Treatment with rivaroxaban monotherapy vs combination therapy was associated with primary endpoint event rates of 4.14% and 5.75% per patient-year, respectively (HR 0.72; 95% CI, 0.55 to 0.95; P<0.001 for non-inferiority). The trial was stopped after a median treatment duration of 23 months because of a higher incidence of death from any cause in the combination-therapy group. Rivaroxaban monotherapy was superior to combination therapy for the primary safety end point, with event rates of 1.62% and 2.76% per patient-year, respectively (HR 0.59; 0.39 to 0.89; P=0.01 for superiority).