Pilot Feasibility and Safety of Administering Weight Adjusted Fixed LMWH Dose

Background Enoxaparin is a commonly used low molecular weight heparin (LMWH) for the treatment of neonatal and children thrombosis that is monitored with anti-factor Xa (anti-Xa) levels. However, this therapeutic range of anti-Xa (0.5 - 1.0 u/ml) was extrapolated from adult studies. The burden of pain to neonates due to venipunctures and of resources to the health care system also warrants an evidence-based review to assess the utility of monitoring LMWH therapy with anti-Xa levels. Methods/Design This is a prospective pilot, feasibility and safety multicenter, randomized controlled trial to compare the approach of treating thrombosis in neonates and children with enoxaparin using weight adjusted fixed dose to variable dose titrated to maintain a pre-determined anti-Xa range (0.5-1.0 u/mL). We plan to recruit 20 neonates and children over the study period, who will be randomized within their first week of anti-coagulation treatment. Key feasibility outcomes include screening/recruitment ratio, monthly recruitment rate, and completeness of data collection. We will also measure the safety outcome of bleeding as well as comment on efficacy of resolution of thrombosis as a secondary outcome. Discussion The administration of weight adjusted fixed dose of enoxaparin without anti-Xa monitoring has the potential to reduce pain from multiple venipunctures in neonates and children as well as resources used in their already complex care. The results of the FiXET trial will set the framework for a larger multicenter randomized controlled trial to compare the efficacy of administering enoxaparin to neonates and children without monitoring to the current conventional approach of routine monitoring with anti-Xa levels.