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(Alliance News) - ReNeuron Group PLC on Wednesday posted positive results from early patients in its ongoing trial of a treatment for retinitis pigmentosa, which causes blindness, but was less profound in later patients.
Shares in ReNeuron were down 20% at 215.70 pence in London in afternoon trading.
The efficacy of treatment in the first three patients enrolled in the phase 2a segment of the study "was rapid and profound" but in subsequent patients efficacy was seen "at a lower rate and magnitude". The total extent of improvement isn't yet known, since the study is still ongoing.
The phase 1/2a clinical trial is assessing ReNeuron's "human retinal progenitor cell (hRPC) therapy candidate". Reneuron said that the improvements in visual acuity so far, as measured by the number of letters read on an eye chart, have been "a clear signal of efficacy".
This was considered to be particularly the case given that RP, which covers a number of conditions that interfere with the retina at the back of the eye, typically worsens over time. Usually, patients have trouble with their peripheral vision and with seeing in the dark, but central vision can also be damaged.
So far 22 patients have been treated in the phase 1/2a study and none experienced "product-related serious adverse events", although two suffered loss of vision relating to the surgical procedure.
Excluding those patients with surgery-related vision loss, at 1 month post-treatment, mean improvement in visual acuity from the treated eye was an additional 14.5 letters, compared to 1.6 letters in the untreated eye. By 6 months, the mean improvement in the treated eye was 28.7 letters versus 7.8 letters in the untreated eye.
However, at 9 months, the mean improvement was 12.0 letters in the treated eye, while the untreated eye did not experience improvement but instead lost 1.0 letters.
ReNeuron Chief Executive Olav Hellebo said: "We are greatly encouraged by the latest efficacy data from the ongoing phase 1/2a clinical study of our hRPC cell therapy candidate in patients with RP. It is especially gratifying to see positive data given the inherent challenge in addressing a disease as complex as RP and we look forward to further progressing the clinical development of this promising cell therapy candidate."
By Anna Farley; annafarley@alliancenews.com
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