NANNING -- In a milestone for genetic medicine, researchers in China have reported the world's first clinical success using a revolutionary "base-editing" technique to treat patients with a severe inherited blood disorder.

The study, published Wednesday in the world-class science journal Nature, reveals that five patients with transfusion-dependent beta-thalassemia were able to discontinue their grueling monthly blood transfusions after receiving a one-time infusion of an experimental therapy called CS-101.

According to the study, while gene editing offers a promising new path towards a cure, many current methods carry risks. Most strategies involve reactivating a specific gene to produce fetal hemoglobin, which can then compensate for the patient's defective adult hemoglobin.

However, traditional techniques often risk triggering DNA damage or chromosomal abnormalities, said Lai Yongrong, the study's lead author and professor at the Hematology Department of the First Affiliated Hospital of Guangxi Medical University.

To address this, the team employed a "transformer base editor," a technology that allows for the direct rewriting of specific genetic bases in a patient's stem cells without cutting the DNA's double-helix structure.

By avoiding these breaks, the therapy can produce more active fetal hemoglobin with lower toxicity.

"Because we aren't cutting the DNA, the risk of collateral damage is significantly lower," Lai noted, marking this approach as a safer and more precise alternative to earlier gene-editing tools.

The clinical trial, led by the First Affiliated Hospital of Guangxi Medical University in collaboration with ShanghaiTech University, Fudan University and CorrectSequence Therapeutics, reported remarkable speed and safety.

On average, within 16 days of receiving the infusion of their edited cells, all five patients showed initial signs that the new cells were functioning.

All participants stopped blood transfusions within one month, reaching stable hemoglobin levels that have remained near normal throughout the study.

The long-term efficacy is highlighted by the first patient in the trial, who has lived without the need for a transfusion for more than 28 months.

Over a median follow-up period of nearly two years, researchers reported no serious side effects associated with the therapy.

Beta-thalassemia is a debilitating condition, particularly prevalent in South China and Southeast Asia, where the carrier rate in regions like Guangxi exceeds 20 percent.

Traditionally, the only cure was a bone marrow transplant, which requires a perfect donor match and carries the risk of "graft-versus-host disease," where the new cells attack the body of recipient. By using the patient's own stem cells, CS-101 eliminates the need for a donor.

This is the first time that a Chinese study on thalassemia has been published in Nature, said Lai. "It proves that our homegrown gene-editing technology is not just world-class, but has the potential to be a best-in-class treatment globally."