The clinical efficacy and suitable implementation of two extracorporeal blood purification therapies: AN69-oXiris versus PMX-HP

Purpose

In septic shock patients, pathogens and excessive endotoxins continuously overstimulate the host's immune system with a cytokine storm that can lead to multi-organ failure and even mortality. Various types of extracorporeal blood purification treatments have recently been introduced to remove excessive endotoxins and cytokines. Herein, we compared the clinical efficacy of two blood purification methods, PMX-HP and AN69-oXiris, and discussed their detailed indications according to disease severity.

Materials and methods

From December 2016 to April 2023, patients who underwent emergent surgery due to septic shock secondary to peritonitis and subsequently received blood purification treatment with AN69-oXiris or PMX-HP were enrolled. Propensity score (PS)-matching was conducted to adjust for baseline characteristics between the two groups, and the changes in clinical parameters and outcomes were compared. Clinical outcomes were assessed in subgroups of patients who underwent PMX-HP treatment divided according to SOFA scores into low (0-7), intermediate (8-13), and high (> 13) disease severity groups.

Results

Forty patients received blood purification therapy with either PMX-HP or AN69-oXiris during the study period. After 1:2 PS matching, six patients in the AN69-oXiris group and 12 patients in the PMX-HP group were finally analyzed. Vasoactive-inotropic scores (VISs) decreased in both groups after 48 h of treatment compared to the baseline values, but the change in VISs was more pronounced in the PMX-HP group {-57.6 [interquartile range (IQR) = -166.4 - (-10)] vs. -22.9 [IQR = -64-0], respectively, p = 0.041}. Decreases in cardiovascular SOFA scores were significantly pronounced in the PMX-HP group [-1.5 (IQR = -4 - 0) vs. 0 (IQR = -1 - 1), respectively, p = 0.035]. The 7-day mortality rate was significantly lower than the predicted mortality rate in a subgroup analysis of patients treated with PMX-HP in both the low disease severity group and the intermediate disease severity group.

Conclusion

PMX-HP and AN69-oXiris could be therapeutic options for refractory septic shock patients with intra-abdominal origins, especially after the surgical elimination of the infectious sources. A tailored modality choice that takes into account patient characteristics, such as disease severity and cost burden, could optimize the efficacy of this strategy.

Potential survival benefit and early recovery from organ dysfunction with polymyxin B hemoperfusion: perspectives from a real-world big data analysis and the supporting mechanisms of action

Background

Endotoxin (ET) removal therapy with polymyxin B-immobilized fiber column hemoperfusion (PMX-HP) has been used for the treatment of septic shock. Some observational studies reported clinical benefits, particularly in specific subgroups of patients. However, larger randomized controlled trial results have been disappointing.

Main body

The four studies that revealed the survival benefit of PMX-HP were based on the Japanese Diagnosis Procedure Combination (DPC) national inpatient database (J-DPC study). Nevertheless, one J-DPC study and a randomized controlled trial (RCT) conducted in France evaluated PMX-HP in patients with abdominal septic shock and did not report a significant survival benefit. In both studies, the severity of illness was too low to find substantial significant differences in mortality. The results of the J-DPC studies further suggest that some subpopulations of patients could benefit from PMX-HP. Based on these results, this review revisited prior RCTs and other large-scale studies on PMX-HP. In addition, four J-DPC studies and one large-scale study reported a survival benefit with PMX-HP. A secondary analysis of the EUPHRATES trial, the most recent double-blinded RCT of PMX-HP conducted in North America, suggested a survival benefit in patients with high levels of endotoxemia. In the J-DPC studies and the EUPHRATES trial, ventilator-free days, vasoactive drug-free days, and renal replacement-free days were significantly improved in the PMX-HP groups. These findings suggest that PMX-HP can contribute to early recovery from organ dysfunction. The reduction of supportive care likely provides important health and economic benefits for managing patients with septic shock. Finally, the blood levels of mediators or biomarkers related to respiratory, cardiovascular, and renal dysfunction have been reported to be normalized with PMX-HP.

Conclusions

These results support the biological rationale for the improvement in organ dysfunction observed in the J-DPC studies and other large-scale studies, including the EUPHRATES trial. Real-world evidence from large data sets suggests an appropriate patient population that are likely to benefit from the utility of PMX-HP for septic shock.