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NCT Number: NCT07101926

Monitoring of Anti-TFPI in Hemophilia

During the development of anti-TFPI antibodies, thrombin generation assay (TGA) was employed using both in vitro measurements (antibodies added to blood samples) and ex vivo approaches (blood samples from patients in phase II and III trials). While a significant improvement in thrombin generation was observed in all samples from patients with severe hemophilia, no correlation with clinical outcomes could be established. Notably, thrombin peak levels were consistently improved even in patients who experienced bleeding episodes. These measurements were conducted in platelet-poor plasma (PPP) with standard reagents, which may not adequately reflect the hemostatic efficacy of anti-TFPI antibodies given their mechanism of action. It is hypothesized that optimizing reagents and utilizing more appropriate biological materials could enhance TGA sensitivity, as previously demonstrated for monitoring emicizumab.

The absence of a laboratory assay to monitor anti-TFPI (tissue factor pathway inhibitor) antibodies poses a significant challenge for managing patients in surgical settings and treating acute severe bleeding. This study aims to develop a reliable assay to evaluate the hemostatic efficacy of anti-TFPI antibodies and their combined procoagulant effect with factor concentrates (FVIII or FIX) or bypassing agents.

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Key information

Conditions

Hemophilia Blood Coagulation Disorders Blood Coagulation Disorders, Inherited Coagulation Protein Disorders Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Hematologic Diseases Hemic and Lymphatic Diseases Hemophilia A Hemorrhagic Disorders Prophylaxis Rebalancing Agents

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Groupement hospitalier Est Hôpital Cardilogique Service d'hémostase clinique, Bron, France

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

  • Inclusion Criteria :
  • - Male Patient
  • 18 years old
  • severe hemophilia patients A or B (FVIII < 1%,FIX<=2%)
  • on prophylaxis with FVIII or IX concentrates after an adequate washout period of 48h for SHL FVIII molecules, at least 4 days for EHL-FVIII Fc and at least 10 days for EHL-FIX molecules.
  • On prophylaxis with Marstacimab
  • Willing to participate
  • Capable of following protocol procedures under investigator appreciation
  • Exclusion Criteria :
  • - patients refusing to provide 4 additional blood tubes for research
  • Patient with an other coagulation disorder
  • patients who received an injection of FVIII or FIX during the required washout period

Treatment and study plan

Blood sampling

Biological

One-time peripheral blood draw (10.8 mL total, 4 citrated tubes) collected during a routine clinical visit for thrombin generation testing on platelet-rich and platelet-poor plasma. No additional medical procedures or treatments are involved in the study.

Primary outcomes

  1. Development of a Laboratory Assay to Assess Hemostatic Efficacy of Anti-TFPI Antibodies

    Time frame: At time of sample analysis (single visit; Day 0)

    Assessment of the thrombin generation assay's ability to evaluate the procoagulant effect of anti-TFPI antibodies alone and in combination with factor concentrates (FVIII or FIX) or bypassing agents (rFVIIa, aPCC).

Secondary outcomes

  1. Analytical Sensitivity of TGA to Anti-TFPI Antibodies

    Time frame: Day 0

    Evaluate the effect of different TGA conditions (e.g., low TF concentration, use of PRP, CTI) to enhance sensitivity to anti-TFPI antibodies.

  2. Identification of Optimal TGA Parameters for Monitoring Anti-TFPI Effect

    Time frame: Day 0

    Determine which parameters (e.g., thrombin peak, ETP, lag time, velocity, time to peak) best reflect the action of anti-TFPI antibodies under optimized assay conditions.

  3. Correlation Between TGA Parameters and Clinical Use of Anti-TFPI Therapies

    Time frame: Day 0

    Compare TGA results from 5 patients treated with marstacimab and 3 patients with concizumab to assess correlation with clinical treatment exposure.

  4. Detection of Hypercoagulability from Combined Therapy in TGA

    Time frame: Day 0

    In vitro testing of anti-TFPI antibodies in combination with FVIII, FIX, rFVIIa, or aPCC to assess risk of excessive thrombin generation.

Study contacts

Contact information is provided by the study sponsor or research team.

Sandra DURANTEL

CONTACT

[email protected]

0472118819 ext. +33

Yesim DARGAUD, Pr

CONTACT

[email protected]

0472118822 ext. +33

Sponsors and collaborators

Lead sponsor

Hospices Civils de Lyon

Other

Registry information

Official study title

Monitoring of Anti-TFPI in Hemophilia EUREKA

Acronym: EUREKA

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Aug 3, 2025
Registry last updated
Mar 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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