A new treatment called Polymyxin B hemoadsorption (PMX) has demonstrated the ability to reduce death rates in patients with endotoxic septic shock by 15.5% at 90 days, according to results from the Tigris trial published in The Lancet Respiratory Medicine. This marks a significant breakthrough for a condition that kills millions worldwide each year, as currently no specific therapy targeting this patient population exists in the United States. What Is Endotoxic Septic Shock and Why Does It Matter? Endotoxic septic shock is a particularly deadly form of sepsis that occurs when harmful bacteria release toxins into the bloodstream, triggering a cascade of organ failure. Approximately 5 to 7 million cases occur worldwide annually, yet doctors have lacked a targeted treatment option. The condition develops rapidly and requires immediate intervention, making the discovery of an effective therapy a major clinical milestone. The Tigris trial enrolled 157 patients across multiple U.S. medical centers in a randomized controlled trial. Researchers assigned 106 patients to receive PMX plus standard care, while 51 received standard care alone. To qualify for the study, patients had to have confirmed endotoxin activity measured by an FDA-cleared diagnostic test called the Endotoxin Activity Assay (EAA), which provides results in approximately 30 minutes. How Does PMX Treatment Work and What Were the Key Results? PMX is a form of extracorporeal blood purification, meaning it works outside the body by filtering blood through a special cartridge that removes harmful endotoxins. The treatment is administered through a catheter, similar to dialysis used in intensive care units. The Tigris trial used a Bayesian statistical approach, which evaluates results in the context of prior research data, aligning with FDA guidance for medical device trials. The results were striking across multiple time points. At 28 days, PMX treatment showed a 95.3% probability of benefit, meeting the study's primary endpoint. After adjusting for baseline severity, the absolute risk reduction for mortality was 10.3% at 28 days, meaning doctors would need to treat approximately 10 patients to prevent one death. The 90-day results were even more impressive, with a 99.4% probability of benefit and an absolute risk reduction of 15.5%, requiring treatment of only 6.5 patients to save one life. Survival curves showed continued separation between treatment groups beyond the initial 28-day period, indicating that the survival benefit was sustained over time. By day 90, nearly all surviving patients (98%) had been discharged from the hospital, suggesting that organ dysfunction had largely resolved. How to Identify Candidates for PMX Treatment - Endotoxin Activity Level: Patients must have an Endotoxin Activity Assay (EAA) result between 0.60 and 0.90, indicating confirmed endotoxin in the bloodstream that can be measured within 30 minutes - Organ Dysfunction Severity: Patients must meet criteria for multiple organ dysfunction, including a Multiple Organ Dysfunction Score (MODS) greater than 9 or a Sequential Organ Failure Assessment (SOFA) score exceeding 11 - Clinical Presentation: Patients must have endotoxic septic shock confirmed through clinical assessment and laboratory findings, allowing physicians to make rapid therapeutic decisions based on EAA results The safety profile of PMX proved reassuring. Serious adverse events occurred in 30% of patients receiving PMX compared to 22% in the standard care group, a difference that was not statistically significant. Only two patients experienced adverse events possibly related to the PMX treatment itself, and neither experienced permanent harm. "The detailed analysis in the publication shows that the trial not only achieved its prespecified goal of greater than 95% posterior probability of benefit for 28-day mortality using a Bayesian analysis, but also demonstrated robust 90-day results across multiple sensitivity analyses, confirming a lasting survival benefit," said Dr. John Kellum, Chief Medical Officer of Spectral Medical. Dr. John Kellum, Chief Medical Officer of Spectral Medical Why Do Longer-Term Outcomes Matter More Than You Might Think? One striking finding from the Tigris trial was the importance of measuring outcomes beyond the initial 28-day period. At day 28, nearly half of surviving patients (46%) remained hospitalized, and 16% were still in the intensive care unit. This reflects the ongoing clinical instability typical of septic shock patients during the acute phase. However, by day 90, the picture had changed dramatically, with 98% of surviving patients discharged from the hospital. "This highlights why longer-term outcomes provide a clearer view of the true impact of therapy in septic shock, a condition where recovery from multiple organ failure often extends well beyond the initial ICU phase," explained Dr. Matthieu Legrand, corresponding author of the Tigris manuscript. Dr. Matthieu Legrand, Corresponding Author of the Tigris Manuscript The publication in The Lancet Respiratory Medicine, one of the leading peer-reviewed journals in critical care medicine, included extensive supplementary analyses beyond the primary endpoint. These included Kaplan-Meier survival curves showing how long patients survived, subgroup analyses examining whether certain patient populations benefited more than others, and Bayesian sensitivity analyses testing whether the results held up under different statistical assumptions. The Tigris trial results represent a watershed moment for septic shock treatment. With no previously approved targeted therapy available in the United States for endotoxic septic shock, PMX offers clinicians a new tool to improve survival in one of the most challenging conditions in intensive care medicine. The trial's rigorous design, peer-reviewed publication, and sustained survival benefit over 90 days provide strong evidence that this treatment could save thousands of lives annually.
