Potential for a Cure
A baby is born with a defective gene, leading to a life-threatening disease. Standard therapies are limited; the child is faced with battling a chronic condition for life.
But perhaps there is an alternative — one that may lead to a permanent cure.
Gene therapy is designed to restore the function of a patient’s defective gene by introducing a healthy copy, with the potential to permanently correct a genetic disease. This compelling concept has intrigued the medical community for more than 20 years. While still primarily performed as part of research studies, gene therapy is becoming more widely adopted for clinical treatment of some conditions.
GENE THERAPY FOR SCID:
Bubble Boy Disease
For children born with SCID, a parent’s touch can be life-threatening. Often called “bubble boy disease,” SCID devastates the immune system and leaves patients vulnerable to lethal infections. Early death is common, even with existing therapies.
X-linked SCID, the most common form of SCID, is caused by defects in a gene encoding a critical protein called the common gamma chain. Without it, immune system cells called T cells, B cells and natural killer cells do not develop normally.
With the aim of pioneering a safe, effective gene therapy approach, St. Jude scientists have spent years developing an innovative vector for X-linked SCID. The vector is manufactured in the on-site Good Manufacturing Practice (GMP) facility using a process developed at St. Jude. The process, which uses stable cultured cell lines to produce the vector, addresses the challenge of manufacturing large quantities of clinical-grade vector in a reproducible manner.
The vector has been designed with features to reduce the risk of activating cancer-causing genes. It has also been subjected to extensive laboratory testing to ensure it does not readily insert into chromosomes near such genes.
Clinical trials led by St. Jude and the National Institute of Allergy and Infectious Diseases (NIAID) are assessing whether this vector can safely provide long-lasting health benefits to patients with X-linked SCID.
Read about the St. Jude trial: LVXSCID-ND: Gene Transfer for X-Linked Severe Combined Immunodeficiency in Newly Diagnosed Infants
Featured Research: Success for SCID Gene Therapy Featured at ASH Meeting
At the 2017 annual meeting of the American Society of Hematology, results from the X-linked SCID gene therapy trial were announced. The outcomes are promising: After treatment, five of the seven patients had immune systems for the first time, and no longer require protective isolation. Four patients have started making antibodies for the first time. One patient has stopped monthly immunoglobulin supplementation and recently received his first set of vaccinations.
THE FUTURE OF GENE THERAPY:
Challenges and Opportunities
To date, results from clinical studies of gene therapies pioneered at St. Jude have been promising. It will be important to follow patients for many years to confirm the therapy’s long-lasting safety and health benefits.
St. Jude researchers are now focused on applying investigational gene therapy approaches to treat X-linked SCID, hemophilia B and a related disorder, hemophilia A. The long-term vision is to apply these technologies to other genetic diseases, such as sickle cell disease, and to explore applications in developing effective immune therapies for cancer.
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