Thromboprophylaxis for patients with newly diagnosed vs. recurrent cancers: a post-hoc analysis of the avert trial.

Abstract

Venous thromboembolic disease (VTE) is a common complication among patients with cancer. Data reporting risk of VTE among patients receiving chemotherapy for recurrent cancer compared to those with newly diagnosed tumors is scarce. Furthermore, it is unclear if thromboprophylaxis is beneficial and safe in these specific patient populations. Post-hoc analysis of the AVERT trial which was a randomized, placebo-controlled, double-blind trial comparing apixaban therapy to placebo for VTE prophylaxis among cancer patients who were intermediate-to-high risk for VTE and who were initiating chemotherapy. The HRs for recurrent VTE and major bleeding episodes in patients with newly diagnosed and recurrent cancers were calculated using a Cox regression model controlling for age, gender, and center. Of the 563 included patients 469 and 93 patients had newly diagnosed and recurrent cancers, respectively. Patients with recurrent cancer have a higher risk of VTE (Hazard ratio (HR): 1.53 (95% CI 1.0 to 2.33; p = 0.047) and major bleeding episodes (HR 2.89 (95% CI 1.52 to 5.49; p = 0.001) compared to those with newly diagnosed cancer. In patients with newly diagnosed cancers, the use of apixaban was associated with a significantly lower risk of VTE (HR 0.45; 95% CI 0.27-0.76; p = 0.002) and a higher rate of major bleeding (HR 2.10; 95% CI 1.09-4.08; p = 0.028). In patients with recurrent cancer, apixaban was associated with a significant lower rate of VTE (HR 0.26; 95% CI 0.13-0.53; p < 0.001) without an associated significantly increased risk of major bleeding (HR 1.82; 95% CI 0.36-9.15; p = 0.466). Patients with recurrent cancer seem to be at higher risk of recurrent VTE and major bleeding complications compared to those with newly diagnosed tumors. Apixaban appears to be safe and effective in these patient populations.