Clinical Trial Enrollment Completed for Potential Retinal Disease Treatment

October 30, 2014

The Foundation Fighting Blindness Clinical Research Institute (FFB CRI) has completed patient enrollment for its Phase II clinical trial for valproic acid, a therapy which has shown some suggestion of slowing loss of visual function in people with autosomal dominant retinitis pigmentosa (adRP). Valproic acid was previously approved by the U.S. Food and Drug Administration (FDA) for the treatment of seizure disorders. The 90-participant study of valproic acid for people with confirmed adRP was launched in late 2010, and is taking place at six clinical sites in the U.S. 

“Recruiting participants for a clinical trial is always challenging,” says Patricia Zilliox, Ph.D., chief drug development officer at FFB CRI. “Given that our valproic acid clinical trial is for a rare condition like autosomal dominant retinitis pigmentosa made the challenge even greater.” Researchers estimate that 30,000 people in the U.S. have adRP.

Dr. Zilliox hopes to report valproic acid clinical trial results in approximately 15 months. The primary outcome measure for the study is the change in the patient’s visual field over 52 weeks. 

The study is placebo-controlled, masked, and randomized. That means half of the patients are being randomly selected to receive a placebo, and neither the patients nor the investigators know who is getting the drug or the placebo while the study is taking place. 

“Having a randomized, masked, placebo-controlled clinical trial is the best way to determine if a drug is actually working,”  Dr. Zilliox said. “It enables us to eliminate bias from both the patient and the investigator. It is the best way to get accurate results from a study in humans.”

The trial is also helping researchers better understand the progression of visual function  loss in adRP patients, thereby improving the design of clinical trials for other emerging adRP therapies. 

The valproic acid human study for adRP is taking place in the following clinical research centers: Retina Foundation of the Southwest in Dallas, Oregon Health & Science University in Portland, the University of Utah in Salt Lake City, the University of Michigan in Ann Arbor, the University of Miami in Miami, Florida,, and the University of Tennessee in Memphis.

“Both the patients and the investigators make extraordinary commitments in these clinical trials. They are our heroes,” Dr. Zilliox said. “Clinical trials require tremendous amounts of time and effort to evaluate potential therapies. Without the sacrifices that they make, the science doesn’t move forward.”