1. The “New Oral Anticoagulant” and the impact for your Lab
Pr François Mullier, Ph Jonathan Douxfils, Pr Jean-Michel Dogné, Pr Bernard Chatelain
Minisymposium “Comprehensive and Practical Coagulation” Brussels,
22 May 2014 1

2. Introduction
Direct oral anticoagulants (rivaroxaban -Xarelto®-, dabigatran etexilate -Pradaxa®- et apixaban -Eliquis®-) are now widely used
Revolution in clinical practice
Important to know the pharmacology
Pharmacokinetics and pharmacodynamics predictable
 no interest of monitoring in the vast majority of patients
Some patient groups will be exposed to infra- and supra- therapeutic levels when gived at fixed doses 2

3. Objectives 1) Why, when and how monitor direct oral anticoagulants?
2) How to interpret hemostasis tests for patients treated by DOAC?
3) Clinical Cases 3

4. Pharmacology of NOACs Dabigatran Rivaroxaban Apixaban
Target
Factor lla
Factor Xa
Prodrug
Yes No
Tmax (h)
Distribution volume (L)
60 – 70
± 50 23
Half-life (h)
11: healthy individuals
: elderly
5 - 9: healthy individuals
: elderly
8 - 15: healthy individuals
Bioavailibility
dabigatran etexilate: %, pH sensitive
%: 10mg
66%: mg under fasting conditions
± 50%
Protein binding
35%
>90%
87%
Metabolism
Conjugation
CYP-dependent and independent mechanism
CYP-dependent mechanism
Active metabolites
Yes - glucuronide conjugates
Elimination
80% renal
33% unchanged via the kidney
25% renal
20% bile (glucuronide conjugation)
66% metabolized in the liver into inactive metabolites then eliminated via the kidney or the colon in an approximate 50% ratio
75% through the kidney while the residue is excreted by the hepatobiliary route in the feces
Effects of food
Tmax delayed; Cmax & AUC unchanged
Tmax delayed; Cmax & AUC increased (76% and %, respectively)
CYP substrate
CYP3A4, CYP2J2
CYP3A4
P-gp substrate
dabigatran etexilate: Yes
Novel OACs that are available for the prevention of stroke
in patients with AF include dabigatran, rivaroxaban, and
apixaban. Compared with warfarin, the novel OACs have
greater specificity (single vs multiple targets within the
clotting cascade), a more rapid onset of action (time to peak
concentration: 2–4 hours vs 72–96 hours), shorter half-lives
(5–17 hours vs 40 hours), considerably fewer interactions
with other drugs, and no food interactions or dietary restrictions
(Table 1).11–13 Because they have more predictable
pharmacokinetic characteristics than warfarin, novel OACs
can be administered using fixed doses and do not require
routine coagulation monitoring. Unlike warfarin, each of the novel OACs is eliminated renally to differing degrees,13
which has important implications that will be discussed.

5. Why point measurement was described as not necessary?
PK-PD studies: response to the drug highly predictable
Significant variation in the drug concentration for a same dose
2) All clinical studies were performed without laboratory monitoring
No clinical study comparing bleeding rates with/without occasional or regular follow-up by the laboratory
3) Wide therapeutic window
Unique well documented and accepted document 5 5
Freyburger et al., 2011
Mani et al., 2013
Samamaet al., 2013

6. Why point measurement could be useful?
>90th percentile of DOAC at Ctrough risk of bleeding
(AF: dabigatran 150mg bid  200ng/ml)
Correlation between bleeding outcomes and dabigatran plasma concentrations with important overlap
In this RE-LY substudy, demographic characteristics (old age, low CrCl and low body weight) played the strongest role in determining risk of clinical events. In patients at highest risk for events, such as the very elderly
and/or those with poor renal function, an adjustment of dabigatran dose to optimize exposure might improve benefit-risk if they are at either extreme of the concentration range.
Reilly PA and coll, JACC 2013
EMA SPC 2013

