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UCL EyeTherapy Blog


A blog by the Gene and Cell Therapy Group at the UCL Institute of Ophthalmology Department of Genetics


UCL RPE65 Gene Therapy Trial Shows Benefit in People with Leber Congenital Amaurosis Type 2 for up to Three Years After Treatment

By Andi M Skilton, on 5 May 2015

NEJM 2015 Cover

We are delighted to be able to announce that yesterday, Monday 4th May, the long-term results of our RPE65 gene therapy trial for Leber Congenital Amaurosis Type 2 (LCA2) were published in the prestigious New England Journal of Medicine.

Begun in 2007, this was the world’s first-in-human trial of gene therapy to treat an inherited form of blindness. Twelve patients were enrolled in the trial over the course of six years and followed up over a three year period to assess the long-term safety and benefit of treatment with gene therapy in this Phase I/II clinical trial.

A number of patients enrolled in the trial experienced gains in night vision for a period of two to three years with greatest improvements seen in the first 6 to 12 months after treatment. This is consistent with the published results and interim findings of other studies of RPE65 gene therapy.

This study confirms our preliminary findings (published in NEJM, 2008) that gene therapy can improve night vision, providing further evidence of benefit in inherited blindness.
Professor James Bainbridge, lead clinician for the trial

Our latest results provide confirmation of efficacy but the data, together with results of a parallel study in dogs, indicate that the demand for RPE65 is not fully met with the current generation of vectors. We have concluded that early intervention using a more potent vector, expressing higher levels of RPE65 is likely to provide greater benefit and protection against progressive degeneration.
Professor Robin Ali, lead for the research group

The group has now developed a new, more powerful gene therapy vector and is aiming to test this in a second clinical trial funded by The UK Medical Research Council.

Links to further information:

  • The full results from this study can be found in the NEJM:
  1. Bainbridge, JWB, Mehat MS, Sundaram V, et al. Long-term Effect of Gene Therapy on Leber Congenital Amaurosis. New England Journal of Medicine. 2015;10.1056/NEJMoa1414221
  2. Bainbridge, JWB, Smith AJ, Barker SS, et al. Effect of Gene Therapy on Visual Function in Leber’s Congenital Amaurosis. New England Journal of Medicine. 2008; 358: 2231-9

2 Responses to “UCL RPE65 Gene Therapy Trial Shows Benefit in People with Leber Congenital Amaurosis Type 2 for up to Three Years After Treatment”

  • 1
    Grace wrote on 5 May 2015:

    Wonderful news. How can one find out how to go about getting research into RP1 mutation? Or will some tweaking of current trail results be able to treat other RP mutations?

  • 2
    Andi M Skilton wrote on 8 May 2015:

    Dear Grace thank you for your comment – it is an important step forward.

    With regards to research into defects in RP1 we wanted to reassure you that research into RP1 is happening at various centres around the world. One of the challenges with RP1 is that the gene is very large which makes it very difficult to work with. For gene therapy it is unfortunately too large for the viruses we use to deliver gene therapy to the eye. To this end a number of groups around the world are looking into new approaches which will allow scientists to work with larger and larger genes with the aim that in the future we may be able to develop new treatments for these conditions.

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