MeiraGTx announces AAV-RPE65 trial meets primary endpoint
MeiraGTx announced data from a Phase 1/2 dose escalation trial of AAV-RPE65, the company's investigational gene therapy for the treatment of RPE65-deficiency, a condition that causes blindness. AAV-RPE65 is a second-generation gene therapy candidate developed specifically to treat RPE65-deficiency, and optimized for transduction efficiency, potency and stability. The trial achieved the primary endpoint of safety and tolerability of AAV-RPE65. Additionally, AAV-RPE65 demonstrated statistically significant improvement across several secondary endpoints designed to assess clinical activity. The Phase 1/2 open-label, multi-center, dose-finding trial evaluated AAV-RPE65 in patients with retinal dystrophy associated with disease-causing variants in the RPE65 gene. The trial was conducted at two centers in the U.S. and UK, and three surgeons undertook the surgery across these sites. The trial enrolled 15 patients, including nine young adults across three dose escalation cohorts, and six children in a pediatric expansion cohort. Each patient was treated with subretinal delivery of AAV-RPE65 in the eye that was more affected at baseline. The patient's other eye served as an untreated control. Significant improvement in vision was demonstrated at six months after AAV-RPE65 treatment, as measured by assessments of vision-guided mobility, retinal sensitivity, visual acuity and contrast sensitivity. Larger improvements from baseline in functional vision were observed between treated and control eyes at lower light levels. These outcomes address the core functional manifestation of RPE65-deficiency, which typically causes vision impairment beginning in early childhood that is most pronounced in low-light conditions and is consistent with the proposed mechanism of action of AAV-RPE65. MeiraGTx intends to meet with regulatory authorities in the second half of 2019 to define the development pathway for regulatory approval of AAV-RPE65.