VTE Risk Reduction for Betrixaban vs. Enoxaparin in Post-Parenteral Period

The results indicated that VTE did not differ between betrixaban vs. enoxaparin during parenteral therapy
The results indicated that VTE did not differ between betrixaban vs. enoxaparin during parenteral therapy

WASHINGTON, DC—Extended use of betrixaban beyond the usual period of parenteral prophylaxis with enoxaparin reduced venous thromboembolism (VTE) incidence among medically ill patients, reported C. Michael Gibson, BIDMC, Boston, MA, at the ACC.17 Scientific Session.

Prophylaxis for VTE while the patient is hospitalized has been shown to cut the risk of an in-hospital VTE by half. "The majority of VTE events, however, occur after the hospital discharge," explained Gibson. 

Currently, there is no approved anticoagulant for extended-duration use in medically ill patients after hospital discharge who are already at a higher risk for VTE. Moreover, clinical guidelines recommend against thromboprophylaxis after leaving the hospital. There have been concerns about the period after discontinuing anticoagulation and how extended anticoagulation may "only delay the occurrence of thrombotic events."

The APEX (Acute Medically Ill VTE Prevention with Extended Duration Betrixaban) trial examined the safety and efficacy of extended thromboprophylaxis with betrixaban (35–42 days) vs. standard duration enoxaparin (10±4 days). For the post hoc analysis, Gibson and coauthors aimed to study the time to first occurrence of the composite of symptomatic deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE), or VTE-related mortality. The primary safety endpoint was ISTH major bleeding happening within 7 days of study drug discontinuation.

These outcomes were evaluated in an analysis following discontinuation of active parenteral therapy in the enoxaparin group vs. discontinuation of placebo parenteral therapy in the betrixaban group. "Following discontinuation of enoxaparin parenteral therapy, active betrixaban was compared to placebo betrixaban in the enoxaparin arm," explained Gibson. 

The results indicated that VTE incidence did not differ between betrixaban vs. enoxaparin during the standard parenteral therapy period (hazard ratio [HR] 0.67, 95% CI: 0.24–1.88; P=0.44). After discontinuation of parenteral therapy, extended betrixaban was found to reduce VTE (HR 0.61, 95% CI: 0.38–0.99; P=0.041). This trend continued after visit 3 until the end of follow-up (HR 0.17, 95% CI: 0.04–0.74; P=0.007), Gibson added.

Findings from the study support that extended duration betrixaban after the usual parenteral prophylaxis with enoxaparin lowered VTE incidence among medically ill patients.