Gene therapy for X-linked retinitis pigmentosa advances

The FDA has granted orphan drug designation (ODD) to MeiraGTx’s adeno-associated virus (AAV)-mediated gene therapy product candidate for treatment of X-linked retinitis pigmentosa (XLRP).

The therapy is designed to deliver a functional copy of the retinitis pigmentosa GTPase regulator (RPGR) gene to the retina of affected individuals. Over 70% of XLRP cases are caused by mutations in this gene, which manifests as night blindness in the first decade of life followed by progressive constriction of the visual field. By age 45, most men with XLRP are legally blind.

MeiraGTx plans to initiate a phase 1/2 clinical study of the candidate at Moorfields Eye Hospital in London in the first half of 2017.

“We are pleased to receive Orphan Drug Designation for our XLRP gene therapy product. It is further verification of the importance of our ocular gene therapy pipeline,” said Alexandria Forbes, PhD, MeiraGTx president and CEO.

The company was previously awarded ODD from the FDA and orphan medicinal product designation from the European Medicines Agency (EMA) for its retinal gene therapy candidates for treatment of Leber congenital amaurosis and for achromatopsia. The company is also working on gene therapies for post-radiation dry mouth (xerostomia), amyotrophic lateral sclerosis, and both wet and dry AMD.