Editas Medicine's EDIT-301 shows safety and efficacy in sickle cell disease

Editas Medicine announced "positive" initial clinical data from the first two patients with sickle cell disease treated with EDIT-301 in the Phase 1/2 RUBY trial. EDIT-301 is under development for the treatment of severe sickle cell disease. The clinical data includes safety data from the first two patients and efficacy data from the first patient treated. Both treated patients demonstrated successful neutrophil and platelet engraftment. Patient 1 achieved neutrophil engraftment at 23 days after EDIT-301 infusion and platelet engraftment at 19 days after EDIT-301 infusion. Patient 2 achieved neutrophil engraftment 29 days after EDIT-301 infusion and platelet engraftment 37 days after EDIT-301 infusion. Additionally, neither patient has experienced any vaso-occlusive events since treatment with EDIT-301, at five and 1.5 months follow up, respectively. At five months post-treatment, the first patient treated with EDIT-301 has a total hemoglobin of 16.4 g/dL, a fetal hemoglobin (or HbF) of 45.4%, and a mean corpuscular HbF of 13.8 pg/red blood cell, exceeding the 10.0 pg/red blood cell threshold to suppress red blood cell sickling. Additionally, HbF increase in the first patient was highly pancellular, with F cells steadily increasing to reach greater than 95% of red blood cells. EDIT-301 was well-tolerated in the two patients and demonstrated a safety profile consistent with myeloablative conditioning with busulfan and autologous hematopoietic stem cell transplant. No serious adverse events occurred, and no adverse events reported were related to treatment with EDIT-301. The company expects to share further clinical updates in mid-2023.