May 1, 2026
A major clinical trial has reported highly encouraging outcomes for a gene edited treatment targeting severe sickle cell disease, a hereditary blood disorder that has long had limited curative options.
The findings, published in the New England Journal of Medicine, come from the multicentre RUBY Trial and indicate that 27 out of 28 participants experienced no painful sickle cell crises following treatment.
Researchers describe this level of response as a functional cure in practical clinical terms.
The therapy, known as renizgamglogene autogedtemcel, also referred to as reni cel, is a one time gene editing treatment that uses a patient’s own blood forming stem cells. These cells are modified to correct the genetic mutation responsible for the disease.
By increasing production of fetal haemoglobin, which does not sickle in the same way as adult haemoglobin, the treatment helps prevent the abnormal shape changes in red blood cells that trigger severe pain episodes and long term complications.
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Early results suggest a significant improvement in haemoglobin levels and overall disease control, marking a notable step forward in genetic medicine for blood disorders.
“We have seen that a benefit of this CRISPR/Cas12a gene-editing technology is that there is no rejection, so it’s different from traditional bone marrow transplants, which is standard treatment for sickle cell patients currently,” says Rabi Hanna, M.D., lead author and chair of the Pediatric Hematology – Oncology & Blood and Bone Marrow Transplant Division at Cleveland Clinic Children’s.
“Our aim has been to achieve a functional cure to help prevent any future damage caused by sickle cell disease, and these latest results are compelling.”
The 28 patients, four of whom were treated at Cleveland Clinic Children’s, underwent a procedure where their stem cells were first collected for gene editing.
They then received chemotherapy to clear their bone marrow, making room for the repaired cells which were later infused back into their body.
The results showed that most patients saw key blood cells recover within a month after treatment and by six months, average total hemoglobin levels rose to 13.8 g/dL, up from 9.8 g/dL before treatment, a level closer to what is seen in people without sickle cell disease.
The average level of fetal hemoglobin (HbF) was 48.1%, and these levels remained stable over time.
Sickle cell disease is a genetic blood disorder that causes red blood cells to be misshapen like a sickle. Normal red blood cells are round and carry oxygen smoothly through blood vessels.
In sickle cell disease, the abnormal cells block blood flow and break apart easily, leading to complications such as severe pain, liver and heart issues, and a shorter life span, typically in the mid-40s.
Medications can help manage the disease, but a cure is possible only through a blood or marrow transplant, which has risks and often requires a sibling donor.
Cleveland Clinic has a specialised centre for the care of adults and children with sickle cell. It provides comprehensive care, including treatment and support services throughout a patient’s lifetime, beginning in childhood.
The RUBY Trial is sponsored by Editas Medicine.
Credit: Cleveland Clinic
