Apixaban Reduces Hospitalization In Patients With Venous Thromboembolism: An Analysis Of The AMPLIFY-EXT Trial

Venous thromboembolism (VTE) is associated with a considerable risk for morbidity and recurrence and related hospitalizations. In the Apixaban after the Initial Management of Pulmonary Embolism and Deep Vein Thrombosis with First-Line Therapy-Extended Treatment (AMPLIFY-EXT) trial, a double-blind placebo-controlled trial with 12 months of treatment, two doses of apixaban (2.5 mg and 5 mg, twice daily) versus placebo significantly reduced symptomatic recurrent VTE or all-cause death without increasing the rate of major bleeding among 2,482 VTE patients who had completed 6-12 months of anticoagulation therapy. In this study, the effects of apixaban therapy versus placebo on medical hospitalization during AMPLIFY-EXT trial were evaluated.

A total of 2,477 patients who received study drugs were included in the analysis. All-cause hospitalizations during the trial were captured by dedicated case report forms. Outcomes of interest were; rate of hospitalizations and time from randomization to the first hospitalization. Patients were censored at either death, loss to follow-up, or end of study, whichever came first. Effects of treatment with apixaban versus placebo on the rates of hospitalization were assessed using Cox proportional hazards regression models.

During a mean follow-up of 12.3 months, 138 patients were hospitalized at least once, 62 (7.5%/year) in the placebo group (n=826), 42 (4.8%/year) in the apixaban 2.5 mg group (n=840), and 34 (4.0%/year) in the apixaban 5 mg group (n=811). Compared with placebo, apixaban 2.5 mg [hazard ratio (HR) 0.65, 95% confidence interval (CI) 0.44–0.96; p=0.030] and 5 mg (HR 0.54, 95%CI 0.36–0.83, p=0.004) were both associated with significant reduction in hospitalization. There was no significant difference in hospitalizations between the 2 doses of apixaban (5 mg vs. 2.5 mg: HR 0.84, 95%CI 0.53–1.32, p=0 .445). The mean time to first hospitalization was 153.7 days in the placebo group, 196.9 days in the apixaban 2.5 mg group, and 202.4 days in the apixaban 5 mg group (Figure).

Figure 1

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Cumulative hazard plot of first hospitalization, according to the treatment group

Figure 1

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Cumulative hazard plot of first hospitalization, according to the treatment group

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Extended anticoagulation with apixaban at either a dose of 5 mg or 2.5 mg significantly reduced the risk of hospitalization, possibly due to the reduction in VTE recurrence.

Liu:Pfizer: Employment, Equity Ownership. Thompson:Pfizer: Employment, Equity Ownership. Phatak:BMS: Employment, Equity Ownership. Mardekian:Pfizer: Employment, Equity Ownership. Porcari:Pfizer: Employment, Equity Ownership. Johnson:Pfizer: Employment, Equity Ownership.