Removal of Anti-Angiogenic Proteins in Preeclampsia Before Delivery

The primary objective of this trial is to determine whether short-term apheresis using a dextran sulfate adsorption (DSA) column (Liposorber LA-15 System; the Device) leads to a reduction in circulating sFLT-1 in the blood of women with pre-term preeclampsia. The following secondary objectives are aimed at evaluating the efficacy and safety of the Device as well as the impact of removing circulating sFlt-1 on maternal and neonatal outcomes: 1. To determine whether short-term apheresis using the Device in women with pre-term preeclampsia leads to: * a prolongation of pregnancy (ie, gestational age) * a reduction in blood pressure (BP) and proteinuria * an increase in fetal birth weight 2. To determine the safety of reducing maternal sFlt-1 levels using the Device. Up to 16 patients will be enrolled. Initially, 4 patients will undergo apheresis UP TO 2 times in the first week and undergo all protocol-related assessments including PK of sFlt-1 levels. Based on an assessment of clinical response by the Investigator, these first 4 patients will be offered the option to continue apheresis treatments (without pharmacokinetic \[PK\] assessments) up to twice weekly until delivery or until 34 weeks gestation, whichever comes first. Following complete review of all parameters and outcomes by an independent Data Safety Monitoring Board (DSMB), up to 12 additional patients will be enrolled (total of up to 16). UPDATE: The DSMB reviewed data after the first 4 patients and again after 10 patients/delivered infants had been treated. In the next 6 patients, DSMB review will occur after every 3 patients/delivered infants. These remaining 6 patients may undergo apheresis up to 3 times per week.