7. Why point measurement could be useful?
Demographic characteristics (mainly age and previous stroke) played the strongest role in determining risk of clinical events.
In addition, the authors concluded that for patients at highest risk for events, such as the very elderly and/or those with poor renal function, an adjustment of dabigatran dose to optimize exposure might improve benefit-risk if they are at either extreme of the concentration range.
In this RE-LY substudy, demographic characteristics (old age, low CrCl and low body weight) played the strongest role in determining risk of clinical events. In patients at highest risk for events, such as the very elderly
and/or those with poor renal function, an adjustment of dabigatran dose to optimize exposure might improve benefit-risk if they are at either extreme of the concentration range. 7
Reilly PA and coll, JACC 2013 7

8. Clinical trials are different from real life
Je la mettrai avant 8 8

9. Why point measurement could be useful?
Pengo V. and coll. JTH 2012 9 9

10. When point measurement could be useful?
Before urgent surgery or procedure (with last administration in the last 24h or more if CLCR < 50ml/min)
Before fibrinolytic therapy of acute ischaemic stroke.
In case of bridging therapy
Patients not eligible for inclusion in the clinical trials (patients at extremes of body weight (<50-60kg and > kg), and/or with kidney ((rivaroxaban: 30 ml/min (trial) 15ml/min (indication), apixaban (25ml/min (trial)15ml/min (indication) ) or liver impairment).
Ten Cate H. Thromb Haemost. 2012
Huber K and coll. Thromb Haemost. 2011
Faxon DP and coll. Thromb Haemost. 2011
Samama MM and coll. Drug Development Research 2013
Baglin T and coll. Brit J Haematol 2012
Turpie Thromb Haemost 2012

11. When point measurement could be useful?
In patients with multiple risk factors for DOACs accumulation (i.e. patients older than 75 years, drug-drug interactions as with frequently used medication like amiodarone and verapamil)
In patients with renal impairment (in case of progressive decrease of renal function but also in acute decrease during deshydration, antibiotics administration, …)
Patients with a high bleeding risk.
Control of laboratory tests in patients receiving a reversal treatment.
Control of patient compliance.
Suspected overdose.
Ten Cate H. Thromb Haemost. 2012
Huber K and coll. Thromb Haemost. 2011
Faxon DP and coll. Thromb Haemost. 2011
Samama MM and coll. Drug Development Research 2013
Baglin T and coll. Brit J Haematol 2012
Turpie Thromb Haemost 2012

12. Renal function
Use of Cockcroft-Gault equation in clinical trials for NVAF
Use of MDRD leads to surestimation of renal function at lower levels .
Dose recommendations by the MDRD4 formula will result in
significantly higher doses, particularly in women. As an example, 19% (82) of the female participants would receive an ordinary dose (300 mg) of dabigatran if the Cockcroft-Gault equation with uncompensated P-creatinine would be used when
estimating renal function, compared to 59% (259) with the MDRD4 formula (A).
Pour la formule de CLCR : Au niveau de la SmPC du dabigatran etexilate OK pour le CG à la place du MDRD. En revanche, rien n’est mentionné pour le rivaroxaban et l’apixaban. Même si dans les études cliniques c’était la formule du CG qui était utilisé. Pour l’apixaban ,ce n’est ni mentionné dans la SmPC, ni dans la publication de Granger (ARISTOTLE).
Cockcroft-Gault MDRD4 12
Hellden A et al. BMJ Open 2013
MacCallum and coll., BMJ Open. 2013 12

13. Renal function
Thus, many elderly patients with AF would either incorrectly become eligible for them or would receive a too high a dose.  13
Hellden A et al. BMJ Open 2013
MacCallum and coll., BMJ Open. 2013 13

14. How point measurement should be performed?
Influence on a wide range of coagulation assays (risk of superfluous investigations in the absence of dialogue).
Assays should be easily available, easily done and should give a result within min.
Interpretation: anticoagulant, dose, time between the last dose and sampling (Cmax ~2-4 hours and Cthrough before the next ingestion) 14
Baglin T. Brit J Haematol 2012 14

15. How point measurement should be performed?
Pernod G and coll. Management of major bleeding complications….Proposals of the Working Group on Perioperative Haemostasis. Archives of Cardiovascular disease 2013

16. How point measurement should be performed?16
Pernod G and coll. Management of major bleeding complications….Proposals of the Working Group on Perioperative Haemostasis. Archives of Cardiovascular disease 2013 16

