ViGeneron Launches Clinical Trial of Gene Therapy for RP Caused by CNGA1 Mutations

ViGeneron GmbH, a gene therapy development company in Munich, Germany, has dosed the first patient in a Phase 1b clinical trial for its gene therapy for people with retinitis pigmentosa (RP) caused by mutations in the gene CNGA1. The six-patient trial is taking place at the University of Tübingen in Germany.

CNGA1 plays a critical role in phototransduction, the conversion of light into electrical signals, in rod photoreceptors, the retinal cells that provide night and peripheral vision. As a result, people with RP caused by CNGA1 mutations initially lose night and peripheral vision. As the condition progresses, loss of rods can lead to loss of cone photoreceptors and central vision.

The emerging gene therapy uses ViGeneron’s adeno-associated virus (AAV) gene-delivery technology known as vgAAV, which enables injection of the treatment into the vitreous, the soft gel in the middle of the eye. Intravitreal injections are frequently performed in a doctor’s office. The company says the vgAAV can broadly deliver copies of the CNGA1 gene to photoreceptors which are at the back of the eye.

Most other AAVs used for retinal gene therapy delivery are injected subretinally, an approach that temporarily detaches the fragile retina but gets the treatment directly to the back of the eye, close to photoreceptors. Subretinal delivery is performed surgically.

ViGeneron is also developing a dual-vector vgAAV to deliver large genes which exceed the cargo capacity of conventional AAV delivery systems. Known as REVeRT, the company’s dual-vector system delivers a gene in two DNA pieces. Once in the cell, the messages (mRNA) encoded from the DNA halves are combined so the cell can make the correct protein for proper cell function and survival. The company is working toward a clinical trial for REVeRT delivery of ABCA4, a gene commonly associated with Stargardt disease.