CRISPR Therapeutics and Vertex Announce New Clinical Data for Investigational Gene-Editing Therapy CTX001 in Severe Hemoglobinopathies at the 25th Annual European Hematology Association (EHA) Congress

-Beta thalassemia: Two patients are transfusion independent at 5 and 15 months after CTX001 infusion; data demonstrate clinical proof-of-concept for CTX001 in transfusion-dependent beta thalassemia-

-Sickle cell disease: Patient is free of vaso-occlusive crises at 9 months after CTX001 infusion-

-Five patients with beta thalassemia and two patients with sickle cell disease have been treated to date with CTX001 and all have successfully engrafted-

ZUG, Switzerland and CAMBRIDGE, Mass. and BOSTON, June 12, 2020 (GLOBE NEWSWIRE) -- CRISPR Therapeutics (Nasdaq: CRSP) and Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) today announced new clinical data for CTX001, an investigational CRISPR/Cas9 gene-editing therapy, from the CLIMB-111 and CLIMB-121 Phase 1/2 trials in transfusion-dependent beta thalassemia (TDT) and severe sickle cell disease (SCD), and highlighted recent progress in the CTX001 development program. These data were presented during an oral presentation at the European Hematology Association (EHA) virtual congress by Dr. Selim Corbacioglu, Professor of Pediatrics and the Chair of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Regensburg University Hospital, Regensburg, Germany.

CLIMB-111 Trial in Transfusion-Dependent Beta Thalassemia Updated Results
Data presented today at EHA demonstrate clinical proof-of-concept for CTX001 in TDT. Data include longer-duration follow-up data for the first patient with TDT treated with CTX001 and new data for the second TDT patient treated. CRISPR Therapeutics and Vertex announced initial data for the first TDT patient in November of 2019.

Patient 1 with TDT has the β0/IVS-I-110 genotype, which is associated with a severe phenotype similar to β0/β0, and had a transfusion requirement of 34 units of packed red blood cells per year (annualized rate during the two years prior to consenting for the trial) before enrolling in the clinical trial. As previously reported, the patient achieved neutrophil engraftment 33 days after CTX001 infusion and platelet engraftment 37 days after infusion. After CTX001 infusion, two serious adverse events (SAEs) occurred, neither of which the principal investigator (PI) considered related to CTX001: pneumonia in the presence of neutropenia, and veno-occlusive liver disease attributed to busulfan conditioning; both subsequently resolved. New data presented today show that at 15 months after CTX001 infusion, the patient was transfusion independent and had total hemoglobin levels of 14.2 g/dL, fetal hemoglobin of 13.5 g/dL, and F-cells (erythrocytes expressing fetal hemoglobin) of 100.0%. Bone marrow allelic editing was 78.1% at 6 months and 76.1% at one year.