Retinitis Pigmentosa clinical trials at UCSF

Retinitis pigmentosa (RP) is an inherited retinal degeneration caused by one of several mistakes in the genetic code. Such mistakes are called mutations. The mutations cause degeneration of rod photoreceptors which are responsible for vision in dim illumination resulting in night blindness. After rod photoreceptors are eliminated, gradual degeneration of cone photoreceptors occurs resulting in gradual constriction of side vision that eventually causes tunnel vision. Oxidative stress contributes to cone degeneration. N-acetylcysteine (NAC) reduces oxidative stress and in animal models of RP it slowed cone degeneration. In a phase I clinical trial in patients with RP, NAC taken by month for 6 months caused some small improvements in two different vision tests suggesting that long-term administration of NAC might slow cone degeneration in RP. NAC Attack is a clinical trial being conducted at many institutions in the US, Canada, Mexico, and Europe designed to determine if taking NAC for several years provides benefit in patients with RP.

Currently enrolling a total of 12 patients for Phase 2a of the study: 6 patients must have VA of no-better-than hand motion in the study eye, and 6 patients must have VA in the study eye to range from no-worse-than count fingers to 20/200 vision.

The overall goal of this project funded by the Foundation Fighting Blindness is to characterize the natural history of disease progression in patients with EYS mutations in order to accelerate the development of outcome measures for clinical trials.