Clinical perspective: Advancing hemophilia treatment through gene therapy approaches

Hemophilia, a congenital bleeding disorder, can cause arthropathy, impaired mobility, pain, and life-threatening hemorrhage events, significantly impacting quality of life for patients and caregivers. Current therapies, although effective, necessitate costly lifelong treatment, often in specialized settings. However, as a monogenic disorder caused by loss-of-function genetic variants, hemophilia is amenable to gene therapy. In this article, three primary gene therapy approaches at the forefront of clinical development are reviewed. Adeno-associated virus-based gene therapy, having secured approval in the EU, UK, and US after promising phase 3 trial results, demonstrates clear superiority over standard-of-care treatment. Lentivirus-based approaches capable of transducing dividing and nondividing cells may improve the durability of treatment and have low susceptibility to pre-existing neutralizing antibodies to viral vectors. Finally, gene editing techniques such as zinc finger nucleases and CRISPR aim to correct genetic defects directly, holding promise as novel, effective, and highly durable therapeutic strategies in adults and children with hemophilia. This review provides a comprehensive summary of the current status of these gene therapy approaches, highlighting advantages, limitations, and potential future developments.