“Overall, the improvements to date represent a clear signal of efficacy in a patient population where inexorable disease progression is the norm,” the company said

Patients treated by ReNeuron were able to read more letters on the eye chart

( ) has seen a “rapid and profound” result in the first three patients of the second phase of clinical studies of its human retinal progenitor cells (hRPC).

The Phase 2a trials of hRPC in sufferers of a blindness-causing disease called retinitis pigmentosa has seen noticeable improvements in visual acuity as measured by the number of letters that could be read on a standard eye chart.

Watch interview: 'All systems go' for ReNeuron's retinitis pigmentosa programme as it looks to follow-up studies

Six months after treatment there was a mean improvement of 18.5 per treated eye, with a mean improvement of 12 letters per treated eye after nine months, whereas inexorable disease progression is the norm for this disease.

With total of 22 patients now treated and the study still ongoing, ReNeuron said the efficacy in subsequent patients was seen but at a lower rate and magnitude, with improvement in visual acuity ranging from +5 to +11 letters in the treated eye three months after treatment.

“I believe that we are seeing a clear signal of efficacy in this patient population where any gain in vision, let alone the levels seen in some of these patients, is so hard to come by and so very much appreciated," said Dr Pravin Dugel, managing partner at Retinal Consultants of Arizona and clinical professor at the Roski Eye Institute in Los Angeles.

The results will be presented in further detail at the American Academy of Ophthalmology Annual Meeting in San Francisco on 12 October and at the Ophthalmology Innovation Summit on 10 October.