Our human retinal progenitor cell (hRPC) programme for blindness-causing diseases of the retina is partnered with the Schepens Eye Research Institute Massachusetts Eye and Ear, an affiliate of Harvard Medical School in Boston, USA and a world-renowned clinical centre for the treatment of retinal diseases. This programme focuses on retinitis pigmentosa (RP) and cone rod dystrophy (CRD), hereditary diseases of the eye that lead to progressive loss of sight due to cells in the retina becoming damaged and eventually dying.

In RP there is a progressive loss of rod cells in the periphery of the retina causing night blindness that then leads to loss of peripheral vision, leading to tunnel vision.  In contrast, CRD is associated with a loss of cone cells in the retina that initially results in deterioration of central visual acuity and colour vision. The recent expansion of our ophthalmology programmes into CRD is part of a broader strategy to evaluate the efficacy of our hRPC therapeutic candidate across a range of genetic diseases of the eye.

We are using proprietary human retinal progenitor cells as the basis of our programme. Pre-clinical studies carried out in disease models by the Company’s academic collaborators have demonstrated that, when transplanted into the retina, our retinal progenitor cell technology has the potential to preserve existing photoreceptors, potentially reducing or halting further deterioration of vision. In addition, the progenitor cells have been shown to mature into functional photoreceptors that engraft into the photoreceptor layer, bringing the possibility of restored vision.

Our hRPC stem cell therapy candidate for RP benefits from Orphan Drug Designation in both Europe and the US. We have worked with world-leading collaborators and academic institutions in the retinal disease field to successfully take our retinitis pigmentosa programme through pre-clinical development.  We are currently conducting a Phase I/II clinical trial in the US with our hRPC therapy candidate for RP. This study, which is being undertaken at Massachusetts Eye and Ear Infirmary in Boston, marks the initiation of clinical trial activity in the US with our cell therapy programmes.

The trial design is an open-label, dose escalation study to evaluate the safety, tolerability and preliminary efficacy of the hRPC stem cell therapy candidate in patients with advanced RP.  The method of administration of the hRPCs will be a single sub-retinal injection. The primary endpoint of the study is safety, with patients being followed up for 12 months post-treatment with monitoring including measurements of visual acuity. Recruitment and treatment in the Phase I element of this study in 9 patients is complete and short term data from these patients indicate that the hRPC cell therapy was safe and well tolerated at the three doses tested. We are now dosing in the Phase II element of the study and it is expected that this will lead to a larger, placebo-controlled Phase IIb clinical trial.

Please click here to access a webcast of the June 2016 Key Opinion Leader event on Retinitis Pigmentosa.