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Emerging Anticoagulants for VTE Prevention and Treatment: Is change upon us?. Amanda C. Walker, PharmD Clinical Pharmacist University of Utah University Thrombosis Service. Objectives. Describe the pharmacology and mechanism of action for new and emerging anti-thrombotic agents
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Emerging Anticoagulants for VTE Prevention and Treatment: Is change upon us? Amanda C. Walker, PharmD Clinical Pharmacist University of Utah University Thrombosis Service
Objectives • Describe the pharmacology and mechanism of action for new and emerging anti-thrombotic agents • Discuss and review current randomized controlled trials for new and emerging anti-thrombotic agents for VTE prevention and treatment • Evaluate the adverse drug reactions and side effects associated with these new agents
Current Limitations Lassen MR. Vasc Health Risk Manag. 2008;4(6):1373-86.
Anti – Xa : direct Rivaroxaban (oral) Apixaban (oral) Betrixiban (oral) Edoxaban (oral) Otamixaban (parenteral) LY – 517717 (oral) DU – 176B (oral) DX – 9065a (parenteral) PRT054021 (oral) Anti – Xa : indirect Idraparinux biotinylated (parenteral) Anti – IIa Dabigatran (oral) Odiparcil (oral) Flovagatran (parenteral) Pegmusirudin (parenteral) Peg Hirudin Desiruidin New and Emerging Anticoagulants
Indirect Xa Inhibitors “-parinux” AT Direct Thrombin Inhibitors “-gatran” warfarin Site of Action for New Anti-thrombotic Agents Extrinsic XII Intrinsic XI Tissue Factor IX VII VIII Direct Xa Inhibitors “-xaban” X V II Fibrinogen Fibrin Clot
Factor Xa One Xa forms many IIa Limited role in diversity of action outside of coagulation cascade Clinical effectiveness Fondaparinux Factor IIa Supports feedback amplification through Factor V, Factor VIII, and Factor IX Has many cellular effects inflammation Clinical effectiveness Argatroban Hirudins Factor Xa vs. Factor IIa
Direct Factor Xa Inhibitors XII Intrinsic Extrinsic XI TF IX VII VIII Direct Xa Inhibitors “-xaban” X V II Fibrinogen Fibrin Clot
Oral tablet Bioavailability: 50% Peak Plasma Levels = 3 hrs Half-life ~ 12 hours Metabolized in liver via CYP3A4 and CYP independent mechanisms Eliminated via multiple pathways No laboratory monitoring required Manufactured by Bristol-Myers Squibb/Pfizer Plan to submit for U.S. approval in 2009-2010 Apixaban
Apixaban Efficacy Outcomes in TKR (Phase II) Incidence of VTE and all-cause death (%) Duration = 10 -14 days 5 QDay 2.5 BID 10 QDay 5 BID 20 QDay 10 BID Enox 30mg BID (n=152) Warf (n=153) Apixaban (mg) (n = 933) Lassen MR, et al. J Thromb Haemost. 2007;5:2368 – 2375.
Apixaban Safety Outcomes in TKR (Phase II) Incidence of bleeding events (%) 5 QDay 2.5 BID 10 QDay 5 BID 20 QDay 10 BID Enox 30mg BID (n=152) Warf (n=153) Apixaban (mg) (n = 933)
ADVANCE – 1: Results of Efficacy vs. Enoxaparin 30 mg BID RR: 1.02 (95% CI: 0.78 to 1.32) P=0.06 for non-inferiorityAbsolute Difference: 0.1% (95% CI: -2.22 to 2.44) P<0.001 for non-inferiority 8.99%N = 1157 8.85%N = 1130 Lassen MR, et al. NEJM 2009;361:594 – 604.
ADVANCE – 2: Primary Efficacy Results RR: 0.62; 95% CI: 0.51 – 0.74p<0.0001* 24.5%n = 997 15.1%n = 975 *Composite of adjudicated asymptomatic DVT by venography; objectively confirmed symptomatic DVT or PE; or death from any cause. One-sided p-value for superiority.
Summary of ADVANCE – 2 Study • Apixaban 2.5mg BID vs. Enoxaparin 40mg QD • Superior for: • Primary endpoint of ANY DVT/PE/All-Cause Death • Secondary endpoint for Major VTE • Lower observed bleeding rates • Major • Clinically relevant non-major • Similar overall safety profile
Brand name Xarelto®, Bayer Oral tablet High oral bioavailability (>80%) Onset of action 2-4 hours Half-life 9-12 hours No observed effects on agonist-induced platelet aggregation Primarily renal elimination No laboratory monitoring required No dosage adjustment for gender, age, extreme body weight Approved by Europe and Canadian agencies, and under FDA review currently Rivaroxaban
RRR 49% RRR 62% Rivaroxaban in VTE Prevention:RECORD 3 - TKA 2531 patients % % No Difference
Rivaroxaban in VTE Prevention:RECORD 4 - TKA Rivarox: RRR 31%; ARR 3.2% % % NotSignificant Turpie, et al. Lancet 2009;373:1673 – 80.
