination: not reported
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Circulation. 2016;134:248-61.
Conclusions
• No guidelines for the emergent reversal of oral
anticoagulants
• Additional studies needed to evaluate effectiveness
and thrombotic risk of factor replacement
• Newly developed and in-development specific reversal
agents give potential for consistent and effective
treatment and management options
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Self-Assessment
• LB 78 yo F presents to ED with ICH and last dose of
dabigatran 8 hours ago. CrCl=25, prolonged aPTT
and TT.
• What is the preferred reversal agent for LB?
A. Kcentra®
B. Feiba®
C. Vitamin K
D. Idarucizumab (Praxbind®)
Department of Pharmacy Services l April 29, 2017 l 27
Self-Assessment
• TB 55 yo F presents to ED with moderate GIB and last
dose of rivaroxaban 36 hours ago. Hx of CHF.
Normal PT. CrCl=98, Hgb=6.8. BP 86/58
• What is an appropriate initial treatment for TB?
A. Feiba®
B. Supportive measures and address hemodynamic
stability
C. FFP
D. Idarucizumab (Praxbind®)
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Self-Assessment
• TL 66 yo M presents to ED with ICH and last dose of
apixaban 10 hours ago. CrCl=29, prolonged PT.
• What is an appropriate treatment for TB?
A. Feiba®
B. Supportive measures and address hemodynamic
stability
C. FFP
D. Idarucizumab (Praxbind®)
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References
• Babilonia K, Trujillo T. The role of prothrombin complex concentrates in
reversal of target specific anticoagulants. Thrombosis Journal. 2014;12:8.
• Ruff CT, Giugliano RP, Antman EM. Management of bleeding with non-
vitamin K antagonist oral anticoagulants in the era of specific reversal
agents. Circulation. 2016;134:248-61.
• Brown KS, Zahir H, Grosso MA, et al. Nonvitamin K antagonist oral
anticoagulant activity: challenges in measurement and reversal. Critical
Care. 2016;20:273.
• Liotta EM, Levasseur-Franklin KE, Maidech AM. Reversal of the novel oral
anticoagulants dabigatran, rivoraxaban, and apixaban. Curr Opin Crit Care.
2015;21:127-33.
• Levi M. Management of bleeding in patients treated with direct oral
anticoagulants. Critical Care. 2016;20:249.
• Riley TR, Gauthier-Lewis ML, Sanchez CK, et al. Role of agents for
reversing the effects of target-specific oral anticoagulants. Am J Health-Syst
Pharm. 2017;74(2):54-61.
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