Platelets are a safe way to deliver factor VIII. After 13 years of preclinical research it is now time for a clinical trial

Treatment of a Hemophilia B Mouse Model with Platelet-Targeted Expression of Factor IX Padua

Targeting the coagulation factor IX (FIX) expression in platelets has been shown to be effective in ameliorating bleeding in hemophilia B (HB) mice. To improve the therapeutic effects and evaluate the safety of this gene therapy strategy, we generated a transgenic mouse model on an HB background with FIX Padua target expressed in platelets. The transgenic mice exhibited stable expression and storage of FIX Padua in platelets. The platelet-stored FIX Padua could be released with the activation of platelets, and the proportion of platelet-stored FIX Padua in whole blood was the same as that of platelet-stored wild-type human FIX. The platelet-derived FIX Padua showed substantially increased specific activity compared with wild-type FIX. Reduced bleeding volume in the FIX Padua transgenic mice demonstrated that bleeding in the mice was improved. Levels of thrombin-antithrombin complex, fibrinogen, D-Dimer, and blood cell counts were normal in the transgenic mice, suggesting that thrombotic risk was not increased in this mouse model. However, the leakage and failure to overcome the presence of inhibitor to wild-type FIX is also observed with FIX Padua, as expected. Taken together, our results support the conclusion that targeting FIX Padua expression in platelets may be an effective and safe gene therapy strategy for HB, and could provide an ideal model to evaluate the safety of platelet-targeted gene therapy for treating hemophilia.

Needs and challenges among physicians and researchers in thrombosis and hemostasis: Results from an international study

BACKGROUND

Specialty societies, such as the International Society on Thrombosis and Haemostasis (ISTH), are a key source of support for clinical and scientific communities, through the provision of educational activities, tools, and resources to support evidence-based care and high-quality, relevant basic science and clinical research.

OBJECTIVE

The aim of this study was to identify areas where the thrombosis and hemostasis (T&H) community is facing challenges and could benefit from the support of ISTH.

METHODS

A 3-phase, mixed-methods study consisting of semistructured individual interviews (phase 1), an online survey (phase 2), and discussion groups (phase 3) was conducted on the challenges experienced by the T&H community. Participants included physicians, clinical and basic science researchers, residents, fellows, students, and industry representatives. Qualitative data were analyzed using thematic analysis. Quantitative data were analyzed using frequency tables and chi-squares.

RESULTS

The study included 468 participants in interviews (n = 45), surveys (n = 404), and discussion groups (n = 19). Nine themes emerged that describe areas where the T&H community may benefit from additional support. Three areas were related to diagnosis and testing: thrombosis risk assessment, genetic testing, and diagnosis of von Willebrand disease (VWD). Another 3 were related to treatment decision making: use of anticoagulants with certain patients, preventive treatments in bleeding disorders, and VWD treatment. The remaining 3 were related to research: collaboration with/among researchers, collaboration between teams to collect data from human subjects, and promotion of basic science research.

CONCLUSIONS

This study provides a comprehensive picture of priorities within the T&H community, which should inform the ISTH in its future interventions, including educational offerings and networking opportunities.