ReNeuron has reported further improvements in the vision of patients treated with its cell therapy. The mean increase in visual acuity across the three retinitis pigmentosa (RP) patients now stands at 23 letters, well above the level deemed clinically meaningful by the FDA.
British biotech ReNeuron is testing its human retinal progenitor cell therapy candidate in advanced RP patients with some remaining retinal function. ReNeuron initiated the trial to validate its belief that the cells preserve existing photoreceptors and mature into functional photoreceptors, thereby preserving and possibly restoring vision.
An early look at data on three patients provided preliminary support for that hypothesis in February. Now, updated data on the same subjects has suggested the cells may drive ongoing improvements in vision, at least up to 60 days after treatment.
ReNeuron now has 120 days of follow-up on one subject and 60 days on the other two. As of those cutoffs, the subjects could, on average, see 23 letters more on a standard vision chart than before being treated with the progenitor cells, compared to an improvement of five letters in the untreated eyes. The improvements ranged from 21 letters in one patient to 23 in another.
The first subject enrolled in the trial could see nine letters at baseline. Sixty days after treatment, the figure increased to 29 letters. Beyond that, there are signs that the effect may have plateaued, with the subject gaining one more letter of vision over the following 60 days.
Data on the other two patients suggest vision continues to improve from day 18 to day 60. Over that period, the vision of the second and third subjects improved by 10 letters and nine letters, respectively. The third subject had better vision at baseline than the other two patients—32 letters versus nine letters—but achieved a comparable improvement following treatment.
Shares in ReNeuron jumped 20% following the news, accelerating the upward trajectory of the stock. ReNeuron’s stock price has risen by more than 300% over the past month, bringing it back up to levels it last hit in 2016.
To maintain and build on those gains, ReNeuron will need to test its cells in more patients and show the effects seen over the first 120 days are durable. If ReNeuron does so, it could have a product capable of winning over the FDA, which views improvements of 15 letters or more as clinically meaningful.