SMC Approves CRISPR Gene Therapy for Sickle Cell Disease

January 23, 2026-The Scottish Medicines Consortium (SMC) has officially accepted exagamglogene autotemcel (Casgevy) for use within NHS Scotland, making it the first CRISPR-based gene therapy available for patients with severe Sickle Cell Disease (SCD) in the country. This historic decision, announced in January 2026, applies to patients aged 12 and older who suffer from recurrent vaso-occlusive crises (VOCs) and lack a matched stem cell donor. For a community that has historically faced limited curative options, this approval represents a transition from life-long symptom management to a “functional cure,” potentially eliminating the excruciating pain and progressive organ damage that define the disorder.

At the core of this breakthrough is the precision of CRISPR/Cas9 technology, which “reprograms” a patient’s own biology to fight the disease. Sickle cell disease is caused by a mutation in the adult hemoglobin gene, but humans also possess a gene for fetal hemoglobin (HbF) that is naturally silenced shortly after birth. Casgevy works by precisely editing the BCL11A gene in the patient’s harvested stem cells. This edit effectively cuts the “off switch” for fetal hemoglobin, allowing the reinfused cells to produce high levels of HbF. Because fetal hemoglobin does not “sickle,” it prevents red blood cells from becoming rigid and sticky, thereby keeping blood vessels clear and oxygen flowing freely to tissues.

Clinical evidence from the CLIMB SCD-121 and CLIMB-131 trials provided the foundation for the SMC’s approval. Data revealed that 97% of treated patients remained free from severe vaso-occlusive crises for at least 12 consecutive months following the one-time infusion. Furthermore, patients saw their average total hemoglobin levels rise from approximately 9.1 g/dL to over 12 g/dL, with fetal hemoglobin making up more than 40% of the total. Long-term follow-up data presented at the end of 2025 further confirmed the durability of these results, with many patients maintaining their VOC-free status for several years.

The treatment process is intensive, requiring patients to undergo stem cell collection, followed by a rigorous course of myeloablative chemotherapy to “make room” in the bone marrow before the modified cells are reinfused. While the upfront cost of £1.65 million is substantial, the SMC accepted it through an orphan medicine process and a confidential Patient Access Scheme, recognizing that the one-time intervention could offset decades of hospitalizations, emergency care, and blood transfusions.