Editas Medicine, Inc. announced new safety and efficacy data in 18 patients living with sickle cell disease (SCD) treated with renizgamglogene autogedtemcel (reni-cel; formerly known as EDIT-301) in the Phase 1/2/3 RUBY clinical trial. Reni-cel, the first investigational AsCas12a gene-edited cell therapy medicine, is being studied in the RUBY trial as a potential one-time, durable medicine for people living with severe SCD. The data will be presented in an oral presentation at the European Hematology Association (EHA) Hybrid Congress in Madrid, Spain and via livestream, on June 15 at 11:30 a.m. CEST (5:30 a.m. EDT).

In the RUBY trial to date, reni-cel was well-tolerated and continues to demonstrate a safety profile consistent with myeloablative conditioning with busulfan and autologous hematopoietic stem cell transplant by all patients (N=18). Since treatment with reni-cel, patients have been free of vaso-occlusive events (VOEs) (N=18) for up to 22.8 months of follow-up. Patients had early normalization of total hemoglobin (Hb) with a mean within the normal range at >14 g/dL and rapid and sustained improvements in fetal hemoglobin (HbF) well above levels of >40%.

Patients in the RUBY trial underwent a median of 2.0 apheresis and mobilization cycles (min: 1.0, max: 4.0). Efficacy of reni-cel in Patients with Severe Sickle Cell Disease: All patients (N=18) are free of VOEs since reni-cel infusion with follow-up ranging from 2.4 to 22.8 months. Reni-cel treatment drives early, robust increases and sustained levels of total Hb and HbF.

Across patients with =6 months follow-up, at month 6, the mean (standard deviation; SD) total Hb was 14.3 g/dL (2.1 g/dL) (n=9) with a mean (SD) HbF of 48.5% (3.7%) (n=10). The mean percentage of F-cells increased early and were sustained at >90% from month 4 through subsequent follow-ups for all patients with =4 months follow-up (n=12). Mean corpuscular fetal hemoglobin (MCH-F) of HbF-containing red cells (F-cells) was sustained above the anti-sickling threshold of 10 pg/F-cell by month 3 after reni-cel infusion for all patients with =3 months follow-up (n=14).

All patients in the RUBY trial showed sustained high levels of editing in the HBG1 and HBG2 promoter regions. Markers of hemolysis have been normalized or improved in patients treated with reni-cel. Safety of reni-cel in Patients with Severe Sickle Cell Disease: Reni-cel was well-tolerated and demonstrated a safety profile consistent with myeloablative conditioning with busulfan and autologous hematopoietic stem cell transplant by all evaluated RUBY trial patients (N=18).

After reni-cel infusion, all patients (N=18) demonstrated successful neutrophil and platelet engraftment. Neutrophil engraftment occurred at a median of 23 days (min: 15 days, max: 29 days), and platelet engraftment occurred at a median of 24 days (min: 18 days, max: 51 days). No serious adverse events (SAEs) related to reni-cel treatment in the RUBY trial have been reported.