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The following is a summary of “In vitro evaluation of global coagulation potential of emicizumab and warfarin using rotational thromboelastometry,” published in the April 2025 issue of International Journal of Hematology by Kajimot et al. 

Researchers conducted a retrospective study to evaluate the combined hemostatic potential of warfarin and emicizumab in people with hemophilia A (PwHA). 

They assessed the coagulation potential of emicizumab combined with warfarin in a simulated model of PwHA. About 19 samples were collected from 10 patients on warfarin, with PT-INR values categorized into near-normal (INR 1.2–1.48; n=4), subtherapeutic (INR 1.56–1.9; n=7), and therapeutic (INR>2.0; n=8) groups. FVIII activity was neutralized using an anti-FVIII inhibitor antibody before adding emicizumab (50 µg/mL). Coagulation potential was measured with Ca2+-triggered rotational thromboelastometry and compared to that of emicizumab-treated PwHA. 

The results showed the average PT-INR in the near-normal, subtherapeutic, and therapeutic groups was 1.3 ± 0.1, 1.7 ± 0.1, and 2.4 ± 0.3, respectively. Hemostatic potential in FVIII-depleted samples with emicizumab in the near-normal group was comparable to emicizumab-treated PwHA. Coagulation potential in FVIII-depleted samples with emicizumab in the subtherapeutic and therapeutic groups was lower than in emicizumab-treated PwHA. 

Investigators concluded that PT-INR monitoring could provide useful information in emicizumab-treated PwHA due to the influence of vitamin K-dependent proteins. 

Source: link.springer.com/article/10.1007/s12185-025-03986-2