Should Clexane (enoxaparin) be continued for 6 months or can oral anticoagulants be used in patients with active Deep Vein Thrombosis (DVT) on chemotherapy?

Management of Anticoagulation in Cancer-Associated DVT

For patients with active cancer and DVT on chemotherapy, either DOACs (apixaban, edoxaban, or rivaroxaban) or LMWH (enoxaparin/Clexane) can be used after the initial 6 months of treatment, with DOACs being a preferred option due to their oral administration and similar efficacy with potentially lower bleeding risk. 1

Initial Treatment Phase (First 6 Months)

• The American Society of Hematology (ASH) 2021 guidelines recommend LMWH or DOACs (apixaban, edoxaban, or rivaroxaban) for the initial treatment of VTE in cancer patients 1
• For the short-term treatment (3-6 months), ASH suggests DOACs over LMWH (conditional recommendation, low certainty evidence) 1
• NCCN guidelines similarly recommend either DOACs or LMWH for initial treatment of VTE in cancer patients 1

Extended Treatment Phase (Beyond 6 Months)

Recommendations for Extended Therapy:

• ASH guidelines suggest long-term anticoagulation for secondary prophylaxis (>6 months) rather than short-term treatment alone (3-6 months) for patients with active cancer and VTE 1
• For patients requiring long-term anticoagulation (>6 months), ASH suggests using either DOACs or LMWH 1
• NCCN guidelines recommend continuing anticoagulation as long as cancer is active, under treatment, or if risk factors for recurrence persist 1

Evidence Supporting DOACs for Extended Treatment:

• Recent evidence shows that reduced-dose apixaban (2.5 mg twice daily) is noninferior to full-dose apixaban (5 mg twice daily) for prevention of recurrent VTE in cancer patients, with a lower incidence of clinically relevant bleeding (12.1% vs 15.6%) 2
• Real-world data demonstrates that extended treatment with apixaban is associated with lower rates of recurrent VTE (4.1 vs 9.6 per 100 person-years), major bleeding (6.3 vs 12.6), and clinically relevant non-major bleeding (26.1 vs 36.0) compared to LMWH 3

Practical Considerations for Switching from LMWH to Oral Anticoagulants

Advantages of DOACs over LMWH:

• Oral administration (improved patient convenience)
• No need for regular monitoring
• Similar or better efficacy with potentially lower bleeding risk
• Improved compliance due to oral administration

Recommended DOAC Options:

• Apixaban: 5 mg twice daily (or reduced dose 2.5 mg twice daily for extended treatment) 4, 2
• Rivaroxaban: 15 mg twice daily for 21 days, then 20 mg daily 1
• Edoxaban: After 5 days of parenteral anticoagulation

Special Considerations

• For patients with gastrointestinal cancers, LMWH may be preferred due to potentially higher bleeding risk with DOACs in this population 1
• Renal function should be monitored, as DOACs require dose adjustments or may be contraindicated in severe renal impairment 1
• Drug interactions should be assessed, particularly with certain chemotherapy agents

Duration of Therapy

• For patients with active cancer, ASH guidelines suggest continuing indefinite anticoagulation over stopping after completion of a definitive period 1
• Reassessment of the risk-benefit ratio should be performed periodically, considering:
  • Cancer status (active vs remission)
  • Ongoing cancer treatment
  • Bleeding risk
  • Patient preference

In summary, while LMWH (Clexane) has historically been the standard of care for cancer-associated thrombosis, current evidence and guidelines support transitioning to oral anticoagulants (DOACs) after the initial 6 months of therapy, particularly for patients who prefer oral medication and don't have contraindications to DOACs.