CRISPR Therapeutics $CRSP and Vertex Pharmaceuticals $VRTX said the FDA placed a clinical hold on the Investigational New Drug Application (IND) for their drug candidate CTX001 as a treatment of sickle cell disease. The hold is pending the resolution of certain questions the FDA will provide as part of its review of the IND.
The IND was submitted to the FDA in April to support the planned initiation of a phase I/II trial in the US in adult patients with sickle cell disease. CRISPR and Vertex expect to obtain additional information on the FDA’s questions in the near future and plan to work rapidly with the FDA toward a resolution, the companies said.
CTX001 is being developed under a co-development and co-commercialization agreement between CRISPR Therapeutics and Vertex that was initiated in 2015. The drug is an investigational, gene-edited autologous hematopoietic stem cell therapy for patients suffering from β-thalassemia and sickle cell disease (SCD). The companies plan to initiate a phase I/II study in adult patients with transfusion dependent β-thalassemia in Europe in the second half of 2018. The European study is not affected by the FDA’s decision regarding the US study.
CTX001 is an investigational ex vivo CRISPR gene-edited therapy for patients suffering from β-thalassemia and sickle cell disease in which a patient’s hematopoietic stem cells are engineered to produce high levels of fetal hemoglobin (HbF; hemoglobin F) in red blood cells. The elevation of HbF by CTX001 has the potential to alleviate transfusion-requirements for β-thalassemia patients and painful and debilitating sickle crises for sickle cell patients, according to the companies.