17. Bridging procedures: timing of discontinuation
Dabigatran etexilate
In general, novel OACs should be interrupted before invasive
or surgical procedures and restarted promptly when
hemostasis has been restored. The time taken to clear
dabigatran is highly dependent on renal function, therefore
prescribing information recommends that dabigatran
should be discontinued for 24 hours if CrCl is ≥80 mL/min,
for 1 to 2 days if CrCl is 50 to <80 mL/min, and for 2 to 3
days if CrCl is ≥30 to 50 mL/min; an additional 1 to 2 days
without dabigatran is recommended if there is a high risk
of bleeding or if major surgery is needed. 17
JI Weitz and coll. Circulation Nov 13 17

18. Bridging procedures: timing of discontinuation
Dabigatran etexilate
JI Weitz and coll. Circulation Nov 13;126:

19. How point measurement should be performed? Dabigatran/APTT
ISTH recommendation: APTT can be used to determine the relative intensity of anticoagulation due to dabigatran
However:
Global test
Limited sensitivity
Particularly sensitive to preanalytical and biological variables
Absence of linear relationship between APTT and plasma concentration
Should not be used to measure directly the plasma concentration
Baglin T and coll. J Thromb Haemost 2013, Eikelboom JW and coll. Thromb Haemost 2006
Kitchens CS J Thromb Haemost 2005, Lippi G and coll. Blood Coagul Fibrinolysis 2010
Douxfils J, Dogne JM, Mullier F and coll. Thromb Haemost 2013 Douxfils J, Mullier F and coll. Thromb Haemost 2012
van Ryn J and coll. Thromb Haemost 2010 19 19

20. How point measurement should be performed? Dabigatran/APTT
APTT reagents: different sensitivities to dabigatran
- To be known by the laboratories
- Each lab should define its cut-offs (sec or ratio) 20 20
Douxfils J, Dogne JM, Mullier F and coll. Thromb Haemost 2013
Douxfils J, Mullier F and coll. Thromb Haemost 2012

21. How point measurement should be performed? Dabigatran/APTT21 21
Pernod G and coll. Management of major bleeding complications….Proposals of the Working Group on Perioperative Haemostasis. Archives of Cardiovascular disease 2013

22. How point measurement should be performed? Dabigatran/APTT22
Douxfils J, Mullier F and coll. Thromb.Haemost May;107(5):985-97

23. How point measurement should be performed? Dabigatran/TT
Advantages:
non influenced by factor deficiencies (exception: fibrinogen),
non influenced by lupus anticoagulant
non influenced by FVIII elevation in inflammatory context
Disadvantage TT:
Sensitivity to analytical variables  difficult standardization (be careful with recommendations with this test)
Normal TT  exclusion of a clinically relevant effect of dabigatran
Douxfils J, Dogne JM, Mullier F and coll. Thromb Haemost 2013
Douxfils J, Mullier F and coll. Thromb Haemost 2012
van Ryn J and coll. Thromb Haemost 2010 23 23

24. How point measurement should be performed? Dabigatran/diluted TT
Lower sensitivity
Calibrated with dabigatran standards
Precise and accurate quantification of plasma concentration
Possible automatization on different coagulometers
Good concordance with LC-MS/MS
<50 ng/mL  LC-MS/MS preferable.
Sensitivity to inhibitors (heparins or hirudine).  be careful with bridgings
Douxfils J, Dogne JM, Mullier F and coll. Thromb Haemost 2013
Douxfils J, Mullier F and coll. Thromb Haemost 2012
van Ryn J and coll. Thromb Haemost 2010 24 24

25. How point measurement should be performed? ECT/ECA/PT
Ecarin clotting time (ECT):
Activity measurement of direct thrombin inhibitors
Absence of validation or standardization for dabigatran
Not recommended
Ecarin chromogenic assay (ECA):
reproducible
better performances than ECT in lower values
Prothrombin time (PT):
not reliable (false increase of INR)
not recommended
Douxfils J, Dogne JM, Mullier F and coll. Thromb Haemost 2013
Douxfils J, Mullier F and coll. Thromb Haemost 2012
van Ryn J and coll. Thromb Haemost 2010
Antovic JP and coll. Eur J Clin Pharmacol 2013
Gosselin RC and coll. Ann. Pharmacother.2013
Hawes EM. J Thromb Haemost 2013 25 25

