Monitoring anti-Xa levels in patients with cancer-associated venous thromboembolism treated with bemiparin

To analyze the relationship between therapeutic (weight-adjusted) dose of bemiparin and anti-Xa activity in patients with venous thromboembolism (VTE) and cancer in comparison with a cohort of patients with VTE without cancer, and its relationship with outcomes.

This is a prospective cohort study that comprised a cohort of patients with cancer-associated VTE and a cohort of non-cancer patients with VTE, all of them treated with bemiparin. The ethics committee approved the study and informed consent was obtained from the patients.

One hundred patients were included (52 with cancer and 48 without cancer), with a median follow-up of 9.8 months. Mean anti-Xa activity was 0.89 (± 0.33) UI/mL in oncological patients and 0.83 (± 0.30) UI/mL in non-cancer patients (mean difference - 0.05 95% CI - 0.18; 0.06). A multiple linear regression model showed that anti-Xa peak was associated with the dose/kg independently of possible confounding variables (presence of cancer, age, sex and eGFR-estimated Glomerular Filtration Rate), in a way that for every 1 UI of dose/kg increase, the anti-Xa peak activity increased 0.006 UI/mL (95% CI 0.003; 0.009) (p < 0.001). The predictive capacity of anti-Xa peak in the oncology cohort showed an area under the ROC curve of 0.46 (95% CI 0.24-0.68), 0.70 (95% CI 0.49-0.91) and 0.74 (95% CI 0.44-0.94) for death, first bleeding and recurrence of VTE, respectively, and none was statistically significant.

In patients with venous thromboembolism treated with bemiparin, anti-Xa levels were not influenced by the presence of cancer.