CorrectSequence Reports Long-Term Success of CS-206 Base Editing Therapy for Sickle Cell Disease

CorrectSequence Therapeutics announced in a press release that its precision base editing therapy CS-206 has shown sustained efficacy and safety over a 15-month follow-up period in the first sickle cell disease patient treated in China. The 21-year-old patient has remained free of vaso-occlusive crises and anemia since 60 days after her last red blood cell transfusion.

The patient received the CS-206 treatment in February 2025 and achieved rapid hematopoietic recovery, with neutrophil engraftment on day 13 and platelet counts above 50×10⁹/L by day 21. Fetal hemoglobin levels increased steadily while sickle hemoglobin levels decreased, stabilizing at a ratio of about 6 to 4 from the third month onward. No product-related adverse events have been reported.

CS-206 uses CorrectSequence's transformer Base Editor technology to precisely modify the HBG1/2 promoter region in autologous hematopoietic stem cells, reactivating gamma-globin expression and elevating fetal hemoglobin levels. This approach avoids double-strand DNA breaks, reducing risks such as chromosomal abnormalities or off-target mutations.

Based on the same platform, CorrectSequence's CS-101 therapy for beta-thalassemia has achieved transfusion independence in more than ten patients for over 15 months, with some exceeding 30 months. The company is now conducting global recruitment for the investigator-initiated clinical trial of CS-206 and advancing clinical development of both programs.