St. Jude Children’s research hospital has published the results of a lentiviral gene therapy for XSCID, showing early signs of robust improvements in the immune system of 8 patients, ranging from months old to 2 years old, in a pilot study of a gene transfer therapy.
XSCID, AKA X-Linked Severe Combined Immunodeficiency is the result of a mutated chromosome, which can be either be inherited or naturally occurring. The mutation results in an immune system that is inadequate to fight common infections.
The current treatment for this mutation is a stem cell transplant, which requires the child to have a brother or sister. The therapy tested at St. Jude is designed to be allogenic – IE it does not require a human cell donor. In this technique, stem cells from bone marrow are extracted from the patient, a copy of the normal genes are inserted into the cells using lentivirus as a vector, and then the resulting stem cells are reinserted into the bone.
The results in this short trial are promising:
- In 7 of 8 cases, common immunity markers ( CD3+, CD4+, T-Cell, Natural Kiler cell counts, etc ) increased to normal levels within 3-4 months.
- The 1 patient that did not respond within 3-4 months responded to another treatment.
- Previous infections were cleared and growth continued at a normal rate.
- 4 of 8 patients were able to discontinue monthly infusions of intravenous immunoglobulin thus far.
- Most patients were discharged from the hospital within one month.
St. Jude signed a licensing deal with Mustang Bio, Inc. last year, aiming to commercialize the treatment for not only infants, but also adults who have received hematopoietic stem cell transplantation and have decreasing T cell counts.
The Phase 1/2 trial in newly diagnosed infants with XSCID continues to enroll at St. Jude, UCSF Benioff Children’s Hospital and Seattle Children’s Hospital.