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

Abstract

The declarative title is a fair summary of research described in this paper (Targeting Factor VIII expression to platelets for hemophilia A gene therapy does not induce an apparent thrombotic risk in mice)10, is a fair summary of research described in this paper, which is itself the 14th in a series from the group of researchers led by Montgomery who, since 2003 have progressively advanced the idea of storing factor VIII in platelets to treat hemophilia A. Why, one might ask, would one do such a thing when evolution has selected endothelial cells as both the site for synthesis and release of factor VIII complexed with Von Willebrand factor to provide the cofactor when and where needed?1,2 The answer lies in the unfortunate fact that a high proportion of patients with hemophilia develop resistance to factor VIII due to alloimmunity to the protein, which is foreign to their immune system, leading to production of inhibitory antibodies to the cofactor. But Factor VIII released from platelets seems to evade such antibodies3. This article is protected by copyright. All rights reserved.