I NUOVI ANTICOAGULANTI ORALI MECCANISMO D AZIONE E FARMACOLOGIA SOPHIE TESTA CENTRO EMOSTASI E TROMBOSI LABORATORIO ANALISI CHIMICO-CLINICHE E MICROBIOLOGICHE Istituti Ospitalieri di Cremona FARMACI ANTICOAGULANTI J.W. Eikelboom, Circulation 2010 ANTICOAGULANTI ORALI VAO Vecchi Anticoagulanti Orali NOA Nuovi Anticoagulanti Orali AVK Anti Vitamina K AOD Anticoagulanti Orali Diretti DOA: MECCANISMO D AZIONE XIIa XIa IXa VIIa VIIIa inibitori FXa Xa Va inibitori FIIa Fibrinogeno IIa Fibrina warfarin CARATTERISTICHE DEI FARMACI ANTICOAGULANTI AD AZIONE DIRETTA ORIGINE SINTETICA RAPIDO INIZIO SELETTIVITA D AZIONE CONFEZIONE ORIGINALE DEL WARFARIN TAO: MECCANISMO D’AZIONE Vitamin K Antagonism of Vitamin K sintesi di fattori VII emostatici NON IX FUNZIONANTI X II Warfarin Loading Dose then Maintenance Dose Daily Dose Maintenance Dose Only Daily Dose ORAL ANTICOAGULANT TARGET SITES Factor IX Factor VII Factor X Anti-FXa drugs FVIIa VKA drugs FIXa • Apixaban • Betrixaban • Edoxaban • Rivaroxaban • LY 517717 • TAK 442 • YM 150 • Tecarfarin • Warfarin Factor Xa Antithrombin Anti-FIIa drugs Factor II (Prothrombin) Fibrinogen • Dabigatran • Ximelagatran • AZD 0837 Factor IIa (Thrombin) Fibrin FARMACOCINETICA E FARMACODINAMICA • FARMACOCINETICA: assorbimento, distribuzione, metabolismo, escrezione • FARMACODINAMICA: effetti biochimici e funzionali del farmaco e il meccanismo d’azione 1) siti d’azione del farmaco 2) relazione tra dose del farmaco e risposta funzionale AVK- DOA Poulsen BK et al, Drugs 2011 DABIGATRAN: CLINICAL DEVELOPMENT Postsurgical prophylaxis of DVT DVT Treatment RE-MODEL RE-COVER RE-MOBILIZE RE-MEDY RE-NOVATE RE-SONATE RE-NOVATE 2 Stroke Prevention in AF RE-LY ACS RE-DEEM RIVAROXABAN: CLINICAL DEVELOPMENT Postsurgical prophylaxis of DVT DVT Treatment Stroke Prevention in AF ACS ODIXa-KNEE EINSTEIN-DVT ROCKET-AF ATLAS ODIXa-HIP EINSTEIN-EXT ROCKET-J RECORD-1 EINSTEIN-PE RECORD-2 RECORD-3 RECORD-4 ACS-TIMI 46 ATLAS ACS-TIMI 51 APIXABAN: CLINICAL DEVELOPMENT Postsurgical prophylaxis of DVT DVT Treatment APROPOS Botticelli DVT ADVANCE-1 AMPLIFY ADVANCE-2 AMPLIFY-EXT ADVANCE-3 Stroke Prevention in AF ARISTOTLE AVERROES ACS APPRAISE-1 APPRAISE-2 (study terminated because of bleeding) APPRAISE Japan EDOXABAN: CLINICAL DEVELOPMENT Postsurgical prophylaxis of DVT Oral direct FXa inhibition with E for thrombophylaxis after elective THR: a randomized double-blind doseresponse study DVT Treatment The Edoxaban Hokusai-VTE Study Stroke Prevention in AF Randomized, parallel-group, multicenter, multinational Phase II study comparing E, an oral factor Xa inhibitor, with warfarin for SPAF STARS J-1 ENGAGE AF-TIMI 48 STARS J-2 Safety of edoxaban, an oral factor Xa STARS E-3 STARS J-4 STARS J-5 inhibitor, in Asian patients with NVAF DOA Somministrati a dosi fisse in relazione a : -breve emivita - piu’ ampia finestra terapeutica rispetto a warfarin -minori interazioni rispetto a warfarin FDA ANALYSIS OF RE-LY FDA ANALYSIS OF RE-LY FDA ANALYSIS OF ROCKET PT AND RISK OF BLEEDING IN MAJOR ORTHOPEDIC SURGERY (RIVAROXABAN 10mg/die) Douxfils J et al, Thromb Res 2012 PT AND RISK OF BLEEDING IN ATRIAL FIBRILLATION (RIVAROXABAN 20mg/die) Douxfils J et al, Thromb Res 2012 INTERAZIONI FARMACOLOGICHE Interactions should be properly evaluated. Whenever a concomitant therapy is ongoing with a drug likely to interfere with NAO, a lab control should be performed (Pengo, 2011). Many of these drugs interact with warfarin, but INR levels allows dose adjustment, which mitigates the risk of concomitant treatment (Schulman S et al, 2012) Stangier et al. Clin Pharmacokinet 2010 Stangier et al. Clin Pharmacokinet 2010 INFLUENCE OF RENAL IMPAIRMENT ON THE PHARMACOKINETICS AND PHARMACODYNAMICS OF ORAL DABIGATRAN ETEXILATE: AN OPEN-LABEL, PARALLEL-GROUP, SINGLE- CENTRE STUDY • Exposure to dabigatran is increased by renal impairment and correlates with the severity of renal dysfunction • A decrease in the dose and/or an increase in the administration interval in these patients may be appropriate • In patients with end-stage renal disease (ESRD) dabigatran can be partly removed from the plasma by haemodialysis • AUC data was about two-fold greater in elderly men (> 65 years) than in young subjects after twice-daily dosing, presumably due to the 20-30% lower creatinine clearance Stangier et al. Clin Pharmacokinet 2010 Renal disease Hepatic disease Kreutz R, Fundamental Clin Pharmacol 2011 DOA: LIVER AND RENAL FUNCTION LIVER AND RENAL FUNCTION POSSIAMO MISURARE LA CONCENTRAZIONE DEI DOA? SI DOA FARMACO CONTROLLO Dabigatran (ng/ml) dTT aIIa Rivaroxaban (ng/ml) aXa PT R* Apixaban (ng/ml) aXa * Diversa sensibilita’ dei reagenti Pengo V et al, T&H 2011; Tripodi A. et al, 2012; Douxfils J et al, T&H 2012, Baglin T et al, BJH 2012, Douxfils J et al, ASH 2013 (abst) CONCLUSIONI • In tempi brevissimi saranno disponibili numerosi farmaci anticoagulanti orali che presentano caratteristiche differenti • Hanno un meccanismo d’azione selettivo e diretto contro 1 singolo fattore della coagulazione. • Presentano una finestra terapeutica piu’ ampia rispetto ai farmaci dicumarolici e questo favorisce la somministrazione a dosi fisse giornaliere • Alcune condizioni modificano la farmacocinetica e la farmacodinamica dei DOA: insuff epatica, renale, pazienti anziani, interazioni farmacologiche….