Effectiveness of Fondaparinux in the Japanese Population with Acute Venous Thromboembolism -A Study Comparing Patients with and without Cancer.

Objective Venous thromboembolism (VTE) is a common cancer complication. Patients with cancer have a high risk of recurrent VTE and bleeding. We analyzed the effectiveness of VTE treatment via subcutaneous fondaparinux injection for patients with and without cancer. Methods This study included 260 inpatients who had received fondaparinux therapy. Fondaparinux's therapeutic effect was quantitatively and qualitatively evaluated by imaging tests. To quantitatively evaluate the deep vein thrombosis (DVT) clot burden of the lower limbs, we calculated the quantitative ultrasound thrombosis (QUT) score, which was devised by our institution. Results There were 80 and 180 patients with and without cancer, respectively. The QUT score significantly reduced after treatment in both groups (cancer: 6.70±4.37 vs. 4.19±4.17, p<0.001; noncancer: 7.08±4.37 vs. 4.17±3.94, p<0.001). The changes in the QUT score showed no significant difference between the 2 groups (cancer: 2.23±3.09; noncancer: 3.04±3.45, p=0.06). In addition, the quantitative evaluation of pulmonary thromboembolism (PTE) after treatment showed that PTE decreased or disappeared in 38/40 patients (95.0%) in the cancer group and 55/63 patients (87.3%) in the noncancer group, indicating no significant difference in the improvement rate between the groups. Conclusion Fondaparinux was effective for VTE both in patients with and without cancer, with no significant differences in the changes in the QUT score. However, the change in the QUT score was smaller in patients with cancer than in those without cancer, suggesting that the efficacy of fondaparinux might be diminished in patients with cancer.