Enoxaparin in Weight-Based Dosing for Thromboprophylaxis in Hospitalized Cancer Patients
Cancer patients are at higher risk of developing thromboembolic disease during hospitalization. Currently, there is not enough evidence supporting the efficacy and safety of the standard fixed dose of low molecular weight heparin in individuals at high risk of thromboembolic disease. Therefore, a Phase II clinical study evaluated the efficacy and safety of weight-adjusted dosing in these patients.
Introduction
Cancer is a significant risk factor for developing thromboembolic disease. Leading academic societies therefore recommend routine thromboprophylaxis in cancer patients during hospitalization. However, these recommendations are largely derived from results for cohorts without cancer. Published studies show a higher incidence of thromboembolic disease in hospitalized cancer patients compared to other hospitalized individuals.
The standard approach to thromboprophylaxis in hospitalized cancer patients is to administer a standard fixed dose of low molecular weight heparin. When administering enoxaparin at a dose of 40 mg once daily, anti-Xa levels often fall below the effective prophylactic range. Therefore, a Phase II clinical study focused on comparing the efficacy and safety of weight-based dosing of enoxaparin versus standard enoxaparin dosing in hospitalized patients at high risk of thromboembolic disease as determined by the Padua and Khorana scores.
Study Methodology
A total of 50 patients participated in the randomized double-blind Phase II clinical study. They were equally randomized to thromboprophylaxis with a fixed dose of enoxaparin 40 mg once daily or thromboprophylaxis with enoxaparin dosed at 1 mg/kg body weight once daily (with a maximum daily dose of 100 mg). The primary objective was to evaluate the safety of weight-based enoxaparin dosing and the incidence of thromboembolic disease in patients on a fixed dose of enoxaparin.
The treatment lasted for a total of 14 days, after which participants were clinically examined, and for the group receiving a fixed dose of enoxaparin, an ultrasound of the lower limbs was performed to detect possible asymptomatic deep vein thrombosis.
Results
Data from 23 patients on the fixed dose and 24 on the weight-based dose were included in the final analysis. A total of 60% of patients had high or very high thromboembolic disease risk based on the Khorana score. The median weight in the group undergoing weight-based enoxaparin prophylaxis was 76 kg (range 63–124 kg), corresponding to a median increase in the enoxaparin dose by 37 mg (90%) compared to the fixed-dose group.
No serious bleeding or symptomatic deep vein thrombosis was observed in either group. During clinical examination, a pulmonary thrombus was diagnosed incidentally in a patient with extensive mediastinal involvement in the weight-based group. Among patients on the fixed dose who underwent ultrasound of the lower limbs, the cumulative incidence of deep vein thrombosis reached 22%. This involved two patients with high BMI values, specifically 40 kg/m2 and 38 kg/m2, who were diagnosed with asymptomatic distal deep vein thrombosis.
Conclusion
The Phase II clinical study confirms the high incidence of asymptomatic deep vein thrombosis in hospitalized cancer patients at high risk of deep vein thrombosis. Weight-based enoxaparin dosing was evaluated as safe in the study, with no cases of bleeding observed during the monitoring period.
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Source: Zwicker J. I., Roopkumar J., Puligandla M. et al. Dose-adjusted enoxaparin thromboprophylaxis in hospitalized cancer patients: a randomized, double-blinded multicenter phase 2 trial. Blood Adv 2020; 4 (10): 2254–2260, doi: 10.1182/bloodadvances.2020001804.
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