Janssen/MeiraGTx sight loss gene therapy hits targets

Janssen has unveiled six-month data from an ongoing Phase I/II trial of its investigational gene therapy for the treatment of inherited retinal disease X-linked retinitis pigmentosa (XLRP).

The interim data show that low and intermediate doses of the investigational adeno-associated virus retinitis pigmentosa GTPase regulator (AAV-RPGR), jointly developed with MeiraGTx, were generally well-tolerated and indicated “significant improvement in vision”.

In patients with XLRP, the photoreceptors in the eye responsible for converting light into signals sent to the brain don't function as they should, leading to degeneration of the retina and legal blindness in adulthood.

The companies’ AAV-RPGR gene therapy is being investigated to treat the most common and severe forms of XLRP caused by mutations in the RPGR gene by preserving and improving vision and slowing retinal degeneration.

In the dose escalation phase of the trial, at six months, the low and intermediate dose cohorts demonstrated “significant improvement” from baseline in retinal sensitivity after treatment, evident when assessed with two perimetry approaches and three analysis metrics.

Currently, there are no approved treatments for this condition.

“There is an urgent need to deliver a transformational therapy for people living with XLRP who experience progressive visual loss from childhood with eventual blindness in early adulthood,” said Michel Michaelides, trial investigator, consultant ophthalmologist at Moorfields Eye Hospital and Professor of Ophthalmology at University College London.

“We have learned valuable safety and efficacy information from this Phase I/II trial and look forward to applying those learnings in our next phase of study.”