Shanghai, China, March 18, 2025—CorrectSequence Therapeutics Co., Ltd. (Correctseq) announced its self-developed base editing therapy, CS-101, has achieved another major milestone in the treatment of β-thalassemia. In collaboration with the First Affiliated Hospital of Guangxi Medical University, CS-101 has successfully treated the second overseas patient—a Malaysian individual with transfusion-dependent β-thalassemia. This milestone follows the first cure of a β-thalassemia overseas patient from Laos, marking another significant global achievement for the company.
A Malaysian β-thalassemia patient who received base editing therapy (Correctseq’s CS-101) in China
has been transfusion-free and returned to normal life.
A “Single Treatment, Lifetime Cure” for β-Thalassemia
The Malaysian patient diagnosed with transfusion-dependent β-thalassemia required the transfusion of approximately six units of red blood cells (RBC) per month prior to receiving CS-101 treatment. Following the therapy, the patient’s hemoglobin level reached 120 g/L within three months and has maintained this level as of the report date. The patient successfully achieved independence from blood transfusions. This further validates CS-101’s efficacy and safety.
Meanwhile, the first overseas patient, an 18-year-old girl from Laos, has maintained transfusion independence for over eight months since receiving CS-101 treatment. This long-term efficacy demonstrates that CS-101 has the potential to provide a “single treatment, lifetime cure” for β-thalassemia patients of diverse ethnic backgrounds.
CS-101: A Best-in-Class Gene-Editing Therapy
The underlying principle of CS-101 involves the collection of the patient's own hematopoietic stem cells, followed by the treatment of the transformer Base Editor (tBE). Pioneered by scientists at ShanghaiTech University (Wang et al., Nat Cell Biol, 2021), this technology enables the precise editing of the DNA sequence within the promoter region of the gene responsible for encoding γ-globin (HBG1/2).
By generating a naturally occurring beneficial single-nucleotide variant found in individuals with hereditary persistence of fetal hemoglobin, the tBE reactivates γ-globin expression, resulting in the production of functional HbF (Han et al., Cell Stem Cell, 2023). The edited stem cells are then reintroduced into the patient's body, enabling continuous production of blood cells with functional hemoglobin.
Compared to traditional blood transfusion therapy and allogeneic hematopoietic stem cell transplantation, CS-101 offers several compelling advantages. One of the key benefits is its short preparation period. Another is the elimination of the long waiting time for a matching donor, as it utilizes the patient’s own hematopoietic stem cells. CS-101 has the potential to achieve a "single treatment, lifetime cure" in just a few weeks.
In comparison to other CRISPR-based β-thalassemia gene editing therapies, CS-101 does not cause safety risks associated with large DNA fragment deletions, chromosomal translocation, or off-target mutations. This enhances the overall safety profile of the treatment and reduces potential complications.
Overall, CS-101 offers a promising approach for the treatment of transfusion-dependent β-thalassemia, providing faster and safer hematopoietic reconstruction, quicker restoration of hemoglobin levels, and a shorter path to achieving transfusion independence compared to other therapies.
Curing Hemoglobinopathies to Benefit Global Patients and Families
β-thalassemia, one of the most common single-gene diseases in the world, is particularly prevalent in Southeast Asia, Mediterranean countries, the Middle East, and southern regions of China. It is estimated that approximately 300 million people in Southeast Asia carry the thalassemia mutant gene. Additionally, sickle cell disease, another hereditary hemoglobinopathy, is also widespread in many countries around the world, with about 3.5% of the world’s population carrying the mutation and roughly 300,000 infants born with the disease every year. The success of CS-101 brings new hope to patients with β- thalassemia and other hemoglobinopathies around the world.
To date, the Phase I clinical trial of CS-101 for β-thalassemia has completed the autologous stem cell infusion for all patients, with every patient achieving transfusion independence within one month post-infusion and rapidly reaching normal hemoglobin levels. This demonstrates the potential of CS-101 as the world’s “First-in-Class” base editing therapy and “Best-in-Class” gene editing therapy for β-hemoglobinopathies. In the meantime, an IIT study on sickle cell disease is ongoing. We are recruiting sickle cell patients worldwide. Correctseq is committed to advancing the clinical translation of pioneering gene editing technology, and bringing the hope of a complete cure for patients around the world.
Acknowledgement: The First Affiliated Hospital of Guangxi Medical University, ShanghaiTech University, Shanghai Clinical Research and Trial Center.
About CorrectSequence Therapeutics
CorrectSequence TherapeuticsTM (CorrectseqTM), is a clinical-stage biotech company employing its proprietary transformer Base Editor (tBE) to pioneer next-generation gene editing therapies. Our leading pipeline candidate, CS-101, which utilizes an innovative base editor targeting HBG to cure β-hemoglobinopathies, has obtained IND approval from the China NMPA. Clinical data demonstrates its superior performance. Proof-of-concept (POC) data in mice for in vivo pipelines using tBE-editing therapies via lipid nanoparticle (LNP) delivery are available, including targets for metabolic dysfunction and associated diseases. Ex vivo multiplex editing of T cells on multiple targets simultaneously preserved T cell growth and function in vivo compared to non-edited cells, establishing tBE as the ideal gene editing tool for the next-generation cell therapy development. We are developing multiple pipelines targeting genetic diseases, metabolic disorders, and cardiovascular diseases.
Please refer to our homepage for more information about the tBE and its therapeutics applications at www.correctsequence.com
