Biomarkers for new anticoagulants vice and virtue

Transcription

1 Biomarkers for new anticoagulants vice and virtue Dagmar Kubitza, MD AGAH, München 2014 Page 1

2 Definition of Biomarkers?. Surrogate markers are primary measures the effectiveness of investigational drugs. Page 2

3 Biomarkers for new oral anticoagulants which biomarkers? Charles Esmon, Ann Rev Cell Biol 1993 Page 3

4 New oral anticoagulants mode of action? Turpie, Current Opinion in Drug Disc & Dev 2009 Page 4

5 Biomarkers for new anticoagulants - the old fashioned way? Mani et al, Thrombosis Journal 2013 Page 5

6 Dabigatran has a low sensitivity for PT Douxfils et al, Thromb Heamost 2012 Page 6

7 Direct inhibitors of Factor Xa prolong PT Samama et al, Thrombosis Haemostasis 2010 Page 7

8 Direct inhibitors of Factor Xa prolong PT Samama et al, Thrombosis Haemostasis 2010 Samama et al, Thrombosis Research 2011 Page 8

9 Direct inhibitors of Factor Xa prolong PT Samama et al, Thrombosis Haemostasis 2010 Douxfils et al, Thrombosis Haemostasis 2013 Samama et al, Thrombosis Research 2011 Page 9

10 Direct inhibitors of Factor Xa prolong PT Samama et al, Thrombosis Haemostasis 2010 Douxfils et al, Thrombosis Haemostasis 2013 Fonaparinux has no effect on PT Samama et al, Thrombosis Research 2011 Page 10

11 Some direct inhibitors of Factor Xa prolong PT Samama et al, Thrombosis Haemostasis 2010 Douxfils et al, Thrombosis Haemostasis 2013 Fonaparinux has no effect on PT Samama et al, Thrombosis Research 2011 Page 11

12 Calculation of INR does not decrease the variablility of the results of the different thromboplastin reagents Samama et al, Thrombosis Research 2011 Page 12

13 Background information about PT PT assays are designed to reliably measure the effect of Vitamin K antagonists Different reagents use different thromboplastins to start the clot formation ex vivo, e.g. rabbit brain, placenta, recombinant Concentrations of phospholipids and ions vary between tests and even between lots. Components are added to ensure the optimal performance of tests, some assays even contain heparins. ISI (international sensitivity index) should ensure comparability between tests, but they are optimized for Vitamin K antagonists. Page 13

14 What influences the PT sensitivity of direct Factor Xa inhibitors? PT sensitivity of Rivaroxaban varies depending on the composition of the thromboplastin reagent PT sensitivity increases with Decreasing concentrations of tissue factor Increasing concentratíons of phospholipids and NaCL Presence of phosphadidylethanolamine PT sensitivity decreases with Increasing percentage of phosphadidylserine Smith & Morrissey, Blood 2007 Page 14

15 Why? Hpothesis The faster that factor Xa is generated and assembled into the prothrombinase complex, the less sensitive will the clotting time be on Rivaroxaban concentration. Perhaps this is because it allows factor Xa to generate thrombin before Rivaroxaban can inhibit it effectively during the very short duration of most clotting tests. Smith & Morrissey, Blood 2007 It remains unclear why Apixaban behaves different than Rivaroxaban and Edoxaban. Page 15

16 Is PT a useful biomarker? PT can be used to provide insights into the pharmacodynamic effects of anticoagulants if comparisons are made for one compound comparisons are made from preclinical to clinical study results, provided that the same assay is used comparisons are made between studies of one compound and a central lab has been used Comparisons of pharmacodynamic effects between different compounds cannot be reliably done with PT Page 16

17 Will a broader view on the coagulation system provide better insights? Page 17

18 Will a broader view on the coagulation system provide better insights? Endogenous thrombin potential (ETP) Is the total amount of thrombin which is generated in plasma It reflects the sum of the activity and concentration of pro-coagulant and anti-coagulant substances ETP-AUC total amount of thrombin that can be generated Peak Maximal hight of the TG curve Lag time Time interval until thrombin generation starts Time to peak Time interval until the peak of thrombin generation occurrs Page 18

