VY-FXN01

VY-FXN01 is an investigational gene therapy being developed by Voyager Therapeutics for the treatment of Friedreich’s Ataxia (FA).

Voyager is working in collaboration with Sanofi Genzyme to drive the development of VY-FXN01 and other gene therapies.

How VY-FXN01 works

FA is an inherited neurodegenerative disorder, where progressive damage to the nervous system causes loss of control of muscle coordination (ataxia), leading to problems with movement and balance, and to a range of other symptoms.

FA is caused by mutated copies of a gene that cause a lack of a protein called frataxin (FXN). The exact role of FXN is not fully understood, but it is normally located in the mitochondria, the energy-producing centers of the cells. It is thought that FXN may be involved in energy production or protecting cells from damage caused by free radicals, which can be produced as part of the normal energy-making process.

VY-FXN01 aims to deliver a healthy copy of the FXN gene to the body. Supplying the body with a functioning copy of the gene will enable it to produce FXN protein and may improve the symptoms of FA, such as balance, walking, coordination, and strength, and may prevent or slow progression of the disorder.

Voyager’s gene therapy program uses a modified virus called adeno-associated virus (AAV) as a vector or vehicle to deliver the genes into cells and promote their expression. AAV has been safely used as a vector in several clinical trials and has been seen to enable the expression of the replacement gene for eight years.

For the treatment of FA, the AAV vector containing the FXN gene can be administered as an injection into the spinal fluid or into a vein.

VY-FXN01 in preclinical studies

VY-FXN01 has not yet been studied in clinical trials, but it is advancing through preclinical studies.

Voyager reported that injection of VY-FXN01 into the spinal fluid in non-human primates can achieve levels of FXN in the brain that are higher than in the average healthy brain. The injection resulted in FXN expression in multiple brain areas, including those that are difficult to treat normally.

Currently, Voyager is assessing different types of AAV vectors in non-human primates to optimize the safety and delivery of the FXN gene. Voyager researchers are also running tests in a mouse model of FA to understand the effect of VY-FXN01, and to help determine potential endpoints to use in future clinical trials.

Voyager has multiple gene replacement therapy programs, and the company’s lead candidate is a molecule called VY-AADC01 for the treatment of Parkinson’s disease. It is currently in Phase 1b clinical trials in patients with advanced Parkinson’s disease. Voyager announced positive interim results from this trial, showing that the treatment was well tolerated and that the therapy had resulted in an increase in the target protein. A second Phase 1 clinical trial for Parkinson’s disease has also started. This is promising for the progression of VY-FXN01 into clinical trials in FA patients.

Voyager announced in March 2017, that it is aiming to submit an investigational new drug application (IND) for VY-FXN01 to the U.S. Food and Drug Administration (FDA) within the next two years in order to begin clinical trials in humans.