Articles www.thelancet.com Published online May 16, 2017 http://dx.doi.org/10.1016/S0140-6736(17)30979-0 1 Intravitreous injection of AAV2-sFLT01 in patients with advanced neovascular age-related macular degeneration: a phase 1, open-label trial Jeffrey S Heier, Saleema Kherani, Shilpa Desai, Pravin Dugel, Shalesh Kaushal, Seng H Cheng, Cheryl Delacono, Annie Purvis, Susan Richards, Annaig Le-Halpere, John Connelly, Samuel C Wadsworth, Rafael Varona, Ronald Buggage, Abraham Scaria, Peter A Campochiaro Summary Background Long-term intraocular injections of vascular endothelial growth factor (VEGF)-neutralising proteins can preserve central vision in many patients with neovascular age-related macular degeneration. We tested the safety and tolerability of a single intravitreous injection of an AAV2 vector expressing the VEGF-neutralising protein sFLT01 in patients with advanced neovascular age-related macular degeneration. Methods This was a phase 1, open-label, dose-escalating study done at four outpatient retina clinics in the USA. Patients were assigned to each cohort in order of enrolment, with the first three patients being assigned to and completing the first cohort before filling positions in the following treatment groups. Patients aged 50 years or older with neovascular age-related macular degeneration and a baseline best-corrected visual acuity score of 20/100 or less in the study eye were enrolled in four dose-ranging cohorts (cohort 1, 2 × 10⁸ vector genomes (vg); cohort 2, 2 × 10⁹ vg; cohort 3, 6 × 10⁹ vg; and cohort 4, 2 × 10¹⁰ vg, n=3 per cohort) and one maximum tolerated dose cohort (cohort 5, 2 × 10¹⁰ vg, n=7) and followed up for 52 weeks. The primary objective of the study was to assess the safety and tolerability of a single intravitreous injection of AAV2-sFLT01, through the measurement of eye-related adverse events. This trial is registered with ClinicalTrials.gov, number NCT01024998. Findings 19 patients with advanced neovascular age-related macular degeneration were enrolled in the study between May 18, 2010, and July 14, 2014. All patients completed the 52-week trial period. Two patients in cohort 4 (2 × 10¹⁰ vg) experienced adverse events that were possibly study-drug related: pyrexia and intraocular inflammation that resolved with a topical steroid. Five of ten patients who received 2 × 10¹⁰ vg had aqueous humour concentrations of sFLT01 that peaked at 32·7–112·0 ng/mL (mean 73·7 ng/mL, SD 30·5) by week 26 with a slight decrease to a mean of 53·2 ng/mL at week 52 (SD 17·1). At baseline, four of these five patients were negative for anti-AAV2 serum antibodies and the fifth had a very low titre (1:100) of anti-AAV2 antibodies, whereas four of the five non-expressers of sFLT01 had titres of 1:400 or greater. In 11 of 19 patients with intraretinal or subretinal fluid at baseline judged to be reversible, six showed substantial fluid reduction and improvement in vision, whereas five showed no fluid reduction. One patient in cohort 5 showed a large decrease in vision between weeks 26 and 52 that was not thought to be vector-related. Interpretation Intravitreous injection of AAV2-sFLT01 seemed to be safe and well tolerated at all doses. Additional studies are needed to identify sources of variability in expression and anti-permeability activity, including the potential effect of baseline anti-AAV2 serum antibodies. Funding Sanofi Genzyme, Framingham, MA, USA. Introduction Age-related macular degeneration is a complex disease in which multiple gene defects and environmental exposures result in retinal degeneration and gradual loss of central vision. In a subgroup of patients with neovascular age-related macular degeneration, subretinal neovascu- larisation is superimposed, and these patients experience a rapid reduction in visual acuity due to leakage of plasma from incompetent new vessels, which compromises retinal function. Vision loss is reversible with timely fluid elimination, but permanent loss of central vision can occur from chronic persistent or recurrent fluid, subretinal fibrosis, or both. Vascular endothelial growth factor (VEGF) plays a central role in the development of subretinal neovascularisation and excessive plasma leakage into and under the retina. Intraocular injections of VEGF-neutralising proteins reduce leakage, allowing fluid resorption and improvement in visual acuity; 1 however, repeated intraocular injections are needed in most patients. When patients with neovascular age-related macular degeneration who participated in clinical trials with monthly injections of a VEGF-neutralising protein were later enrolled in long-term studies with less frequent visits and injections, much of the visual gains obtained during intensive treatment were lost. 2 Clinical trials randomly assigning patients with neovascular age- related macular degeneration to monthly injections of an antibody that neutralises VEGF versus monthly visits with injections only when intraretinal or subretinal fluid was present showed only a small decrease in overall number of Published Online May 16, 2017 http://dx.doi.org/10.1016/ S0140-6736(17)30979-0 See Online/Comment http://dx.doi.org/10.1016/ S0140-6736(17)31262-X Ophthalmic Consultants of Boston, Boston, MA, USA (J S Heier MD, S Desai MD); Departments of Ophthalmology and Neuroscience, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore MD, USA (S Kherani MD, Prof P A Campochiaro MD); Retinal Consultants of Arizona, Phoenix, AZ, USA (P Dugel MD); University of Massachusetts Medical Center, Worcester, MA, USA (S Kaushal MD); and Sanofi Genzyme, Cambridge, MA, USA (S H Cheng PhD, C Delacono OD, A Purvis MSPH, S Richards PhD, A Le-Halpere PharmD, J Connelly MBA, S C Wadsworth PhD, R Varona MD, R Buggage MD, A Scaria PhD) Correspondence to: Prof Peter A Campochiaro, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9277, USA pcampo@jhmi.edu