AT-GTX-501 is an experimental treatment for Batten disease that Amicus Therapeutics is developing

How AT-GTX-501 works

A genetic mutation in one of 14 different genes can be responsible for Batten disease. One of these genes is CLN6. It plays a role in the production and “packaging” of enzymes to be transported to lysosomes. Lysosomes are special compartments inside cells that contain digestive enzymes. When there is a mutation in the CLN6 gene, it cannot properly produce CLN6 protein. This leads to a buildup of molecules called lipofuscins inside lysosomes. These molecules are toxic for cells, especially nerve cells.

AT-GTX-501 is a gene therapy that uses a harmless adeno-associated virus to deliver a working copy of the CLN6 gene to the cells of the nervous system.

AT-GTX-501 in clinical trials

Researchers are investigating AT-GTX-501 in a Phase 1/2 open-label clinical trial (NCT02725580) in 13 patients with Batten disease. Patients, ages 1 year and older, receive a single intrathecal (into the spinal column) injection of AT-GTX-501. They then return for checkups on days 7, 14, 21, and 30, and then every three months for up to two years. During the monitoring period, researchers look for any adverse side effects. They also monitor any functional changes using the Hamburg motor and language (HML) scale and the unified Batten disease rating scale (UBDRS). The trial has completed enrollment, but is ongoing.

Once patients complete two years in this study, they have the option to join a long-term follow-up clinical trial (NCT04273243). Here, researchers will monitor them for up to an additional 13 years.

Amicus released interim results from the study in a press conference and a presentation at the joint 16th International Child Neurology Congress and 49th Annual Child Neurology Society Meeting. The results showed that all 13 participants tolerated the treatment well and that none of them had any adverse side effects.

The 12 patients who had completed at least one year of the study showed an average rate of decrease of 0.4 points on the HML scale compared with a drop of 1.2 points in a group of untreated Batten disease patients (NCT03285425). Eight patients had completed at least 24 months of treatment. They showed a mean rate of decline of 0.6 points compared to a decline of 2.4 points in the untreated group. Researchers estimate completing the initial trial in November 2021 with the follow-up study expected to finish in January 2035.

Other information

AT-GTX-501 received PRIME (priority medicines) designation from the European Medicines Agency in September.


Last updated: Dec. 18, 2020


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