Shanghai – September 12, 2026 -- CorrectSequence Therapeutics (Correctseq) reported that its transformer Base Editor (tBE) therapy CS-101/CS-206 delivered durable clinical remission in patients with sickle cell disease (SCD) and transfusion-dependent β-thalassemia (TDT) across four distinct genetic backgrounds, according to a peer-reviewed study published in Cell Stem Cell on September 7, 2026.
The study, conducted with multiple research institutions, expands on earlier data showing five Chinese TDT patients treated with CS-101 all achieved transfusion independence. The new cohort includes four patients from Nigeria, Laos, Malaysia and Pakistan -- one with SCD and three with TDT -- covering genotypes βS/βS, β0/βE, and two β0/β0 variants with different mutation types.
Nigerian SCD patient reaches 62.2% HbF and zero vaso-occlusive crises in 15.5 months
A 21-year-old SCD patient from Nigeria, who had experienced more than four vaso-occlusive crises (VOCs) in the year before enrollment, achieved neutrophil engraftment on day 13 and platelet engraftment on day 21 post-infusion. Total hemoglobin rose from 7.7 g/dL at baseline to 12.9 g/dL by month three and remained above 11 g/dL. Fetal hemoglobin (HbF) climbed from 3.5% to 62.2%, while sickle hemoglobin (HbS) fell from 76.1% to 31.6%, stabilizing near a 6:4 ratio. No VOCs occurred over 15.5 months of follow-up.
Three TDT patients from Laos, Malaysia and Pakistan reach durable transfusion independence
Across three TDT patients aged 3 to 29, median neutrophil engraftment occurred at 13 days and platelet engraftment at 27 days. Mean total hemoglobin reached 11.6±1.2 g/dL, with mean HbF at 9.8 g/dL by month three. After a median follow-up of 17.5 months, all three achieved durable transfusion independence with no off-target edits or product-related adverse events detected.
tBE outpaces nuclease-based editing on engraftment speed and HbF expression
In SCD trials, tBE achieved neutrophil engraftment in 13 days versus 27 days for Cas9 and 23 days for Cas12a, and platelet engraftment in 21 days versus 35 days for Cas9 and 25 days for Cas12a. tBE sustained HbF above 60% of total hemoglobin, compared with under 50% for Cas9 and Cas12a regimens. Because tBE performs base conversion without cutting DNA, the company said the platform avoids double-strand breaks, p53 activation, large deletions and chromosomal rearrangements associated with nuclease-based approaches.
More than 30 patients treated globally as CS-101 advances toward pivotal trials
Correctseq has now treated over 30 patients across China, Africa, Southeast Asia and South Asia with CS-101 and CS-206, with 100% achieving transfusion independence or VOC freedom alongside sustained high hemoglobin expression. CS-101, described as the first base-editing therapy candidate to enter clinical development globally, dosed its first patient in October 2023, has completed Phase I, and is now in pivotal trials. All Phase I patients have remained transfusion-independent for more than one year, with the longest duration approaching three years.
Professor Chen Jia, founder of Correctseq and director of the Gene Editing Center at ShanghaiTech University, said the Cell Stem Cell publication confirms tBE's applicability across diverse genetic backgrounds and completes its path from laboratory research to global clinical use. Dr. Mou Xiaodun, CEO of Correctseq, said the company is expanding into metabolic and cardiovascular indications, including hypertriglyceridemia/familial chylomicronemia syndrome, ASCVD/hyperlipoproteinemia, homozygous familial hypercholesterolemia and metabolic dysfunction-associated steatohepatitis, while pursuing multiple IND filings worldwide.