26. How point measurement should be performed? Rivaroxaban/PT
ISTH recommendation:
PT can be used to determine the relative intensity of anticoagulation due to rivaroxaban
But:
Different sensitivities to rivaroxaban and apixaban
Inter-reagents variation
Does not allow quantification of plasma concentrations of rivaroxaban.
Weak correlation with LC-MS/MS
Influenced by many biological factors
Baglin T and coll. J Thromb Haemost 2013
Douxfils J, Mullier F, Thromb Res 2012
Douxfils J, Chatelain C, Chatelain B, et al. Thromb Haemost 2013 26 26

27. How point measurement should be performed? Apixaban/PT
PT may be normal with therapeutic plasma concentration of apixaban
May give information on drug intake but no information on plasma concentration
Baglin T and coll. J Thromb Haemost 2013
Douxfils J, Mullier F, Thromb Res 2012
Douxfils J, Chatelain C, Chatelain B, et al. Thromb Haemost 2013
Gouin-Thibault I. et al. A GEHT study. Thromb Haemost 2014 27 27

28. How point measurement should be performed? Rivaroxaban-apixaban/PT28 28
Douxfils, Mullier and coll. Thromb. Haemost. 2013
Douxfils, Mullier and coll. Thromb. Res. 2012

29. How point measurement should be performed? Rivaroxaban-apixaban/PT
Je préciserai que c’est que pour le rivaroxaban. 29 29
Pernod G and coll. Management of major bleeding complications….Proposals of the Working Group on Perioperative Haemostasis. Archives of Cardiovascular disease 2013

30. How point measurement should be performed? Rivaroxaban-apixaban/PT30 30
Douxfils J, Mullier F Thromb Res 2012

31. How point measurement should be performed
How point measurement should be performed? Rivaroxaban-apixaban/anti-Xa chromogenic assays
Advantage:
Less sensitive to sampling issues and factor concentrations
Rivaroxaban:
Good correlation with LC-MS/MS for concentrations higher than 30 ng/mL
<30 ng/mL, LC-MS/MS is recommended
Apixaban:
Good concordance with LC-MS/MS for concentrations > 15 ng/mL.
<15ng/ml, LC-MS/MS is recommended
Exception apixaban: Biophen heparin
® used with ACL TOP: 40ng/ml
Barrett YC, and coll. Thromb Haemost 2010
Douxfils J, and coll. Thromb Haemost 2013
Samama MM, Thromb Haemost 2012
Gouin-Thibault I. et al. A GEHT study. Thromb Haemost 2014 31 31

32. How point measurement should be performed
How point measurement should be performed? Rivaroxaban-apixaban/anti-Xa chromogenic assays
anti-Xa kits dedicated to DOACs: different methods in comparison to heparins
No recommendation on the choice of the chromogenic test
Advisable to choose kits specifically dedicated to DOACs assays, on specific platforms with respect to homogeneity (calibrator of the manufacturer of the chromogenic assay)
Not widely available, which makes complex the management of patients in acute situations.
Barrett YC, and coll. Thromb Haemost 2010
Douxfils J, and coll. Thromb Haemost 2013
Samama MM, Thromb Haemost 2012
Gouin-Thibault I. et al. A GEHT study. Thromb Haemost 2014 32 32

33. Influence of dabigatran, rivaroxaban and apixaban on coagulation tests.
Dabigatran
Rivaroxaban
Apixaban
Prothrombin Time (PT)
Time prolonged + (relative to reagent sensitivity)
Time prolonged + to +++ (relative to reagent sensitivity)
Time non-prolonged or prolonged + (relative to reagent sensitivity)
Activated Partial Thromboplastin Time (aPTT)
Activated Clotting Time
Time prolonged ++
Time prolonged +
PT-based coagulation factors measurement
(II, VII, IX, X)
Slightly decreased (depending on the reagent)
APTT-based coagulation factors measurement
(VIII, IX, XI)
Fibrinogen
No influence or slightly decrease (depending on the reagent)
No influence
D-dimer
Thrombin Time
Time prolonged +++++
Lupus anticoagulant
(dilute Russell’s Viper Venom Time)
False positive
Anti-Xa based antithrombin measurement
Increased : 10% per 100 ng/mL
Anti-IIa based antithrombin measurement
Increased : 5-10% per 100 ng/mL
AntiXa activity
Increased: variable
Protein S (chronometric)
Increased
Protein C (chronometric)
Activated protein C resistance
Influence on the ratio 33
Douxfils J,….,Mullier F Submitted

