Spectral Medical PMX shows sustained mortality benefit at 12 months
Spectral Medical and its US distribution partner Vantive have announced topline 12-month follow-up data from the Tigris Phase 3 trial, showing that the mortality benefit of Polymyxin B Hemoadsorption (PMX) in endotoxic septic shock persisted well beyond the acute treatment window.
Among the 157 patients enrolled — all of whom were successfully followed up — mortality at 12 months was 52.8% (56 of 106 patients) in the PMX arm versus 66.7% (34 of 51 patients) receiving standard care alone. That translates to an absolute risk reduction of 13.9% and a number needed to treat (NNT) of 7.2. A Bayesian analysis drawing solely on the Tigris dataset, without incorporating prior data from the earlier EUPHRATES study, estimated a 95.9% probability of benefit for PMX at 12 months.
The results extend a consistent signal across the trial's timepoints: Lancet Respiratory Medicine published the 28-day and 90-day data in May 2026, reporting absolute risk reductions of 10.3% and 15.5% respectively. The 12-month data, a pre-planned secondary endpoint, suggest the treatment effect is not merely a short-term deflection of mortality but a durable improvement in survival.
Regulatory path
Spectral submitted the final Premarket Approval (PMA) module — Module 3 — to the US FDA on 28 May 2026, days before this data announcement. The company has previously said it believes a PMA decision could come in the first quarter of 2027, though it cautioned this remains subject to the regulatory process. PMX already carries FDA Breakthrough Device Designation, granted in July 2022, which provides for more intensive FDA interaction during development and review.
John Kellum, Chief Medical Officer of Spectral Medical, said the 12-month results "clearly indicate that the benefits of PMX therapy observed in Tigris persisted over the months following hospital discharge," describing durability of benefit as "the ultimate goal of any acute therapy."
Vantive holds exclusive US and Canadian distribution rights for PMX and would commercialise the device alongside Spectral's Endotoxin Activity Assay (EAA) — an FDA-cleared diagnostic that identifies eligible patients by endotoxin activity level — if approval is granted. The combined TREA Therapy framework positions the pairing as a precision-medicine approach within a sepsis indication that currently has no approved targeted treatment in the United States.
Market context
Endotoxic septic shock affects an estimated five to seven million people annually worldwide, and approximately 330,000 patients are diagnosed with septic shock in North America each year. Despite decades of research, the broader sepsis space has seen repeated late-stage trial failures, making a positive Phase 3 dataset with durable follow-up relatively unusual. PMX is already approved in Japan and Europe, with more than 360,000 units sold globally, providing a commercial proof-of-concept that the US regulatory filing can draw upon.
Analysts and clinicians will be watching for the fuller Bayesian analysis incorporating the EUPHRATES prior, which the companies say is ongoing, as well as any FDA requests for additional data during PMA review. The NNT of 7.2 at one year — if it holds through that analysis — would be regarded as clinically meaningful in a high-mortality acute care setting, and could underpin reimbursement and formulary discussions once approval is secured.