Posted on: 23 June 2009, source: Recombinant DNA Advisory Committee
The National Institutes of Health Office of Biotechnology Activities (OBA) has been informed that a "relative clonal dominance" was detected during follow-up of a subject who is participating in a French human gene transfer trial being conducted for individuals with β-Thalassemia Major and Sickle Cell Anemia. The clinical trial, sponsored by Genetix France, used hematopoietic stem cells transduced by a self inactivating (SIN) HIV-1 lentiviral vector containing the gene for β-globin under the control of the β-globin promoter. The subject received the gene modified cells in June 2007.
This clonal dominance appears to result from the integration of the vector in the gene encoding for the HMGA2 protein, which is associated with both benign and malignant tumors. The clone however has been stable for five months and the subject remains in good health. In fact, although the subject required almost monthly blood transfusions during the 11 months prior to the gene transfer intervention, the subject has not since required a blood transfusion.