World first clinical trial to treat X-linked RP

A 29-year-old British man has become the first patient with X-linked retinitis pigmentosa to undergo gene therapy.

He is one of at least 24 patients who will receive a subretinal injection of a modified RPGR gene, which is associated with retinitis pigmentosa.

The modified gene will be delivered to retinal cells using a viral vector. The present trial is the first in the world to test a treatment for retinitis pigmentosa caused by RPGR.

The trial is being conducted by the biopharmaceutical company Nightstar and researchers from the University of Oxford.

A research team led by Oxford University Professor Robert MacLaren reprogrammed the genetic code of RPGR to make it more stable without affecting its function.

Professor MacLaren told OT that the effect of RPGR-related disease on families with retinitis pigmentosa was devastating.

“We have spent many years working out how to develop this gene therapy. Changing the genetic code is always undertaken with great caution, but the new sequence we are using has proven to be highly effective in our laboratory studies,” he emphasised.

Nightstar chief medical officer, Dr Aniz Girach, highlighted to OT that the trial was an open-label dose-escalation study.

“The primary goal of the study is to assess the safety and tolerability of this gene therapy over a 12-month period,” he explained.

Fight for Sight chief executive officer, Michele Acton, told OT that the organisation was proud to support research that led to the start of the clinical trial.

“This could make a significant difference to the lives of so many people and we wish the team in Oxford continued success in the coming months,” she concluded.