Category:DOACs

A DOAC (direct oral anticoagulant; older abbreviation NOAC for "novel oral anticoagulant", now retired because the medicines are no longer novel) is an oral medicine that directly binds and inhibits a specific factor of the coagulation cascade, in contrast to the vitamin K antagonists (which indirectly reduce the synthesis of multiple coagulation factors) and the heparins (which act indirectly through antithrombin). The category contains four approved medicines in two mechanistic subclasses: the direct thrombin inhibitor dabigatran, and the direct factor Xa inhibitors rivaroxaban, apixaban, and edoxaban (the U.S./European set; betrixaban, the Asian-market darexaban, and the recently approved abelacimab targeting factor XI are mechanistically related additions in selected jurisdictions).

The DOAC pharmacology is described in detail under anticoagulants; the contents of this sub-category page focus on what is distinctive about the class: the direct-binding mechanism, the predictable pharmacokinetics that allow fixed-dose administration without routine laboratory monitoring, the rapid onset and offset that simplify perioperative management, and the increasingly available reversal-agent armamentarium.

The DOAC era began with the 2010 RE-LY trial of dabigatran versus warfarin in atrial fibrillation, which demonstrated non-inferior stroke prevention with substantially lower intracranial hemorrhage and a small mortality advantage.^[1] The 2011 ROCKET-AF trial of rivaroxaban, the 2011 ARISTOTLE trial of apixaban, and the 2013 ENGAGE AF-TIMI 48 trial of edoxaban extended the demonstration to the three principal factor Xa inhibitors, each showing non-inferior or superior efficacy versus warfarin with reduced bleeding (intracranial hemorrhage in particular) for atrial fibrillation stroke prophylaxis. Parallel trials in venous thromboembolism (RECOVER, RECOVER II, RE-MEDY, RE-SONATE for dabigatran; EINSTEIN-DVT, EINSTEIN-PE, EINSTEIN-CHOICE for rivaroxaban; AMPLIFY, AMPLIFY-EXT for apixaban; Hokusai-VTE for edoxaban) established the DOACs for treatment of deep vein thrombosis and pulmonary embolism. The DOACs have largely displaced warfarin for the major thromboembolic indications in patients without specific contraindication.

The contraindications of the DOACs remain warfarin's domain. The DOACs are not approved for the antiphospholipid syndrome (the TRAPS trial of rivaroxaban in high-risk APS showed inferior outcomes versus warfarin), for mechanical heart valves (the RE-ALIGN trial of dabigatran was stopped early for excess thromboembolic and bleeding events; warfarin remains the standard), or for moderate-to-severe mitral stenosis with atrial fibrillation. Severe renal impairment (apixaban being the most renal-friendly with caveats; dabigatran requiring substantial dose reduction below CrCl 30; rivaroxaban contraindicated below CrCl 15; edoxaban requiring careful dose-titration and not above CrCl 95) and substantial hepatic dysfunction limit DOAC use. The DOACs are not currently considered safe in pregnancy or lactation; low-molecular-weight heparins remain the standard anticoagulants for those indications.

The reversal-agent development for the DOACs is among the most active areas of contemporary haemostasis pharmacology. The humanised Fab fragment idarucizumab (Praxbind, Boehringer Ingelheim 2015) binds dabigatran with affinity 350-fold higher than dabigatran's affinity for thrombin and reverses anticoagulant effect within minutes; the REVERSE-AD study established its clinical efficacy. The recombinant inactive factor Xa decoy andexanet alfa (Andexxa/Ondexxya, Portola/Alexion 2018) binds the factor Xa inhibitors (rivaroxaban, apixaban, edoxaban) and the indirect anti-Xa medicines (low-molecular-weight heparins, fondaparinux); the ANNEXA-4 trial demonstrated efficacy in major bleeding on these agents. Four-factor prothrombin complex concentrate (4F-PCC) has off-label efficacy for factor Xa inhibitor reversal at substantially lower cost than andexanet alfa, and the comparative ANNEXa-I trial is intended to clarify the relative role.

The newest DOAC subclass is the factor XI inhibitor. Selective factor XI inhibition is hypothesised to provide anticoagulation with substantially reduced bleeding risk because factor XI is more important for pathological thrombus formation than for physiological hemostasis. Abelacimab (monoclonal antibody, Anthos), asundexian (oral small molecule, Bayer), milvexian (oral small molecule, BMS/Janssen), and several other agents are in Phase 3 trials for stroke prevention in atrial fibrillation, for VTE treatment, and for secondary cardiovascular event prevention. The OCEANIC-AF trial of asundexian in atrial fibrillation was stopped in 2023 for inferior efficacy versus apixaban; the field continues with the remaining factor XI agents.

• Direct thrombin inhibitor (factor IIa):
  • Dabigatran etexilate (Pradaxa; oral prodrug of dabigatran; the first DOAC)
• Direct factor Xa inhibitors:
  • Rivaroxaban (Xarelto, Bayer/Janssen)
  • Apixaban (Eliquis, BMS/Pfizer)
  • Edoxaban (Savaysa, Lixiana; Daiichi Sankyo)
  • Betrixaban (Bevyxxa; FDA-approved 2017 for VTE prophylaxis in acute medical illness; commercial withdrawal 2019)
• Factor XI inhibitors (in trial, not yet approved for stroke prophylaxis):
  • Abelacimab (monoclonal antibody)
  • Asundexian (oral small molecule; OCEANIC-AF stopped 2023)
  • Milvexian (oral small molecule)
• Reversal agents (cross-listed under anticoagulants; not DOACs but listed here for clinical-decision context):
  • Idarucizumab (Praxbind; for dabigatran)
  • Andexanet alfa (Andexxa; for factor Xa inhibitors)
  • Four-factor prothrombin complex concentrate (KCentra; off-label for factor Xa inhibitor reversal)

The boundary of this category is "medicine that directly binds and inhibits a coagulation-cascade factor and is administered orally." The intravenous direct thrombin inhibitors (argatroban, bivalirudin, hirudin, the recombinant lepirudin and desirudin) are mechanistically related but not oral and are listed under anticoagulants separately. The factor Xa inhibitors that act indirectly through antithrombin (low-molecular-weight heparins, fondaparinux) are not DOACs in this category sense and are listed under anticoagulants. The antiplatelet agents act on platelets rather than the coagulation cascade and are categorised separately. The fibrinolytic medicines (tissue plasminogen activator and related) lyse already-formed thrombus rather than preventing its formation and are listed elsewhere.

This category page is an encyclopedia article about its subject. The actual index of medicines belonging to the category is generated automatically by the wiki engine, from category-membership declarations on the individual medicine pages, and appears at the foot of the page below the references.