ReNeuron Group plc (AIM: RENE), a company involved in the development of cell-based therapeutics, has revealed positive long-term data from the ongoing Phase 1/2a clinical trial of its hRPC stem cell therapy candidate in retinitis pigmentosa (RP), and plans to expand the ongoing study, it was reported on Monday.

The data indicated that a group of patients had had a successful surgical procedure with sustained clinically relevant improvements in visual acuity compared with baseline, as measured by the number of letters read on the ETDRS chart (the standardised eye chart used to measure visual acuity in clinical trials).

The company has submitted a protocol amendment to the United States Food Drug Administration (FDA) to expand the Phase 1/2a study to treat up to a further nine patients in the Phase 2a segment of the study with a dose of two million hRPC cells, which compares with the dose of one million cells used in the study thus far. The amended clinical trial protocol also enables a greater range of pre-treatment baseline visual acuity in patients and includes changes that improve the ability to use microperimetry testing to measure and detect changes in retinal sensitivity in patients treated.

The company says that it expects to present further data from the expanded Phase 1/2a clinical trial during the course of 2020 and expects to have sufficient data from the study to enable it to seek approval in the first half of 2021 to commence a pivotal clinical study with its hRPC cell therapy candidate in RP.