(HealthDay News) – Gene therapy has successfully improved vision in six patients with a genetic form of progressive blindness, according to a study published online Jan. 16 in The Lancet.

Robert E. MacLaren, MB, ChB, from the University of Oxford in the United Kingdom, and colleagues treated six male patients with choroideremia with an adeno-associated viral vector encoding the correct protein via a subfoveal injection into one eye. Choroideremia is an X-linked recessive disease that leads to blindness due to mutations in the Rab escort protein 1.

After six months, the researchers found that the mean gain in visual acuity was 3.8 letters, despite retinal detachment as part of the surgical procedure in all six patients. The two patients with low baseline visual acuity gained 21 and 11 letters and the four patients with near normal visual acuity recovered to within one to three letters. Dark-adapted microperimetry showed an increase in maximal sensitivity from 23–25.3dB, which significantly correlated with vector dose per square millimeter.

“The initial results of this retinal gene therapy trial are consistent with improved rod and cone function that overcome any negative effects of retinal detachment,” MacLaren and colleagues conclude.

Several authors are inventors on a related patent owned by the University of Oxford. One author is a director at Gene Technology Solutions.

Full Text (subscription or payment may be required)
Editorial (subscription or payment may be required)