Establishing Evidence Based Application of AN69-oXiris and PMX-HP Therapies Based on the Endotoxin Activity Assay in Septic Patients

This is a prospective, randomized, open-label, active-comparator study evaluating patients who require intensive care for sepsis or septic shock related to an intra-abdominal infection, including patients who have undergone emergency surgery or another procedure for infection source control. After written informed consent and confirmation of eligibility, participants will be randomized in a 1:1 ratio to AN69-oXiris-based blood purification or PMX-HP. Because the devices and treatment procedures are visibly different, treatment allocation will not be blinded.

In the AN69-oXiris group, blood will be circulated through an AN69-oXiris filter using an extracorporeal blood purification system during sequential treatment cycles over the 72-hour study period. In the PMX-HP group, blood will be circulated through a polymyxin B-immobilized cartridge for one or two hemoperfusion sessions, with the second session occurring approximately 24 hours after treatment initiation when administered. Both treatments will be delivered through a central venous catheter with standard intensive care monitoring. Standard treatment for sepsis and septic shock, including infection source control, antimicrobial therapy, hemodynamic support, organ support, and other treatment considered necessary by the attending clinicians, will continue according to each participant's clinical condition.

Endotoxin activity will be assessed using the Endotoxin Activity Assay before and after blood purification. Clinical and laboratory assessments will be performed at prespecified time points from baseline through 72 hours. These assessments will include blood pressure, vasopressor dose, lactate level, inflammatory markers, complete blood count, blood urea nitrogen and creatinine, C-reactive protein, procalcitonin, arterial blood gas measurements, and measures of organ function. Additional clinical outcomes will include complications, intensive care unit and hospital length of stay, and mortality.

The study will compare changes in endotoxin activity and clinical response between the two treatment groups and will examine whether baseline endotoxin activity and illness severity are associated with differential treatment response. The investigators hypothesize that integrating endotoxin activity with short-term physiologic and organ-function changes may help identify which blood purification strategy is more appropriate for specific patients.

Study treatment may be discontinued or modified if a participant's condition worsens or if the attending medical team determines that continued treatment is not appropriate. Necessary standard intensive care treatment will be maintained regardless of discontinuation or modification of the assigned study treatment.