Early results from two clinical trials are raising hopes for CRISPR-Cas9-based therapy for β-thalassemia and sickle cell disease, Nature Biotechnology reports.
Last month, Vertex Pharmaceuticals and CRISPR Therapeutics announced that they had successfully treated two patients, one with β-thalassemia and one sickle cell, with CTX001. CTX001 treatment involves obtaining hematopoietic stem cells from patients, then altering them with CRISPR–Cas9 to increase the production of fetal hemoglobin, and re-introducing the engineered cells back into the patients. According to NPR, Victoria Gray, the sickle cell patient, has been producing fetal hemoglobin at levels higher than what the researcher estimated would be needed to treat her condition. The companies add that the β-thalassemia patient was transfusion free after nine months.
These, Nature Biotech writes, are encouraging outcomes. But, it adds that some researchers want to see more data. For instance, the Children's Hospital of Philadelphia's Stefano Rivella tells it that it is unclear how many patients the firms have treated thus far and whether the observed rise in HbF levels is due only to the treatment. Additionally, Rivella says it's also not yet clear whether this treatment approach would be appropriate for all forms of the disease.