REGENXBIO Presents Positive Three-Year Durability Data for Surabgene Lomparvovec in Diabetic Retinopathy at Retina Society Annual Scientific Meeting

Majority of Dose Level 3 participants with NPDR demonstrated a > 2-step DRSS improvement at 3 years post-one-time, in-office sura-vec gene therapy treatment, with no vision-threatening events and no additional treatment for diabetic retinopathy No IOI observed with short-course prophylactic topical steroids ROCKVILLE, Md. , Sept. 24, 2026 / PRNewswire / -- REGENXBIO Inc. ( Nasdaq : RGNX ) today announced positive long-term follow-up data from the Phase II ALTITUDE ® study of investigational surabgene lomparvovec ( sura - vec , ABBV - RGX -314) in diabetic retinopathy (DR) using suprachoroidal delivery. These new data were presented at the Retina Society 59 th Annual Scientific Meeting in Los Angeles. "These latest long-term results are highly encouraging and reinforce the potential of sura - vec to change the treatment landscape for the millions of patients with non- proliferative diabetic retinopathy ," said Steve Pakola , M.D., Chief Medical Officer of REGENXBIO . "Building on the positive data seen at two and two and a half years after a single treatment, the three-year data continues to show meaningful improvements in DRSS alongside a reduction in disease progression. The durability of these results strengthens our conviction in sura - vec as a potentially transformative, one-time treatment." "For patients with non- proliferative diabetic retinopathy , the goal is to intervene before the disease progresses to vision-threatening complications and irreversible vision loss. However, current preventive treatment requires repeat injections, which is a significant burden for a population that is largely working-age adults," said Nikolas London, M.D., FACS , FASRS , Retina Consultants San Diego, ALTITUDE study investigator. "These three-year ALTITUDE results are encouraging and support continued study of sura - vec as a one-time, in-office treatment with the potential to change the course of the disease. A single treatment that reduces or eliminates the need for ongoing intraocular injections, and reduces the risk of vision-threatening complications, would be a meaningful change for our diabetic patients." Phase II ALTITUDE Long-term follow up data (as of August 17, 2026) In long-term follow-up from the Phase II ALTITUDE ® trial, a single in-office administration of sura - vec using suprachoroidal delivery in participants with non- proliferative DR ( NPDR ) at Dose Level 3 (1.0×10¹² GC /eye) with short-course prophylactic topical steroids demonstrated a durable efficacy profile at three years with no new sura - vec -related safety signals observed during long-term follow up. 60% of all Dose Level 3 participants with three-year visits (n=6/10) achieved > 2-step improvement on the Diabetic Retinopathy Severity Scale ( DRSS ) without additional treatment for diabetic retinopathy . 1 These participants did not experience any vision-threatening events. Additionally, the majority of participants (n=3/4) who achieved a 1-step DRSS improvement at one year without supplemental anti- VEGF injections went on to achieve a > 2-step DRSS improvement by three years without additional treatment for diabetic retinopathy . There were no new sura - vec -related safety signals and no intraocular inflammation observed through three years (n=17) with short-course prophylactic topical steroids. These data are consistent with previously presented two and a half-year Dose Level 3 NPDR data from the ALTITUDE trial and support the potential of one-time in-office sura - vec to modify the underlying disease and decrease risk of vision-threatening events. Dose Level 3 is being evaluated in the Phase IIb /III NAAVIGATE trial of sura - vec in NPDR . About Surabgene Lomparvovec ( sura - vec , ABBV - RGX -314) Sura - vec is a one-time investigational gene therapy designed to deliver sustained treatment effect in wet AMD, diabetic retinopathy and other chronic retinal conditions. Sura - vec uses the NAV ® AAV 8 vector to encode an antibody fragment designed to inhibit vascular endothelial growth factor ( VEGF ). The sura - vec transgene protein inhibits the VEGF pathway by which new, leaky blood vessels grow and contribute to the accumulation of fluid in the retina. 2 About Diabetic Retinopathy Diabetic retinopathy (DR) is the leading cause of vision loss in adults between 24 and 75 years of age worldwide. 3 DR affects nearly 10 million people in the United States alone. 4 The spectrum of DR severity ranges from non- proliferative diabetic retinopathy ( NPDR ) to proliferative diabetic retinopathy ( PDR ). 4 As DR progresses, a large proportion of patients develop vision-threatening events, including diabetic macular edema ( DME ) and neovascularization that can lead to blindness. 5 Current treatment options for patients with NPDR typically include "watchful waiting" or anti- VEGF treatment. For patients with PDR , current treatment options include anti- VEGF treatment or retinal laser; surgical treatment may be required for advanced PDR . 2 AB