ON JUNE 23, 2017, the U.S. Food and Drug Administration (FDA) approved betrixaban (Bevyxxa) for the prophylaxis of venous thromboembolism in adult patients hospitalized for an acute medical illness who are at risk for thromboembolic complications due to moderate or severe restricted mobility and other risk factors for venous thromboembolism.
The APEX Study
APPROVAL WAS BASED on data from the APEX study, a randomized, double-blind, multinational clinical trial comparing extended duration betrixaban (35 to 42 days) to short duration of enoxaparin (6 to 14 days) in the prevention of venous thromboembolism in an acutely medically ill hospitalized population with risk factors for venous thromboembolism. The trial randomized 7,513 patients to receive either betrixaban or enoxaparin treatment.
Patients on the betrixaban arm took an initial dose of 160 mg orally on day 1, then took 80 mg once daily for 35 to 42 days, and received a placebo injection once daily for 6 to 14 days. Patients on the enoxaparin arm received 40 mg subcutaneously once daily for 6 to 14 days and took a placebo pill orally once daily for 35 to 42 days.
Efficacy was measured in 7,441 patients by a composite outcome score comprising either the occurrence of asymptomatic or symptomatic proximal deep-vein thrombosis, nonfatal pulmonary embolism, or venous thromboembolism–related death. Fewer events were observed in patients receiving betrixaban (4.4%) compared with those taking enoxaparin (6%; relative risk = 0.75, 95% confidence interval = 0.61–0.91).
The most common adverse reactions (≥ 5%) with betrixaban were related to bleeding. Overall, 54% of patients receiving betrixaban experienced at least one adverse reaction compared with 52% taking enoxaparin. The frequency of patients reporting serious adverse reactions was similar between betrixaban (18%) and enoxaparin (17%). The most frequent reason for treatment discontinuation was bleeding, with an incidence rate for all bleeding episodes of 2.4% and 1.2% for betrixaban and enoxaparin, respectively. The incidence rate for major bleeding episodes was 0.67% and 0.57% for betrixaban and enoxaparin, respectively.
The recommended dose of betrixaban is an initial single dose of 160 mg starting on day 1, followed by 80 mg once daily taken for 35 to 42 days at the same time each day with food. ■