34. Influence of dabigatran, rivaroxaban and apixaban on fibrinogen assay
Clauss method:
dabigatran: depends on thrombin concentration
rivaroxaban-apixaban: no influence
TP-derived fibrinogen method:
overestimation in presence of high concentrations of rivaroxaban or apixaban
negligible influence of dabigatran
Douxfils J, Mullier F, and coll. Thromb Haemost 2012
Douxfils J, Mullier F, and coll. Thromb Res 2012
Douxfils J, Chatelain C and coll.Thromb Haemost 2013 34

35. Influence of dabigatran, rivaroxaban and apixaban on antithrombin assay
Influence of dabigatran if activity measurement is based on FIIa (not FXa)
Influence of rivaroxaban-apixaban if activity measurement is based on FXa (not FIIa)
Douxfils J, Mullier F, and coll. Thromb Haemost 2012
Douxfils J, Mullier F, and coll. Thromb Res 2012
Douxfils J, Chatelain C and coll.Thromb Haemost 2013 35

36. Influence of dabigatran, rivaroxaban and apixaban on factor assays
Dose-dependent decrease
More impact in intrinsic pathway (dabigatran-APTT) or extrinsic pathway (rivaroxaban-apixaban – PT)
Disappearance of the effect if higher plasma dilutions are used
Reduction of the effect by using APTT or PT reagents with low or no sensitivity to DOACs
Chromogenic assays: rivaroxaban doesn’t influence factor XIII activity, but shows a dose-dependent effect on the chromogenic determination of factor VIII.
Samama MM and coll. 58th Annual Meeting of the SSC of the ISTH, Liverpool; 2012.
Gerotziafas GT and coll.Thromb Res 2012
Mani H and coll. Thromb Haemost 2011
Asmis LM, and coll. Thromb Res 2012
Tichelaar V and coll. Thromb Haemost 2011
Douxfils J, Mullier F. Thromb Res 2012 36

37. Influence of dabigatran, rivaroxaban and apixaban on thrombophilic assays
Influence on coagulometric assays but not on immunological, chromogenic and ELISA assays.
Samama MM and coll. 58th Annual Meeting of the SSC of the ISTH, Liverpool; 2012.
Gerotziafas GT and coll.Thromb Res 2012
Mani H and coll. Thromb Haemost 2011
Asmis LM, and coll. Thromb Res 2012
Tichelaar V and coll. Thromb Haemost 2011
Douxfils J, Mullier F. Thromb Res 2012 37

38. EMA position Rivaroxaban

39. Clinical Cases 39

40. Case 1 Woman, 79y: BMI 33, 86kg, Cockroft 70,7ml/min
Thyroidectomy (multinodular goitre)
Cordarone 200mg 1X/j, D-cure 1x/mois, Xarelto 20 mg 1X/j (FA), Buscopan, Imodium, Zocor 40mg 1X/j
Stop Xarelto 72h, bridging by Clexane 40mg 1X/j sc (stop 24h preop)
48h after rivaroxaban arrest: 32,7 ng/ml (MS: 10ng/ml)
15 days after intervention: 37,2ng/ml 40

41. Case 1 41
Tamigniau A, Douxfils J, ……..Mullier F. Revue Med Suisse 2014

42. Case 1 42
Pernod G and coll. Management of major bleeding complications….Proposals of the Working Group on Perioperative Haemostasis. Archives of Cardiovascular disease 2013

43. Case 1: Key Messages
Optimization of lab tests still required for low values
Safety studies in the preoperative setting still required
Be careful with the interpretation 43

44. Acknowledgments Pr Bernard Chatelain Pr Jean-Michel Dogné
Ph.Jonathan Douxfils
Ph. Anne Tamigniau
Mrs Justine Baudar
Dr Nicolas Mardyla
PhAnne-Laure Sennesael
Ph Anne-Sophie Larock
Pr Anne Spinewine
Dr Anne-Sophie Dincq
Dr Sarah Lessire 44