ProgStar Study Identifies Potential Endpoint for Clinical Trials of Emerging Stargardt Disease Treatments

Stargardt disease, an inherited form of macular degeneration, causes progressive central vision loss. People with the condition lose their ability to read, drive, and recognize faces, though they do retain peripheral vision. The condition affects more than 100,000 people in the US and Europe.

Researchers developing vision-saving therapies for Stargardt disease have been challenged in identifying a way to measure changes in vision in patients over a short period of time (e.g., several months or a year). An eye chart, for example, doesn’t capture vision changes well in Stargardt disease patients, because central vision is often preserved until latter stages of the disease. Coming up with a sensitive and reliable outcome measure can enable therapy developers to determine quickly if a potential therapy is working in a clinical trial.

An international research team funded by the Foundation recently showed that microperimetry may be an effective outcome measure for clinical trials of emerging Stargardt disease therapies. A microperimeter is a device that measures retinal sensitivity in the macula, the central region of the retina. The Nidek MP-1 microperimeter used in the study measured the macula’s response to varying intensities of light at 68 different points. Microperimetry readings for patients in the study were taken at baseline and 12 months. Results of the study were published online in JAMA Ophthalmology.

“The results of the study showed that significant vision changes for patients were captured consistently and effectively by microperimetry over one year,” says Janet Cheetham, PharmD, a clinical consultant to the ProgStar study. “Though we can measure structural changes in the retina using other techniques, the functional changes captured in the macula by microperimetry are, from a regulatory standpoint, more meaningful.”

The Foundation has invested more than $6 million in the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) study. Launched in 2013, the Stargardt disease natural history study prospectively followed 259 Stargardt disease patients for two years. The study’s retrospective arm enrolled 251 patients. The last patient visit was in 2017. To date, 14 study-related research papers have been published in peer-reviewed journals. Analyses of the data continue with additional publications in process.

The overarching goal of the ProgStar study is to boost development of emerging therapies for Stargardt disease by: 1) gaining a better understanding of disease progression, 2) developing outcome measures that can be used in clinical trials, and 3) identifying potential clinical trial participants.