All these results from preclinical studies and clinical trials led to the approval of Etranacogene dezaparvovec (HEMGENIX, AAV‐FIX) and Valoctocogene roxaparvovec (ROCTAVIAN, AAV‐FVIII) in 2022 and 2023 by the US Food and Drug Administration (FDA) and by the European Medicines Agency (EMA) for the treatment of severe HB and HA patients. This evidence concerns the gene F8 and hemoglobin measurement.