Anti-TFPI for hemostasis induction in patients with rare bleeding disorders, an ex vivo thrombin generation (TG) guided pilot study

Assaf A. Barg, Tami Brutman-Barazani, Einat Avishai, Ivan Budnik, Omri Cohen, Rima Dardik, Sarina Levy-Mendelovich, Tami Livnat, Gili Kenet

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background: Rare bleeding disorders (RBD) are inherited coagulopathies, whose hemostatic control is based upon replacement therapy. Marstacimab (PF-06741086) is a human monoclonal IgG that targets the Kunitz2 domain of tissue factor pathway inhibitor [TFPI]. Marstacimab is currently in development for bleeding prophylaxis in patients with hemophilia. Objectives: To assess the potential impact of Marstacimab upon thrombin generation (TG) in RBD patients' plasma samples. Results: Our cohort included 18 RBD patients, with severe deficiencies: 5 Von Willebrand Disease (VWD) type 3, 4 FVII, 3 FXI, 2 FXIII deficiency and 1 patient with: FX, FV + FVIII, Fibrinogen, combined vitamin K dependent factors' deficiency. Citrated samples from RBD patients were collected and spiked with Marstacimab, TG was measured by calibrated automated thrombogram. Among all patients a reduced baseline TG was observed as compared to controls. Improvement of median (lag time, peak and ETP was observed in Marstacimab spiked samples from 8 min, 99 nM, 1116 nMx min to 5.5 min, 194 nM,1614 nMx min, respectively. None of the values measured among RBD patients exceeded normal controls. Conclusion: These in vitro data suggest that Marstacimab may serve as a promising approach for restoring the hemostatic balance in various RBD, though potential clinical implications should be further investigated.

Original languageEnglish
Article number102663
JournalBlood Cells, Molecules, and Diseases
StatePublished - Jul 2022
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2022


The authors declare no conflict of interest except Gili Kenet - receives grant and research support from Alnylam, Bayer, BPL, Opko Biologics, Pfizer, Shire and honoraria for consultancy/lectures from Alnylam, Bayer, CSL, Opko Biologics, Pfizer, Takeda and ROCHE. Assaf A. Barg receives honoraria for lectures from ROCHE. The study was supported by an investigator initiated study grant, yet Pfizer company was not involved in study design, data generation and interpretation.

FundersFunder number
Takeda Pharmaceutical Company
Commonwealth Serum Laboratories


    • Marstacimab (PF-06741086)
    • Rare bleeding disorders
    • TFPI
    • Thrombin- generation


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