A new antivascular endothelial growth-factor (VEGF) drug, OPT-302 (Opthea), appears to be safe and shows signs of effectiveness in the treatment of neovascular age-related macular degeneration, new research shows.
When the experimental drug is used in combination with currently approved VEGF inhibitors, the potency and durability of the VEGF inhibitors could improve because OPT-302 suppresses different forms of VEGF, said Pravin Dugel, MD, clinical professor at the Keck School of Medicine in Los Angeles and managing partner at Retinal Consultants of Arizona.
Neovascular macular degeneration is the result of abnormal blood vessels, which grow under the retina, bleeding and leaking fluid. VEGF binds to VEGF receptors in endothelial cells, stimulating angiogenesis. Ranibizumab (Lucentis, Genentech) and bevacizumab (Avastin, Genentech) bind to VEGF-A, which prevents the protein from binding to its receptors, inhibiting angiogenesis.
In clinical trials, these two VEGF inhibitors have improved the vision of many patients with neovascular macular degeneration, but not all patients benefit. This could be because other forms of VEGF also stimulate angiogenesis. In fact, suppressing VEGF-A stimulates the production of VEGF-C and VEGF-D, said Dr Dugel.
Aflibercept (Eylea, Regeneron), which binds to both VEGF-A and VEGF-B, has also been shown to improve vision in some patients with macular degeneration but, again, not all patients benefit. Currently, no approved drugs bind to VEGF-C or VEGF-D, but OPT-302 inhibits both these forms of the protein. In a mouse model of macular degeneration, OPT-302 was more effective than a control antibody, and became even more effective when combined with aflibercept.