Hemoglobinopathies provide the first clinically validated delivery model for CRISPR therapeutics, and offers a donor-independent alternative to allogeneic hematopoietic stem-cell transplantation without graft rejection or graft-versus-host disease.
Recent developments and refinements in gene transfer and editing technologies for HSPCs are reviewed, while also discussing the critical limitations and hurdles to clinical translation, as recently presented at the New Investigator Committee Gene Therapy webinar.
Kohei Shiroshita, A. Stolz, C. Malouf et al.· Experimental Hematology· 0 citations
Sickle cell disease (SCD) is caused by pathogenic variants in the β-globin gene (HBB), most commonly the variant responsible for hemoglobin S, and affects an estimated 515,000 newborns each year, with the highest burden occurring in sub-Saharan Africa. Gene editing and hematopoietic stem cell transplantation have changed the therapeutic landscape, but their cost, technical complexity, and procedure-related risks still limit their wider use. For this reason, pharmacological induction of fetal hemoglobin (HbF) remains an important therapeutic strategy. HbF reduces HbS polymerization and is associated with lower disease severity, morbidity, and mortality. Among the mechanisms involved in γ-globin silencing, epigenetic regulation offers several targets that can be explored using small molecules. This review discusses medicinal chemistry approaches primarily targeting HDAC1/2, LSD1, and DNMT1, with emphasis on inhibitor classes, binding mechanisms, structural features, preclinical evidence, and translational limitations. The available data show that each target presents a distinct set of challenges. HDAC-directed strategies require improved isoform and cellular selectivity; LSD1 inhibitors must reconcile strong HbF induction with the risks associated with prolonged target engagement; and DNMT1 modulation is moving from DNA-incorporating nucleoside analogs toward reversible non-nucleoside inhibitors. We also discuss emerging approaches, including multi-target epigenetic modulation and targeted protein degradation. Together, these strategies show how a better understanding of γ-globin repression may guide the development of safer and more accessible HbF-inducing agents.
Mateus Mello de Souza, A. R. Pavan, Victor Gabriel de Faria Pastre et al.· European journal of medicina...· 0 citations
The 2025 American Society of Hematology (ASH) Annual Meeting highlighted rapid advances in gene editing for hematologic diseases, with increasing emphasis on precision editing and early exploration of in vivo delivery strategies. Beyond technological development, several measurable parameters are emerging as potential biomarkers, including fetal hemoglobin (HbF), F-cell proportion, HbF/F-cell, editing durability, and long-term clonal monitoring. Clinical studies demonstrated that disruption of the BCL11A enhancer or editing of the HBG1/2 promoter can induce sustained HbF reactivation, which is associated with reduced transfusion burden or transfusion independence in transfusion-dependent β-thalassemia and improved clinical outcomes in sickle cell disease. Near-pancellular HbF distribution and HbF/F-cell levels above anti-sickling thresholds further support the pharmacodynamic value of HbF-related biomarkers. Long-term follow-up studies have also incorporated editing durability and clonal monitoring into safety assessment frameworks. Emerging platforms such as RNA Gene Writer and CD90-targeted virus-like particles have demonstrated the feasibility of in vivo hematopoietic stem cell editing, although challenges related to targeting efficiency, delivery specificity, immunogenicity, and long-term safety remain. Overall, ASH 2025 suggests a shift from achieving gene editing to quantifying efficacy, durability, and safety, with standardized biomarker frameworks likely to play an increasingly important role in future clinical translation.
