Comparative evaluation of the safety and effectiveness of rivaroxaban (riva) and enoxaparin (enox) for treatment of venous thromboembolism (VTE) in cancer patients.

Abstract

e18268 Background: The current standard for VTE management in patients with active malignancy is low molecular weight heparin (LMWH). Direct oral anticoagulants (DOACs) are convenient options, but comparative data is lacking in cancer patients. Methods: An observational cohort study was conducted to identify patients with cancer treated with either enox or riva (institutional preferences) from December 2012 to April 2015. Patients were excluded if they received prophylactic dosing of enox, prior anticoagulation, transitioned to warfarin, or received anticoagulation for less than 15 days unless they had a bleeding event. Results: A total of 182 patients were included: enox (n = 97) and riva (n = 85). Median age was 65 years at initiation for riva vs 57 years for enox, p = 0.0007. Gender was similar between groups (54% male). Fifty-three percent (n = 97) had metastatic disease and 54% (n = 99) were actively receiving chemotherapy when diagnosed with initial VTE. Sixty-five percent (n = 119) were treated for deep venous thrombosis (DVT), 19 percent (n = 35) had pulmonary embolism (PE), and 11 percent (n = 20) had both DVT and PE. More patients initiated riva for extensive VTE’s 48% vs 29% (p = 0.02). Median duration of anticoagulation was 3.1 months in the enox group and 7.1 months in the riva group (p < 0.0001). Recurrent VTE occurred in 3 patients (one on riva). Ten percent of patients (n = 10) had a bleeding event on enox compared to 15 percent on riva (n = 13, p = 0.3). Major bleeds occurred in seven percent (n = 7) in the enox group and 8 percent (n = 7) in the riva group (p = 0.4). One fatal bleed occurred with each anticoagulant. Pharmacodynamic interactions with antiplatelet agents may have contributed to 3 major bleeds (two with riva). Three percent of patients (n = 3) experienced minor symptomatic bleeds on enox compared to six (7%) on riva. Mean time to bleeding will be presented. Conclusions: Riva is a safe and effective alternative to enox for VTE management in cancer patients. Concomitant medications must be reviewed before initiation and during anticoagulant therapy to minimize drug interactions. Randomized trials are needed to directly compare LMWH to DOACs in this population.