Rivaroxaban Ongoing Phase III Clinical Trials DVT Einstein-DVT Rivarox 15mg BID x 3 wks then 20mg Qday vs Enox/VKA PE Einstein-PE Rivarox 15mg BID x 3 wks then 20mg Qday vs Enox/VKA DVT/PE Einstein-Extension Rivarox 20mg Qday vs Placebo AF Rivarox 20 mg Qday vs Warfarin Medically Ill Rivarox 10mg Qday x 35 days vs Enox 40mg Qday x 10 days
Indirect Xa Inhibitors “-parinux” AT Indirect Factor Xa Inhibitors XII Intrinsic Extrinsic XI TF IX VII VIII X V II Fibrinogen Fibrin Clot
Idraparinux • Once weekly SC injection • 100% SC bioavailability • Half-life ~ 96-130 hours • Renal elimination • No monitoring required • Manufactured by Sanofi-Aventis • Plan to file for U.S. approval in 2009
Van Gogh Trials Idraparinux 2.5 mg SC qweek vs standard therapy (heparin/LMWH + VKA) DVT Study PE Study VTE Extended Study Idraparinux vs placebo 2904 patients 2215 patients 1215 patients ↔ 3- and 6-month recurrence ↓ bleeding at 3 mo ↔ bleeding at 6 mo ↔ mortality ↑3- and 6-month recurrence ↓ bleeding at 3 and 6 mo ↑ mortality ↓ recurrent events ↑ bleeding ↔ mortality
Amadeus Trial 4576 patients • Non-valvular atrial fibrillation • Idraparinux 2.5 mg SC qweek vs VKA • Trial stopped early due to excess clinically relevant bleeding with idraparinux
Idraparinux Biotinylated Idraparinux sodium Idraparinux Biotinylated Avidin Biotin arm with spacer • No pharmacological effect • IV injection • Short half-life (10-16 min)
E Q U I N O X C SSIO EA Phase III Clinical Trials with Idraparinux Biotinylated Idraparinux biotinylated 3 mg weekly vs warfarin in 6-month PE treatment (3200 patients) Idraparinux biotinylated 3 mg weekly vs idraparinux 2.5 mg weekly in 6-month DVT tx (700 patients) BOREALIS-AF Idraparinux biotinylated 3 mg weekly vs warfarin in AF (9600 patients)
Direct Thrombin Inhibitors “-gatran” Direct Thrombin Inhibitors XII Intrinsic Extrinsic XI TF IX VII VIII X V II Fibrinogen Fibrin Clot
COMPANY NEWS; F.D.A. PANEL VOTES AGAINST BACKING DRUG BY ASTRAZENECA COMPANY NEWS; F.D.A. REJECTS ASTRAZENECA'S ANTI-CLOTTING DRUG Published: September 11, 2004 Published: October 9, 2004 AstraZeneca failed to win backing from a federal government panel for its Exanta blood thinner, a possible first alternative to the drug Coumadin in more than 50 years. AstraZeneca said yesterday that federal regulators did not approve its anti-clotting drug, Exanta.
No dietary/food interactions Brand name Rendix™ or Pradaxa®, Boehringer-Ingelheim Approved in Europe March 2008; plans are to obtain U.S. FDA approval by 2010 Oral capsule Rapid onset of action Half-life 12-17 hours Renal elimination No routine monitoring required P-gp substrate—use with caution when administered concomitantly with P-gp inhibitors Dabigatran
Dabigatran Dabigatran in TKR:RE-MODEL (Phase II) % Total VTE & Death % Adverse Events n=1541 patients treated 6-10 days, followed for 3 months post-surgery Dabigatran
Dabigatran Dabigatran Dabigatran in THR:RE-NOVATE (Phase II) % Total VTE & Mortality % Adverse Events n=2651 patients treated 28-35 days, followed for 3 months post-surgery Eriksson BI et al. Lancet 2007;370:949-56.
Summary Time to Market for New Anti-Thrombotic Agents Apixaban Dabigatran Otomaxiban Idraparinuxbiotinylated Rivaroxaban 2010 2011 2012 2013
Adapted from: Gross, PL. Arterioscler Thromb Vasc Biol. 2008; 28:380-386.
Potential Limitations of New Anticoagulants • Antidotes • None of the newer agents has a specific antidote • Monitoring • Adverse Drug Events • Compliance • Cost • Clinical Trials vs. Actual Clinical Practice • Patient populations not even studied (i.e. Cancer)
Conclusion • Several oral and parenteral Anti Xa and Anti IIa drugs are under development at this time • Rivaroxaban and Dabigatran are approved in the European Union and Canada for the prophylaxis of DVT and awaiting FDA review/approval • Safety issues are of prime importance in the development of these drugs and will be strongly scrutinized upon review
What about RE-LY? Dabigatran versus Warfarin in Patients with Atrial Fibrillation • Non-inferiority trial • Over 18,000 patients • Followup = 2 years Dabigatran 110 mg and 150mg vs. Adjusted dose warfarin