Comparison of Clinical Outcomes in Patients with Active Cancer Receiving Rivaroxaban or Low Molecular Weight Heparin - The OSCAR-UK Study.

BACKGROUND: In most patients with cancer-associated venous thromboembolism (CAT), essentially those not at high-risk of bleeding, guidelines recommend treatment with direct oral anticoagulants as an alternative to low molecular weight heparins (LMWHs). Population-based studies comparing these therapies are scarce.

OBJECTIVES: To compare the risk of venous thromboembolism (VTE) recurrences, significant bleeding and all-cause mortality in patients with CAT, receiving rivaroxaban or LMWHs.

PATIENTS/METHODS: Using UK Clinical Practice Research Datalink data from 2013-2020, we generated a cohort of patients with first CAT treated initially with either rivaroxaban or LMWH. Patients were observed 12 months for VTE recurrences, significant bleeds (major bleeds or clinically-relevant non-major bleeding requiring hospitalisation) and all-cause mortality. Overlap weighted sub-hazard ratios (SHRs) compared rivaroxaban with LMWH in an intention-to-treat analysis.

RESULTS: The cohort consisted of 2259 patients with first CAT, 314 receiving rivaroxaban, and 1945 LMWH, mean age 72.4 and 66.9 years, respectively. In the 12-month observational period, 184 person-years following rivaroxaban and 1057 following LMWH, 10 and 66 incident recurrent VTE events, 20 and 102 significant bleeds, and 10 and 133 deaths were observed in rivaroxaban and LMWH users, respectively. The weighted SHR at 12 months for VTE recurrences in rivaroxaban compared with LMWH were 0.80 (0.37-1.73); for significant bleeds 1.01 (0.57-1.81); and for all-cause mortality 0.49 (0.23-1.06).

CONCLUSION: Patients with CAT, not at high risk of bleeding, treated with either rivaroxaban or LMWH have comparable effectiveness and safety outcomes. This supports the recommendation that rivaroxaban is a reasonable alternative to LMWH for the treatment of CAT.