UKHCDO gene therapy taskforce: Guidance for implementation of haemophilia gene therapy into routine clinical practice for adults.

Introduction: 2022 was a landmark year with two adeno-associated viral vectors (AAVs) receiving conditional marketing authorization from EMA for the treatment of persons with severe haemophilia A and severe to moderately severe haemophilia B and a third in 2024. Gene therapy is a transformative, irreversible treatment with long-lasting effects, necessitating development of new clinical pathways to ensure optimal outcomes.

Aim: To develop a consensus framework and service specification for delivery of AAV gene therapy for haemophilia in adults within the UK using the hub-and-spoke model proposed by the European Association of Haemophilia and Allied Disorders and the European Haemophilia Consortium.

Adeno-associated viral vector integration: implications for long-term efficacy and safety.

Adeno-associated virus (AAV) vector gene therapy provides a promising platform for treatment of monogenic inherited disorders. Clinical studies have demonstrated long-term expression with reduction in bleeding using this approach for the treatment of hemophilia. Despite these advances, there are unknowns surrounding the natural history of recombinant AAV (rAAV) vectors and the cellular mechanisms mediating vector persistence.

Vector integration and fate in the hemophilia dog liver multiple years after AAV-FVIII gene transfer.

Gene therapy using adeno-associated virus (AAV) vectors is a promising approach for the treatment of monogenic disorders. Long-term multiyear transgene expression has been demonstrated in animal models and clinical studies. Nevertheless, uncertainties remain concerning the nature of AAV vector persistence and whether there is a potential for genotoxicity.

Lipid nanoparticles and siRNA targeting plasminogen provide lasting inhibition of fibrinolysis in mouse and dog models of hemophilia A.

Antifibrinolytic drugs are used extensively for on-demand treatment of severe acute bleeding. Controlling fibrinolysis may also be an effective strategy to prevent or lessen chronic recurring bleeding in bleeding disorders such as hemophilia A (HA), but current antifibrinolytics have unfavorable pharmacokinetic profiles. Here, we developed a long-lasting antifibrinolytic using small interfering RNA (siRNA) targeting plasminogen packaged in clinically used lipid nanoparticles (LNPs) and tested it to determine whether reducing plasmin activity in animal models of HA could decrease bleeding frequency and severity.