The evolving landscape of gene therapy for congenital severe hemophilia: a 2024 state of the art

Abstract

Despite major advances in prophylaxis, no repeated dosing regimen with currently employed extended-half-life or non-factor products replaces the advantages of a long-term cure in persons with severe congenital hemophilia A and B (HA, HB). They indeed live with the risk of breakthrough bleedings, and treatment is still invasive, both physically and psychologically. Early studies showed that adeno-associated virus-based in vivo gene therapy (AAV-based in vivo GT), could convert hemophilia persons from a severe to mild a phenotype for years. However, the proportion of the hemophilia population likely to benefit from this transformative strategy was uncertain. Current evidence is expanding the eligibility criteria, and helps to predict risks, complications and unexpected side effects of this advanced treatment. Thus, among future options, AAV-based in vivo GT is likely to become the treatment of choice in HA and HB, if real-life data confirm its negligible short-term adverse events. However, while the global use of AAV-based in vivo GT is endorsed as a key objective of future studies in hemophilia, the liberating capability of a potentially one-off treatment on individuals with chronic diseases for whom lifelong cure has been inaccessible so far remains to be thoroughly recognized by government bodies. This is critical for reimbursement agencies to absorb the cost of the cure and calls for a partnership between health care systems and the pharmaceutical industry. However, bridging the gap between the costs of the advanced treatments approved for commercialization and their readiness to persons with HA and HB is still a challenging task.

Keywords

• Adeno-associated virus gene therapy
• person-reported outcomes
• laboratory monitoring
• emicizumab
• extended half-life products