What it is
Ristoglogene autogetemcel (risto-cel) uses an adenine base editor to alter the HBG1 and HBG2 promoters in a patient's own stem cells, switching hemoglobin production from sickle hemoglobin back to protective fetal hemoglobin without making double-strand DNA breaks. Across 31 patients followed for a mean of 6.6 months, fetal hemoglobin rose above 60% of total hemoglobin and sickle hemoglobin fell below 40%, durably resolving the chronic anemia.
Why it matters
Base editing rewrites single DNA letters without cutting both strands, a mechanistic step beyond the nuclease approach used by approved therapies such as Casgevy. Raising fetal hemoglobin above 60% is well past the level thought to suppress the painful vaso-occlusive crises that define the disease. Doing so with the patient's own cells avoids the need for a matched donor.
Underlined numbers link to their source. Every metric and quoted figure is listed under Sources and data below.
Filed undersickle cell disease, base editing, gene therapy, fetal hemoglobin, hematology