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

Dr. Robert MacLaren during surgery. 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.

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

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

  1. John says:

    Dr. Rose,

    My sister and I both have Rod Cone Dystrophy. Is this condition being studied by Spark? Will it be included in any of the clinical trials?


  2. Muhammad Saleem Malik says:

    Dear Sir my four children have night blindness iam very worry about them ages are 17-14-11-8
    doctor said they have RP

  3. Szilvia Beylik says:


    Both my two daughters, (16 and 18) their father, their aunt and their paternal grandfather (late adult onset) have RP. Do you know if RP patients would benefit from gene therapy? They are currently being treated with low energy laser therapy, by Dr Luttrull, in Ventura, California. To my understanding, he is the only one using this procedure. I’ll try anything promising, but gene therapy sounds more definitive. I’d like to know more and hopefully be able to participate in clinical trials to preserve my daughters’ vision.
    Any information you have regarding this is much appreciated.

    • EyeOnTheCure says:

      I have not heard of laser therapy being used to treat RP. You should consider genetic testing to try and identify the mutant gene responsible for causing your daughter’s disease. If the gene is identified, medical databases such as PubMed ( can be searched to identify any research that is being conducted. With a molecular diagnosis, one may also qualify for gene therapy trials that are taking place. For information on genetic testing, please see the following web link to download a PDF document:

      Whether the disease gene is identified or not, one should still consider participating in FFB’s “My Retina Tracker”, a free registry that monitors clinical trials that are recruiting for various retinal diseases. For more information on “My Retina Tracker” please see the following web link:

      It may also be helpful to periodically check the website: http://WWW.CLINICALTRIALS.GOV which is maintained by the National Institutes of Health and contains a searchable list of clinical trials for most known diseases. Each clinical trial listing will provide you with information on what the study is about, the requirements for participating and contact information.

  4. louiza wali says:

    Miss Louisa age 42 suffer from blindness due to a genetic disease
    I was ready for testing this technology with optimism and I’ve made a irm rays and told me competent in Algeria that I can conduct experiments carried out by Dr. Robert McLaren

  5. gina says:

    My 16 yr old son was recently diagnosed with CHM. Its frustrating the trials they have are limited to over 18— when they have done it on an 8yr old with positive results…

    • Dr. Tim Schoen says:

      Dear Gina, Once the gene therapy choroideremia clinical trials demonstrate safety and move into Phase 2 and 3, it should be possible to petition the FDA to gain authorization for treating individuals less than 18.

  6. Hope Addison says:

    Please help my two boys with rp

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