CSL Backs Late-Stage Development of VarmX’s Coagulation Therapy VMX-C001X

BillionPhotos.com - stock.adobe.com

The Netherlands-based VarmX, a biotech company specializing in bypassing direct oral anticoagulants targeting activated factor Xa (FXa DOACs) and inherited coagulation disorders, announced a new strategic collaboration on Sept. 16, 2025 with CSL to advance the late-stage clinical development, manufacturing, and potential commercialization of its lead asset, VMX-C001. Additionally, CSL entered into an exclusive option agreement with VarmX shareholders to acquire all issued and outstanding shares of the company (1).

VMX-C001, a novel investigational treatment to help restore blood coagulation in patients requiring urgent surgery or experiencing severe bleeding while on FXa DOACs, has been developed as a recombinant modified Factor X protein that bypasses Factor Xa inhibitor activity. It is administered as a single rapid infusion and is being studied in patients requiring urgent surgery or experiencing severe bleeding.

“The collaboration with CSL represents a transformative step for VarmX. By securing full funding for the registrational trial, product development, CMC [chemistry, manufacturing, and controls], and pre-launch activities, we are well positioned to bring VMX-C001 to patients,” said John Glasspool, chief executive officer, VarmX, in a company press release (1). “We are proud to partner with CSL, whose expertise and global reach will be invaluable as we move forward.”

What are the clinical development and manufacturing implications of this collaboration?

Under the agreement, CSL will fully fund a global Phase III clinical trial (EquilibriX-S) of VMX-C001 in patients on Factor Xa inhibitors who require urgent surgery. CSL will also support late-stage product development, manufacturing scale-up, and pre-launch preparation (1).

The collaboration demonstrates how option-based partnerships can de-risk late-stage development for smaller firms while ensuring robust support for chemistry, manufacturing, and controls activities. Such arrangements are increasingly shaping the landscape of high-cost biologic development, particularly for therapies targeting acute and complex indications.

“We are excited to partner with VarmX to develop a novel treatment and address a significant unmet need aligning strongly with our strategic ambition to deliver enduring patient impact,” said Paul McKenzie, PhD, chief executive officer of CSL, in the release. “It also aligns with our portfolio of medicines designed to minimize bleeding, preserve a patient’s own blood supply, improve surgical and medical outcomes, and support global public health approaches to patient blood management.”

In early September 2025, VMX-C001 received fast track designation from FDA. The designation underscores the growing demand for new treatment strategies to manage life-threatening bleeding and urgent surgery in patients taking anticoagulants. “This FDA fast track designation significantly strengthens the position of VMX-C001 to potentially become a new option for the substantial number of patients on FXa DOACs who need emergency surgery,” Glasspool said in a press release at that time (2).

How does VMX-C001 address unmet clinical need?

By 2030, an estimated 30 million patients in the United States, Europe, and Japan will be prescribed Factor Xa direct oral anticoagulants for chronic conditions such as atrial fibrillation and deep vein thrombosis (3). Although these agents are highly effective, up to 4% of patients experience severe bleeding or require emergency surgery each year—representing more than 30,000 cases weekly. Currently, no fully approved therapies exist in the US or European Union for reversal of acute bleeding associated with these drugs (4,5).

“CSL was particularly interested in VMX-C001’s unique mechanism of action, how it specifically targets Factor Xa inhibitors, compared to the more general action of other treatments, and the preclinical and early clinical data which led to [FDA] approval to proceed straight to a single Phase III study,” said Bill Mezzanotte, executive vice-president and head of Research & Development, CSL, in the release (1).

A potential commercial launch of VMX-C001 is projected for 2029, according to the companies. If successful, the therapy could address a critical gap in perioperative and emergency care and influence how biopharmaceutical developers approach anticoagulation reversal technologies.

What impact on industry can be expected from this collaboration?

The collaboration is structured around an exclusive option agreement under which CSL will pay VarmX shareholders $117 million upfront for the option to acquire the company, with the right to exercise that option contingent on Phase III data. Additional payments could total $388 million through acquisition and pre-commercial milestones, while sales-based milestones can potential reach up to $1.7 billion (1).

For the biopharmaceutical industry, this model underscores how large biotechnology firms increasingly use staged acquisition strategies to mitigate risk while securing access to promising assets. The financial structure of this deal also reflects growing investor confidence in targeted biologics addressing high-burden, underserved conditions.

References

1. VarmX. VarmX Partners with CSL in a Strategic Collaboration and Option Agreement to Develop Novel Investigational Coagulation Treatment. Press Release. Sept. 16, 2025.
2. VarmX. VarmX receives FDA Fast Track Designation for lead asset VMX-C001. Press Release. Sept. 3, 2025.
3. Polaris Market Research. Direct Oral Anticoagulants (DOACs) Device Market Size, Share, Trends, & Industry Analysis Report by Product Type, by Disease Indication, by Application, by Patient Demographic, by End User, and by Region—Market Forecast, 2025–2034. Market Research Report. June 2025. https://www.polarismarketresearch.com/industry-analysis/direct-oral-anticoagulants-doacs-device-market
4. Kocjan, M.; Kosowski, M.; Mazurkiewicz, M.; et al. Bleeding Complications of Anticoagulation Therapy in Clinical Practice-Epidemiology and Management: Review of the Literature. Biomedicines 2024, 12 (10), 2242. DOI: 10.3390/biomedicines12102242
5. Milling, T. J. Jr.; Ziebell, C. M. A Review of Oral Anticoagulants, Old and New, in Major Bleeding and the Need for Urgent Surgery. Trends Cardiovasc. Med. 2020, 30 (2), 86–90. DOI: 10.1016/j.tcm.2019.03.004