MeiraGTx, a New York and London based gene therapy company, have announced the first patient in its clinical study for X-Linked Retinitis Pigmentosa (XLRP) was treated at Moorfields Eye Hospital in London. This clinical study is the first-in-man Phase I/II dose escalation study of AAV2/5-hRKp.RPGR, MeiraGTx’s AAV-mediated gene therapy for XLRP caused by mutations in the RP GTPase regulator gene (RPGR).
In addition, the first patient in the 2nd cohort in the company’s clinical study of AAV-mediated gene therapy AAV2/8-hCARp.hCNGB3 for Achromatopsia patients with mutations in the CNGB3 gene has also been treated at Moorfields Eye Hospital. This follows the safe completion of treatment of the first three patients in the low dose cohort in the CNGB3 clinical trial.
MeiraGTx has also treated 7 patients in the PhaseI/II clinical study of AAV2/5-OPTIRPE65 in LCA2 patients with RPE65 deficiency, with the final two patients in the high dose cohort to be treated during Q3 2017.
In addition to these therapeutic clinical studies, MeiraGTx is conducting ongoing Natural History studies in each of these indications. In the Natural History study of XLRP caused by mutations in RPGR, 70 subjects are enrolled, all of whom are deep phenotyped, including 50 patients with more than 2 years natural history data.
Retinitis Pigmentosa (RP) is the most common inherited retinal dystrophy, and is characterised by progressive constriction of visual field with eventual central vision loss, and legal blindness. An estimated 10% to 20% of cases are X-linked, and more than 70% of X-linked cases are caused by mutations in the RPGR gene. RPGR encodes a protein located in the cilium that connects the inner and outer segments of photoreceptors, which is required to maintain directional protein transport between the inner and outer segments. Mutations in RPGR result in disrupted transport and lead to photoreceptor cell death. Currently, there are no treatments available for this condition.
Achromatopsia is a severe inherited retinal disorder characterszed by markedly reduced visual acuity (legal blindness), extreme light sensitivity, nystagmus, and absence of color discrimination from birth. Achromatopsia is genetically heterogeneous, with mutations in CNGB3 and CNGA3 accounting for 70-80% of patients. Currently, there are no effective treatments for this disease.
MeiraGTx has received Orphan Drug Designation (ODD) from the FDA and Orphan Medicinal Product Designation from the EMA Committee for Orphan Medical Products (COMP) for each of their proprietary AAV-mediated ocular gene therapy product candidates with on-going clinical trials.
“MeiraGTx is pleased to have initiated its third clinical trial in rare inherited retinal disease,” said Alexandria Forbes, Ph.D., President and CEO of MeiraGTx. “We continue our commitment to treating genetic diseases of the eye for patients globally.”
“We are delighted that the first patient has had successful surgery in our clinical trial for XLRP, and also with the rapid advancement of our two other ocular gene therapy clinical studies. We are excited to be making such progress in the development of treatments for inherited retinal blindness which collectively account for the commonest cause of blindness in the working age population and the second commonest in children” said Dr. Michel Michaelides, a founding member of MeiraGTx, and Professor of Ophthalmology, UCL Institute of Ophthalmology in the Department of Genetics, and Consultant Ophthalmic Surgeon in the Departments of Medical Retina, Genetics and Pediatric Ophthalmology at Moorfields Eye Hospital.