Effectiveness and Safety of Extended Treatment Apixaban Versus Low-Molecular-Weight Heparin in Cancer-Associated Venous Thromboembolism.

Background: Limited real-world evidence is available comparing the safety and effectiveness of apixaban and low-molecular-weight heparins (LMWHs) for preventing recurrent venous thromboembolism (VTE) in patients with active cancer receiving anticoagulation in an extended treatment setting. This study evaluated the risk of bleeding and recurrent VTE in patients with cancer-associated VTE who were prescribed apixaban or LMWH for ≥3 months.

Methods: A US commercial claims database was used to identify adult patients with VTE and active cancer who initiated apixaban or LMWH 30 days following the first VTE diagnosis and had ≥3 months of continuous enrollment and 3 months of primary anticoagulation treatment. Patients were followed from the day after the end of primary anticoagulation treatment until the earliest of: date of disenrollment, discontinuation of index anticoagulant, switch to another anticoagulant, or end of the study period. Inverse-probability treatment weighting (IPTW) was used to balance treatment cohorts. Incidence rates (IRs) for the outcomes were calculated per 100 person-years (PY). Cox proportional hazard models were used to evaluate the adjusted risk of recurrent VTE, major bleeding (MB), and clinically relevant nonmajor bleeding (CRNMB).

Results: A total of 13,564 apixaban- and 2,808 LMWH-treated patients were analyzed. Post-IPTW, the treatment cohorts were balanced. Patients receiving apixaban had lower adjusted IRs for recurrent VTE (4.1 vs 9.6 per 100 PY), MB (6.3 vs 12.6), and CRNMB (26.1 vs 36.0) versus LMWH (P<.0001 for all comparisons) during the follow-up period. Patients on apixaban had a lower adjusted risk of recurrent VTE (hazard ratio [HR], 0.42; 95% CI, 0.34-0.53), MB (HR, 0.50; 95% CI, 0.41-0.61), and CRNMB (HR, 0.76; 95% CI, 0.68-0.85) versus LMWH.

Conclusions: Extended anticoagulation treatment of ≥3 months with apixaban was associated with lower rates of recurrent VTE, MB, and CRNMB compared with LMWH in adults with cancer-associated VTE.