CTX001™ (CRISPR Therapeutics and Vertex Pharmaceuticals) has received Regenerative Medicine Advanced Therapy (RMAT) designation from the U.S. Food and Drug Administration (FDA) for the treatment of sickle cell disease (SCD) and transfusion-dependent β-thalassaemia (TDT). CTX001™ is an investigational gene-editing cell therapy that uses the CRISPR-Cas9 gene-editing tool to modify patient-derived stem cells to express fetal haemoglobin (HbF). An increase in HbF levels can compensate for the abnormal synthesis and function of adult haemoglobin in adult patients with SCD and TDT, and ameliorate the clinical and hematologic severity of both disorders. Preliminary data from the Phase 1/2 CLIMB-SCD-121 trial (NCT03745287), assessing the safety and effectiveness of a single dose of CTX001™ in patients 18 to 35 years of age with SCD, has shown that the therapy safely increased HbF levels and effectively prevented the occurrence of vaso-occlusice crises. Positive early findings have also been reported for the first TDT patient receiving CTX001™ in the Phase 1/2 CLIMB-Thal-111 trial (NCT03655678), for which patients are still being recruited. In addition to RMAT designation, CTX001™ has received Orphan Drug Designation from the FDA for TDT and from the European Medicines Agency (EMA) for TDT and SCD. CTX001™ has also Fast Track Designation from the FDA for both disorders. For more information, see here.