Our results demonstrate an efficient approach for in situ gene correction via introduction of a tiny deletion using ssODN and CRISPR/Cas9 to reframe the F8 transcript and restore FVIII function in HA-iPSC-derived EPCs with potential clinical impact in HA gene therapy.
This is the first demonstration that the FVIII locus is a suitable site for integration of the normal FVIII gene and can restore FVIII expression by the EF1α promoter in endothelial cells differentiated from the hemophilia A patient-derived gene-corrected iPSCs.
For decades, the monogenetic bleeding disorders hemophilia A and B (coagulation factor VIII and IX deficiency) have been treated with systemic protein replacement therapy.
A hemizygous c.602G > A variant in the F8 gene, leading to a single amino acid substitution at codon 201 from glycine to glutamic acid (p.G201E) within the factor VIII (FVIII) A1 domain, was identified in the HA family.
Here, we discuss current laboratory monitoring methods, including activated partial thromboplastin time, FVIII one-stage clotting assays, FVIII chromogenic assays, and global coagulations assays; address why these conventional methods may be inappropriate for monitoring of HA patients receiving emicizumab; and suggest alternative methods applicable to monitoring HA treatment in an evolving treatment landscape.
Together, the presented data suggest that individuals with haemophilia may have a compensatory procoagulant response of both plasma and platelet proteins to the decreased concentrations of FVIII or FIX.
Emicizumab has been approved in several countries for regular prophylaxis in patients with congenital haemophilia A and FVIII inhibitors because it substantially reduces their bleeding risk and improves quality of life.
In children with haemophilia A and a history of target-joint and/or FVIII inhibitor, abnormalities may occur in the long bones as were revealed by pQCT, where low trabecular density and weak cortical bone quality in upper and lower extremities, respectively, were confirmed.
Together, these technologies contribute to an AAV-fVIII vector that confers sustained, curative levels of fVIII at a minimal dose in hemophilia A mice.
The addition of anti-emicizumab mAbs to the assay mixtures completely neutralized the emicizumab and facilitated accurate determination of FVIII:C. Anti-FVIII inhibitor titers were undetectable in the presence of emicizumab in HA plasmas with inhibitor or normal plasmas mixed with anti-FVIII neutralizing antibodies.
To assess real-world experience of ADYNOVATE<sup>®</sup> (Antihemophilic Factor (Recombinant), PEGylated prophylaxis in children and adults with haemophilia A.
In addition, plasma-derived FVIII concentrates remain the primary replacement therapy for haemophilia A in the developing world, where access to recombinant therapy is more limited.
Subcutaneous emicizumab-kxwh is awaiting approval in several countries worldwide, including in the EU and Japan, and is undergoing phase 3 development in haemophilia A without FVIII inhibitors.
In addition, it has been reported that rFVIIIFc may induce tolerance to FVIII more readily than FVIII alone in HemA patients that have developed inhibitors.
Replacement therapy for coagulation factor VIII (hemophilia A) or factor IX (hemophilia B) may result in the development of high-affinity alloantibodies ('inhibitors') to the replacement therapy, thus making it ineffective.
Wave changes in the APTT were observed in all 22 patients positive for LA, while a biphasic waveform was observed in patients with hemophilia with FVIII activity <10.0%.
Mutations in FVIII gene results in hemophilia A, a recessive coagulation disorder that is clinically managed by administration of purified FVIII from blood donors or recombinant FVIII.
Although nonreplacement therapies and HA gene therapy appear to be promising alternatives for HA, rFVIII will very likely remain as a critical component for the treatment of HA because of its physiological activity and mode of action, as well as its unique ability to induce or restore tolerance to exogenous FVIII.