VarmX enrols first patient in Phase 3 trial of FXa reversal agent
VarmX, the Leiden-based biotech spun out of Leiden University Medical Centre, has enrolled its first participant in EquilibriX-S, a randomised controlled Phase 3 study of VMX-C001 in patients taking Factor Xa (FXa) inhibitors who require urgent surgery or an invasive procedure. Enrolment across more than 20 countries is now under way, with the trial data intended to support regulatory submissions worldwide.
VMX-C001 is a recombinant modified human coagulation Factor X protein engineered to be insensitive to FXa inhibitors, allowing it to bypass their anticoagulant activity and restore the coagulation cascade. The agent is designed for rapid, fixed-dose intravenous administration and is intended to work regardless of which specific FXa inhibitor a patient is taking. The company also highlights a profile that preserves the activity of common anticoagulants such as heparin, and is positioned as carrying a minimised additional thrombotic risk, though both properties remain under evaluation in the pivotal trial.
The trial design
EquilibriX-S (NCT07288489) will assess whether a single IV dose of VMX-C001 can restore haemostasis in participants who received an FXa inhibitor within the previous 15 hours. The primary endpoint is the proportion of participants achieving good or excellent haemostatic efficacy, with safety co-endpoints running in parallel. The trial is fully funded through a strategic collaboration with CSL, the Australian plasma-products and biologics group, which VarmX disclosed earlier this year.
Chief executive John Glasspool said the enrolment milestone was significant "for the millions of patients taking Factor Xa inhibitors who may one day need an urgent surgery or procedure," adding that the Phase 3 data would provide "the pivotal evidence needed for regulatory approval."
VarmX estimates that by 2030 roughly 30 million patients across the United States, Europe and Japan will be on chronic FXa inhibitor therapy, primarily for stroke prevention in atrial fibrillation and deep vein thrombosis prophylaxis. The company cites industry analyses suggesting that more than 30,000 of these patients each week face severe bleeding episodes or emergency surgical requirements, creating a substantial unmet clinical need.
Competitive landscape
The reversal-agent market for direct oral anticoagulants has attracted considerable attention since the approval of andexanet alfa (marketed as Ondexa in Europe and AndexXa in the United States by AstraZeneca, following its acquisition of Alexion's portfolio) as an FXa reversal agent. Andexanet alfa is a modified, catalytically inactive form of Factor Xa that acts as a decoy to sequester FXa inhibitors. VarmX is positioning VMX-C001 on a mechanistically distinct approach: rather than sequestering the inhibitor, it provides a modified Factor X protein that restores the coagulation cascade while remaining insensitive to the inhibitor's effects.
That distinction matters commercially as well as clinically. Fixed-dose administration, if validated in the trial, could simplify emergency department protocols compared with weight-based or inhibitor-specific regimens. The MHRA, FDA and EMA have each shown willingness to support haemostatic agents in this space on the basis of haemostatic efficacy endpoints rather than requiring large-scale mortality studies, which is a precedent that may benefit VarmX's regulatory path.
The company's investor syndicate includes EQT Life Sciences, Lundbeckfonden BioCapital and Ysios Capital, alongside European Innovation Council funding, providing a reasonably broad capital base to support a multi-country registrational programme. Completion of enrolment and a topline readout timeline have not been disclosed. Investors will be watching for interim safety data and an updated enrolment rate as the next near-term markers of trial progress.