The Journey of Gene Therapy in Sickle Cell Disease: How Molecular Advances Meet Clinical Care.

Sickle cell disease (SCD) is a monogenic disorder responsible for recurrent vaso-occlusive crises, progressive organ damage, and shortened life expectancy. For decades, allogeneic hematopoietic stem cell transplantation from a matched sibling donor has been the only established cure, but its reach remains limited by donor availability and transplant-related toxicity. The approval of two autologous gene therapy products in 2023, exagamglogene autotemcel (exa-cel) and lovotibeglogene autotemcel (lovo-cel), marked a turning point for the SCD population and the gene therapy field in general. This review proposes a molecular rationale for fetal hemoglobin reactivation and β-globin gene addition, describes the engineering of lentiviral and CRISPR-based platforms, and highlights the clinical evidence accumulated to date that demonstrated durable disease modification with acceptable short-term toxicity. We then assess the clinical positioning of gene therapy within the broader spectrum of curative options compared to current available treatments and address the financial, ethical and psychosocial barriers that limit access to gene therapy both within high-income countries and globally. Critical research priorities include long-term safety surveillance, comparative effectiveness studies, pediatric trials below 12 years, and validated patient-reported outcome instruments. Base editing, non-genotoxic conditioning, and in vivo delivery represent the most promising avenues to broaden access and reduce treatment burden.