The FDA has granted a fast track designation for CTX001 (CRISPR Therapeutics and Vertex Pharmaceuticals Incorporated) for the treatment of transfusion-dependent beta thalassemia (TDT). CTX001 is an investigational, autologous, gene-edited hematopoietic stem cell therapy for patients with severe hemoglobinopathies.
TDT is a severe, progressive type of beta thalassemia characterized by severe anemia, transfusion dependence, unavoidable iron overload, serious comorbidities, and a shorter lifespan compared with the general population. Patients with TDT need lifelong supportive care and must undergo blood transfusions every few weeks to alleviate anemia and enable survival.
Currently, allogeneic hematopoietic stem cell transplant (allo-HSCT) is the sole treatment option with the potential to correct the genetic deficiency in TDT.
In February 2019, the first patient was treated with CTX001 in a phase 1/2 clinical study of patients with TDT. The open-label trial is designed to assess the safety and efficacy of a single dose of CTX001 in patients aged 18 to 35 years who have TDT, non-beta zero/beta zero subtypes.
The new therapy is also being evaluated for the treatment of sickle cell disease (SCD) and received fast track designation status for the purpose in January 2019.
CTX001 is being evaluated for adults with TDT or severe SCD. The investigational ex vivo therapy modifies the hematopoietic stem cells to produce high levels of fetal hemoglobin (HbF) in red blood cells. HbF is a form of the oxygen-carrying hemoglobin that is naturally present at birth and then replaced by the adult form of hemoglobin. Elevating HbF through CTX001 could relieve the transfusion requirements for TDT patients as well as the painful, debilitating crises in patients with SCD.
Source: CRISPR Therapeutics, April 16, 2019