ST-920 Gene Therapy

ST-920 is an experimental gene therapy being developed by Sangamo Therapeutics to treat Fabry disease. It is designed to deliver a fully functioning version of the GLA gene to cells in the liver.

How does ST-920 work?

Fabry disease is caused by mutations in the GLA gene, which carries the instructions for an enzyme called alpha-galactosidase A (alpha-GalA). These mutations lead to the accumulation of a fat molecule called globotriaosylceramide (Gb3) inside cells and tissues, ultimately causing a range of symptoms.

ST-920 contains a modified viral vector that, when injected into the bloodstream, is designed to deliver a healthy version of the GLA gene to the liver. Conceptually, modified cells in the liver would then be able to make a functional alpha-GalA enzyme, which would be released into the bloodstream.

The specific vector used to deliver ST-920’s genetic payload is a laboratory-engineered virus called adeno-associated virus (AAV). This type of virus is commonly used in gene therapies because it does not make people sick, and it’s relatively easy to manipulate in a laboratory.

Preclinical studies in mouse models of Fabry showed that treatment with ST-920 increased alpha-GalA levels, which were accompanied by a marked reduction in Gb3 buildup in tissues. Three months after a single injection of the gene therapy, alpha-GalA activity in mice’s blood also was more than 400-fold higher than in normal mice.

ST-920 in clinical trials

Sangamo is sponsoring a first-in-human Phase 1/2 clinical trial (NCT04046224) to test the safety and efficacy of increasing doses of ST-920. An estimated 48 participants will receive a single infusion of the experimental gene therapy, and will be followed for 52 weeks (about a year). 

The trial is open to adults of all sexes, ages 18 and up, with a confirmed diagnosis of Fabry disease.

To be eligible, participants must be experiencing at least one of the following four symptoms: a whorl-like pattern of opacities in the outer part of the eye, feelings of tingling, numbness, or burning in the hands and feet, an inability to sweat normally, and/or small, dark spots on the skin.

The trial is actively recruiting participants at several locations in the U.S. and U.K.


Last updated: Oct. 21, 2021


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