CorrectSequence Therapeutics Co., Ltd. (Correctseq), a clinical-stage biotechnology company pioneering transformer Base Editing (tBE) technology for severe diseases, announced that the first sickle cell disease (SCD) patient being treated in China with its high-precision base-editing therapy CS-206 has remained free of vaso-occlusive crises (VOCs) for more than 15 months following engraftment. Starting from 60 Days after the last red-cell transfusion, the patient has remained free from VOCs and anemia for 13 consecutive months, achieving the primary efficacy endpoint. The follow-up data demonstrated favorable safety and efficacy of CS-206.
The patient, a 21-year-old woman from Nigeria, had experienced recurrent severe VOCs prior to treatment with CS-206. After receiving CS-206 treatment in February 2025, the patient achieved rapid and efficient hematopoietic reconstitution, with neutrophil engraftment observed on Day 13 and platelet counts exceeding 50×10^9/L on Day 21 post-treatment. Within one month after treatment, fetal hemoglobin (HbF) levels increased significantly and continuously, while sickle hemoglobin (HbS) levels declined substantially and persistently. Beginning at Month 3 after treatment, the HbF-to-HbS ratio stabilized at approximately 6:4 and has remained stable thereafter. No product-related adverse events have been observed to date.