French Researchers Planning Clinical Study of Vision-Preserving Protein

A promising treatment aimed at preserving cones, the retinal cells that provide central and daytime vision, is poised to move into a Phase I clinical trial within the next year. Known as rod-derived cone viability factor (RdCVF), the therapeutic protein has consistently preserved vision in several preclinical studies.

RdCVF has received an orphan medicinal product designation from the European Commission, a regulatory agency similar to the FDA in the U.S. The orphan designation provides marketing, financial, and clinical research benefits to Fovea Pharmaceuticals, the French company developing the treatment. 

In 2005, Drs. José-Alain Sahel and Thierry Léveillard received the Foundation’s Annual Trustee Award for their discovery of RdCVF as a potential vision-saving treatment. The Foundation-funded French research team screened 210,000 genes to find a rod-derived protein that would protect cones.

A majority of retinal degenerative diseases, including retinitis pigmentosa (RP), are caused by mutations in genes that affect rod cells. As a result, rods are the first photoreceptors to degenerate. Rods provide peripheral eyesight and vision in dark settings.

However, once rods are gone, cones subsequently degenerate. This phenomenon led researchers to suspect that rods were secreting a factor (or multiple factors) that helped to preserve cones.

Initially, the France-based clinical trial will involve monthly ocular injections of RdCVF into people with RP. The investigators are also evaluating gene therapy as a delivery mechanism to provide long-term, sustained release of RdCVF. One gene therapy treatment will likely be effective for several years.

While the researchers will initially evaluate RdCVF in people with RP, they believe the treatment may preserve vision in people with a wide range of retinal degenerative diseases.

Dr. Sahel notes that by keeping as few as 5 percent of cones alive, a person can continue to function independently.

Drs. Sahel and Léveillard are co-founders of Fovea Pharmaceuticals. Dr. Sahel is center director for the Foundation’s Paris Research Center for the Study of Retinal Degenerative Diseases.