19 Influence of Dabigatran on Thrombin Generation Dabigatran mainly delayed the initiation phase with strong dose-dependent increase of lag time and time to peak and a slight dose-dependent decrease in peak hight and ETP Douxfils et al, Thromb Haemost 2012 Page 19

20 Influence of Rivaroxaban on Thrombin Generation a contol b 5nM ~ 2,2 µg/l c 10nM ~ 4,4 µg/l d 20nM ~ 8,7µg/L e 50nM ~21,7µg/L f 80nM ~34,9µg/L g100nm ~43,5µg/L Gerotziafas et al, J Thromb Haemost 2007 Page 20

21 Influence of Rivaroxaban and Edoxaban on Thrombin Generation a contol b 5nM ~ 2,2 µg/l c 10nM ~ 4,4 µg/l d 20nM ~ 8,7µg/L e 50nM ~21,7µg/L f 80nM ~34,9µg/L g100nm ~43,5µg/L Rivaroxaban and Edoxaban affect the initiation and amplification phase of thrombin generation by affecting all parameters of TG Gerotziafas et al, J Thromb Haemost 2007 Samama et al, Thrombosis Research 2012 Page 21

22 Influence of Apixaban on Thrombin Generation Douxfils et al, Thrombosis Haemost 2013 Page 22

23 Influence of Apixaban and Fondaparinux on Thrombin Generation Douxfils et al, Thrombosis Haemost 2013 Samama et al, Thrombosis Research 2012 Apixaban and Fondaprinux mainly act on the amplification phase of TG by affecting the peak and the velocity rate index Page 23

24 Will a broader view on the coagulation system provide better insights? Thrombin Generation is a sensitive marker for anticoagulant effects independent of the mode of action. Compounds with a different mode of action have different effects on TG. Compounds with the same mode of action have different effects on TG. Comparisons of pharmacodynamic effects between different compounds cannot be reliably done. It remains unclear what the clinical relevance of the differences in influence of individual parameters of TG is. Page 24

25 Can the DOAKs be reliably measured in clinical practice? Page 25

26 Dabigatran can be measured with HTI Hemoclot Thrombin Inhibitor Douxfils et al, Thromb Haemost 2012 Hemoclot Thrombin Inhibitor shows a concentation dependent prolongation of clotting time with linear relation and a good reproducibility Page 26

27 Anti-Xa assays with specific calibrators and controls for Rivaroxaban show linear concentration dependent decrease in OD Samama et al, J Thromb Thrombolysis, 2012 Hyphen Biomed, France Samama et al, Thromb Heamost, 2010 Page 27

28 Anti-Xa assays with specific calibrators and controls for Rivaroxaban and Edoxaban show linear concentration dependent decrease in OD Samama et al, J Thromb Thrombolysis, 2012 Hyphen Biomed, France Samama et al, Thromb Heamost, 2010 Samama et al, Thrombosis Research 2012 Page 28

29 Anti-Xa assays with specific calibrators and controls for Apixaban Douxfils et al, Thrombosis Haemost 2013 Most sensitive reagents show an exponential correlation but the dynamic range of quantification is lower. Page 29

30 Can the DOAKs be reliably measured in clinical practice? Chromogenic assays with drug specific calibrators and controls can be used to reliably measure direct oral anticoagulants Page 30

31 Biomarkers for new anticoagulants vice and virtue Yes, the pharmacodynamic effects of the DOACs can be determined by biomarkers BUT Mani et al, Thrombosis Journal 2013 Page 31

32 Biomarkers for new anticoagulants vice and virtue Yes, the pharmacodynamic effects of the DOACs can be determined by biomarkers BUT Many influencing factors have to be considered in interpreting the results. Mani et al, Thrombosis Journal 2013 Page 32

33 Thank you!