Monitoring Anti-TFPI Antibodies in Adults with Severe Hemophilia A or B Evaluating Blood Tests to Assess Treatment Effects

What this Trial Is About

Researchers are investigating anti-TFPI tissue factor pathway inhibitor antibodies in patients with severe hemophilia A or B to develop a laboratory assay that better reflects their hemostatic effects. While previous tests showed improved thrombin generation in blood samples, these did not correlate well with clinical outcomes, especially for patients who still experienced bleeding. The study aims to improve testing methods by using optimized reagents and biological materials that could more accurately monitor these antibodies and their combined effects with factor concentrates or bypassing agents. Participants include adults with severe hemophilia A or B who are on prophylaxis with factor VIII or IX concentrates or marstacimab after appropriate washout periods. The main intervention is a one-time peripheral blood draw during a routine clinic visit for thrombin generation testing on different plasma types. No additional treatments or procedures are involved in this observational study. During the single study visit, blood samples will be analyzed to develop and assess the sensitivity of thrombin generation assays for anti-TFPI antibodies. Researchers will evaluate assay parameters, correlate lab results with clinical use of anti-TFPI therapies, and detect any hypercoagulability from combined treatments. This study provides important data on monitoring anti-TFPI therapies to better manage patients with severe hemophilia, with participation lasting only one visit.

Monitoring of Anti-TFPI in Hemophilia