Eye On the Cure Research News

Apr 28, 2016

ARVO 2016: Choroideremia Gene Therapy in Clinical Trial Continues to Perform Well

Five of six patients in NightStaRx’s choroideremia gene-therapy trial continue to benefit from the treatment.

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Photo of Dr. Robert MacLaren

Dr. Robert MacLaren, principal investigator for the choroideremia gene-therapy study, courtesy of University of Oxford.

The annual meeting of the Association for Research in Vision and Ophthalmology (ARVO) in Seattle won't start for another three days, but already there's exciting research news to report. Five of six patients in NightStaRx's choroideremia gene-therapy trial at the University of Oxford in the United Kingdom, which began in 2013, continue to benefit from the treatment.

The two patients with the most advanced disease have sustained vision improvements in their treated eyes. One has improvement of about three lines on an eye chart. The other has roughly two lines of improvement. Vision in their untreated eyes deteriorated. The treatment preserved vision for three other patients. Vision in their treated eyes has been stable, whereas vision loss continued in the untreated eyes of two participants. One patient who received a low dose of the therapy experienced continued vision loss in both eyes.

For a safety-oriented human study of a cutting-edge therapy, this news is simply outstanding. That's because we are still very much at a learning stage for this treatment. Among many things, we're determining the best stage of disease for treatment, the optimal dose and best injection site. So sustained vision improvements at this point are icing on the cake.

I'd be remiss if I didn't mention that the Foundation Fighting Blindness provided decades of funding to Miguel Seabra, M.D., Ph.D., for lab studies that made this trial possible. He did painstaking work to understand the CHM gene, develop a mouse model of choroideremia, develop the gene therapy and then test it in the mice. And, now, other choroideremia gene therapy clinical trials are being launched by Spark Therapeutics in Philadelphia, the University of Alberta in Canada and Bascom Palmer Eye Institute in Miami.

In case you didn't know, choroideremia is a vision-robbing retinal disease affecting primarily males. During the person's childhood or adolescence, it causes loss of peripheral and night vision, and progressively leads to significant vision loss in adulthood.

We'll be hearing more about what's happening in choroideremia gene therapy at an ARVO session Monday, May 2. It's just one of thousands of presentations at a meeting that attracts about 12,000 eye and retina geeks like me every year.

You can also read about the choroideremia gene therapy trial at the University of Oxford in a letter from the study's principal investigator, Robert MacLaren, M.D., published today in the The New England Journal of Medicine